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The combination of rituximab, bendamustine, and low dose cytarabine (R-BAC) has been studied in a phase 2 prospective multicenter study from the Fondazione Italiana Linfomi (FIL RBAC500). In 57 previously untreated elderly patients with mantle cell lymphoma (MCL), R-BAC was associated with complete remission rate of 91%, and 2-years progression free survival (PFS) of 81% (95%CI 68-89). Here, we report the long-term survival outcome, late toxicities, and results of minimal residual disease (MRD) evaluation. After a median follow-up of 86 months (57-107), the median overall survival (OS) and progression-free survival (PFS) were not reached. The 7-years PFS and OS rates were 55% (95%CI 41-67), and 63% (95%CI 49-74), respectively. Responding patients (n=53) had a 7-years PFS of 59% (95%CI 44-71), with no relapse or progression registered after the 6th year. At multivariate analysis blastoid/pleomorphic morphology was the strongest adverse predictive factor for PFS (p=0.04). Patients with an end of treatment negative minimal residual disease (MRD) had better, but not significant, outcomes for both PFS and OS than MRD positive patients (p=0,148 and p=0,162, respectively). There was no signal of late toxicity or increase of secondary malignancies during the prolonged follow-up. In conclusion, R-BAC, which was not followed by maintenance therapy, showed sustained efficacy over time in elderly patients with MCL. Survival outcomes compare favorably with other immuno-chemotherapy regimens (with or without maintenance), including combinations of BTK-inhibitors upfront.

Background. Proteasome inhibitor (PI)-based induction/consolidation proved to be effective in newly diagnosed multiple myeloma (NDMM) patients (pts) eligible for melphalan 200 mg/m2 plus autologous stem-cell transplantation (MEL200-ASCT). High response rates have been reported with carfilzomib (K) plus lenalidomide-dexamethasone (KRd) or cyclophosphamide-dexamethasone (KCd). Lenalidomide (R) alone is a standard of care for post-ASCT maintenance; K maintenance showed promising results in phase I/II studies, but no data on KR maintenance vs R are available. Aims. The aims of this analysis were to evaluate the progression-free survival (PFS) of KRd induction-ASCT-KRd consolidation (KRd_ASCT) vs 12 cycles of KRd (KRd12) vs KCd induction-ASCT-KCd consolidation (KCd_ASCT) and the PFS of KR vs R maintenance. Secondary aims were efficacy in different subgroups of pts and safety of the maintenance phase. Methods. NDMM pts ≤65 years were randomized [R1: 1:1:1, stratification International Staging System (ISS) and age] to: KRd_ASCT: 4 28-day cycles with KRd induction (K 20/36 mg/m2 IV days 1,2,8,9,15,16; R 25 mg days 1-21; dexamethasone [d] 20 mg days 1,2,8,9,15,16) followed by MEL200-ASCT and 4 KRd consolidation cycles; KRd12: 12 KRd cycles; KCd_ASCT: 4 28-day induction cycles with KCd (K 20/36 mg/m2 IV days 1,2,8,9,15,16; cyclophosphamide 300 mg/m2 days 1,8,15; d 20 mg days 1,2,8,9,15,16) followed by MEL200-ASCT and 4 KCd consolidation cycles. Thereafter, pts were randomized (R2) to maintenance with KR (K 36 mg/m2 days 1,2,15,16, subsequently amended to 70 mg/m2 days 1,15 for up to 2 years; plus R 10 mg days 1-21 every 28 days until progression) or R alone (10 mg days 1-21 every 28 days until progression). Centralized minimal residual disease (MRD) evaluation (8-color second-generation flow cytometry, sensitivity 10-5) was performed in pts achieving ≥very good partial response before maintenance and every 6 months (m) during maintenance. Data cut-off was June 30, 2020. Results. 474 NDMM pts were randomized (KRd_ASCT, n=158; KRd12, n=157; KCd_ASCT, n=159) and analyzed. Pt characteristics were well balanced. Intention-to-treat (ITT) data of pre-maintenance MRD (KRd_ASCT, 62%; KRd12 56%, KCd_ASCT 43%) and safety of the induction/consolidation phases in the 3 arms were already reported (F. Gay et al. ASH 2018; S. Oliva et al. ASH 2019). After a median follow-up from R1 of 45 m, median PFS was not reached with KRd_ASCT, 57 m with KRd12 and 53 m with KCd_ASCT (KRd_ASCT vs KCd_ASCT: HR 0.53, P During maintenance, a similar proportion of pts experienced ≥1 grade (G)3-4 hematologic adverse events (AEs)/serious AEs (SAEs) in the 2 arms (KR 22% vs R 23%); the most frequent were neutropenia (KR 18% vs R 21%) and thrombocytopenia (KR 3% vs R 3%). Rate of ≥1 G3-4 non-hematologic AEs/SAEs was higher with KR (27%) compared with R (15%), P=0.012; the most frequent were infections (KR 4% vs R 7%); all other events were reported in ≤5% of pts and included: gastrointestinal (KR 5% vs R 2%), cardiac (KR 4% vs R 1%), hypertension (KR 3% vs R 0%), and thrombotic microangiopathy (3% vs 0%). 4 pts developed a second primary malignancy in KR (breast 1 pt; thyroid 1 pt; myelodysplastic syndrome 1 pt; non-melanoma skin cancer 1pt) vs 1 pt in R (acute lymphoblastic leukemia). Dose reductions of R were reported in 23% of KR and 29% of R pts; dose reductions of K were reported in 20% of pts. The rate of discontinuation due to AEs was similar in the 2 arms (KR 10% vs R 9%). Conclusions. Treatment with KRd_ASCT significantly improved PFS compared with both KRd12 and KCd_ASCT. Maintenance with KR also improved PFS vs R. Figure Disclosures Gay: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Musto:Celgene: Honoraria; Amgen: Honoraria. Galli:BMS: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Belotti:Jannsen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Zamagni:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. De Sabbata:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. D'Agostino:GSK: Membership on an entity's Board of Directors or advisory committees. Liberati:VERASTEM: Honoraria, Research Funding; ROCHE: Honoraria, Research Funding; PFIZER: Honoraria, Research Funding; ONCOPEPTIDES AB: Honoraria, Research Funding; TAKEDA: Honoraria, Research Funding; MORPHOSYS: Honoraria, Research Funding; ONCONOVA: Honoraria, Research Funding; ABBVIE: Honoraria, Research Funding; NOVARTIS: Honoraria, Research Funding; KARYOPHARM: Honoraria, Research Funding; INCYTE: Honoraria; JANSSEN: Honoraria; CELGENE: Honoraria; AMGEN: Honoraria; BMS: Honoraria; BEIGENE: Honoraria; ARCHIGEN: Honoraria; BIOPHARMA: Honoraria; FIBROGEN: Honoraria. Offidani:Janssen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Cavo:AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm: Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau. Boccadoro:AbbVie: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Research Funding; Amgen: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding. OffLabel Disclosure: The presentation includes discussion of off-label use of a drug or drugs for the treatment of multiple myeloma (including carfilzomib, cyclophosphamide, lenalidomide and dexamethasone).

Background: T-cell large granular lymphocytic leukemia (T-LGLL), a rare lymphoproliferative disorder of mature T cells, is characterized by the accumulation of activated effector T cells leading to a clonally restricted T-cell receptor (TCR) repertoire. Chronic antigen stimulation together with activating somatic STAT3 mutations have been proposed to lead to clonal expansion of leukemic cells. However, no holistic research has been done to show how leukemic and non-leukemic cells liaise to sustain abnormal immune reactivity in T-LGLL. Methods: We investigated the transcriptome and TCR repertoire in T-LGLL using: 1) single-cell RNA and TCR (scRNA+TCRαβ) sequencing from CD45+ sorted blood cells (T-LGLL n=11, healthy n=6), 2) TCRβ sequencing from blood mononuclear cells (T-LGLL n=48, healthy n=823), 3) bulk RNA sequencing (T-LGLL n=15, healthy n=5), 4) plasma cytokine profiling (T-LGLL n=9, healthy n=9), and 5) flow cytometry validations (T-LGLL n=6, healthy n=6) (Figure) Results: ScRNA+TCRαβ-seq data revealed that in healthy controls, hyperexpanded CD8+ T-cell clones (at least 10 cells with identical TCRs) preferentially had an effector memory phenotype, whereas in T-LGLL, the hyperexpanded clonotypes represented a more cytotoxic (increased expression of GZMB, PRF1, KLRB1) and exhausted (LAG3 and TIGIT) phenotype. Using flow cytometry, we confirmed that upon anti-CD3/CD28/CD49 antibody stimulation, T-LGLL clones (CD8+CD57+) expressed higher levels of cytotoxic proteins (GZMA /GZMB , PRF1) but were deficient in degranulation responses and cytokine secretion as measured by expression of CD107a/b and TNFα/IFNγ, respectively. Focused re-clustering of the extracted T-LGLL clones from the scRNA+TCRαβ-seq data revealed considerable heterogeneity among the T-LGLL clones and partly separated the mutated (mt) STAT3 and wild type (wt) STAT3 clones. STAT3wt clones upregulated T-cell activation and TCR signaling pathways, with a higher cytotoxicity and lower exhaustion score as compared to STAT3mt clones. This was validated with bulk RNA-seq data. To understand the antigen specificities of the T-LGLL clones, we combined previously profiled T-LGLL TCRs with our data to form the largest described dataset of 200 T-LGLL clones from 170 patients. Notably, T-LGLL clones were found to be private to each patient. Furthermore, the analysis by GLIPH2 algorithm grouping TCRs did not reveal detectable structural similarities, suggesting the absence of a unifying antigen in T-LGLL. However, in 67% of T-LGLL patients, the TCRs of leukemic clones shared amino acid level similarities with the rest of the non-leukemic TCR repertoire suggesting that the clonal and non-clonal immune repertoires are connected via common target antigens. To analyze the non-clonal immune repertoire in T-LGLL in detail, we compared our data to other published scRNAseq data from solid tumors (n=4) and hematologic cancers (n=8) and healthy controls (n=6). The analysis revealed that in T-LGLL also the non-leukemic CD8+ and CD4+ T cells were more mature, cytotoxic, and clonally restricted. When compared to healthy controls and other cancer patients, in non-leukemic T-LGLL the most upregulated pathway was IFNγ response. Finally, most of the upregulated cytokines in T-LGLL (e.g., CCL2/3/7, CXCL10/11, IL15RA) were secreted predominantly by monocytes and dendritic cells, which also had upregulated HLA class II expression and enhanced scavenging potential in T-LGLL patients. Ligand-receptor analysis with CellPhoneDB revealed that the number of predicted cell-cell interactions was significantly higher in T-LGLL as compared to reactive T-cell clones in healthy controls. The most co-stimulatory interactions (e.g., CD2-CD58, TNFSF14-TNFRSF14) occurred between the IFNγ secreting T-LGLL clones and the pro-inflammatory cytokine secreting monocytes. Conclusions: Our study shows a synergistic interplay between the leukemic and non-leukemic immune cell repertoires in T-LGLL, where an aberrant antigen-driven immune response including hyperexpanded CD8+ T-LGLL cells, non-leukemic CD8+ cells, CD4+ cells, and monocytes contribute to the persistence of the T-LGLL clones. Our results provide a rationale to prioritize therapies that target the entire immune repertoire and not only the T-LGLL clones in patients with T-LGLL. Figure 1 Figure 1. Disclosures Loughran: Kymera Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bioniz Therapeutics: Membership on an entity's Board of Directors or advisory committees; Keystone Nano: Membership on an entity's Board of Directors or advisory committees; Dren Bio: Membership on an entity's Board of Directors or advisory committees. Maciejewski: Alexion: Consultancy; Novartis: Consultancy; Regeneron: Consultancy; Bristol Myers Squibb/Celgene: Consultancy. Mustjoki: Novartis: Research Funding; BMS: Research Funding; Janpix: Research Funding; Pfizer: Research Funding.

Background: Lenalidomide (R) plus dexamethasone (d) triplet combinations have been indicated by ESMO guidelines as standard of care in first relapse for lenalidomide sensitive multiple myeloma (MM) patients (pts) (Dimopoulos et al, 2021). Meta-analysis of randomized clinical trials (RCT) shows better outcome with the combination of Daratumumab + Rd (DaraRd) over other Rd-based combinations (carfilzomib+Rd (KRd), elotuzumab+Rd (EloRd), Ixazomib+Rd (IxaRd). There are few real-life studies focusing on the pattern of utilization and outcome of different Rd triplets in first relapse MM. Aims: To explore performances of market-approved Rd-based triplets in unselected MM pts in first relapse. Patients and methods: After ethics committee approval, we review data of 366 MM pts in first relapse consecutively addressed to Rd-based triplets according to market-approved schedule after 2017. Rd-based therapies was distributed as follows: DaraRd 51.6% (189 pts), KRd 36.1% (132 pts), EloRd 8.7% (32 pts), IxaRd 3.6% (13 pts). Given the limited number of pts treated with IRd and EloRd, the analysis is focused only on DaraRd and KRd group after further excluding 51 pts (13%) addressed to salvage autologous stem cell transplant (ASCT) after daraRd (n=9)/KRd(n=42) fixed induction. Few pts in both groups were previously exposed to R/K/Dara (respectively 12 pts (3%), 8 (2%), 0). Treatment choice was influenced by market approval, with KRD regimen used more commonly in the IQR 2017- 2019, while DaraRd more commonly in the IQR 2018-2020. To limit the bias of a retrospective observation, we calculated a propensity score and we used it (after trimming of 5% of observations) to re-weight the data, according to the Inverse Probability of Treatment method (IPTW analysis). For the estimation of the propensity score, we used: age at Rd-triplet starting, ISS stage, presence of high-risk FISH, previous exposure to Bortezomib, previous ASCT, good response at first-line therapy (≥VGPR), time between diagnosis and relapse, myeloma defining events at diagnosis, type of relapse (symptomatic/biochemical), center. Details of these characteristics are reported in table1. Of note, pts addressed to DaraRd were slightly older (68,7 vs 63,4 years in KRd, p Conclusions: Our real-life study shows that DaraRd represents the most commonly received regimen at first relapse followed by KRd triplet. After propensity score matching, DaraRd and KRd combinations proved to be both effective with similar outcomes when used early in the treatment history, after one line of therapy. This study, in addition, points out the possible gap of outcome between RCT and clinical practice. Figure 1 Figure 1. Disclosures Mangiacavalli: BMS: Honoraria; Janssen: Honoraria; Takeda: Honoraria; GSK: Honoraria. Galli: BMS, Celgene, Janssen, Sanofi, Takeda: Honoraria. Belotti: Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; GSK: Membership on an entity's Board of Directors or advisory committees. Fazio: Janseen: Honoraria. Petrucci: Celgene: Honoraria, Other: Advisory Board; Janssen-Cilag: Honoraria, Other: Advisory Board; BMS: Honoraria, Other: Advisory Board; Takeda: Honoraria, Other: Advisory Board; Amgen: Honoraria, Other: Advisory Board; GSK: Honoraria, Other: Advisory Board; Karyopharm: Honoraria, Other: Advisory Board.

The activity of the combination of rituximab, bendamustine, and low dose cytarabine (R-BAC) was evaluated in a phase 2 multicentre trial from the Fondazione Italiana Linfomi (FIL RBAC500) in previously untreated patients with mantle cell lymphoma (MCL) who were not eligible to stem cell transplant. Maintenance treatment was not planned after induction therapy, and no patient in the study received rituximab maintenance. Fifty-seven patients (median age 71 years, range 61-79) were recruited and treated with 4 to 6 cycles between 2012 and 2014. Despite some concern in terms of hematological toxicity, the R-BAC regimen was associated with high complete remission (CR) rate (91%), 2-years overall survival (OS) of 86% (74-93), and 2-years progression free survival (PFS) of 81% (68-89). Here, we present long-term survival outcomes. After 7 years of median follow-up (86 months, range 57-107), the median OS and PFS for all patients were not reached (Figure 1A and 1B). The 7-years PFS and OS rates were 56% (95%CI 41-67) and 63% (95%CI 46-72), respectively. Patients who achieved CR (n=53) had a 7 years PFS of 59% (95% CI 44-71), with the curve that appears to plateau after 6 years. Adverse predictive factors affecting PFS were blastoid morphology (p 30% (p Eight patients (14%) developed a secondary neoplasia: 1 parotid heteroplasia, 1 parotid nodular hyperplasia, 1 prostate cancer, 1 bladder cancer, 1 larynx, 1 thyroid cancer, 1 lung cancer and 1 secondary acute myeloid leukemia. Among the 25 relapsed patients, 8 did not receive any other treatment. Six had Ibrutinib monotherapy as second line, of whom 4 responded (3 are still in CR), 4 had CHOP or CHOP-like regimens with only partial responses. As per protocol, 31 patients with molecular marker at diagnosis and available samples were followed-up for minimal residual disease (MRD) with ASO-droplet digital polymerase chain reaction (D-PCR). Patients with MRD persistence at the end of induction, either in peripheral blood or bone marrow, had significantly worse 7 years-PFS (p In conclusion, in elderly patients with newly diagnosed MCL, R-BAC showed sustained efficacy over time, which compared favorably with any other reported immuno-chemotherapy regimen (with or without maintenance) in similar populations. With a median OS exceeding 60% after 7-years this regimen has significantly impacted on the life-expectancy of elderly patients with MCL. Figure 1 Figure 1. Disclosures Tisi: Incyte: Membership on an entity's Board of Directors or advisory committees; BWS: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees. Nassi: Takeda: Consultancy; Incyte: Consultancy; Kyowa Kirin: Consultancy; Roche: Consultancy. Ferrero: Gilead: Research Funding, Speakers Bureau; Morphosys: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Servier: Speakers Bureau; EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Clinigen: Membership on an entity's Board of Directors or advisory committees. Zilioli: Takeda: Other: travel expenses, accommodation; MSD, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations; Roche, Italfarmaco: Consultancy, Honoraria; Gentili, Takeda, Gilead, Servier: Consultancy, Speakers Bureau. Merli: Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; Gilead Science: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; MSD: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accomodations, Expenses; EUSA Pharma: Other: Travel, Accomodations, Expenses; Celgene: Other: Travel, Accomodations, Expenses.

T-cell large granular lymphocyte leukemia (T-LGLL) is a rare disease characterized by clonal proliferation of CD3+ lymphocytes whose pathogenesis is not completely understood. LGL resistance to the activation-induced cell death is sustained by anti-apoptotic pathways, mainly due to constitutive activation of the JAK-STAT axis by activating somatic mutations of STAT3 or STAT5B genes or epigenetic disturbances. STAT3 mutations are peculiar to CD8+ T-LGLL and are associated with cytopenias, treatment requirement, and reduced survival. STAT5B lesions are mostly found in CD4+ T-LGLL, a disorder presenting with a mild clinical course. A similar behaviour has been observed also in both STAT wild type (WT) CD8+ and CD4+ forms. The link between STAT3-dependent miR-146b repression and neutropenia exemplifies the role that the pathogenetic effect of somatic mutations can exert through complex axes, also involving non-coding RNAs. Since in the most symptomatic form of LGLL an urgent need to discover new mechanisms in place is demanded, we focused on additional regulatory molecules such as circular RNAs (circRNAs), single-stranded covalently closed RNA molecules generated by backsplicing (Figure 1A). CircRNAs' oncogenic potential is linked to their activity as miRNA sponges, modulators of RNA-binding protein activity, and their ability to encode oncogenic peptides. The study group includes 20 patients recruited at the Hematology Unit of Padua University Hospital (Italy) and diagnosed with T-LGLL according to the WHO criteria, plus 5 healthy controls (CTR). Patient leukemic clones were equally distributed among CD8+ WT and STAT3-mutated and CD4+ WT and STAT5B-mutated. RNA-seq of ribodepleted RNA from immunomagnetically purified CD57+ leukemic clones and CD8+ cells from CTR was obtained to study circRNAs. CircRNAs were identified and quantified from RNA-seq data by CirComPara v0.6.3. Differential expression was assessed by edgeR with robust estimation of dispersion. The circular to linear proportion (CLP), indicating the relative abundance of each circRNA with respect to all the overlapping host gene transcripts, was calculated, and differential CLP across conditions was assessed with CircTest. We detected 68.619 circRNAs and focused on 5.948 with high expression. These were expressed from 2,940 loci, mostly from annotated genes (99.95%). We identified 28 circRNAs derived from genomic regions without known genes. About one-half of circRNA host genes expressed multiple, up to 20, circular isoforms. About 4% of circRNAs had a CLP of at least 0.25, with 95 circRNAs more expressed than the linear counterpart, including circGUSBP2, circSHOC1, circTCEANC, circZNF609, and circKLHL8. Unsupervised analysis of circRNA expression showed a clear separation of T-LGLL from CTR samples, pointing toward circRNA dysregulation in T-LGLL, particularly for the CD8+ STAT3 mutated group, which diverged from the other subtypes (Figure 1B). The direct comparison between the CD8+ STAT3-mutated, the three molecular subtypes as a single group (OTH), and the CTR samples identified differences in circRNA expression specifically linked to the most symptomatic group with STAT3 lesions and those commonly observed in T-LGLL. In STAT3-mutated, 500 circRNAs were dysregulated with an excess (71%) of upregulation compared to CTR (Figure 1C). Most circRNAs commonly altered in both LGLL groups had a more marked dysregulation in patients with STAT3 mutations, as observed for circIKZF2 and a newly discovered intergenic circRNA. Most circRNAs with a significantly varied CLP (96%) showed an increased expression of the circular than linear transcripts in T-LGLL compared to CTR, uncovering genes with an imbalance of circular to linear transcripts proportion in leukemic cells (Figure 1D). The ongoing validation of the differential circRNA expression in an extended cohort of 40 LGLL patients is prioritizing circRNAs for functional investigation. The integration of computational predictions and in vitro functional screening through specific circRNA silencing will attempt to understand the link between circRNAs dysregulated in T-LGLL and disease mechanisms, unveiling possible circRNA-involving axes governed by hyperactivating STAT3 somatic variants that contribute to the malignant LGL phenotypes. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Background: 18F-FDG-PET/CT is currently the standard technique to define imaging-minimal residual disease (MRD) in multiple myeloma (MM) patients. A joint analysis of 2 prospective randomized trials in newly diagnosed transplant-eligible MM (NDTEMM) patients applied for the first time the Deauville Scores (DS) to focal lesions (FS) and bone marrow uptake (BMS) showing the liver background (DS < 4) as the best cut-off to define PET/CT negativity after therapy and complete metabolic response (CMR) (Zamagni et al, ASH 2018). Validation of this new standardized criteria in an independent prospective series of NDTEMM patients is highly required. Imaging-PET/CT MRD also showed to be complementary to Multiparameter Flow Cytometry (MFC) in predicting patient's outcomes (Moreau P, JCO 2017). In this analysis, we aimed at confirming the applicability and validity of DS criteria to define PET/CT CMR and showing their impact on patient's outcomes in the multicenter phase II randomized FORTE trial for NDTEMM patients. We also looked at the complementarity with BM techniques, especially MFC. Methods: NDTEMM patients ≤ 65 years were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRD) induction - autologous stem cell transplantation (ASCT) intensification-KRd consolidation (arm A); KRd12 (arm B) and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction-ASCT intensification-KCd consolidation (arm C). Thereafter, patients were randomized to maintenance with lenalidomide alone or plus carfilzomib. PET/CT scans were performed locally at baseline (B) and prior to the start of maintenance (PM). DS were applied both in the BM and FLs, as previously described (Zamagni E, EHA 2020). CMR was defined as DS < 4 both in the FLs and BM. MRD evaluation was performed by 8-color second-generation flow cytometry (sensitivity 10-5) in patients who achieved at least VGPR before maintenance (Gay F, ASCO 2019). The impact of each parameter on outcomes was evaluated by landmark analyses at PM. A multivariable Cox regression analysis was adopted to identify independent predictors for PFS and OS. Results: 182 out of the 474 global patients enrolled in the trial had a pre- and post-treatment PET/CT evaluation available and were included in this analysis. Patients' baseline characteristics were: median age 57 years, ISS and R-ISS stage III 18% and 10%, respectively, high-risk cytogenetics (t(4;14) ± del(17p) ± t(14;16), detected by FISH) 26%, reflecting baseline clinical features of the entire FORTE population. At B, 93% of patients had FLs, with a median maximum standardized uptake value (SUVmax) of 5.7 [IQR: 4.1-8.1], 7% presented extra-medullary lesions and nearly all patients had increased BM uptake, with a median SUVmax of 3.4 [IQR: 2.8-4.3]. FS and BMS ≥ 4 were present in 87% and 57% of patients, respectively. At PM, PET/CT negativity according to DS < 4, was present in 80% in the FLs and 85% in the BM, respectively. 63% showed CMR. 92% and 61% of patients achieved ≥ VGPR and CR as best response, respectively, while 73% of them achieved MFC MRD negativity. The achievement of a best CR significantly correlated with BMS < 4 at PM (P= 0.003). In univariate analysis, at Landmark time PM, FS Conclusion: In conclusion, the present analysis confirms the applicability and validity of DS criteria to define PET/CT CMR in an independent prospective series of NDTEMM patients. CMR significantly and independently correlated in uni- and multivariable analysis with patient's outcomes in terms of PFS and OS and was complementary to the MFC MRD negativity. Figure Disclosures Zamagni: Takeda: Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau. Gay:Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. D'Agostino:GSK: Membership on an entity's Board of Directors or advisory committees. Galli:Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria; BMS: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Rivolti:Celgene: Membership on an entity's Board of Directors or advisory committees. Tacchetti:Bristol-Myers Squibb: Honoraria; AbbVie: Honoraria; Takeda: Honoraria; Celgene: Honoraria; Oncopeptides: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Fanti:Bayer, Astellas, GE Healthcare, ANMI, Janssen: Membership on an entity's Board of Directors or advisory committees; Bayer, Astellas, GE Healthcare, Sanofi, AAA: Honoraria. Boccadoro:Bristol-Myers Squibb: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Cavo:AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; GlaxoSmithKline: Honoraria, Speakers Bureau; Karyopharm: Honoraria. Musto:Amgen: Honoraria; Celgene: Honoraria. Oliva:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria.

Background: To understand carfilzomib (K) usage, effectiveness and safety in patients (pts) with relapsed or refractory multiple myeloma (RRMM) in real-life, we describe the results of an interim analysis by K-based regimens from a large prospective observational study (NCT03091127). Methods: Adult pts who received ≥1 prior line of therapy and ≥1 K dose in routine care were enrolled from 11 participating countries across the EU and Israel. Follow-up was until 30 days after last K dose or up to 18 months from initiation. Medical history and pt characteristics at the time of diagnosis and K initiation were collected. Cytogenetic risk status was as assessed by the physician and frailty was derived (Palumbo et al., Blood 2015;125:2068-74; Facon et al., Blood 2015;126:4239). Adverse events (AEs) of grade 3 or above (Gr3+) including serious adverse events (SAEs) were collected during the study. Results: As of 17 March 2020, a total of 701 pts were included in the analysis. Over half (55%) received the triplet K, lenalidomide and dexamethasone (KRd), and 39% were treated with K and dexamethasone alone (Kd). The remaining pts (n=46, 7%) received other K-based triplets, mainly: K, cyclophosphamide, dexamethasone (KCyd, 2%), K, pomalidomide, dexamethasone (KPomd, 2%), or K, daratumumab, dexamethasone (KdD, 1%). Due to the heterogenous nature of this subgroup, this data is not further described. At K initiation, pts who received KRd were younger than Kd pts: 65 vs 68 years (median age), respectively. Of the 32% of pts with known ISS status at K initiation, 23% and 38% had an ISS stage 3 in KRd and Kd pts, respectively. Among pts with derived frailty score at K initiation (65%), 31% of the KRd subset, and 51% of Kd were calculated as frail. Cytogenetic risk was reported in 34% and 18% of KRd and Kd pts, in which 43% and 64% were high risk, respectively. A large proportion of pts presented with pre-existing cardiovascular conditions in both cohorts (49% and 61% for KRd and Kd, respectively) which mostly consisted of hypertension (35% and 41% for KRd and Kd, respectively). KRd pts had received a median of 1 prior line of therapy while Kd pts were more heavily treated with a median of 3 prior lines. Previous autologous stem cell transplant was described for 64% of KRd pts 44% of Kd pts. Nearly all pts regardless of treatment (96% of KRd and 97% of Kd) had a prior exposure to bortezomib although more Kd pts (54%) were refractory to bortezomib according to IMWG criteria than KRd pts (31%). The proportions of lenalidomide-exposed/refractory pts were higher in Kd pts (68%/55%) than KRd pts (34%/19%). More pts treated with Kd had been previously treated with a monoclonal antibody (28%) than KRd pts (9%). Of pts with a response assessment reported, a high overall response rate (ORR) was seen in KRd pts with nearly one-third achieving a complete response (CR) or better and 66% achieving a very good partial response (VGPR) or better (Table). A good ORR (68%) was also seen in Kd pts considering the prognosis of this pt population, however, an ORR of 80% was achieved for pts with 1 prior line of therapy. Deeper responses were seen in earlier lines of therapy for both cohorts. The mean K dose intensity received relative to EU label for KRd (20/27 mg/m2 for K) and Kd pts (20/56 mg/m2 for K) was 90% and 83%, respectively. The Kaplan-Meier median estimate of treatment duration was 14.6 months (95% confidence interval [CI]: 12.9, 16.4) for KRd and 7.5 months (95% CI: 6.5, 8.8) for Kd pts. Gr3+ AEs were reported in 47% of KRd pts and 45% of Kd pts and 25% and 21% of KRd and Kd pts experienced an event considered to be treatment related. The most commonly reported events were blood disorders (21% KRd, 14% Kd), infections (14% KRd, 17% Kd), and vascular disorders (7% KRd, 5% Kd). SAEs occurred in 30% and 36% of KRd and Kd pts, respectively, and 3% and 8% were fatal. Conclusions: In this real-life setting, KRd use was in accordance with the label, inducing high responses that could be maintained for long durations. Compared with KRd pts, Kd was used in later lines to treat older and more heavily pre-treated pts with refractory disease. The benefit-risk profile of KRd and Kd in the real-world was consistent with clinical trial results from ASPIRE and ENDEAVOR, respectively. Both KRd and Kd achieved deeper responses in earlier lines of therapy, emphasizing the importance of optimizing MM therapies. Disclosures Terpos: Janssen: Honoraria, Other: travel expenses , Research Funding; Amgen: Honoraria, Research Funding; Takeda: Honoraria, Other: travel expenses , Research Funding; Celgene: Honoraria; Genesis: Honoraria, Other: travel expenses , Research Funding; Medison: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Badelita:Janssen: Consultancy, Honoraria, Other: Travel, accommodations, expenses; Takeda: Consultancy, Honoraria, Other: Travel, accommodations, expenses; Novartis: Consultancy, Honoraria; Fundeni Clinical Institute: Current Employment; Amgen: Consultancy, Honoraria, Other: Travel, accommodations, expenses. Katodritou:Takeda: Honoraria, Other: Expenses, Research Funding; Karyopharm: Research Funding; Genesis Pharma: Honoraria, Other: Expenses, Research Funding; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Theagenion Cancer Hospital: Current Employment; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Research Funding. Caers:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kühr:Pfizer: Other; Celgene: Honoraria; Merck: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Abbvie: Honoraria; Roche: Honoraria; Lilly: Honoraria, Other: travel, accommodation, expenses; Amgen: Honoraria; Bayer: Honoraria, Other: Travel, accommodations, expenses; Janssen: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Klinikum Wels-Grieskirchen: Current Employment. Suzan:Amgen: Current Employment, Current equity holder in publicly-traded company. Mohammad:Amgen: Current Employment, Current equity holder in publicly-traded company. Wetten:Amgen: Current Employment, Current equity holder in publicly-traded company. Leleu:Oncopeptide: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria; Amgen: Honoraria; AbbVie: Honoraria; GSK: Honoraria; Novartis: Honoraria; BMS-celgene: Honoraria; Janssen: Honoraria; Merck: Honoraria; Carsgen: Honoraria; Incyte: Honoraria.

INTRODUCTION. The proteasome inhibitor (PI) Ixazomib, approved for the treatment of relapsed/refractory multiple myeloma (MM), represents an appealing option for the management of elderly patients, due to its oral administration and the lack of peripheral neuropathy. We previously presented preliminary results of the phase II EMN10-Unito study investigating Ixazomib in combination with dexamethasone (Id), Cyclophosphamide-dexamethasone (ICd), Thalidomide-dexamethasone (ITd) or Bendamustine-dexamethasone (IBd) as induction therapy followed by single-agent Ixazomib maintenance in transplant-ineligible newly diagnosed (ND) MM patients. Here we present updated results of the study with a longer follow-up. METHODS. Transplant-ineligible NDMM patients ≥65 years were enrolled. Treatment consisted of 9 28-day induction cycles of Ixazomib 4 mg on days 1,8,15 and dexamethasone 40 mg on days 1,8,15,22 or Id plus either Cyclophosphamide 300 mg/m2 orally on days 1,8,15 or Thalidomide 100 mg/day or Bendamustine 75 mg/m2 iv on days 1,8; followed by Ixazomib maintenance (4 mg on days 1,8,15) for up to 2 years. The primary endpoint was the selection of the most effective induction regimen considering a 2-year progression-free survival (PFS) ≥65% as satisfactory; secondary endpoints were very good partial response (VGPR), PFS2, overall survival (OS) and adverse events (AEs) during induction and maintenance. RESULTS. 171 patients (Id 41, ICd 59, ITd 60 and IBd 11) with a median age of 74 years were enrolled and started treatment. Two of the four investigational arms were prematurely closed due to low-enrollment (IBd arm, 11 patients enrolled) and high risk of inefficacy (Id, 41 patients enrolled). Median follow-up was 27 months. After the induction phase, ICd and ITd resulted in higher ≥ PR (75%-84% vs. 57%; p Overall, 102 patients (60%) completed the induction phase and proceeded to ixazomib maintenance (median follow-up from start of maintenance: 18 months). The best response during maintenance was PR in 26%, VGPR in 29%, and complete response (CR) in 26% of patients; 18% of patients improved the response obtained during induction by at least one IMWG category. The median PFS from start of maintenance was 15 months. The median duration of maintenance was 12 months. All grades AEs occurred in 39% of patients during maintenance, while grade 3-4 AEs occurred in 10% of patients. Grade 1-2 peripheral neuropathy (PN) was reported in 15% of patients, without grade 3-4 events. Overall, 15% required at least one dose reduction of ixazomib and 12% discontinued ixazomib maintenance due to AEs. CONCLUSIONS. Safety and efficacy data suggest that Id combined with cyclophosphamide was the most promising induction strategy compared to the other investigated combinations. Continuous treatment with single-agent Ixazomib confirmed its efficacy and tolerability in elderly NDMM patients. Disclosures Mina: Amgen: Honoraria; Celgene: Honoraria; Takeda: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Larocca:GSK: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees. Corradini:KiowaKirin: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Sanofi: Consultancy, Honoraria; Servier: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other; BMS: Other; Kite: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Daiichi Sankyo: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Other: Travel and accommodations paid by for; Incyte: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel and accommodations paid by for; F. Hoffman-La Roche Ltd: Consultancy, Honoraria. Liberati:CELGENE: Honoraria; BIOPHARMA: Honoraria; ARCHIGEN: Honoraria; BEIGENE: Honoraria; BMS: Honoraria; AMGEN: Honoraria; FIBROGEN: Honoraria; INCYTE: Honoraria; VERASTEM: Honoraria, Research Funding; ROCHE: Honoraria, Research Funding; PFIZER: Honoraria, Research Funding; ONCOPEPTIDES AB: Honoraria, Research Funding; TAKEDA: Honoraria, Research Funding; MORPHOSYS: Honoraria, Research Funding; ONCONOVA: Honoraria, Research Funding; ABBVIE: Honoraria, Research Funding; NOVARTIS: Honoraria, Research Funding; KARYOPHARM: Honoraria, Research Funding; JANSSEN: Honoraria. Zambello:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Belotti:Amgen: Membership on an entity's Board of Directors or advisory committees; Jannsen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees. Bringhen:Takeda: Consultancy; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The presentation includes discussion of off-label use of a drug or drugs for the treatment of multiple myeloma (including ixazomib, dexamethasone, cyclophosphamide, thalidomide and bendamustine).

Background: With approvals of lenalidomide (Len) based therapy for the treatment of transplant ineligible patients (pts) with newly diagnosed multiple myeloma, and for pts receiving maintenance following transplant, there is an increasing use of Len as induction and maintenance therapy. As a result, treatment options for pts who become Len-refractory (LR) has become an emerging critical challenge. We report updated results from a large real-life cohort of pts by LR status, who received approved K regimens (K, lenalidomide and dexamethasone [KRd] at the dose of 27 mg/m2 twice-weekly or Kd at the dose of 56 mg/m2 twice-weekly). Methods: In 11 participating countries across the EU and Israel, adults with relapsed/refractory multiple myeloma (RRMM), who received ≥1 dose of a K regimen in routine clinical practice were included in the prospective cohort study (NCT03091127). Cytogenetic risk status was as assessed by the physician and frailty at K initiation was calculated according to Palumbo et al.,Blood 2015;125:2068-74 and Facon et al., Blood 2015;126:4239. Pts were classified as LR if they met at least one of the following 3 criteria to any prior regimen containing Len, as defined by the International Myeloma Workshop Group (Rajkumar et al., Blood 2011;117:4691-95): best response was stable or progressive disease; progression was the reason for stopping any regimen; or/and date of relapse/progression was after the start date and within 60 days after the last dose of Len. Results: At the data cut-off of 17 March 2020, the study included 382 KRd pts and 273 Kd pts. At K initiation, nearly one-fifth (19%, n=74) of KRd pts and over half (55%, n=151) of Kd pts were LR. In the KRd cohort, LR pts were older than non-LR (NLR) pts (median: 66 vs 64 years). At KRd initiation, characteristics of LR pts were comparable with NLR pts in terms of cytogenetic risk (over 40% at high-risk of 34% reported overall) but were more frail (43% vs 28% of 67% reported) and with higher ISS stage (ISS 3: 28% vs 22% of 30% reported). LR pts had a median of 3 prior lines of therapy vs 1 for NLR pts and were more likely to have received a monoclonal antibody (mAb) (20% and 6%, respectively). Most LR pts (60%) became refractory in their last prior therapy of whom 55% became refractory from their 2nd line (2L) therapy. In the Kd cohort, LR pts were older than NLR pts at K initiation (median: 69 vs 67 years). At Kd initiation, more LR pts had a high cytogenetic risk than NLR pts (71% vs 33% of 18% reported) but were more fit (22% vs 7%, of 71% reported) and had a lower ISS stage (ISS 1: 41% vs 31% of 35% reported). LR pts had received a median of 3 prior lines vs 2 for non-LR pts and were more likely to have received a mAb (41% and 12%, respectively). In LR pts, 43% became refractory in their last prior therapy of whom 52% became refractory from their 2L therapy. Among 93% of pts with an assessment overall, high overall response rates (ORR) were achieved in NLR pts for both KRd and Kd (Table). LR pts achieved lower ORRs in both cohorts although there are differences in pt population and treatment history. Despite this, almost half of LR pts in the KRd cohort and 30% in the Kd cohort achieved a very good partial response or better. The clinical benefit rate for LR pts was 72% and 62% in the KRd and Kd cohorts, respectively. The mean K relative dose intensity was comparable for LR and NLR pts (90% vs 88%) in the KRd cohort and slightly lower for LR (74%) vs NLR (80%) in the Kd cohort. The Kaplan-Meier estimate of median treatment duration was shorter for the LR vs NLR subgroups (KRd: 11.1 [95% CI: 5.7-13.9] vs 16.2 [95% CI: 13.5 - 16.9] months; Kd: 6.3 [95% CI: 4.7-7.7] vs 9.7 [95% CI: 7.4-11.6] months). The occurrence of adverse events of ≥grade 3 (Gr3+ AEs) was comparable between KRd subgroups (49% vs 47%, LR and NLR). Kd NLR pts experienced less Gr3+ AEs than LR pts (39% vs 50%). LR pts in both cohorts experienced more SAEs and fatal events than NLR pts (SAEs: KRd: 38% vs 28%; Kd: 39% vs 33%; fatal events: KRd: 7% vs 3%; Kd: 9% vs 7%), although there are differences in pt population and treatment history. Conclusion: In this real-world cohort, LR pts had received more prior lines of therapy and were exposed to more agents than NLR pts. Fair responses were achieved for this difficult to treat population in this unadjusted analysis, which are consistent with published subgroup analyses of the clinical trials. This real-world data further supports the use of carfilzomib for RRMM and emphasizes the strength of Kd as a strong back-bone treatment for LR pts. Disclosures Leleu: Karyopharm: Honoraria; Amgen: Honoraria; AbbVie: Honoraria; BMS-celgene: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; GSK: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; Oncopeptide: Honoraria; Novartis: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Badelita:Amgen: Consultancy, Honoraria, Other: Travel, accommodations, expenses; Janssen: Consultancy, Honoraria, Other: Travel, accommodations, expenses; Takeda: Consultancy, Honoraria, Other: Travel, accommodations, expenses; Novartis: Consultancy, Honoraria; Fundeni Clinical Institute: Current Employment. Katodritou:Karyopharm: Research Funding; Abbvie: Research Funding; Genesis Pharma: Honoraria, Other: Expenses, Research Funding; Takeda: Honoraria, Other: Expenses, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Theagenion Cancer Hospital: Current Employment. Caers:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kühr:Celgene: Honoraria; Merck: Honoraria; Pfizer: Other; Takeda: Honoraria; Novartis: Honoraria; Abbvie: Honoraria; Roche: Honoraria; Lilly: Honoraria, Other: travel, accommodation, expenses; Amgen: Honoraria; Bayer: Honoraria, Other: Travel, accommodations, expenses; Janssen: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Klinikum Wels-Grieskirchen: Current Employment. Suzan:Amgen: Current Employment, Current equity holder in publicly-traded company. Mohammad:Amgen: Current Employment, Current equity holder in publicly-traded company. Wetten:Amgen: Current Employment, Current equity holder in publicly-traded company. Terpos:Takeda: Honoraria, Other: travel expenses , Research Funding; Celgene: Honoraria; Medison: Honoraria; Janssen: Honoraria, Other: travel expenses , Research Funding; Amgen: Honoraria, Research Funding; Genesis: Honoraria, Other: travel expenses , Research Funding.

Introduction: The multicentre, randomized, open-label, phase 3 EMN02/HO95 study for patients with newly diagnosed multiple myeloma (NDMM) included two randomization stages (1:1) to (R1) intensification therapy with either upfront ASCT or bortezomib-melphalan-prednisone (VMP), and thereafter to (R2) consolidation therapy or no consolidation, followed by lenalidomide maintenance in both arms. Results of the final analysis from R1 (M. Cavo et al. Lancet Haematol. 2020, 7, e456-68) showed that at a median follow-up of 60.5 months progression-free survival (PFS), the primary study endpoint, was significantly improved with ASCT compared with VMP (median, 57 versus 42 months; HR 0.73, 95% CI 0.62-0.85, adjusted p=0.0001). However, no difference between these groups was found in terms of overall survival (OS), a secondary endpoint (HR 0·90, 0·71-1·13, adjusted p=0·35). Methods: We performed an updated analysis of the study with longer-term follow-up. Efficacy endpoints included OS, PFS on next-line therapy (PFS2), and time to next treatment (TTnT). Analyses were restricted to patients randomized to either ASCT (n=702) or VMP (n=495). Clinical outcomes of patients randomized to upfront ASCT or receiving ASCT at the time of progression after primary randomization to VMP (delayed ASCT) were also explored. Results: At an extended median follow-up of 75 months (IQR 67-84), patients randomized to ASCT had a significantly longer OS than those randomized to VMP (Figure). Median OS was not reached in both arms, and the 75-month survival estimate was 69% (95% CI 65-73) in the ASCT group versus 63% (95% CI 59-68) in the VMP group (HR 0.81, 95% CI 0.66-0-98, adjusted p=0.034). Patients who benefited the most from randomization to ASCT were those with unfavourable prognostic characteristics at baseline, including ISS disease stage 2-3 (HR 0.78, 95% CI 0.61-0.99, p=0.047), R-ISS stage 2-3 (HR 0.79, 95% CI 0.62-0.99, p=0.042), and the presence of at least one of the following cytogenetic abnormalities on FISH analysis: t(4;14) and/or t(14;16) in ≥10% CD138-positive plasma cells, and/or del(17p) in ≥20% enriched plasma cells. Overall, the 75-month OS estimate for patients with a high-risk cytogenetic profile was 54% with ASCT versus 39% with VMP (HR 0.61, 95% CI 0.42-0.89, p=0.010). The magnitude of OS benefit with ASCT, as measured by the HR value, was the highest for patients with del(17p) positivity (HR 0.49, 95% CI 0.28-0.86, p=0.013). PFS2 from R1 was significantly longer for patients in the ASCT arm than for those in the VMP arm. The 75-month PFS2 estimate was 57% in the ASCT group and it was 49% in the VMP group (HR 0.76, 95% CI 0.64-0.90, adjusted p=0.002) (Figure). Patients randomized to ASCT had a significantly longer TTnT in comparison with those who were randomly assigned to VMP. Median TTnT values for these groups were 66 versus 47 months, respectively (HR 0.71, 95% CI 0.60-0.82, adjusted p Conclusions: Upfront ASCT significantly prolonged OS, PFS2 and TTnT in comparison with VMP in NDMM patients. Figure Disclosures Cavo: Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Gay:AbbVie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees. Beksac:Janssen&janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Deva: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Dimopoulos:Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Petrucci:GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees. Zweegman:Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Zamagni:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Takeda: Honoraria, Other: Travel, Accommodations, Expenses, Speakers Bureau; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Speakers Bureau. Palumbo:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Galli:BMS: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Takeda: Honoraria. Maisnar:Janssen, Takeda, Amgen, BMS/Celgene, The Binding Site: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hansson:Amgen, Celgene, Takeda, Janssen Cilag: Consultancy. Belotti:Celgene: Membership on an entity's Board of Directors or advisory committees; Jannsen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Offidani:Janssen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Zambello:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Liberati:Verastem: Research Funding; Janssen: Honoraria, Research Funding; Takeda: Research Funding; Morphosys: Research Funding; Novartis: Research Funding; GSK: Research Funding; Incyte: Honoraria; Oncopeptides: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Honoraria, Research Funding; Onconova: Research Funding; Pfizer: Research Funding; Karyopharm: Research Funding. Broyl:Janssen, Celgene, Takeda, Amgen: Honoraria. Musto:Amgen: Honoraria; Celgene: Honoraria. Ludwig:Seattle Genetics: Other: Advisory Boards; Takeda: Research Funding; Sanofi: Other: Advisory Boards, Speakers Bureau; Bristol Myers: Other: Advisory Boards, Speakers Bureau; Amgen: Other: Advisory Boards, Research Funding, Speakers Bureau; Janssen: Other: Advisory Boards, Speakers Bureau; Celgene: Speakers Bureau. Hajek:Roche: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding; Pharma MAR: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Waage:Janssen: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy; Shire: Honoraria. Mellqvist:Janssen. Celgene, Amgen: Honoraria. Boccadoro:Novartis: Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Mundipharma: Research Funding; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Research Funding; AbbVie: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding. Sonneveld:Karyopharm: Consultancy, Honoraria, Research Funding; Skyline Dx: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding.

Background. Chronic Lymphoproliferative Disorder of Natural Killer cells (CLPD-NK) is a rare disease characterized by chronic NK cell lymphocytosis, typically equipped with a restricted pattern of activating killer immunoglobulin like receptors. Several lines of evidence point to a putative role of viral agents in the pathogenetic mechanisms accounting for NK cell proliferation. A role of Epstein Barr Virus (EBV) has been claimed in the aggressive form of NK cell proliferation [i.e. Aggressive NK Cell Leukemia (Kawa Ha et al, JCI 1989)]. At variance, in the indolent CLPD-NK, EBV DNA was seldom detected by PCR (Loughran TP Jr et al, Blood 1993), whereas we provided serologic evidence for previously experienced viral infections in the majority of CLPD-NK patients (Zambello R et al, Leukemia 1995). However, the role of infectious agents in the pathogenesis of chronic antigen stimulation of NK cells in CLPD-NK patients is still elusive. Methods. Several studies showed that whole exome sequencing (WES), as well as RNA-seq, can identify pathogens, particularly viruses, in cancer clones enabling the definition of possible integration sites in the host genome or their presence as episomal forms. In the present study, we searched viral sequences in WES data of a cohort of 10 CLPD-NK patients. High-depth (average 51 M reads) WES data of highly purified (>97% purity) leukemic NK clone and autologous granulocytes, as control, from CLPD-NK patients were analyzed for pathogen discovery. Three different methods for virus detection were used: i) Centrifuge (Kim et al, Genome Research 2016), a metagenomic tool performing a wide search against GenBank viral and bacterial sequences, which has been recently used to detect EBV load in ANKL and NK T cell Lymphoma (NKTCL) tumor clones (Dufva et al. Nat Comm 2018); ii) VirusSeq (Chen et al., Bioinformatics 2013), a software to identify viruses and eventually their integration sites, grounding on its custom and relatively wide viral sequence database; and iii) ViFi (Nguyen et al. Nucleic Acids Res, 2018), which can find viral integration in the human genome, with an analysis focused on a narrow set of viruses (EBV, HPV, HBV) with well-established oncogenic potential. Results. First, as positive control two datasets were used: RNA-seq data of an HBV positive sample with known site of integration (provided by VirusSeq) and WES data of three NKTCL tumor and control clones with high, moderate or low EBV load in the tumor samples previously detected by Dufva et al. (Dufva O et al, Nat Comm 2018), publicly available at NCBI SRA. HBV presence was detected in the positive sample by all the three methods and our reanalysis of NKTCL samples with Centrifuge confirmed published results, detecting EBV in all tumoral samples and in none of the matched control samples. Next, analysis of samples from the 10 CLPD-NK patients with the three methods did not identify a significant viral load neither in tumor nor in control specimens. Neither VirusSeq nor ViFi found viruses in CLPD-NK samples, whereas, according to Centrifuge analysis, the human disease virus with the highest load in most patients was Varicella Zoster (Human alphaherpesvirus 3) but with low read count and, most relevant, without specificity for the cancer clone. Conclusions. Our very thorough WES analysis did not identify a significant and meaningful viral load in CLPD-NK samples, neither in leukemic clones nor in control cell population. Although not ruling out that a viral infection might play a role as starting event for inciting NK cell proliferation, our data do not support a role of viral infections in maintaining the proliferation in CLPD-NK. Disclosures Zambello: Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Background: 18F-FDG-PET/CT is currently the standard technique to define minimal residual disease (MRD) status outside the bone marrow (BM) in multiple myeloma (MM) patients. A joined analysis of two prospective randomized trials in newly diagnosed transplant-eligible MM (NDTEMM) patients applied for the first time the Deauville Scores (DS) to focal lesions (FS) and bone marrow uptake (BMS) and showed the liver background (DS < 4) to be the best cut-off to define PET negativity after therapy (Zamagni et al, ASH 2018). Multiparameter Flow cytometry (MFC) at the sensitivity level of 10-5 is one of the standardized methods to assess MRD in the BM (Kumar SK, Lancet Oncol 2016). In this analysis, we aimed at comparing MRD data by PET/TC assessment and MFC in the multicenter phase II randomized FORTE trial for NDTEMM patients. Methods: NDTEMM patients ≤65 years were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRD) induction - autologous stem cell transplantation (ASCT) intensification-KRd consolidation (arm A); KRd12 (arm B) and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction-ASCT intensification-KCd consolidation (arm C). Thereafter, patients were randomized to maintenance with lenalidomide alone or lenalidomide plus carfilzomib. MRD evaluation was performed by 8-color second-generation flow cytometry (sensitivity 10-5) in patients who achieved at least VGPR before maintenance (Gay F, ASCO 2019). PET/CT scans were performed locally at baseline (B) and prior to the start of maintenance (PM) and the DS were applied both in the BM and FLs as previously described. Cramér's V coefficient was used to measure the concordance between PET/TC and MFC; Fisher or X2 tests were adopted, where appropriate, to evaluate the statistical significance, at the level of 0.05. Results: 182 out of the 474 global patients enrolled in the trial had a matched PET/CT and MFC evaluation available and were included in the present analysis. Baseline characteristics of the patients were as follows: median age 57 years, ISS and R-ISS stage III 18% and 10%, respectively, high-risk cytogenetics (t(4;14) ± del(17p) ± t(14;16), detected by FISH) 26%, reflecting baseline clinical features of the entire FORTE population. At B, 92% of the patients had FLs, with a median maximum standardized uptake value (SUVmax) of 5.7 [IQR: 4.1-8.1], 11% presented extra-medullary lesions and nearly all the patients had increased BM uptake, with a median SUVmax of 3.3 [IQR: 2.8-4.3]. FS and BMS ≥4 were present in 87% and 59% of the patients, respectively. A higher FS at B was significantly correlated with ISS stage III (P= 0.04), while higher BMS with lower hemoglobin level (P= 0.002) and higher free light chain ratio (P= 0.004). At PM, PET/TC negativity according to DS < 4, was present in 78% in the FLs and 85% in the BM, respectively. No significant correlations between PET/CT negativity after therapy and baseline prognostic factors or PET/CT characteristics were found. 95% and 67.5% of the patients achieved ≥ VGPR and CR as best response, respectively, while 75% of them achieved MFC MRD negativity. The achievement of a best CR significantly correlated with BMS < 4 at PM (P= 0.013). We analyzed the concordance between MRD results by the two techniques and Cramér's V coefficient measured a strong association, with a value of 0.76 (p Conclusion: In conclusion, the present analysis confirms the applicability and validity of DS criteria for the definition of PET/CT MRD outside the BM in an independent prospective series of NDTEMM patients. PET/CT negativity significantly correlated with the achievement of best CR. PET/CT and MFC at the sensitivity level of 10-5 showed a good concordance in the BM, while were also confirmed to be complementary outside (FLs). Future analyses will show the impact of PET/CT in comparison with BM MRD techniques on patient's outcomes. Disclosures Zamagni: Celgene Corporation: Honoraria, Other: Advisory board, Speakers Bureau; Janssen: Honoraria, Other: Advisory board, Speakers Bureau; Amgen: Honoraria, Other: Advisory board, Speakers Bureau; BMS: Honoraria, Other: Advisory Board, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Sanofi: Honoraria, Other: Advisory Board, Speakers Bureau. Gay:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Omedé:Janssen: Membership on an entity's Board of Directors or advisory committees. Galli:Janssen: Honoraria; Leadiant (Sigma-Tau): Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Honoraria; Celgene: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Gamberi:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Patriarca:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Tacchetti:Celgene: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Janssen: Honoraria; Oncopeptides: Honoraria, Speakers Bureau; BMS: Honoraria. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding. Cavo:bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; novartis: Honoraria; takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau. Oliva:Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees.

Introduction: Aberrant phosphorylation-mediated signaling is a well-established condition involved in the onset and progression of virtually all types of cancer. That not only depends on the over-activation of protein kinases, but also on the lack of the proper counterbalance of protein phosphatases, because of their decreased expression or activity. In turn, this is likely to be due to genetic and epigenetic alterations, or interactions with cellular inhibitors and inhibitory post-translational modifications, respectively. In Large Granular Lymphocyte Leukemia (LGLL), a rare lymphoproliferative disorder characterized by clonal expansion of either cytotoxic T lymphocytes (T-LGLL) or natural killer cells (chronic lymphoproliferative disorder of NK cells, CLPD-NK), constitutive activation of phosphorylation-regulated survival pathways, especially the JAK2/STAT3 axis, but also PI3K/Akt and NF-κB pathways among others, has been found to account for the molecular mechanisms sustaining monoclonal cell proliferation and resistance to apoptosis. Interestingly, since such pathways are modulated by the tyrosine phosphatase SHP-1 under normal conditions, it is conceivable that putative alterations of this phosphatase, and consequent inability to disrupt hyperactive pathways, play a role in LGLL pathogenesis. In this study, we assessed the ability of small molecules inducing the expression and stimulating the activity of SHP-1 to abrogate the survival pathways in LGL by counteracting aberrant signals generated by constitutively activated protein kinases. Methods: Peripheral blood specimens were collected from untreated patients with LGLL (both T-LGLL and CLPD-NK). Peripheral blood mononuclear cells (PBMCs) were isolated by Ficoll-Hypaque (Sigma Aldrich) gradient separation. LGLs were further separated from PBMCs by using immunomagnetic beads (Miltenyi Biotec). LGLs were incubated either with acetyl-11-keto-β-boswellic acid (AKBA), a pentacyclic triterpene capable of inducing SHP-1 expression, or SC-78, a regorafenib-like derivative specifically stimulating SHP-1 activity, or both at increasing concentrations and discrete time points. After such treatments, LGLs underwent annexin V-PI flow cytometry to assess the extent of apoptosis or were lysed to monitor the abundance of SHP-1 and the phosphatase activity thereof. Moreover, the phosphorylation/activation status and the protein level of factors directly involved in the constitutively activated survival pathways of LGLs were evaluated by Western blot analysis. Results: Both AKBA and SC-78 proved effective at eliciting a significant level of apoptosis in the low micromolar range, exhibiting an additive effect when used in combination. Moreover, both compounds activated SHP-1 activity, as demonstrated by in-vitro phosphatase assays. As to the phosphorylation-dependent signals affected by SHP-1 activation, we observed a marked decrease in the phosphorylation status of STAT3, resulting in the downregulation of the STAT3-induced expression of downstream target genes (Mcl-1, survivin, Cyclin D and S1P5), as well as the dephosphorylation of Akt and p65, which confirmed the role of SHP-1 as a functional antagonist of survival pathways in LGLs. Conclusion: Taken together, our results support the newly emerging evidence that the targeted activation of SHP-1, which is already recognized as a tumor suppressor in other tumor cells, may serve as a mechanism countering the aberrant pro-survival signals, thus opening new options for the treatment of LGLL. Disclosures Zambello: Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Introduction: Secondary CNS dissemination (SCNSL) is a rare but lethal event in pts with diffuse large B-cell lymphoma (DLBCL). It can occur both at presentation, in pts with systemic disease, or at relapse, during or after primary therapy. Following the experience from primary CNS lymphoma, pts with SCNSL are currently treated with high-dose-methotrexate-based chemo and autologous transplant (ASCT). However, this strategy is associated with poor control of extra-CNS disease, and only 1/3 of pts proceed to ASCT and recover from this event. Thus, we designed a multicenter phase II trial addressing an intensified chemoimmunotherapy consolidated by ASCT in HIV-neg pts with SCNSL (NCT02329080). Methods: Inclusion criteria were: histologically confirmed DLBCL; CNS involvement at presentation (concomitant to systemic disease) or relapse (isolated or concomitant to systemic lymphoma); age 18-70 ys; ECOG-PS ≤3; no prior treatment with high-dose methotrexate. Registered pts received 3 courses of MATRIX followed by 3 courses of RICE combined with intrathecal chemo and consolidated by BCNU-thiotepa/ASCT. The primary endpoint was 1-yr PFS. The Fleming design was used; to detect a difference in 1-yr PFS from 50% (P0) to 65% (P1), 69 pts were required (one-sided, type I error 5%, power 80%), with a dropout of 10%, 76 pts were needed. If ≥41 pts were progression-free at 1 yr, the strategy would be considered effective. Results: Between 3/2015 and 8/2018, 79 pts were enrolled at 24 centers in 4 countries; 75 pts (median age 58, range 23-70; 38 males) were assessable. CNS involvement was recorded at presentation in 32 (43%) pts and at relapse in 43 (isolated site in 15, concomitant to systemic relapse in 28). CNS sites were brain parenchyma in 34 (45%) pts, brain + eyes in 10 (13%), brain + CSF in 13 (17%), brain + CSF + eyes in 6 (8%), CSF/meninges in 8 (11%), spinal cord in 2 (3%), and eyes in 2 (3%). Median time to CNS involvement was 5 months (range 1-61) in the 43 pts registered at relapse; 20 (47%) of them had refractory disease. 320 (71%) of the 450 planned chemo courses were delivered; 64 (85%) pts received intrathecal chemo. 78 SAEs were recorded in 42 pts, mostly due to FN and infections (64) or bleeding (5); 74 (95%) SAEs were followed by recovery. The 4 lethal SAEs (TRM= 5%) and the 5 transient interruptions occurred during MATRIX. Dose reductions were indicated in 33 (10%) courses. Most common g4 toxicities were thrombocytopenia in 118 (37%) courses, neutropenia in 113 (35%) and infections in 9 (3%). Stem cells collection was successful (median of 6.75M/kg; range: 2.4 - 45) in 42 (88%) of the 48 pts referred for leukapheresis. 55 (73%; 95%CI 63-83%) pts achieved a response after 2 courses of MATRIX; 19 (95%) of the 20 pts who had a CR after 2 MATRIX maintained the response after RICE; 9 (26%) of the 35 pts who had a PR after 2 MATRIX achieved a CR after RICE. Conversely, only 3 of 16 pts with PD/SD after 2 MATRIX achieved a response from RICE. 49 pts (65%; 95%CI 54-76%) achieved a response after MATRIX-RICE induction, and 36 responders received ASCT; 13 responders did not receive ASCT due to insufficient mobilization (n=4), PD due to treatment delay (5), frailty (2), neurological decline (1), and consent withdrawal (1). 45 pts (60%; 95%CI 50-70%) had responsive disease after the whole treatment. At 1 year from registration, 41 pts were progression free (efficacy threshold ≥41). At a median follow-up of 25 (12-47) months, 31 pts are progression free, with a 2-yr PFS of 42 ± 6% for the whole series and 75 ± 7% for the 36 transplanted pts (Fig. A & B). Sites of relapse/progression were CNS in 10 pts, extra-CNS organs in 9 and both in 18. Overall, 33 pts are alive, with a 2-yr OS of 42 ± 6% for the whole series and 82 ± 7% for transplanted pts. Causes of death were lymphoma (35) and toxicity (4); 3 pts died without evidence of disease due to neurological decline, PTE and sudden death. Pts with CNS disease at presentation had the best outcome (Fig. C), whereas CSF/meningeal disease (Fig. D) and age >60 ys were independently associated with poor outcome. Conclusions: MATRIX-RICE followed by ASCT achieved the primary endpoint in this very-poor-prognosis population, without major safety concerns. Survival figures of transplanted pts seem a little better than reported in prior trials, whereas pts with MATRIX-refractory disease had no benefit from crossing to RICE. The best survival figures were recorded in chemo-naïve pts treated at presentation and in pts without CSF/meningeal disease. Figure Disclosures Ferreri: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Roche: Research Funding. Doorduijn:Roche: Honoraria, Research Funding. Nassi:Merck: Consultancy; Takeda: Consultancy; Janssen: Consultancy. McKay:Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Epizyme: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Davies:ADCT Therapeutics: Honoraria, Research Funding; Karyopharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; MorphoSys AG: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Janssen: Honoraria, Research Funding; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Honoraria, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta Pharma: Honoraria, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioInvent: Research Funding. Fox:Celgene: Consultancy; Gilead: Consultancy; AbbVie: Consultancy; Janssen: Consultancy; Sunesis: Consultancy; Takeda Pharmaceuticals: Consultancy; Atara Biotherapeutics: Consultancy; Adienne: Other: Travel Support. Osborne:Gilead: Membership on an entity's Board of Directors or advisory committees; NIL: Employment; NIL: Other: leadership; NIL: Other: Stock & other ownership interests; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Honoraria, Speakers Bureau; MSD: Membership on an entity's Board of Directors or advisory committees. Liberati:Incyte: Consultancy; Novartis: Other: Clinical trial support; Janssen: Honoraria; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Roche: Other: Clinical trial support; Amgen: Membership on an entity's Board of Directors or advisory committees, Other: Clinical trial support; Celgene: Honoraria, Other: Clinical trial support; Bristol-Myers Squibb: Honoraria; Takeda: Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Zucca:Celltrion Helathcare: Membership on an entity's Board of Directors or advisory committees; AstraZenaca: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Merck: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant, Research Funding; Kite, A Gilead Company: Membership on an entity's Board of Directors or advisory committees; Abbvie: Other: Travel Grant. Cwynarski:Adienne: Consultancy; Takeda: Consultancy, Other: conference and travel support , Speakers Bureau; Roche,: Consultancy, Other: conference and travel support, Speakers Bureau; Autolus: Consultancy; KITE: Consultancy; Gilead: Consultancy, Other: conference and travel support, Speakers Bureau; Celgene: Consultancy; Atara: Consultancy; Janssen: Other: conference and travel support, Speakers Bureau.

Background: The role of Minimal residual disease (MRD) as surrogate for survival in Multiple Myeloma (MM) patients is well established. Therefore, new response criteria recommend including Multiparameter Flow cytometry (MFC) and next generation Sequencing (NGS) MRD negativity (minimum sensitivity of 1 in 105 nucleated cell) to deeply characterize complete remission (CR) [Kumar SK, Lancet Oncol 2016]. Here we analyzed and compared MRD data from the FORTE trial both by MFC and NGS techniques. Methods: Newly diagnosed MM patients ≤65 years were randomized to receive carfilzomib, lenalidomide, dexamethasone (KRd) induction - autologous stem cell transplantation (ASCT) intensification - KRd consolidation (KRd_ASCT); KRd12 and carfilzomib, cyclophosphamide, dexamethasone (KCd) induction - ASCT intensification - KCd consolidation (KCd_ASCT). Thereafter, patients were randomized to maintenance therapy with lenalidomide alone or lenalidomide plus carfilzomib. MRD evaluation was performed by 8-color second generation flow cytometry (sensitivity 10-5) in patients who achieved at least a very good partial response (VGPR) before maintenance. In a subgroup of these ≥ VGPR patients, next generation flow (NGF; sensitivity 10-5 - 10-6) was performed. Moreover, in patients achieving ≥ CR, MRD pre-maintenance was also assessed by NGS (Adaptive Biotechnologies, Seattle, WA; sensitivity 10-5 - 10-6). Therefore, only patients achieving ≥ CR have both MFC and NGS evaluations, and we focused on this ≥ CR population to compare MRD results with the 2 techniques. Spearman's rank correlation coefficient was used to measure the concordance between MFC and NGS. Fisher or Pearson's Chi-squared tests were adopted, where appropriate, to evaluate the statistical significance, at the level of 0.05. Results: ≥ CR pre-maintenance was achieved in 233 patients enrolled in the trial; at data cut-off, MFC and NGS data were available for 176/233 (76%) patients who were included in this analysis (62 received KRd_ASCT, 65 KRd12 and 49 KCd_ASCT). Median age of this ≥ CR population is 57 years (IQR 52-62), 14% have International Staging System (ISS) III stage and 26% high risk cytogenetics by FISH features [either del(17p) or t(4;14) or t(14;16)] reflecting baseline clinical features of the entire FORTE population. 139/176 (79%) ≥ CR patients were MFC negative at a cut-off of at least 10-5. Rate of MRD negative MFC among ≥ CR negative in the 3 arms were: 53/62 (85%) in KRd_ASCT, 51/65 (78%) in KRd12 and 35/49 (71%) in KCd_ASCT, reflecting the higher rate of MCF MRD negativity pre-maintenance reported by ITT in the overall population in the 2 KRD arms [Gay F, ASH 2018]. NGS negativity at a cut-off of at least 10-5 was detected in 87/176 (49%) of ≥ CR patients. Rate of MRD negative NGS at least 10-5 among ≥ CR negative in the 3 arms were: 35/62 (56%) in KRd_ASCT, 31/65 (48%) in KRd12 and 21/49 (43%) in KCd_ASCT. NGS negativity at a cut-off 10-6 was detected in 34/123 (28%) of ≥ CR patients (for 53/176 CR patients 10-6 sensitivity was not reached). Rate of MRD negative NGS at least 10-6 among ≥ CR negative in the 3 arms were:14/41 (34%) in KRd_ASCT, 10/44 (23%) in KRd12 and 10/38 (26%) in KCd_ASCT. Thereafter, we have analyzed the concordance between MRD results by the two techniques. Overall (samples at 10-5 and 10-6 sensitivity), Spearman's coefficient is 0.63 (p < 0.001); discordances between the two methods have been observed in 54/176 paired samples (30%). In particular, 53 samples (30%) are NGS positive but MFC negative, of which 34/53 (64%) have reached 10-6 sensitivity by NGS. Only 1 MFC positive sample is NGS negative. In a subgroup of patients evaluable both by NGS and NGF (26 paired samples, sensitivity 10-6), Spearman' s coefficient is 0.83 (p < 0.001), although a higher sample size is needed to confirm these preliminary concordant results. Conclusion: In patients who achieved ≥ CR, rate of at least 10-5 MRD MCF negativity was 79% and rate of at least 10-5 NGS negativity was 49%. Assessment both by MFC and NGS showed a good concordance, particularly if the same sensitivity is reached. Longer follow up is needed to assess the impact of MFC in comparison with NGS on patients' outcomes, particularly to evaluate if 10-6 NGS or NGF sensitivity may provide further clinical information, possibly identifying patients with very long survival or potentially cured. Disclosures Oliva: Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Belotti:Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Galli:Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Leadiant (Sigma-Tau): Honoraria; Janssen: Honoraria; Celgene: Honoraria. Offidani:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Vozella:Amgen: Honoraria; Celgene: Honoraria. Zambello:Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Kirsch:Adaptive Biotechnologies: Employment. Jacob:Adaptive Biotechnologies: Employment, Other: shareholder. Ballanti:Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria; Celgene: Honoraria. Corradini:Roche: Honoraria; Sanofi: Honoraria; KiowaKirin: Honoraria; Kite: Honoraria; Novartis: Honoraria, Other: Travel Costs; BMS: Other: Travel Costs; Servier: Honoraria; Takeda: Honoraria, Other: Travel Costs; Gilead: Honoraria, Other: Travel Costs; AbbVie: Consultancy, Honoraria, Other: Travel Costs; Amgen: Honoraria; Celgene: Honoraria, Other: Travel Costs; Daiichi Sankyo: Honoraria; Jazz Pharmaceutics: Honoraria; Janssen: Honoraria, Other: Travel Costs. Omedé:Janssen: Membership on an entity's Board of Directors or advisory committees. Cavo:takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel accommodations, Speakers Bureau; bms: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; novartis: Honoraria; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Musto:Amgen: Honoraria; Celgene: Honoraria. Boccadoro:Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding. Gay:AbbVie: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The presentation includes discussion of off-label use of a drug or drugs for the treatment of multiple myeloma.

Introduction Lenalidomide (Len) and low-dose Dexamethasone (dex) (Rd) in continuous is a new standard of care for elderly newly-diagnosed multiple myeloma (NDMM) patients (pts), as established by FIRST trial (Facon et al, Blood 2018). Methods and results This is a retrospective, multicentric study conducted in Italy with the aim of evaluating efficacy and tolerability of Rd in a real-life population. Thirty-seven centers were involved and data of 429 pts are available. Pts were considered eligible for the study when completing at least 2 cycles of Rd regimen. Table 1 summarizes the characteristics of pts at time of MM diagnosis. Median age was 78 years (range 57-92), 36.6% had an ECOG PS≥2, creatinine clearance (ClCr) was After a median follow-up of 11 months, most pts are still on treatment (60,4%), the median number of administered cycles was 7 (range 2-33). Overall response rate (ORR, ≥PR) was 74.5% with 34.1% of pts obtaining at least a VGPR. Clinical Benefit Rate (CBR, including minimal responses) was 83.3%. Responses were rapid with median time to first and to best response respectively of 1.8 (range 1-8) and 5 (1-26) months. Median OS and PFS were not reached with a 1-y and 2-y OS of 84.8 and 73.8% and a 1-y and 2-y PFS of 78.6 and 65%. Median EFS was 19.8 months. In univariate analysis, factors significatively impairing ORR were frailty (fit/unfit/frail 91.2/77/55.9%, p2 81.7/61.6%, p upper level of normal (ULN) (65.8 vs 77%, p=0.034). 1-y PFS is significantly shorter in pts with lower ECOG (0-1 vs 2, 66.5 vs 84.8%, pULN (66.4 vs 83.2%, p=0.02), lower ClCr (50 57.2/81.3/80.1%, P=0.01), presence of t(14;16) (42.9 vs 80.4% p=0.01) and amp(1q) (63.5 vs 85.6%, p=0.01); factor impairing OS are ECOG (0-1/>2 93.4 vs 69.4%, pULN (75.1 vs 97.1, p=0004), impaired ClCr (50 64/83.7/88.2%, p2 74.2 vs 47.3%, p In multivariate analysis ORR is significantly correlated with ECOG>2 (p=0.05), LDH >ULN (p=0.005) and presence of amp1q (p=0.006); PFS was significantly affected by R-ISS III (p=0.04), LDH >ULN (P=0.01) and ClCr2 still impact on OS (p Dose reduction of Len or dex was required respectively in 20.7% and 22.1% and 39.2% needed cycle delay for adverse events (AEs). Grade 3-4 (G3-4) AEs occurred in 52% of pts with 30.9 and 36.6% having at least a hematological or extra-hematological G3-4 AE. In particular, 17.9 and 16.6% of pts had severe neutropenia and anemia while the most common non-hematological AEs were infections (25.8%, G3-4 12.2%), mainly involving respiratory tract (71.2%). Gastroenteric and cutaneous AEs were quite common (22.1 and 19.2%), mainly diarrhea and itching, but in the vast majority were mild. G3-4 asthenia was present in 22.8% of pts. Although 99% of pts was given antithrombotic prophylaxis, 8.5% had a thromboembolic event, a third of severe entity. G-CSF and EPO analogs were required in 27.4 and 26% of pts. Conclusion Real-life data confirm efficacy and tolerability of Rd in elderly NDMM pts. Performance status by ECOG and IMWG frailty score and severe renal impairment but not age itself act as limiting factors affecting outcome. These data must be confirmed by longer follow-up. Disclosures Conticello: Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Mangiacavalli:Janssen cilag: Consultancy; celgene: Consultancy; Amgen: Consultancy. Zambello:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Belotti:Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Molteni:Celgene: Membership on an entity's Board of Directors or advisory committees. Aquino:Celgene: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Del Fabro:Janssen: Consultancy. Galli:Leadiant (Sigma-Tau): Honoraria; Janssen: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Celgene: Honoraria.

The JAK/STAT pathway is altered in T-cell large granular lymphocytic leukemia. In all patients, leukemic LGLs display upregulation of phosphorylated STAT3 (P-STAT3) that activates expression of many antiapoptotic genes. To investigate the mechanisms maintaining STAT3 aberrantly phosphorylated using transcriptional protein and functional assays, we analyzed interleukin (IL)-6 and suppressor of cytokine signaling-3 (SOCS3), 2 key factors of the JAK/STAT pathway that induce and inhibit STAT3 activation, respectively. We showed that IL-6 was highly expressed and released by the patients' peripheral blood LGL-depleted population, accounting for a trans-signaling process. By neutralizing IL-6 or its specific receptor with specific antibodies, a significant reduction of P-STAT3 levels and, consequently, LGL survival was demonstrated. In addition, we found that SOCS3 was down-modulated in LGL and unresponsive to IL-6 stimulation. By treating neoplastic LGLs with a demethylating agent, IL-6-mediated SOCS3 expression was restored with consequent P-STAT3 and myeloid cell leukemia-1 down-modulation. Methylation in the SOCS3 promoter was not detectable, suggesting that an epigenetic inhibition mechanism occurs at a different site. Our data indicate that loss of the inhibitor SOCS3 cooperates with IL-6 to maintain JAK/STAT pathway activation, thus contributing to leukemic LGL survival, and suggest a role of demethylating agents in the treatment of this disorder.

Background: Lenalidomide (LENA) maintenance is associated with significantly improved outcome in patients (pts) with chemosensitive relapse of DLBCL not eligible for ASCT or experiencing relapse after ASCT. Preliminary results of a multicentre phase II trial (NCT00799513), reported after a median follow-up of 25 months, showed a 1-yr PFS of 70 ± 7% and a 1-yr OS of 81 ± 6%, with good tolerability (Ferreri AJM, et al. Lancet Haematol 2017). However, LENA was ongoing in 41% of pts at time of analysis, and late side effects and events after maintenance completion remained to be defined. Herein, we report efficacy and safety results of the trial after a median follow-up of 56 (range 27-100) months. Methods: HIV-neg pts (age ≥18 ys) with de novo or transformed DLBCL and relapsed disease responsive to conventional rituximab-containing salvage therapy were registered and treated with LENA 25 mg/day for 21 days out of 28, until lymphoma progression or unacceptable toxicity. A protocol amendment in 2015 allowed physicians to interrupt maintenance after a minimum duration of two years. Primary endpoint was 1-year PFS. Simon's two-stage optimal design was used. To demonstrate a 1-yr PFS improvement from 30% (P0) to 50% (P1), 47 pts (one-sided; α 5%; β 80%) were needed. Maintenance would be considered effective if ≥19 pts were progression-free survivors at 1 yr. Cell of origin was assessed by NanoString Technology (n=23) and Hans algorithm (n=39). Results: Between 3/2009 and 12/2015, we recruited 48 pts; 46 of them were assessable (median age 72 ys; range 34-86); 36 pts had de novo DLBCL, 10 had transformed DLBCL. All pts were previously treated with anthracycline- and rituximab-based combination, plus ASCT in 6 pts. Thirty-three pts were enrolled at 1st relapse; salvage therapy contained high doses of cytarabine or ifosfamide in two-thirds of cases, and response was complete in 26 pts and partial in 20. Most pts had unfavourable features: IPI ≥2 in 38 (83%) pts, advanced stage in 35 (76%), extranodal disease in 29 (63%), high LDH level in 21 (46%); 28 (61%) pts were older than 70 ys. Sixteen pts received ≥2 years of LENA (5 received >2 ys), 30 pts interrupted treatment due to progressive disease (PD; n= 17), toxicity (9) or pt refusal (4) (Table). LENA was well tolerated after an average of 18 courses/pt (range 3-82). With the exception of neutropenia, grade-4 toxicities occurred in At one year from trial registration, 31 pts were still progression free, which was significantly higher than the pre-determined efficacy threshold (n≥19). During the whole observation period, there were 24 events: progressive disease in 21 pts and death of toxicity in 3, with a 1-yr (primary endpoint) and 5-yr PFS of 67 ± 7% and 50 ± 7%, respectively. The duration of response to LENA was longer than response duration after the prior treatment line in 28 (61%) pts, and was twice as long in 21 (46%) of them. Twenty-six pts were disease-free at the last LENA course (Table), 22 of them remain relapse free after a median observation period from maintenance completion of 26 (8-92) months; 3 of the 4 relapses occurred in pts who received The benefit of LENA was observed both in pts with de novo or transformed DLBCL. According to the Hans' algorithm, the 4-yr PFS was 50 ± 11% for GCB-DLBCL and 42 ± 11% for nonGCB-DLBCL (p= 0.58). Results using the Nanostring technique were consistent with the Hans' algorithm. Overall, 28 (61%) pts are alive, with a 1- and 5-yr OS of 80 ± 6% and 60 ± 8%, respectively. Conclusions: Long-term results of this trial soundly promotes the use of LENA maintenance in pts with chemosensitive relapse of DLBCL not eligible for ASCT or experiencing relapse after ASCT. LENA was well tolerated in this elderly population, without higher toxicity rates in pts treated for ≥2 years, and with enhanced survival figures. These results warrant further investigation of immunomodulatory drugs as maintenance in these high-risk pts. Table. Table. Disclosures Ferreri: Celgene: Research Funding. Zaja:Abbvie: Honoraria; Takeda: Honoraria; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen: Honoraria; Janssen: Honoraria; Sandoz: Honoraria. Di Rocco:Janssen: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Rusconi:Celgene: Research Funding.

INTRODUCTION: Neutropenia represents the most frequent clinical manifestation in T-Large Granular Lymphocytes Leukemia (T-LGLL) patients. Literature data provided evidence of the involvement of soluble Fas Ligand (sFasL) in this process. Consistently, we confirmed that neutropenic T-LGLL patients were characterized by higher levels of sFasL than non neutropenic patients. We also demonstrated that FasL transcription was mediated by the Signal Transducer and Activator of Transcription (STAT)-3 and we showed that high STAT3 activation correlated with high levels of sFas. However, the mechanism through which STAT3 regulates FasL production still remains elusive. It is well known that FasL expression depends on post-transcriptional events involving ARE-binding proteins, such as Human antigen R (HuR). Important regulators of post-transcriptional modifications are microRNAs (miRNAs), that are small non-coding RNA molecules able to bind target mRNAs, promoting their degradation or blocking protein translation. Among them, miR-146b was identified to be induced by STAT3 in non-transformed cells. This work aims to determine whether miR-146b might regulate STAT3-mediated expression of FasL, thus playing a role in the pathogenesis of neutropenia in T-LGLL patients. METHODS: T-Large Granular Lymphocytes (T-LGLs) were purified by FACSAria cell sorter from PBMCs of untreated T-LGLL patients. High throughput and single miRNA analysis were carried out on purified LGLs by using the TaqMan® Human microRNA Array and Assays, respectively. Transfection with miR-146b mimic was performed using the Amaxa Nucleofactor and the Ingenio Electroporation Solution. Transcriptional and protein expression levels were evaluated by Real Time-PCR and Western Blot (WB) assays. RESULTS: By assessing the expression of 756 mature miRNAs on purified patients' T-LGLs, we identified miRNAs differentially expressed in patients characterized by neutropenia as compared to those with normal absolute neutrophil count (ANC); selected miRNAs were then analyzed for correlation with ANC. Among them, miR-146b expression was the only one correlated with ANC, being down-regulated in neutropenic patients. To investigate miR-146b role in neutropenia development, we transfected purified T-LGLs with a miR-146b mimic. We showed that restoration of miR-146b led to a decrease of FasL mRNA, without changes in the FasL primary transcript as compared to control, indicating that miR-146b affected FasL expression at a post-transcriptional level. However, FasL was not identified among the putative miR-146b target genes, suggesting that miR-146b could regulate FasL expression indirectly. Therefore, we checked for genes involved in mRNA stability and we found that the defective miR-146b expression lead to increased transcriptional levels of the mRNA stabilizer HuR, that is required for FasL expression in T-lymphocytes. Consistently, by WB assays, we demonstrated that in T-LGLs of neutropenic patients HuR endogenous protein levels were higher than in T-LGLs of non neutropenic ones. HuR-mediated FasL mRNA stabilization explained the increased FasL expression observed in neutropenic patients. In the end, we demonstrated the mechanism affecting miR-146b expression in the presence of STAT3 activation, pointing to a role of epigenetic modulation taking place, since the hypomethylating agent 5-aza-2'-deoxycytidine (DAC) can restore STAT3-miR-146b axis. CONCLUSIONS: In this work we suggest a pathogenetic link between STAT3 activation, a defective miR-146b expression and neutropenia development in T-LGLL. Treatment with a demethylating agent may restore STAT3-dependent induction of miR-146b and may represent a new potential therapeutic strategy for the treatment of neutropenia in T-LGLL patients. Disclosures No relevant conflicts of interest to declare.

Introduction: The phase 3 GIMEMA-MMY-3006 trial comparing bortezomib-thalidomide-dexamethasone (VTD) versus thalidomide-dexamethasone (TD) as induction therapy before, and consolidation after, double autologous stem cell transplantation (ASCT) for newly diagnosed multiple myeloma (MM) provided the first demonstration of increased CR rate, the primary study endpoint, and prolonged PFS with VTD (Cavo M et al, Lancet 2010). However, updating trial results with longer follow-up than earlier reported is needed to assess the effects of treatment interventions on OS and to identify factors predicting for favorable long term outcomes. Aims: We performed a post-hoc analysis of that study to evaluate long term results and construct a prognostic index of survival. Methods: 474 patients were enrolled, 236 randomized to VTD and 238 to TD. Median follow-up for surviving patients was 124 months (IQR: 117-131). Analyses were performed on an intention-to-treat basis. Semi-parametric Cox regression analysis was used to construct the prognostic index. To assess the evolution of prognosis over time, conditional survival CS(t|s) estimate for PFS was calculated as the probability of surviving without progression a further 2 (t) years (yrs) after having already survived s yrs. Results: Estimates of PFS and OS at 10 yrs for the VTD arm were 34% (HR=0.62; 95% CI=0.50-0.77; p Conclusions: With a follow up of 10 yrs, the final analysis of the GYMEMA MMY-3006 trial comparing VTD versus TD showed a persistent PFS benefit translating into extended OS for the VTD arm. A prognostic model based on cytogenetic, ISS stage and achievement of CR, identified three risk groups with statistically different long-term survival probabilities. Both IR and HR groups significantly benefited from VTD. A PFS time of 78 months predicted for long term survival outcomes in the LR and IR groups. Disclosures Tacchetti: Celgene: Honoraria; Janssen: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Di Raimondo:Takeda: Honoraria, Research Funding; Celgene: Honoraria. Zamagni:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bringhen:Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Amgen: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Takeda: Consultancy. Offidani:Celgene: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Amgen: Honoraria, Other: Advisory Board; Bristol-Myers Squibb: Honoraria, Other: Advisory Board; Takeda: Honoraria, Other: Advisory Board. Montefusco:Celgene: Other: Advisory Board; Amgen: Other: Advisory Board; Janssen: Other: Advisory Board. Cavo:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Introduction Elotuzumab (Elo), an immunostimulatory monoclonal antibody targeting signaling lymphocytic activation molecule F7 (SLAMF7), received marketing approval in Italy for relapsed or refractory multiple myeloma (RRMM), in combination with lenalidomide (R) and dexamethasone (d) (EloRd) in April 2017. Here we report preliminary data of an Italian real-life experience on EloRd as salvage therapy for RRMM patients treated outside of controlled clinical trials. The primary objectives of this study were to assess the toxicity profile and the efficacy of EloRd administered as salvage therapy in a real-world setting. Methods Retrospective data collection received approval from local ethic committee. The cohort included 180 RRMM patients from 28 Italian centers who received at least one cycle of EloRd as salvage treatment between April 2017 and June 2018. Patients were treated with EloRD according to marketing approval as follows: Elo 10 mg/kg i.v. on days 1, 8, 15, and 22 during the first two cycles and then on days 1 and 15 of each following cycle, R 25 mg on days 1 to 21 of each cycle and d at a dose of 40 mg during the week without Elo, and 36 mg on the day of Elo administration. Responsive patients had to reach at least a partial remission (PR). Results Baseline characteristics are shown in Table 1. Median age of the 180 patients was 72 years (range 48-89 years); 53.9% were males (Table 1). The median number of previous therapy regimens was 1 (range 1-7); 69 patients (38.3%) received a previous autologous stem cell transplantation (ASCT). One hundred and ten patients (61.1%) showed a symptomatic relapse, 36 (20%) a biochemical relapse, and 34 cases (18.9%) were refractory to the last therapy, including bortezomib in 12.8% of patients. Forty-four patients (24.4%) had creatinine clearance ≤60 mL/min. Among the 138 cases evaluable for International Scoring System (ISS), 54 (39.1%) had stage I, 56 (40.6%) stage II, and 28 (20.3%) stage III. At last data collection (June 2018), 164 cases were evaluable for response. The median number of courses administered so far was 5 (range 1-18). The overall response rate (ORR) was 78%, with 9 complete remissions (CRs) (5.5%) and 49 very good partial remissions (VGPRs) (35.4%). A significant higher ORR was observed in patients who had received only 1 previous line of therapy than those who had received >1 line (64% vs 37.5%; p=0.004). Age ( After a median follow-up of 6 months (range 1-18 months) 33 patients stopped treatment due to disease progression and 4 due to toxicity (2 cases after 1 cycle for pneumonia, 1 after 1 cycle for dexamethasone-related psychosis, and 1 after 2 cycles for lenalidomide-related severe skin rash). A total of 17 patients died (7 patients from progressive disease; 2 from an infection; 1 from a second neoplasia; 7 from causes unrelated to therapy). Follow-up data regarding PFS and overall survival are not sufficiently mature to be analyzed. Common grade 3 or 4 adverse events were fatigue (18.9%), anemia (17%), neutropenia (16.5%), lymphocytopenia (15.9%), and pneumonia (15.9%). Infusion reactions occurred in 13 patients (7.2%) and were always of grade 1 or 2. Infusion reactions resolved in all patients and no case discontinued treatment. Conclusions Our real world preliminary data confirm that EloRd is an effective and safe regimen for RRMM patients, particularly if used as first salvage regimen, basically resembling results obtained in controlled clinical trials. Table 1. Table 1. Disclosures Galli: Celgene: Honoraria; Janssen: Honoraria; Sigma-Tau: Honoraria; Bristol-Myers Squibb: Honoraria. Giuliani:Janssen Pharmaceutica: Other: Avisory Board, Research Funding; Celgene Italy: Other: Avisory Board, Research Funding; Takeda Pharmaceutical Co: Research Funding. Mangiacavalli:Janssen: Consultancy; Celgene: Consultancy; Cilag: Consultancy. Ballanti:Celgene: Honoraria; Janssen: Honoraria; Amgen: Honoraria; BMS: Honoraria. Montefusco:Celgene: Other: Advisory Board; Amgen: Other: Advisory Board; Janssen: Other: Advisory Board. Bringhen:Bristol-Myers Squibb: Honoraria; Celgene: Honoraria; Amgen: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Takeda: Consultancy. Zamagni:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees. Patriarca:Celgene: Other: Advisory Role; Travel, accommodations, expenses; Janssen: Other: Advisory role; Jazz: Other: Travel, accommodations, expenses; Medac: Other: Travel, accommodations, expenses; MSD Italy: Other: Advisory Role. Di Raimondo:Takeda: Honoraria, Research Funding; Celgene: Honoraria. Petrucci:Takeda Oncology; Amgen; Celgene; BMS; Janssen Cilag: Honoraria, Other: Advisory Board. Offidani:Bristol-Myers Squibb: Honoraria, Other: Advisory Board; Amgen: Honoraria, Other: Advisory Board; Takeda: Honoraria, Other: Advisory Board; Janssen: Honoraria, Other: Advisory Board; Celgene: Honoraria, Other: Advisory Board.

Introduction. Bortezomib (Bort) and lenalidomide (Len) are standard treatments for relapsed MM, but, so far, a comparative trial between them has never been conducted. We designed a multicenter, open label, phase III study to compare bortezomib/cyclophosphamide/dexamethasone and lenalidomide/cyclophosphamide/dexamethasone in a fixed duration design protocol. The combination of Bort and Len with chemotherapy was devised to improve efficacy and to allow a fixed duration treatment in patients not heavily pretreated. Methods. The primary endpoint was the achievement of very good partial remission (VGPR) or better at six weeks after 9 cycles. The study enrolled patients at first relapse with measurable disease. Patients could have received Bort or Len in their first line, but they should have obtained at least a PR longer than one year, and previous Bort or Len maintenance was an exclusion criteria. Enrollment started on April 2011, and was ended on April 2015. Patients were assigned 1:1 to sc Bort 1.3 mg/ms on days 1, 8, 15, 22, oral dexamethasone (Dex) 20 mg on days 1-2, 8-9, 15-16, 22-23, iv cyclophosphamide (Cyclo) 500 mg/ms on day 1 and 8 in a 35 days cycle (VCD) or to Len 15 mg from day 1 to 21, oral Dex 20 mg on days 1-2, 8-9, 15-16, 22-23, iv Cyclo 500 mg/ms on day 1 and 8 in a 28 days cycle (RCD). Nine courses of therapy without maintenance were planned. Efficacy and safety were assessed at each cycle using the IMWG response criteria for efficacy assessment (Durie et al. Leukemia 2006), and CTCAE v4.0 for safety. Results. One hundred fifty-seven patients were enrolled, 155 were randomized, 77 were assigned to the VCD, and 80 to the RCD arm, respectively. Both arms were well balanced according to the baseline characteristics. Median age was 65 years (range 41-79), and 63 years (range 46-76) for VCD and RCD, respectively. ISS stage was grade I in 36 and 33, grade II in 20 and 28, and grade III in 16 and 15 patients in the VCD and RCD arms, respectively. Previous treatment included Bort in 35 and 42, Len in 7 and 7, Bort- and Len-free chemotherapy in 32 and 29, thalidomide in 35 and 31, and autologous stem cell transplantation in 58 and 63 patients in the VCD and RCD arms, respectively. The primary endpoint, represented by achievement of VGPR or better at 6 weeks after 9 courses, was met by 12 (16%) and 16 (20%) patients in the VCD and RCD arms, respectively (p=0.70). Median progression-free survival (PFS) was 16.3 (range 13.3 - 22.4) and 20.2 (range 14.7 - 26.8) months (p=0.70), and median overall survival (OS) was 31.1 and 36.2 months (p=0.83), in the VCD and RCD arms, respectively. In subgroup analysis, patients that were Bort and Len naïve at enrollment had a PFS of 20.0 (range 12.2 - 31.8) and 20.2 months (range 12.0 - 29.9) (p=0.44), and a median OS of 31.1, and 22.5 months (p=0.72), for the VCD and RCD arms, respectively. Patients that were Bort exposed, but Len naïve at enrollment, had a PFS of 15.6 (range 9.9 - 22.4) and 19.5 months (range 11.1 - 28.6) (p=0.35), and a median OS of 29.2, and 34.7 months (p=0.62), for the VCD and RCD arms, respectively. Adverse events were consistent with the well-established safety profile of Bort and Len, and grade III and IV toxicities were not significantly different between the 2 arms. Conclusions. This is the first head-to-head study comparing fixed duration therapy of Bort and Len in first relapse patients. We show that both drugs are equally effective, in terms of depth of response, PFS, and OS. Despite drug-specific toxicity profiles, incidence of grade III and IV toxicities were not different between the 2 arms. Disclosures Corradini: Novartis: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Sanofi: Honoraria; Roche: Honoraria; Amgen: Honoraria; Gilead: Honoraria.

Introduction : Rd and MPR showed to be effective combinations in elderly newly diagnosed multiple myeloma (NDMM) patients (pts). Cyclophosphamide is a less toxic alkylating alternative agent. EMN01 is the first trial to formally compare these three different Lenalidomide-based combinations. Maintenance with Lenalidomide has been recently approved in patients eligible for autologous stem cell transplant (ASCT). Few data are available about the best combination as maintenance in patients not eligible for ASCT. Methods : 662 pts with NDMM were randomized to receive 9 28-day cycles of Rd (lenalidomide 25 mg/day for 21 days; dexamethasone 40 mg on days 1,8,15 and 22 in pts 65-75 years old and 20 mg in those >75 years), MPR (lenalidomide 10 mg/day for 21 days; melphalan orally 0.18 mg/Kg for 4 days in pts 65-75 years old and 0.13 mg/Kg in >75 years pts; prednisone 1.5 mg/Kg for 4 days) or CPR (lenalidomide 25 mg/day for 21 days; cyclophosphamide orally 50 mg/day for 21 days in pts 65-75 years old and 50 mg every other day in >75 years pts; prednisone 25 mg every other day). After induction, pts were randomized to receive maintenance with lenalidomide alone (R; 10 mg/day for 21 days) or with prednisone (RP; R, 10 mg/day for 21 days and P, 25 mg every other day), until disease progression. Results : Pts characteristics were well balanced in all groups; 217 pts in Rd, 217 in MPR and 220 in CPR arms could be evaluated. After a median follow-up of 63.7 months, median PFS was 23.2 months in MPR, 18.9 months in CPR and 18.6 months in Rd (MPR vs CPR p=0.02; MPR vs Rd p=0.08). Median overall survival (OS) was 79.9 months in MPR, 69.4 months in CPR and 68.1 months in Rd (MPR vs CPR p=0.98; MPR vs Rd p=0.64). The most common grade ≥3 adverse event (AEs) was neutropenia: 64% in MPR, 29% in CPR and 25% in Rd pts (p Conclusion : This phase III trial compared 2 different Lenalidomide-containing induction regimens and 2 different Lenalidomide-containing maintenance regimens in an elderly community-based NDMM population. MPR prolonged PFS by approximately 5 months, yet the higher incidence of hematologic toxicity should be carefully considered. The addition of low-dose prednisone to standard lenalidomide maintenance reduced the risk of death/progression by 20%, with a good safety profile. Updated results will be presented at the meeting. Disclosures Bringhen: Mundipharma: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; Celgene: Honoraria; Bristol Myers Squibb: Honoraria; Karyipharm: Membership on an entity's Board of Directors or advisory committees. Offidani: celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Musto: Celgene: Honoraria; Janssen: Honoraria. Gaidano: Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Roche: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. De Sabbata: Celgene: Membership on an entity's Board of Directors or advisory committees. Palumbo: Sanofi: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Binding Site: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Merck: Consultancy, Honoraria, Research Funding; Genmab A/S: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Employment, Equity Ownership, Honoraria, Research Funding. Hájek: Amgen, Takeda, BMS, Celgene, Novartis, Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria; Pharma MAR: Consultancy, Honoraria. Boccadoro: Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; Sanofi: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding.

Lyn, a tyrosine kinase belonging to the Src family, plays a key role as a switch molecule that couples the B-cell receptor to downstream signaling. In B-CLL cells, Lyn is overexpressed, anomalously present in the cytosol, and displays a high constitutive activity, compared with normal B lymphocytes. The aim of this work was to gain insights into the molecular mechanisms underlying these aberrant properties of Lyn, which have already been demonstrated to be related to defective apoptosis in B-cell chronic lymphocytic leukemia (B-CLL) cells. Herein, Lyn is described to be in an active conformation as integral component of an aberrant cytosolic 600-kDa multiprotein complex in B-CLL cells, associated with several proteins, such as Hsp90 through its catalytic domain, and HS1 and SHP-1L through its SH3 domain. In particular, Hsp90 appears tightly bound to cytosolic Lyn (CL), thus stabilizing the aberrant complex and converting individual transient interactions into stable ones. We also demonstrate that treatment of B-CLL cells with geldanamycin, an Hsp90 inhibitor already reported to induce cell death, is capable of dissociating the CL complex in the early phases of apoptosis and thus inactivating CL itself. These data identify the CL complex as a potential target for therapy in B-CLL.

We investigated whether dendritic cells (DCs) play a role in favoring granular lymphocyte (GL) proliferation in patients with lymphoproliferative disease of granular lymphocytes (LDGL). The presence of in vivo circulating DCs was studied in 11 patients (5 CD3+ and 6 CD3- LDGL). Autologous immature (iDCs) and mature (mDCs) DCs generated in vitro were studied for stimulatory activity on cell proliferation of CD3+ and CD3- GLs. The topographic organization of GLs and DCs was also studied in bone marrow (BM) biopsies. Peripheral blood (PB) CD3- GLs from patients showed significant proliferative activity in the presence of iDCs and mDCs. Conversely, monoclonal CD3+ GLs were unresponsive to autologous and allogeneic PB DCs. Analysis of BM biopsies demonstrated a topographic distribution of DCs and GLs that indicates contact between the 2 cell types. On functional assays, DCs obtained from BM were more efficient than PB DCs in stimulating CD3- GLs, and surprisingly, a low but definite stimulatory effect was demonstrated also on CD3+ GLs. The putative contact between DCs and GLs in the BM and, more crucial, the proliferative response of discrete GL populations to DC stimulation suggest the presence of a specific antigen within BM DCs, providing evidence for a role of DCs in the pathogenesis of LDGL.

Using monoclonal antibodies (mAbs) specific for different natural killer (NK) receptors, we studied the lymphocyte population from 18 patients with NK-type lymphoproliferative disease of granular lymphocytes (LDGL). The analysis of both resting and cultured NK cell populations demonstrated that these patients are frequently characterized by NK cells displaying a homogeneous staining with given anti–killer Ig-like receptor (anti-KIR) mAb (11 of 18 patients). In most patients NK cells were characterized by the CD94/NKG2A+ phenotype, whereas only a minor fraction of the cases expressed CD94/NKG2C. In 7 of these patients we could also assess the function of the various NK receptors. Remarkably those KIR molecules that, in each patient, homogeneously marked the NK cell expansion were found to display an activating function as determined by cross-linking with specific anti-KIR mAb. The KIR genotype analysis performed in 13 of 18 cases revealed that in NK-type LDGL certain activating KIRs, as well as certain infrequent KIR genotypes, were detected with higher frequencies as compared to previously analyzed healthy donors. Moreover, most KIR genotypes included multiple genes coding for activating KIRs. The analysis of non–HLA-specific triggering receptors indicated that the natural cytotoxicity receptors (NKp46, NKp30) were expressed at significantly low levels in freshly drawn NK cells from most patients analyzed. However, in most instances the expression of NKp46 and NKp30 could be up-regulated on culture in interleukin 2. Our data indicate that in NK-LDGL the expanded subset is frequently characterized by the expression of a given activating KIR, suggesting a direct role for these molecules in the pathogenetic mechanisms of this disorder.

Background: Patients (pts) with rDLBCL not eligible for ASCT or experiencing relapse after ASCT have a low likelihood of cure. Single-drug maintenance after salvage therapy may be an attractive strategy to prolong survival in these pts. Lenalidomide (LEN) is a suitable candidate for long-lasting maintenance as it is an oral drug, active against DLBCL, that can be taken for years with an acceptable toxicity profile. Accordingly, we designed a multicentre phase II trial addressing LEN maintenance in pts with chemosensitive relapse of DLBCL not eligible for ASCT or experiencing relapse after ASCT (clinicaltrials.gov NCT00799513). Methods: HIV-neg pts (age ≥18 ys) with histologically-proven de novo or transformed DLBCL and relapsed disease responsive to conventional rituximab-containing salvage therapy were registered and treated with LEN 25 mg/day for 21 days out of 28, until lymphoma progression or unacceptable toxicity. Primary endpoint was 1-year progression-free survival (PFS). Simon's two-stage optimal design was used. To demonstrate a 1-yr PFS improvement from 30% (P0) to 50% (P1), 47 pts (one-sided; α 5%; β 80%) were needed. Maintenance would be considered effective if ≥19 pts were progression-free survivors at 1 yr. Cell of origin was assessed by NanoString Technology and Hans algorithm, and cereblon expression was assessed by immunohistochemistry. Results: 46 of 48 enrolled pts were assessable (median age 72 ys; range 34-86); 36 pts had de novo DLBCL, 10 had transformed DLBCL. All pts were previously treated with anthracycline- and rituximab-based combination, plus ASCT in 6 pts; the median TTP after the prior therapy was 16 months (range 3-121). Thirty-three pts were enrolled at 1st relapse, 13 at 2nd relapse; salvage therapy contained high doses of cytarabine or ifosfamide in two-thirds of cases, and response was complete in 26 pts and partial in 20. Most pts had unfavourable features: IPI ≥2 in 38 (83%) pts, advanced stage in 35 (76%), extranodal disease in 29 (63%), high LDH level in 21 (46%); 28 (61%) pts were older than 70 ys. At a median follow-up of 25 (range 6-87) months, 556 LEN courses were delivered, with an average of 12 courses/pt (range 3-41); 19 pts are still in treatment. LEN was well tolerated: with the exception of neutropenia, grade 3-4 toxicities were uncommon, occurring in ≤3% of delivered courses. Infections were rare, and well controlled with oral antibiotics (grade 1-2 in 8 courses; grade 3 in 3). LEN dose reduction was indicated in 23 pts (transient in 19), and was due to neutropenia (12), rash (7), diarrhoea (2), and neurotoxicity (2); LEN was discontinued in 6 of them. One (2%) pt died of acute toxicity (intestinal infarction) and one due to secondary myelodysplastic syndrome at 56 months of follow-up. Pts with HBV/HCV seropositivity (n=12) or prior ASCT (n=6) did not experience unexpected toxicity after >1 yr of treatment. At one year from trial registration, 28 pts were still progression free, which was significantly higher than the pre-determined efficacy threshold (n≥19). During the whole observation period, there were 21 events: progressive disease in 19 pts, death of toxicity in one, death while off therapy in one, with a 1-yr PFS (primary endpoint) of 70 ± 7%. The duration of response to LEN was longer than response duration after the prior treatment line in 27 (59%) pts, and was twice as long in 15 of them. The benefit of LEN maintenance was observed both in pts with de novo or transformed DLBCL. According to the Hans' algorithm, the 1-yr PFS was 64 ± 11% for GCB-DLBCL and 67 ± 11% for nonGCB-DLBCL (p= 0.67). Results using the Nanostring technique were consistent with the Hans' algorithm, with a concordance rate of 86%. There was no significant association between cereblon expression and PFS. Multivariate analysis confirmed that treatment at first relapse and a prior TTP ≥12 months were independently associated with better PFS. Overall, 33 (72%) pts are alive, with a 1- and 3-yr OS of 81 ± 6% and 71 ± 8%, respectively. Conclusions: With the limitations of a non-randomized design, this trial soundly promotes the use of LEN maintenance in pts with chemosensitive relapse of DLBCL not eligible for ASCT or experiencing relapse after ASCT. LEN was well tolerated in this elderly population, with survival benefit both in pts with de novo or transformed DLBCL, and both in pts with GCB- or nonGCB-DLBCL. These results warrant further investigation of immunomodulatory drugs as maintenance in these high-risk pts. Disclosures Spina: Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee; Mundipharma: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee. Rusconi:Teva: Consultancy, Other: Congress attendance; Takeda: Consultancy; Janssen: Consultancy, Other: Congress attendance. Couto:Celgene: Employment, Equity Ownership. Ren:Celgene: Employment, Equity Ownership.

Background: The combination of rituximab (R, 375 mg/m2 intravenously [IV], day 1), bendamustine (B, 70 mg/m2IV, days 2 and 3), and cytarabine (800 mg/m2, IV on days 2 to 4) was highly active in patients with mantle-cell lymphoma (MCL) in a phase 2 study [R-BAC; Visco et al, JCO 2013]. This regimen was well tolerated, but hematologic toxicity was quite relevant, especially in terms of transient grade 3 to 4 thrombocytopenia (76% of cycles). Aiming at reducing hematologic toxicity, the Fondazione Italiana Linfomi (FIL) designed a phase 2 trial adopting the R-BAC schedule, but lowering cytarabine dose to 500 mg/m2 (RBAC500). Materials and Methods: Patients with newly diagnosed MCL, aged 61 to 80 years, not eligible for autologous transplant and fit according to the comprehensive geriatric assessment, were enrolled. Patients presenting with non-nodal leukemic disease were excluded. The primary endpoints were complete remission rate (CR) measured by FDG-PET according to Cheson criteria 2007, and safety. Secondary endpoints included rate of molecular response (MR) by nested-PCR using patient specific IGH or BCL1 based targets, progression-free (PFS) and overall survival (OS). The study was conducted according to the Bryant and Day two-stage design. Results: From May 2012 to February 2014, 57 patients with MCL from 29 centers were recruited and treated. Central pathology revision was performed in 87% of cases. Median age was 71 years (range 61-79), 75% were males, and 91% had Ann Arbor stage III/IV disease. Mantle Cell International Prognostic Index (MIPI) was low in 15%, intermediate in 40%, high in 45%, Ki-67 was ≥30% in 31%, and 9% had the blastoid cytological variant. Overall, 53 patients (91%) received at least 4 cycles, while 36 (63%) had 6 cycles (median 5.3 cycles per patient). Fifteen patients (26%) discontinued treatment before reaching cycle 6 because of toxicity/adverse events, that mainly consisted of prolonged hemato-toxicity between cycles. Only one patient discontinued due to progressive disease. Grade 3 or 4 neutropenia and thrombocytopenia were observed in 49% and 52% of administered cycles, respectively. Febrile neutropenia occurred in 6% of cycles. Extra-hematologic toxicity was mainly cardiac (5%). Overall response rate was 96%, and CR was 93%. The MR rate at the end of treatment was 76% on peripheral blood and 55% on bone marrow (BM) samples. With a median follow-up of 34 months (28-52), the 2-years PFS (± confidence interval) was 81%±5% and the OS 85%±4%. Elevated Ki-67 (≥30%), and the blastoid variant were the strongest independent predictors of adverse PFS. Patients with either of these two features (33%), had a significantly inferior PFS (41% vs 97% after 34 months) compared to patients with classical/pleomorphic variants and low proliferative index (p Conclusions: The R-BAC500 regimen can be safely administered as first line therapy to elderly patients with MCL. Hematologic toxicity is substantially reduced compared to our previous experience. With 93% of FDG-PET negative CR, and a 2-years PFS of 81% without maintenance therapy, the R-BAC500 regimen is a highly effective treatment for patients with MCL, and compares favourably with previously reported regimens in this patient population, including R-bendamustine. Figure 1 Figure 1. Disclosures Visco: Gilead: Speakers Bureau; Lundbeck: Consultancy; Mundipharma: Research Funding; Celgene: Speakers Bureau. Spina:Mundipharma: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee; Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee. Di Rocco:Celgene: Honoraria. Carella:Millenium: Speakers Bureau; Genentech: Speakers Bureau. Vitolo:Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria; Gilead: Honoraria; Celgene: Honoraria.

Background Invasive fungal infections (IFI) are serious and life-threatening complications of hematological malignancies particularly in patients affected by acute myeloid leukemia and following hematopoietic stem cell transplantation. However, only few epidemiological data concerning fungal infections in chroniclymphoproliferativedisorders are available. In this work we aimed to identify the clinical and biological features of patients with chronic lymphocytic leukemia (CLL) affected by IFI. Methods We performed a single-center retrospective study based on the CLL patients referred to the Hematology Unit of University of Padua from 1983 to 2015. IFI were defined as infective events caused by yeasts ormouldsthat required inpatient management and/or intravenous antifungal therapies. We included only proven and probable IFI. Time to IFI (TIFI) and overall survival (OS) were calculated from the date of CLL diagnosis to IFI development or death (event), respectively, or last available follow-up (censored). Diagnostic work-up of fungal infection included blood cultures, serumgalactomannanantigen test for 3 consecutive days (cut-off 0.5), β-1,3-(D)-glucanand high resolution chest computed tomography andbronchoalveolarlavages when clinically indicated. We also collected the closest immunoglobulin (IG) levels data before the onset of each IFI or serious bacterial infective events. IGs measured during infections were not included in the analysis, because they could have been influenced by the infectious event. The last available serum IG levels were considered for patients who did not suffer from any IFI. Results 795 patients with CLL were recruited in this study. 60% were male and the median age at diagnosis and at IFI onset were 65 and 68 years, respectively. The median follow-up was 8.5 years and 316 patients required treatment during the follow-up. 11 out of 795 (1.4%) patients developed IFI during the follow-up. Among them, 7 patients (64%) had probable Aspergillosisand 4 had proven IFI (3 Aspergillusspp and 1 Candida kruseii) based on histological confirmation and/or microbiological isolation of the specific fungal agent. 9 patients wereBinet stage A, 2Binet B and noneBinet C at CLL diagnosis. The median lines of treatment were 5 ranging from 2 to 9. Six out of 11 (55%) patients showed high-risk cytogenetic by FISH analysis (11q or 17p deletion), 2 harbored complex karyotypes, 62% (5/8) hadunmutated IGVH gene. By Kaplan-Meyer analysis we showed that IFI occurred in 2.1% and 7.0% of the cohort after 10 and 20 years of follow-up, respectively (Figure 1A). However, considering the number of chemotherapy regimens, the estimated cumulative incidence of IFI was higher in patients who were treated with at least 4 lines of chemo-immunotherapy (10-year TIFI were 9.0% and 0.3%, p IFI occurrence was associated with a very poor prognosis. In fact, the median overall survival of patients who developed IFI was 125 months as compared to 250 months of the remaining cohort (Log-rank test, p=0.0001, Figure 1C). Since IFI was itself the main cause of death of these subjects. In multivariable analysis, patients with IFI had almost 10 times higher-risk of death (HR 10, p=0.0012) that other patients. We demonstrated that, at the time of IFI events, patients had lower levels of IG as compared to a group of 72 patients who had serious bacterial infections or to 712 subjects who did not have any infections. The medianIgGlevels were 4.11, 6.38 and 8.38 g/L for patients with IFI, bacterial infections and without history of infections, respectively (ANOVA test, p Conclusions Herein, we described the epidemiology of invasive fungal infections among a large cohort of CLL patients from a single institution over 32 years. We demonstrated that IFI significantly impacts on the survival of CLL patients and we provided evidence of the importance of previous chemo-immunotherapy and IG levels on the risk of developing IFI. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

In 21 patients with lymphoproliferative disease of granular lymphocytes (LDGL), we investigated the expression and the function of molecules belonging to TNF-receptor and TNF-ligand superfamilies (CD30/CD30L; CD40/CD40L; CD27/CD70; Fas [CD95]/FasL[CD95L]). Fourteen patients were characterized by a proliferation of granular lymphocytes (GLs) expressing the CD3+CD16+phenotype, whereas 7 cases showed the CD3−CD16+ CD56 ± phenotype. Our data show that both CD3+ and CD3-GLs are preferentially equipped with CD30, CD40, CD40L, CD70, and CD95 antigens; this pattern is usually associated with the lack of CD27 and CD30L antigens expression. CD95L was demonstrated in the cytoplasm in 14 of 21 cases by flow cytometry, but a definite signal was demonstrated in all cases studied using polymerase chain reaction analysis. On functional grounds, a stimulatory activity on rIL-2 mediated redirected-cytotoxicity against Fcγ+ P815 targets was demonstrated with anti-CD30, CD40, CD40L, CD70, CD95, and CD95L mAbs, although resting cells were unable to exhibit significant redirected-cell lysis. The addition of anti-CD30, CD30L, CD40, CD40L, CD95, and CD95L mAbs did not show any significant effect on cell proliferation at resting conditions or after rIL-2 stimulation, whereas anti-CD70 mAb mediated cell proliferation in 6 of 10 cases tested. This figure was not related to an increase in apoptotic cells, as investigated by Annexin-V expression. Our data indicate that both CD3+ and CD3− GLs are equipped with different costimulatory antigens, supporting the concept that these cells are in vivo activated and suggesting that these molecules might play a role in the cytotoxic mechanisms of GLs.

Natural killer (NK) cells are CD3− large granular lymphocytes (LGL) responsible for immunity against viral infections. A chronic lymphoproliferative disorder of NK cells has been described in which the expanded NK cells display a restricted phenotype and cytotoxic activity. These data raise the hypothesis that proliferating LGL in these patients result from discrete expansions of NK cells responding to an unknown, perhaps viral, antigen. Recently, it was found that mice transgenic for the tax gene of human T-cell leukemia/lymphoma virus (HTLV) develop NK leukemia. Therefore, we studied 15 patients with chronic NK lymphoproliferative disorder for evidence of HTLV infection. Sera were tested using an HTLV-I/II-enzyme linked immunosorbent assay and a modified Western blot assay containing recombinant env proteins. None of the sera met conventional criteria for HTLV seroreactivity. However, sera from 11 patients (73%) reacted with the recombinant HTLV env protein p21E. The anti-p21E reactivity of these sera was then mapped employing the recombinant proteins GD21 and BA21. No reactivity to the immunodominant HTLV epitope GD21 was observed, suggesting that prototypical HTLV infection is unlikely in these patients. This was confirmed by finding no evidence for HTLV nucleic acids by PCR analyses employing primers specific for conserved regions in the env, pol, and pX genes. In contrast, 10 of the 15 sera reacted with the epitope BA21, documenting for the first time an association between a unique seroreactivity and disease. The high incidence of BA21 seroreactivity in these patients suggests that exposure to a protein containing homology to BA21 may be important in the pathogenesis of this lymphoproliferative disorder.

The lymphoproliferative disease of granular lymphocytes (LDGL), also referred to as LGL leukemia, is a heterogeneous disorder, but is clinically, morphologically, and immunologically distinct. Although LDGL has recently been included in the revised classification of lymphomas as an independent clinical entity, no consensus exists on the criteria to establish the diagnosis. The aim of this report was to refine the parameters needed to make the diagnosis of LDGL. We studied 11 patients with chronic granular lymphocytosis selected from among 195 cases observed by our institutions from three different geographic areas (North America, Europe, and Asia). These cases did not meet the current criteria for inclusion in LDGL, since all patients had less than 2,000 GL/μL. However, in each of these patients, we found evidence for expansion of a discrete GL population. Clonal rearrangement of the T-cell receptor (TCR) β gene was found in peripheral blood mononuclear cells (PBMC) of all nine patients with CD3+ LDGL. Using recently generated monoclonal antibodies (MoAbs) against the TCR Vβ gene regions, we identified a unique TCR Vβ on GL from each of three patients studied. In two patients with CD3− LDGL, we also identified a restricted pattern of reactivity, by staining with MoAbs against p58 antigen found on normal natural killer (NK) cells. The clinical features of these 11 patients with relatively low absolute number of GL were similar to those reported previously for patients with greater than 2,000 GL/μL. These data demonstrate that newer techniques such as MoAbs against Vβ gene regions and p58 molecules and molecular analyses are useful to identify expansions of discrete GL proliferations. Demonstration of an expansion of a restricted GL subset is evidence for the diagnosis of LDGL, even in patients with a relatively low GL count. Our results also contribute to distinguish between the end of normality and the beginning of pathology in the broad spectrum of GL lymphocytoses.

BACKGROUND: Patients (pts) with relapsed DLBCL who cannot be treated with consolidative ASCT or allogeneic transplantation exhibit a poor prognosis, with a 1-year PFS of 30-40%. Despite a high response rate to salvage therapy, these pts invariably experience early relapse and die of lymphoma. Single-drug maintenance may be a good alternative to intensified consolidation to prolong response duration in these high-risk pts. Lenalidomide is an oral immunomodulatory agent, active against DLBCL, which can be taken for years with an excellent safety profile. Accordingly, we designed a multicenter phase II trial addressing safety and efficacy of lenalidomide maintenance in pts with chemosensitive relapse of DLBCL not eligible for consolidative ASCT or experiencing relapse after ASCT (NCT00799513). Herein, we report the primary endpoint analysis. METHODS: Selection criteria were: 1) adult HIV-negative pts; 2) histologically-proven de novo or transformed DLBCL; 3) relapsed disease responsive (partial or complete response) to conventional-dose rituximab-containing salvage therapy; 4) ECOG PS ≤3; 5) time to progression (TTP) from the previous line ≥3 months. After confirmation of objective response to salvage therapy, pts were registered and treated with lenalidomide 25 mg/day once daily for 21 days out of 28, for two years or until lymphoma failure or unacceptable toxicity. Primary endpoint was the 1-yr PFS. Simon's two-stage optimal design was used. The null hypothesis that the true 1-yr PFS is 30% was tested against a one-sided alternative. The trial design yields a type I error rate of 5% and power of 80% when the true 1-year PFS is 50%. To demonstrate this PFS improvement, 47 pts were needed. The null hypothesis would be rejected if 19 or more pts progression-free at one year were observed. RESULTS: 41 pts were enrolled (median age 72, range 34-86; M:F ratio: 1.5). Thirty pts had a de novo DLBCL, 11 had a transformed DLBCL; 29 pts were enrolled after the first relapse, 12 after the 2nd - 4th relapse. All pts were previously treated with anthracycline- and rituximab-based combination, plus ASCT in 6 pts. The median TTP after the previous line was 17 months (range 3-121). Most pts had unfavourable features: IPI ≥2 in 34 (83%) pts, advanced disease in 33 (80%), extranodal disease in 29 (71%), high LDH in 18 (44%). Twelve pts had HCV and/or HBV infection. Salvage combination included high-dose-cytarabine in 23 pts, high-dose-ifosfamide in 6, anthracycline in 6 and bendamustine in 6. Response to salvage therapy was complete in 25 pts and partial in 16. Twenty-three pts received the planned maintenance; lenalidomide was interrupted due to lymphoma relapse in 8 pts, toxicity in 5 (diarrhoea in 2, rash, prolonged neutropenia, intestinal infarction), and patient's refusal in 5 (diarrhoea in 4, rash). Dose reduction to 10 or 15 mg/d, mostly due to rash or neutropenia, was indicated in 17 pts. Toxicity was mild; there were 6 SAEs (febrile neutropenia in 4, diarrhoea, intestinal infarction) in 5 pts. Grade 4 haematological toxicity consisted of neutropenia in 17 pts and thrombocytopenia in 2. Grade 3-4 non-haematological toxicity consisted of diarrhoea in 3 pts and rash in 5. HBV/HCV seropositivity was not associated with higher toxicity. Six of the 16 pts in partial response after salvage therapy achieved a complete remission during lenalidomide maintenance. At a median follow-up of 16 months, 29 pts remained relapse free, with a 1-year PFS of 75±8%. Importantly, 21 pts were progression-free at one year, with the early achievement of the primary endpoint. Thirty-two pts are alive (NED in 25), 8 pts died of lymphoma and one of intestinal infarction, with a 1-yr OS of 84±7%. Age ≤70 years, normal LDH level, and complete response at registration were independently associated with better PFS and OS, whereas gender, DLBCL category, HBV/HCV infection, and TTP after previous line (< vs. ≥12 months) were not. Assessment of prognostic effect of ontogenic stratification by NanoString is ongoing. CONCLUSIONS: With the early achievement of the primary endpoint, this is the first prospective trial showing a positive effect of maintenance in pts with relapsed DLBCL. Lenalidomide maintenance is feasible and well tolerated in this elderly population, but diarrhoea and rash remain frequent dose-limiting side effects. The evident improvement in survival figures warrants further investigation of immunomodulators maintenance in these high-risk pts. Disclosures Ferreri: celgene: Consultancy, Research Funding. Rusconi:Roche: Honoraria.

Introduction: For pts with RRMM who have failed or progressed on treatment (Tx) with newer agents, such as lenalidomide (LEN) and bortezomib (BORT), there are few Tx options, and overall survival (OS) is short (Kumar et al, Leukemia, 2012). POM is a distinct immunomodulatory agent with tumoricidal and immunoregulatory effects, and POM + LoDEX is approved in the United States and European Union for the Tx of pts with RRMM who have had ≥ 2 prior Tx, including LEN and BORT. Tx with POM + LoDEX has shown statistically greater survival benefits than high-dose DEX (MM-003; San Miguel et al, Lancet Oncol, 2013) or POM alone (MM-002; Richardson et al, Blood, 2014). POM + LoDEX has also demonstrated high overall response rates in pts with RRMM in the STRATUS trial (MM-010), a single-arm, open-label phase 3b study being conducted in 19 countries across Europe with a primary endpoint of safety (Dimopoulos et al, EHA 2015). Italian pts constituted the largest national subset in MM-010; hence, this subanalysis examines the safety and efficacy of POM + LoDEX in pts from Italy. Patients and Methods: Pts with RRMM (progressive disease [PD] on or within 60 days of last prior Tx) who had experienced Tx failure with BORT and LEN and had received adequate prior alkylator therapy were eligible. Pts received POM 4 mg on days 1-21 of a 28-day cycle in combination with DEX 40 mg (20 mg for pts aged > 75 yrs) on days 1, 8, 15, and 22. Thromboprophylaxis was required for all pts, and Tx was continued until PD or unacceptable toxicity. Results: A total of 219 pts were enrolled in MM-010 in Italy. The median age of this patient population was 67.0 yrs (range, 42-84 yrs), and 54.8% of pts were male. The median time since diagnosis was 5.5 yrs, and 37.0% of pts were International Staging System stage III. Patients were heavily pretreated, with a median of 4 prior anti-myeloma regimens (range, 2-11), and most pts were refractory to LEN (95%), BORT (82.2%), or both LEN and BORT (78.1%). As of May 4, 2015, 2 pts (0.9%) were not treated, 54 pts (24.7%) were still on treatment, and 163 pts (74.4%) had discontinued. After a median follow-up of 11.3 mos, in the intention-to-treat population, the overall response rate was 37.9% (range, 31.4%-44.7%), the median duration of response was 6.8 mos (95% CI, 4.9-10.8 mos), progression-free survival (PFS) was 5.2 mos (95% CI, 4.4-6.4 mos), and OS was 12.0 mos (95% CI, 10.6-15.2 mos). The most frequent grade 3/4 treatment-emergent AEs were neutropenia (56.7%), anemia (25.8%), thrombocytopenia (23.5%), and pneumonia (12.4%). Incidence of grade 3/4 venous thromboembolism (deep vein thrombosis and pulmonary embolism) and peripheral neuropathy were infrequent (2.3% and 0%, respectively). The most common reasons for discontinuation were disease progression (49.8%), death (10.0%), and adverse events (AEs; 5.0%). AEs led to dose reductions or interruptions of POM in 23.0% and 71.0% of pts, respectively, and the median relative dose intensity for POM was 0.90. Conclusions: In line with previous studies, POM + LoDEX was active in Italian pts, a representative subset of the heavily pretreated MM-010 population. PFS and OS were consistent with those seen in previous trials. POM + LoDEX treatment was well tolerated, and discontinuations due to AEs were infrequent, consistent with the well-known toxicity profile and the appropriate drug management. This study confirms that POM + LoDEX is effective in patients with advanced RRMM, including those who have experienced failure of prior Tx with BORT and/or LEN. Disclosures Cavo: Janssen-Cilag, Celgene, Amgen, BMS: Honoraria. Petrini:Novartis: Research Funding; Celgene Corporation: Research Funding; Italfarmaco: Research Funding; Roche: Research Funding. Caravita di Toritto:Celgene Corporation: Honoraria, Research Funding. Offidani:Celgene, Janssen: Honoraria. Petrucci:Celgene Corporation: Honoraria; Janssen-Cilag: Honoraria; Amgen: Honoraria; Mundipharma: Honoraria; BMS: Honoraria. Rodeghiero:Celgene Corporation: Honoraria, Research Funding. Simcock:Celgene Corporation: Employment. Slaughter:Celgene Corporation: Employment, Equity Ownership. Herring:Celgene Corporation: Employment. Peluso:Celgene Corporation: Employment. Palumbo:Celgene, Millennium Pharmaceuticals, Amgen, Bristol-Myers Squibb, Genmab, Janssen-Cilag, Onyx Pharmaceuticals: Consultancy, Honoraria; Novartis, Sanofi Aventis: Honoraria.

Background and objectives. Bendamustine in combination with rituximab has demonstrated a relevant clinical activity and a good toxicity profile in patients with mantle cell lymphoma (MCL). Cytosine arabinoside (Ara-C) is a key drug in induction chemotherapy regimens of young patients with MCL. In vitro studies have shown that bendamustine increases the cytotoxic effect of Ara‐C in leukemic blasts and lymphoma cells, and the two drugs display high synergistic activity when used in consecutive combinations. Clinically, it has recently been demonstrated that rituximab + bendamustine + Ara‐C (R-BAC) combination has a remarkable activity and is well tolerated both in untreated and in relapsed/refractory patients with MCL (Visco C et al. J Clin Oncol 2013 31:1442-1449). In the present study, we report data from an Italian single-center experience evaluating the efficacy and tolerability of R-BAC association in previously untreated MCL patients both eligible and ineligible for transplantation. Design and methods. From January 2009 to November 2014, 25 newly diagnosed patients with MCL (median 67 years; range 57-83 years) were treated with immunochemotherapy according to R-BAC schedule (Rituximab 375 mg/mq day 1; Bendamustine 70 mg/mq days 2, 3; Ara-C 500 mg/mq days 2-4) x 4 or 6 28-day cycles. All patients received G-CSF prophylaxis. Ninety-six percent of patients had stage III/IV disease; MIPI score was high in 24%, intermediate in 60% and low in 12%; in one patient it was not evaluable. Results. Twenty-two patients (88%) completed the scheduled treatment (4 or 6 cycles). The ORR was 88%: CR 84% (21 patients); PR 4% (1 patient); 1 patient was in SD, but he received only 1 cycle due to toxicity and died still in SD about three years later. Seven patients (28%) underwent autologous stem cell transplantation (ASCT); seven patients (28%) received rituximab maintenance for two years. Two patients (8%) experienced disease progression during first line therapy, both had intermediate MIPI score. After a median follow up of 33 months (range 4-65 months), the OS was 80% (one patient died for unrelated causes) and the PFS was 80%. At this time point, 19 (76%) and 1 (4%) patient were in CR and in PD, respectively. The latter patient is currently undergoing salvage chemotherapy. Patients who received either maintenance immunotherapy with rituximab or consolidation with ASCT after R-BAC (overall 56%) seemed to experience longer PFS and OS. In the ASCT group the OS was 100% at a median follow up of 23 months; in the rituximab maintenance group the OS was 71% at a median follow up of 41 months. In the group of patients that received R-BAC induction therapy only, the OS was 61% at a median follow up of 26 months (p=0.14, likely due to the low number). The most common adverse events (AEs) during R-BAC were hematological: grade 3-4 neutropenia (88%), grade 3-4 thrombocytopenia (64%) and grade 3-4 anemia (36%). The numbers of common grade 3/4 non hematological AEs in the study included: febrile neutropenia (28%), acute coronary syndrome (4%), lung infection (4%) and hyperglycemia (4%). No treatment-related mortality was observed, one patient died of secondary acute myeloid leukemia four years later from induction therapy. Conclusions. The present retrospective study confirms that R-BAC as frontline regimen in MCL is well tolerated and highly effective in ASCT ineligible patients and that it can be administered also in ASCT eligible patients as induction therapy. Moreover, our data suggest that a consolidation therapy (ASCT or maintenance immunotherapy) after R-BAC induction could improve the outcome. Disclosures No relevant conflicts of interest to declare.

Background NK cells represent a subset of lymphocytes belonging to the innate immunity branch typically expressing CD16 and CD56 associated to CD3 negativity. Two major subtypes of NK cells can be distinguished through CD16 and CD56 expression: CD56high/CD16dim/neg NK cells with low cytotoxic function and CD56dim/CD16high NK cells with high cytotoxic function. Recently a subtype of NK cells with memory properties characterized by CD56dim/CD16high/CD57+/CD62L- phenotype has been discovered. Chronic Lymphoproliferative Disorders of Granular Lymphocytes are characterized by the clonal expansion of Large Granular Lymphocyte (LGL) that can be CD3 positive (T-LGLL) or CD3 negative (Chronic Lymphoproliferative Disorder of NK Cell, CLPD-NK). The disease generally has indolent course but some patients develop cytopenia, particularly neutropenia, exposing to potentially lethal bacterial infections. Furthermore, NK-CLPD is usually referred as a more indolent disorder with respect to T-LGLL, with lower incidence of cytopenia and treatment need. CLPD-NK therapy does not differ from that of T-LGLL and is usually represented by an immunosuppressive therapy with low dose cyclophosphamide or methotrexate, with cyclosporine A usually being reserved to refractory patients. Somatic STAT3 mutations represent a new diagnostic marker of these disorders, initially reported in T-LGLL in about 40% oh patients, but also present in CLPD-NK in about 30% of cases. Using flow analysis, the aim of the present study was to identify a subset of CLPD NK patients characterized by a more severe disease requiring a shorter follow-up as compared to patients with a more indolent disease. Methods In a cohort of 16 patients affected by CLPD-NK, NK cells were analysed by flow for CD3, CD16, CD56, CD57 and CD62L antigen expression. These patients were studied for the presence of cytopenia and treatment requirement. STAT3 mutation analysis of exon 21 was performed with Sanger sequencing. Finally, p-STAT3 tyr 705 level and total STAT3 level were examined by western blotting. Results In relation to CD16 and CD56 expression, three major NK cells populations can be recognized in CLPD-NK patients: CD56high/CD16neg NK cells, CD56dim/CD16neg NK cells and CD56neg/dim/CD16high. As a consequence, patients can be separated into three groups characterized by the preferentially expansion of one of these populations: 2/16 (13%) with CD56high/CD16neg NK population, 4/16 (25%) with CD56dim/CD16neg NK population and 10/16 (62%) with CD56neg/dim/CD16high NK population. Furthermore, patients with predominance of this last NK cells subset were studied for CD57 and CD62L expression to identify NK cytotoxic subset (CD57-/CD62Llow/neg) and NK memory subset (CD57+/CD62Llow/neg); a NK cytotoxic/memory ratio (C/M ratio) was then calculated. 4 of 10 CD56neg/dim/CD16high patients (40%) were characterized by prevalence of NK cytotoxic cells expansion and high C/M ratio (≥3) while the remaining 6/10 patients were characterized by NK memory cells expansion with low C/M ratio (≤1.6). We then evaluated the presence of cytopenia, in particular neutropenia, in our patients' cohort. Neutropenia was shown in 7/16 (44%) patients with 4/16 (25%) experiencing severe neutropenia. Anemia and thrombocytopenia were less frequent (19% and 6% respectively). Interestingly, 6 out of 7 (86%) neutropenic patients were in the CD56neg/dim/CD16high subset and all patients with severe neutropenia belonged to the high C/M ratio subset. Interestingly, 3 out of 4 patients (75%) of this subset required therapy during the natural history of the disease. Concerning STAT3 mutation analysis, no one mutated patient was found in this setting. By western blot analysis, patients with high C/M ratio presented higher p-STAT3 levels than other patients and normal NK cells. Summary Although CLPD-NK represents an extreme heterogeneous disorder, discrete subtypes of disease characterized by different NK cells population expansion can be identified by flow analysis. Interestingly, this splitting allows to identify a subset of patients with prevalence of CD56neg/dim/CD16high NK cells with high C/M ratio that are characterized by high level of p-STAT3, high frequency of severe neutropenia and treatment requirement. Disclosures No relevant conflicts of interest to declare.

Introduction According to WHO classification, large granular lymphocyte leukemia (LGL leukemia) includes three entities: T-cell LGL leukemia, chronic NK lymphoproliferative disorders (NK-CLPD) and aggressive NK cell leukemia. Since no standard therapies for immature NK cell neoplasms have been established so far and the overall outcomes are dismal, new therapeutic options are needed. A pyrazolo[3,4-d]pyrimidine library of compounds have already been studied in a previous work by Tintori et al. It has been demonstrated that one of these compounds proved to be efficient against some member of Src-family of nonreceptor protein-tyrosine kinases, in particular against Fyn. Its abnormal activity has been shown to be related to various hematological malignancies. In this context we verified the effect of the pyrazolo[3,4-d]pyrimidine 4c compound on LGL leukemia cells and we investigated its mechanism of action. Methods The pyrazolo[3,4-d]pyrimidine 4c compound was tested in a time course MTS test (24, 48, 72 h) at different concentrations (0.1, 0.5, 1, 2, 4, 8, 10 µM) on NK leukemia cells (KHYG1 and NK92), hepatosplenic gamma-delta T cell lymphoma cells (Derl-2 and Derl-7), acute T cell leukemia cells (Jurkat), chronic myeloid leukemia cells (Jurl-MK1), acute myeloid leukemia cells (OCI), multiple myeloma cells (SKM-M1), cervical cancer cells (HeLa) and healthy stem cells (CD34+). Fyn mRNA and protein expression was evaluated in all cell lines by quantitative RT-PCR and western blotting (WB). Fyn mRNA levels were evaluated in cells from 10 healthy controls, 10 T-LGL leukemia, 5 GD-LGL leukemia and 8 NK-CLPD patients by qRT-PCR. Apoptosis and cell cycle studies were performed on KHYG1 after treatment with this compound at 4 µM for 24 h using cytometric analysis by labeling cells with annexin V and propidium iodide. Apoptosis pathway was investigated using proteome profiler human apoptosis array kit; pro-caspase 3, activated caspase 3, Akt and p70S6 kinase were validated by WB. Fyn immunoprecipitation was conducted on treated KHYG1 at 4 µM for 24 h. Results The pyrazolo[3,4-d]pyrimidine 4c compound reduced cell viability in KHYG1 cells (50% of reduction after 24 h of treatment at 4 µM), in Derl-2 cells (about 50% after 72 h at 4 µM), in Derl-7 (about 40% after 72 h at 8 µM), in Jurkat cells (50% after 72 h at 2 µM), in NK92 cells (40% after 72 h at 4 µM). No differences in cell viability were observed in Jurl-MK1, OCI, SKM-M1, HeLa and CD34+. To evaluate Fyn expression level, we performed qRT-PCR and WB showing that both transcript and protein levels were highest in NK and T cells (KHYG1>NK92>Jurkat>Derl-7>Derl-2) compared to other cells. Furthermore, we investigated the viability reduction in treated KHYG1 cells demonstrating that pyrazolo[3,4-d]pyrimidine 4c compound induced 45% of apoptosis caspase-3 mediated and cell cycle arrest in G2/M phase. In these cells we detected a reduction of Fyn phosphorylation after treatment and we also observed a decrease of total levels of Akt and p70S6 kinase, other two protein involved in apoptotic process and cell proliferation. Interestingly, qRT-PCR data showed a significant over-expression of Fyn mRNA level also in T-LGL, GD-LGL and NK-CLPD patients compared to healthy controls (p Conclusion In this study we demonstrated a higher Fyn expression in LGL leukemia patients compared to healthy controls. We also demonstrated an apoptotic effect of pyrazolo[3,4-d]pyrimidine 4c compound on NK leukemia cells and we provided in vitro preliminary evidences that Fyn is its possible cellular target. Disclosures Musto: Novartis: Honoraria; Celgene: Honoraria; Sanofi: Consultancy; Genzyme: Consultancy; Sandoz: Consultancy; Janssen: Honoraria; Mundipharma: Honoraria; Roche: Honoraria.

INTRODUCTION: Secondary central nervous system (CNS) dissemination is a lethal event in patients (pts) with aggressive lymphomas. A few studies focused on the treatment of this condition are available, confirming the dismal prognosis and the high rate of severe neurotoxicity in pts managed with radiotherapy-based induction. Thus, the most effective treatment for secondary CNS lymphoma remains an important, unmet clinical need. Herein, we report the final results of a multicenter phase II trial addressing a new treatment in pts with aggressive B-cell lymphoma and CNS involvement (NCT00801216). Experimental treatment is based on the encouraging experiences with high doses of antimetabolites in pts with primary CNS lymphoma (Ferreri et al. Lancet 2009), and with high-dose sequential chemotherapy combined with rituximab (R-HDS) and supported by autologous stem cell transplant (ASCT) in pts with relapsed aggressive B-cell lymphoma (Tarella et al. JCO 2008). METHODS: Selection criteria were: 1) histological diagnosis of diffuse large B-cell lymphoma (DLBCL), mantle cell lymphoma blastoid variant (MCLb) or grade-3 follicular lymphoma (FL); 2) secondary CNS involvement at diagnosis or relapse; 3) age 18-70 years; 4) ECOG PS ≤3; 5) absence of HIV infection; 6) adequate organ functions. Pts with primary CNS lymphoma (exclusive CNS disease at diagnosis) were excluded. Experimental treatment consisted of an induction phase with 2 courses of methotrexate 3.5 g/m2 d1 + cytarabine 2 g/m2 x2/d d2-3, followed by an intensification phase with R-HDS (cyclophosphamide 7 g/m2 d1; cytarabine 2 g/m2 x2/d d22-25; pts with residual extra-CNS disease received also etoposide 2 g/m2 d43) and a consolidation phase with BCNU-thiotepa conditioning + ASCT (figure). Treatment included 8 doses of rituximab and 4 of intrathecal liposomal cytarabine. The primary endpoint was 2-year PFS; the planned accrual was 38 pts. RESULTS: 39 pts were registered (age 32-70 ys, median 59; M/F ratio 1.5): 33 had DLBCL, 3 MCLb, 3 FL. CNS disease (brain 21, meninges 5, spinal cord 2, multiple 11) was detected at diagnosis in 16 pts (all with extra-CNS disease) and at relapse in 23 (8 with extra-CNS disease). The median TTP from the previous treatment line was 3 months (range 0-77 months). Thirty-four pts completed the induction phase; 73 (93%) of 78 planned courses were actually delivered; G4 neutropenia, thrombocytopenia and anemia were recorded in 77%, 63% and 5% of courses, G3-4 febrile neutropenia in 16%, CMV reactivation in 3 pts. Transient G4 transaminases increase (3% of courses) was the only G4 non-hematological toxicity. Drugs dose reduction was indicated in 3 pts. Response after induction phase was complete in 11 pts and partial in 19 (ORR= 77%; 95%CI=64-90%). Thirty pts were referred to intensification phase (figure); 58 (97%) of 60 planned courses were actually delivered; G4 neutropenia, thrombocytopenia and anemia were recorded in 67%, 60% and 7% of courses, G3-4 febrile neutropenia in 22%, G4 sepsis in 8%. CMV reactivation was diagnosed in 4 pts, pulmonary aspergillosis in 1. No cases of G4 extra-hematological toxicity were recorded. Response after intensification phase (before conditioning) was complete in 22 pts and partial in 2 (ORR= 62%; 95%CI=47-77%). ASCs were collected in 21/22 (95%) pts (median 9.5 x 106/kg; range 6-19); 20 pts underwent ASCT. Response at the end of the whole program was complete in 23 pts and partial in 1 (ORR= 62%, 95%CI= 47-77%), 1 pt had SD, 10 experienced PD (all in the CNS), and 4 died of toxicity (sepsis 2, stroke, acute tracheal obstruction). Importantly, no pt was irradiated to the brain to achieve lymphoma remission, and no evidence of neurotoxicity was recorded in pts with a survival longer than 3 years. One pt was referred to sibling-donor transplant due to sMDS, and is alive and NED at 91 months of follow-up. At a median follow-up of 42 months, 16 pts remain relapse-free, with a 2-yr PFS of 42±8%. Sixteen pts are alive, with a 2-yr OS of 42±8%; 2-yr OS of transplanted pts was 72±11%. Extra-CNS and/or meningeal disease did not affect outcome, and survival was similar in both pts treated at presentation or at relapse. CONCLUSION: This radiotherapy-free combination of high doses of antimetabolites, R-HDS and ASCT is feasible and effective in pts ≤70 ys with secondary CNS lymphoma. Toxicity is usually haematological and manageable. Survival benefit is attainable also in pts with meningeal and/or concomitant extra-CNS disease. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Introduction : a formal comparison between Lenalidomide-Dexamethasone (Rd) and Lenalidomide-Prednisone plus Melphalan (MPR) or Cyclophosphamide (CPR) has not been performed yet. We compared Rd vs. MPR vs. CPR in newly diagnosed multiple myeloma (NDMM) patients ≥65 years old in a multicenter phase III trial. Per protocol, upfront dose reductions of Dexamethasone, Melphalan and Cyclophosphamide were performed, according to patients age ( ≤75 years vs. >75 years). The primary endpoint was progression-free survival (PFS). Methods : 662 patients with NDMM were randomized to receive nine 28-day cycles of Rd (n=222), MPR (n=218) or CPR (n=222). Rd: lenalidomide 25 mg/day for 21 days; dexamethasone 40 mg on days 1,8,15,22 in patients 65-75 years old and 20 mg in those >75 years; MPR: lenalidomide 10 mg/day for 21 days; melphalan orally 0.18 mg/Kg for 4 days in patients 65-75 years old and 0.13 mg/Kg in patients >75 years; prednisone 1.5 mg/Kg for 4 days; CPR: lenalidomide 25 mg/day for 21 days; cyclophosphamide orally 50 mg/day for 21 days in patients 65-75 years old and 50 mg every other day in patients >75 years; prednisone 25 mg every other day. After induction, patients were randomized to receive maintenance with lenalidomide alone (R) or with prednisone (RP). Results : Patients characteristics were well balanced. Eighty-three (37%) patients in the Rd, 86 (39%) in the MPR and 80 (36%) in the CPR groups were older than 75 years. In intention to treat analysis, after a median follow-up of 31 months, no difference in PFS and overall survival (OS) was observed. Median PFS was 23 months in Rd, 27 months in MPR and 23 months in CPR (Rd vs MPR p=0.216; Rd vs CPR p=0.872; MPR vs CPR p=0.148). Median OS was not reached and was 73% in Rd, 67% in MPR and 72% in CPR at 3 years (Rd vs MPR p=0.663; Rd vs CPR p=0.754; MPR vs CPR p=0.448). A subgroup analysis, according to age was performed. No difference in response rate was observed. In patients ≤75 years, median PFS was 23 in Rd, 30 in MPR and 23 months in CPR (Rd vs MPR, p Median OS was not reached and was 75% in Rd, 76% in MPR, 77% in CPR at 3 years (Rd vs MPR p=0.251; Rd vs CPR p=0.280; MPR vs CPR p=0.975). In patients >75 years, no PFS difference was noticed: median PFS was 22 in Rd, 18 in MPR, 21 months in CPR (Rd vs MPR p=0.572; Rd vs CPR p=0.699; MPR vs CPR p=0.914). An OS advantage was reported with Rd: median OS was not reached in Rd patients, and was 37 and 43 months in the MPR and CPR groups, respectively (Rd vs MPR p=0.04; Rd vs CPR p=0.430; MPR vs CPR p=0.323). The rate of at least one hematologic grade 3-4 adverse event was 29% in Rd, 66% in MPR, 33% in CPR patients ≤ 75 years and 29% in Rd, 70% in MPR, 33% in CPR patients > 75 years (MPR vs Rd/CPR p< 0.0001). No difference was observed in extra-hematologic adverse events: 25% in Rd, 24% in MPR and 25% in CPR patients ≤75 years; 29% in Rd, 35% in MPR, 34% in CPR patients >75 years. Conclusion : this trial compared for the first time Rd, MPR and CPR in elderly NDMM. In all patients, the addition of alkylating agent to Lenalidomide-steroid combination did not show any advantage on PFS and OS. In a subgroup analysis, safety and efficacy data suggest that triplet regimens may be indicated in patients ≤75 years, while a doublet regimens for those >75 years. The MPR combination showed a PFS advantage in patients ≤75 years, with a higher incidence of hematologic toxicity and SPM. In patients >75 years an OS advantage was reported with Rd, mainly due to a higher efficacy of salvage treatments. Updated results will be presented at the meeting. Disclosures Off Label Use: Use of Lenalidomide as off label. Bringhen:Onyx: Consultancy; Merck Sharp & Dohme: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Janssen and Cilag: Honoraria; Celgene: Honoraria. Offidani:Mundipharma: Honoraria; Sanofi: Honoraria; Janssen and Cilag: Honoraria; Celgene: Honoraria; Amgen: Honoraria. Patriarca:Merck Sharp & Dohme: Honoraria; Janssen and Cilag: Honoraria; Celgene: Honoraria. Hajek:Janssen: Honoraria; Celgene: Consultancy, Honoraria; Merck: Consultancy, Honoraria. Boccadoro:Onyx: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen and Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Palumbo:Onyx Pharmaceuticals: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc.: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Genmab A/S: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Sanofi: Honoraria; Amgen: Consultancy, Honoraria; Array BioPharma: Honoraria.

Background The quality of response and the residual disease after treatment are important prognostic factors in several hematological diseases including multiple myeloma (MM). Several papers demonstrated that the deeper the response after treatment, the longer the survival. However few data are available on the monitoring of minimal residual disease (MRD) during the maintenance therapy in transplant eligible MM patients. Aims to evaluate the role of maintenance therapy in reducing MRD and the role of monitoring the response to predict clinical relapse. Patients and Methods newly diagnosed MM patients enrolled in the RV-MM-EMN-441 trial (NCT01091831) and achieving at least a very good partial response (VGPR) after consolidation were included in the study. Patients received 4 Lenalidomide-Dexamethasone (RD) courses as induction, Cyclophosphamide to mobilize bone marrow stem cells (BMSC) and then were randomized to receive 6 cycles of Cyclophosphamide-Lenalidomide-Dexamethasone (CRD) or Autologous Stem Cell Transplantation (ASCT) with Melphalan 200 mg/m2. All patients received maintenance therapy with Lenalidomide (R) or Lenalidomide-Dexamethasone (RD) until relapse. MRD analysis was performed in a single laboratory (University of Turin, Italy) using flow cytometry according to European Myeloma Network guideline (Rawstron AC, Haematologica 2008). Samples of bone marrow (BM) were collected at diagnosis, after consolidation, after 3 and 6 courses of maintenance and then every 6 months until clinical relapse. The samples were considered MRD +ve if ≥ 0.01% of PC were detected. Immunophenotypic (IF) relapse was defined as an increase of ≥ 25% in the amount of malignant plasma cells in BM compared to the previous determination. Results Fifty patients (27 female/23 male) with a median age of 57 yrs (40-65) entered the study. According to ISS, 27 patients were stage I, 15 stage II and 8 stage III. Fish risk profile was standard in 31 patients, high in 11 and not available in 8. Twenty-five patients received CRD as consolidation and 25 underwent ASCT. The median follow-up was 28.6 months. After consolidation 16 (32%) patients achieve a complete response (CR) and 34 (68%) a VGPR. MRD was negative in 19/48 (40%) patients, of which 12 received ASCT (out of 23, 52%) and 7 received CRD (out of 25, 28%). Patients receiving ASCT showed a lower value of residual cells (median 0.08%, range 0 – 1.00) compared to patients receiving CRD (median 0.5%, range 0 – 2.9%, p=0.0134). The lower MRD value was achieved after consolidation in 31 patients (62%), after 3 courses of maintenance in 6 patients (12%) and after 6 or more courses of maintenance in 13 patients (26%). The increase in quality of response was observed primarily in patients receiving CRD: the average amount of residual plasma cells in bone marrow was 71/uL after induction, lowering to 51/uL after 6 and 12 courses of maintenance therapy. Nine patients clinically relapsed after an average time of 25.6 months from the beginning of the therapy and in all patients this was anticipated by immunophenotypic relapse. Conclusion 1) consolidation therapy with ASCT determines a deeper response compared to CRD; 2) maintenance therapy can improve the quality of response, in particular in patients not receiving ASCT; 3) Immunophenotypic relapse anticipate the clinical relapse. These results suggest the possible role of MRD monitoring to better assess the response to therapy also during maintenance and as marker of early relapse. Disclosures: Ladetto: Celgene: Research Funding, Speakers Bureau; Janssen Cilag: Research Funding, Speakers Bureau; Mundipharma: Research Funding, Speakers Bureau; Roche: Research Funding, Speakers Bureau; Amgen: Research Funding, Speakers Bureau. Boccadoro:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Palumbo:Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Millenium: Consultancy, Honoraria; Onyx: Consultancy, Honoraria.

T large granular lymphocytes leukemia (T-LGLL) and NK-type chronic lymphoproliferative disorder (CLPD-NK) are rare diseases characterized by the abnormal expansion of large granular lymphocytes (LGLs) with cytotoxic activity, belonging to T and NK lineage, respectively. Currently, the etiology of these diseases is still largely unknown. Several data support the hypothesis that the inciting event is represented by the persistence of antigenic stimulation, maintained by the abnormal release of cytokines (mainly IL-6 and IL-15), establishing an inflammation status not achieving resolution. Recently, we showed that IL-6 and soluble IL-6Rα were highly expressed and released by patients’ LGL-depleted peripheral blood mononuclear cells (PBMC), accounting for a trans-signaling process. IL-6 trans-signaling is critically involved in inflammatory disease and promotes the transition from acute to chronic inflammation. Additionally, LGL proliferation is maintained for an impairment of the apoptotic machinery due to the activation of many survival signaling pathways, including JAK/STAT and RAS/MEK/ERK pathways. In some patients (both T-LGLL and CLPD-NK) STAT3 hot-spot mutations, inducing STAT3 activation, have been demonstrated. With this as a background, we investigated the IL-15 contribution to sustain IL-6 trans-signaling and in turn inflammation. We analyzed the relationships between STAT3 mutations, IL-6 and IL-15 in disease progression to assess the hypothesis that these findings characterize different stages of LGL disease. Thirty T-LGLL and 15 CLPD-NK patients were included in this study. Patients were subdivided according to the percentage of LGLs in PBMCs (LGL range: 35-90%). By ELISA in patients’ plasma, we showed that IL-6 concentrations were significantly higher in patients characterized by a disease with less than 60% circulating LGLs (35.7 ± 11.4 pg/ml with respect to patients with LGLs >60%: 9.1 ± 2.7 pg/ml; p These results suggest that an initial step along the development of disease characterized by a low lymphocytosis (LGLs 60% of total PBMCs) in which LGL disease goes on independently from exogenous stimuli, likely becoming self-maintaining due to the contribution of the emerging STAT3 mutations. It is suggested that these phases can represent two sequential steps in the progression of disease. Disclosures: No relevant conflicts of interest to declare.

Over the last years, incorporation of novel agents into autologous stem cell transplantation (ASCT) has improved markedly the outcomes of younger patients with newly diagnosed multiple myeloma (MM). Superior results with experimental treatments vs previous standards of care have been frequently reported after preliminary analyses and need to be confirmed with longer follow up. The randomized phase 3 GIMEMA-MMY-3006 study was designed to compare bortezomib-thalidomide-dexamethasone (VTD) vs thalidomide-dexamethasone (TD) as induction therapy before, and consolidation after, double ASCT. Data from the initial analysis, with a median follow up of 36 months, demonstrated that patients randomized to the VTD arm enjoyed superior complete/near complete response (CR/nCR) rates after both induction and consolidation therapy, and had a significantly longer PFS compared to those prospectively assigned to the TD arm. We performed an updated analysis of the study after a median follow up of 59 months and results are herein reported. A persistent TTP and PFS benefit with incorporation of VTD into ASCT was confirmed. On an intention-to-treat analysis of 236 patients randomized to the VTD arm, median TTP was 62 months and median PFS was 57 months. The median values for 238 patients randomly assigned to the TD arm were 45 months for TTP (HR=0.64, p=0.001) and 42 months for PFS (HR=0.66, p=0.001) (Fig. 1). With the longer follow up of this analysis, an initial divergence between OS curves could be appreciated after 4 years, although the difference was not yet statistically significant at 6 years (75% for VTD vs 69% for TD). Superiority of VTD over TD for TTP and PFS was retained across prespecified subgroups of patients with high risk and low risk disease. In particular, PFS benefit with VTD was seen for patients age >60 years (HR=0.62, p=0.013) and younger than 60 years (HR=0.70, p=0.026), with ISS stage 1 (HR=0.59, p=0.009) and ISS stage 2-3 (HR=0.69, p=0.018), and for those with t(4;14) and/or del(17p) (HR=0.43, p3.5 mg/L (HR=1.7, p Disclosures: Cavo: Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Onyx: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Millennium: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Tacchetti:Janssen and Celgene: Honoraria. Zamagni:Celgene: Honoraria; Janssen-Cilag: Honoraria. Caravita:Celgene: Honoraria, Research Funding. Brioli:Celgene: Honoraria.

Introduction The large granular lymphocytes (LGL) disorders are characterized by expansions of T or NK cells with cytotoxic activity. WHO classification considers these disorders as separate entities, referred to as T-LGL Leukemia (T-LGLL) or NK-Chronic Lymphoproliferative Disease (NK-CLPD). The marker of clonality is the rearrangement of TCR in T-LGLL and a restricted pattern of Killer Immunoglobulin-like Receptor (KIR) expression in NK-CLPD. Although these disorders are characterized by the expansion of different cells types, compelling evidence supports the hypothesis that a common pathogenetic mechanism would be involved in both these disorders. Accordingly, the transcription factor STAT3 has been found mutated in a consistent percentage in both T-LGLL and NK-CLPD, suggesting a similar molecular dysregulation. Here, we evaluated whether clonal T and KIR restricted NK cell populations were detectable in patients with LGL, to support the hypothesis that a common pathogenetic mechanism takes place in both T-LGLL and NK-CLPD disorders. Methods We enrolled 370 therapy-free patients with LGL, 133 of which were available for serial measurements over 2 to 15 years. Peripheral blood sample and data collection from patients were performed at clinically indicated testing after informed consent, according to the protocols approved by the Institutional Review Board of the Experimentation Ethic Committee of Padua and in accordance with the Declaration of Helsinki. Based on World Health Organization guidelines, the diagnosis of T-LGLL was made according to the presence of monoclonal TCRγ-chain rearrangement, flow cytometric evidence of an abnormal CTL population characterized by expression of CD2, CD3, TCRαβ (or γδ), CD4, CD5dim, CD8, CD16/56 and CD57, TCR Vβ expansions (when detectable) with negativity of CD28. The diagnosis of NK-CLPD was made according to flow cytometric evidence of a KIR restricted CD16+/CD3- NK population. For both disorders, a LGL count by peripheral blood smear of > 2,000 LGL/μL (this is not a critical criteria, since patients who met all other criteria but with an LGL count < 2,000 cells/μL were included) and persistence of these conditions for more than 6 months were confirmed. Results Based on World Health Organization guidelines for T-LGLL and NK-CLPD diagnosis, we classified our patients in 3 group: Group 1 (n=247), with a T clonal expansion characteristic of T-LGLL, Group 2 (n=79), with a KIR restricted NK expansion characteristic of NK-CLPD, and Group 3 (n=44), characterized by patients in whom the presence of both KIR restricted NK population and T clonal expansion were present. Moreover, during the follow-up, we observed that 15 patients underwent a clonal switch of pathologic clones as follows. Five patients switched from NK-CLPD to T-LGLL. Seven patients developed additional clone(s) during follow-up, leading to the coexistence of both NK and T clonal populations; 3 patients demonstrated either a gradual emergence of a dominant T or NK clone from an oligoclonal background observed at diagnosis. Conclusions These results support the hypothesis that an antigenic pressure present in LGL disorders sustains the proliferation of both NK and T clones, triggering in some circumstances the gradual switch from a disorder to the other one. This observation challenges the classification of these disorders as two separate entities, questioning the accuracy of T-LGLL and NK-CLPD classification made by WHO in 2008. Disclosures: No relevant conflicts of interest to declare.

Abstract 4210 In a previous analysis performed with a median follow-up of 36 months (mos), superior CR/nCR rates and extended PFS were demonstrated with bortezomib-thalidomide-dexamethasone (VTD) vs thalidomide-dexamethasone (TD) as induction therapy before, and consolidation after, double autotransplantation (ASCT) for newly diagnosed myeloma (MM). Here we report an updated analysis of that study, including a detailed analysis of outcomes after relapse or progression (R/P), an important issue for patients (pts) who received up-front a triplet novel agent-based therapy incorporated into ASCT. After a median follow-up of 52 mos, continued TTP and PFS benefits with VTD vs TD were demonstrated, while no difference in OS was seen between the two arms. Median PFS for pts randomized to the VTD arm was 56 mos vs 42 mos for those assigned to TD (HR=0.64, p=0.001). Similarly to PFS, median TTP for pts in the VTD group was longer than in the TD group (57 vs 45 mos, HR=0.63, p=0.0006), reflecting a 37% reduction in the risk of R/P with VTD. The probabilities of R/P in the VTD and TD arms were 41% vs 55% (p=0.002). In comparison with the VTD-treated group, a higher percentage of pts in the TD arm required the immediate start of salvage therapy after symptomatic R/P was documented (67% vs 82.5%). By the opposite, the fraction of pts with asymptomatic R/P that did not require any antimyeloma therapy until the cut-off date for the analysis was higher in the VTD arm compared with the TD-treated group (33% vs 17.5%, p=0.016). In these pts, the median interval from the date of R/P to the cut-off date for the analysis was 7 mos for the TD-treated group vs 17 mos for the VTD-treated group. Median time to subsequent antimyelomatherapy (defined as the interval between start of induction therapy and administration of the first dose of second-line therapy) was significantly longer for pts who experienced R/P in the VTD arm in comparison with pts who progressed in the TD arm (35 vs 29 mos, p=0.018). The associated interval between last administration of front-line therapy (e.g. consolidation for pts who received the entire treatment program or every other treatment before consolidation for those who discontinued earlier) and first administration of second-line therapy (salvage therapy-free interval) was 22.5 mos for the VTD-treated group vs 15 mos for the TD-treated group (p=0.009). Both bortezomib and lenalidomide were the most frequently used agents at the time of R/P (82% of all cases), while only 18% of pts were treated with conventional cytotoxic drugs. As expected, the majority of pts in the TD arm received a second-line therapy that included bortezomib (70%), while lenalidomide-dexamethasone was received by 10% of pts. By the opposite, in the VTD arm both bortezomib- and lenalidomide-based salvage therapies were equally distributed (41% vs 39%). The probability to achieve at least a partial response after second-line therapy including bortezomib was 60% for pts with prior exposure to VTD vs 63% for those randomized to TD. No difference in post-R/P OS was demonstrated between VTD-treated and TD-treated subgroups of pts who received bortezomib-based salvage therapy after R/P (2-yr estimates: 48% vs 53%, p=0.59). In the overall population, post-R/P OS was significantly shorter for pts who received salvage therapy with conventional cytotoxic drugs (2-yr estimate: 41%) in comparison with pts treated with novel agents, including bortezomib or lenalidomide (2-yr estimates: 52% and 53%, respectively) (p=0.0001). In conclusion, front-line therapy with VTD incorporated into ASCT was superior in comparison with TD plus ASCT in terms of extended TTP, PFS, time to subsequent antimyeloma therapy and salvage therapy-free interval. VTD-treated pts had a higher probability than TD-treated pts to experience long-lasting asymptomatic R/P not requiring second-line therapy. VTD-treated and TD-treated pts who subsequently received bortezomib-based salvage therapies had similar rates of response and post-R/P OS. This finding suggests that short-term exposure to VTD, as planned in our study, did not favor the selection of bortezomib-resistant clones, thus allowing to rechallenge bortezomib as (part of) second-line therapy after symptomatic R/P. Disclosures: Cavo: Janssen, Celgene, Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria. Di Raimondo:Celgene, Janssen: Honoraria, Speakers Bureau. Offidani:Janssen, Celgene: Honoraria. Caravita:Celgene, Janssen, Novartis, Genzyme: Honoraria. Boccadoro:Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract 2595 Background: Posaconazole is indicated for prophylaxis and salvage therapy of invasive fungal infections. Based on pharmacokinetic-pharmacodynamic data, a minimum serum concentration higher than 0.5 mg/L and 1.0 mg/L has been proposed for prophylaxis and therapy, respectively. While therapeutic drug monitoring (TDM) of plasma concentrations is widely accepted for triazole antifungal agents such as voriconazole, the utility of TDM for posaconazole is controversial due to debate over the relationship between posaconazole exposure in plasma and clinical response to therapy. In fact only few reports correlate posaconazole plasma concentrations (PPCs) with breakthrough infection. Methods: In this retrospective single center study we evaluated the correlation of PPCs with breakthrough invasive mould infections (IMIs) in 50 patients with acute myeloid leukaemia (AML) who underwent chemoterapy (induction or salvage therapy) between July 2009 and March 2012. To measure the posaconazole concentration in human plasma, we developed and validated a rapid and simple high-performance liquid chromatography method. The method involved a solid-phase extraction of posaconazole using Oasis HLB cartridges, a reversed-phase liquid chromatography on an XTerra RP18 column with a mobile phase consisting of acetonitrile/ammonium acetate and ultraviolet detection. Patient characteristics and microbiological data such galactomannan detection and TDM were collected retrospectively. A total of 454 PPCs were measured before and 4 hours after administration in 50 patients with AML receiving posaconazole prophylaxis at dose of 200 mg 3 times/day. When plasma levels were below 0.5 mg/L, the dose was increased to 200 mg 4 times/day. Results: Average levels below the target of 0.5 μg/mL were detected in 38 (76%) out of 50 cases; 5 out of 38 cases showed plasma concentrations Conclusions: Our data demonstrate that low PPCs are common in patients receiving posaconazole prophylaxis during chemotherapy for AML. However, in spite of low PPCs, the rate of IMIs was low. This is possibly due to the good lung bioavailability of the drug, despite the presence of low drug serum levels. In addition, our data seems to confirm that refractory disease is a strong risk factor for the development of IMIs. Even in this high risk group, low PPCs did not correlate with high IMIs' incidence. A prospective evaluation of TDM of posaconazole is needed. Disclosures: No relevant conflicts of interest to declare.

Abstract 4860 Background At present, the standard salvage treatment for relapsed/refractory (R/R) T-cell non Hodgkin lymphoma (NHL) has not been defined yet. Several studies indicated the high therapeutic activity and good safety profile of Bendamustine in B-cell NHL while, on the contrary, only few data are available in T-cell NHL. Recently, a multicenter phase II study showed that Bendamustine is active in angioimmunoblastic lymphoma and other T-cell NHL with 50% overall response rates (OR) and 28% complete responses (CR) (Gressin et al. J Clin Oncol, 2012 ASCO Annual Meeting Proceedings, 30, 15 suppl: 8026). Purpose On this basis we evaluated in the contest of everyday clinical practice the efficacy and safety of Bendamustine salvage monotherapy in unselected adult patients with T-cell NHL. Patients and Methods Hematological and Oncological Italian centers involved in the treatment of patients with lymphomas were asked to report retrospectively the results of their experience regarding the use of Bendamustine in T-cell NHL. Response status and toxicity were evaluated according to Cheson 2007 and to the Common Terminology Criteria For Adverse Events V 4.0. Results Clinical data of 20 patients with R/R T-cell NHL (median age 73 years, range 31–83; 14 males) treated with Bendamustine in seven Italian centers between March 2009 and June 2012 were analyzed. Investigated series included 6 peripheral T-NHL-NOS, 4 angioimmunoblastic (AILT), 3 prolymphocytic T-cell leukemia (PLL), 3 advanced- stage Mycosis Fungoides (MF)/Sezary Syndrome (SS), 2 large granular lymphocyte (LGL) NHL and 2 ATLL- like HLTV-1 negative NHL. The median interval from diagnosis to Bendamustine treatment was 18 months (range 1–74). Eleven patients received up to 2 previous lines of therapy, while 9 received more than 2, including CHOP or CHOP-like therapy (14 patients), Fludarabine or Pentostatine (5), Gemcitabine based therapy (7), Alemtuzumab (4), Romidepsin (1), allogeneic stem cell transplant (1). Nearly 70% of patients were refractory to the last previous chemotherapy. Bendamustine was given as monotherapy at a dosage of 60 and 70 mg/m2 (7 patients) or 90–100 mg/m2(13) for a median number of 2.5 cycles (range 1–8) and a total number of 67 cycles. Response to Bendamustine was CR in 2 (10%) and PR in 8 (40%), with an ORR of 50%, including 3 PR in T-cell NHL/NOS, 1 CR in AILT, 3 PR in PLL, 1 PR in MF/SS, 1 CR and 1 PR in LGL NHL. The median period of observation was 6 months (range 1–18 months); 6- months estimated PFS, OS and response duration are 63%, 70% and 60%, respectively. Three patients in PR (2 PLL and 1 MF) progressed after 3, 4 and 7 months. Grade 3–4 neutropenia, thrombocytopenia and anemia were registered in 44%, 25% and 19% of cases. Three patients developed pneumonia (1 invasive aspergillosis) and 1 had septic shock; no grade 3–4 extra hematological toxicity was reported. Conclusions Bendamustine is a safe and active agent that desertes further investigation in patients with T-cell NHL. Combinations with other cytostatics or target therapy with potential synergistic effect should be assessed in future prospective trials. Disclosures: Zaja: Mundipharma: Honoraria. Off Label Use: Bendamustine In T-NHL. Fanin:Mundipharma: Honoraria.