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CAPTIVATE (NCT02910583) is an international phase 2 study in patients aged ≤70 years with previously untreated chronic lymphocytic leukemia (CLL). Results from the cohort investigating fixed-duration (FD) treatment with ibrutinib plus venetoclax are reported. Patients received 3 cycles of ibrutinib lead-in then 12 cycles of ibrutinib plus venetoclax (oral ibrutinib [420 mg/d]; oral venetoclax [5-week ramp-up to 400 mg/d]). The primary endpoint was complete response (CR) rate. Hypothesis testing was performed for patients without del(17p) with prespecified analyses in all treated patients. Secondary endpoints included undetectable minimal residual disease (uMRD) rates, progression-free survival (PFS), overall survival (OS), and safety. Of the 159 patients enrolled and treated, 136 were without del(17p). The median time on study was 27.9 months, and 92% of patients completed all planned treatment. The primary endpoint was met, with a CR rate of 56% (95% confidence interval [CI], 48-64) in patients without del(17p), significantly higher than the prespecified 37% minimum rate (P < .0001). In the all-treated population, CR rate was 55% (95% CI, 48-63); best uMRD rates were 77% (peripheral blood [PB]) and 60% (bone marrow [BM]); 24-month PFS and OS rates were 95% and 98%, respectively. At baseline, 21% of patients were in the high tumor burden category for tumor lysis syndrome (TLS) risk; after ibrutinib lead-in, only 1% remained in this category. The most common grade ≥3 adverse events (AEs) were neutropenia (33%) and hypertension (6%). First-line ibrutinib plus venetoclax represents the first all-oral, once-daily, chemotherapy-free FD regimen for patients with CLL. FD ibrutinib plus venetoclax achieved deep, durable responses and promising PFS, including in patients with high-risk features.

Ibrutinib, a once-daily oral inhibitor of Bruton tyrosine kinase, has greatly improved outcomes for patients with chronic lymphocytic leukemia (CLL). The phase 3 RESONATE trial, which compared single-agent ibrutinib to ofatumumab in high-risk, relapsed patients with CLL, provided support for approval of ibrutinib in the United States and Europe. We describe long-term follow-up of patients treated in RESONATE, where continued superiority of progression-free survival (PFS) (hazard ratio [HR], 0.133; 95% confidence interval [CI], 0.099-0.178) was observed. Overall survival benefit continues (HR, 0.591; 95% CI, 0.378-0.926), although with decreased magnitude relative to that seen before crossover to ibrutinib was implemented for patients on ofatumumab (HR, 0.426; 95% CI, 0.220-0.823). Notably, overall response to ibrutinib increased over time, with 91% of patients attaining a response. The PFS benefit with ibrutinib was independent of baseline risk factors, although patients with ≥2 prior therapies had shorter PFS than those with

High-risk chronic lymphocytic leukemia (CLL) has been defined by clinical and/or genetic resistance (TP53 abnormalities) to treatment with chemoimmunotherapy (CIT). With the availability of pathway inhibitors (PIs), such as kinase inhibitors and BCL2 antagonists, the outlook of CIT-resistant patients has dramatically improved. Here, we propose a revision of the concept of high-risk CLL, driven by TP53 abnormalities and response to treatment with PI. CLL high-risk-I, CIT-resistant is defined by clinically CIT-resistant disease with TP53 aberrations, but fully responsive to PI. This category is largely the domain of PI-based therapy, and cellular therapy (ie, allogeneic hematopoietic cell transplantation) remains an option only in selected patients with low individual procedure-related risk. In CLL high-risk-II, CIT- and PI-resistant, characterized by increasing exhaustion of pharmacological treatment possibilities, cellular therapies (including chimeric antigen receptor-engineered T cells) should be considered in patients eligible for these procedures. Moreover, molecular and cellular therapies are not mutually exclusive and could be used synergistically to exploit their full potential.

Introduction: The BCL-2 inhibitor venetoclax (Ven) has been approved on monotherapy or combined with rituximab in relapsed/refractory CLL patients (pts) and combined with obinutuzumab in previously untreated CLL pts. However, evidence from clinical trials can be difficult to generalize to real-world patient populations. The VENARES study assesses the real-world use of Ven following approval to inform of subpopulations underrepresented in clinical trials. Methods: This is Spanish non-interventional retrospective, multicenter post-marketing observational study. The main objective was to evaluate the effectiveness of Ven in adult CLL pts by the overall response rate (ORR) at 9 months (mo) after the first Ven dose administration. Secondary objective was to evaluate the effectiveness for the Ven monotherapy and the Ven combined with rituximab subpopulations. Consecutive adult pts with diagnosis of CLL who have initiated Ven at least 9 mo before the inclusion in the study were included. Data of pts are retrospectively reviewed until the date of last follow-up or death. Results: 125 pts diagnosed with CLL and who met the eligibility criteria were analyzed. The median age was 72 years (67 - 77) with 76.8% being older than 65 years. Most patients were male (68.8%), had a concurrent disease (65.6%). ECOG PS was recorded in 76 pts: 40 pts (32%) had PS 0, 30 pts (24%) PS 1 and 6 pts (4.8%) PS 2. Pts had received a median of 4 prior lines of therapy (range 1-13 lines). At baseline, among the 92 pts with known Binet stage, 31 (33.7%) had stage C and 38 (41.3%) had stage B; bulky nodes ≥ 5 cm were present in 20 of 87 pts; 49 pts (39.2%) had an absolute lymphocyte count ≥ 25 x 10 9/L and 33 of 54 pts (61%) baseline beta-2 microglobulin value above of 3500 ng/mL. In total, 29 of 90 patients (32%) assessed had Cr 17p deletion, 28 of 86 patients (32%) tested had TP53 mutations, and 46 of 56 patients (82%) who were tested had unmutated immunoglobulin heavy-chain variable (IGHV) status. Ven was administered as monotherapy in 71 pts (57.6%), combined with rituximab in 36 pts (28.8%), combined with obinutuzumab in 5 pts (4%) and combined with other drugs in 13 pts (10.4%). 83 of 125 patients included were evaluable for the primary objective of the study: the ORR at 9 mo was 84.3% (70 patients): CR/CRi in 44 (53%) pts, PR/nPR in 26 pts (31.3%), SD in 9 pts (10.8%) and PD in 4 pts (4.8%). By treatment, in the evaluable patients, ORR at 9 months were 79.2% (38 of 48 patients) in the Ven monotherapy group, with 45% of CR/CRi, and 92.3% (24 of 26 patients) in the Ven combined with rituximab, with 61% CR/Cri. The median duration of PFS was not reached at the time of the analysis (1-June-2021). Kaplan-Meier estimates of the probability of PFS at 24 mo was 75.4% (95% CI, 58.2 - 86.3). Disease progression occurred in 21 pts. Assessment of minimal residual disease (MRD) was available for 32 patients (25.6%) on the basis of peripheral-blood samples, bone marrow or both. Best undetectable MRD was reached in fourteen patients (43.8%). uMRD was more common in pts treated with Ven combined with R (83.3%, 5 of 6 pts) than in pts treated with Ven monotherapy (33.3%, 7 of 21 pts). Adverse events (AEs) were reported during Ven therapy in all 125 patients, 93 of these pts reported AEs related to Ven. Related to Ven, 67 patients (53.6%) experienced at least one AE: 52 pts (41.6%) had neutropenia being grade 3 and 4 in 22 (42.3%) and 9 (17.3%) pts, respectively. 9 pts (7.2%) had febrile neutropenia. Thrombocytopenia and anemia were less common occurring in 5.6% and 2.4%, respectively. Tumor lysis syndrome (TLS) occurred in 4 of 125 pts during ramp-up (3 laboratory and 1 clinical), 2 of them were related to Ven both lab TLS. None of the pts discontinued therapy due to TLS. Richter transformation was observed in 6 pts (4.8%). Other common AEs was diarrhea (10.4%), but most cases were mild. Conclusions: Our first real-world data show that Ven monotherapy or combined with rituximab is effective in highly pre-treated CLL patients, ORR at 9 mo was 84.3% in all population and PFS estimate at 24 mo was 75.4% with similar outcomes to those in the pivotal clinical trials. The safety profile of Ven was consistent with prior experience of Ven in monotherapy or combined with rituximab and no new safety signals were detected. Disclosures Baltasar: Janssen, Abbvie: Consultancy. Terol: Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; BMS: Consultancy; Roche: Consultancy; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Hospital Clinico Valencia: Current Employment. Moreno: Janssen, Abbvie: Research Funding; Abbvie, Janssen, AstraZeneca: Speakers Bureau; Abbvie, Janssen, AstraZeneca, Beigene: Membership on an entity's Board of Directors or advisory committees. Osorio: Janssen, Abbvie, Roche: Consultancy. De la Cruz: Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Beigene: Membership on an entity's Board of Directors or advisory committees; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees; JANSSEN: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirkin: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. de la Serna: AbbVie, AstraZeneca, Roche: Speakers Bureau; ABBVIE, ASTRAZENECA,ROCHE: Research Funding; AbbVie, AstraZeneca, Beigene, Gilead, GSK, Janssen, Jazzpharma, Novartis, Roche: Consultancy. Arguiñano: Takeda, Sanofi, Janssen, BMS-Celgene, Abbvie: Speakers Bureau; Takeda, Sanofi, Janssen, BMS-Celgene, Abbvie: Consultancy. Loscertales: Janssen, Abbvie, Roche, Gilead: Speakers Bureau; Janssen, Abbvie, Astra-Zeneca, Beigene, Roche, Gilead: Consultancy. García: Janssen, Roche, Gilead, Celgene: Consultancy; Janssen, AbbVie: Research Funding; Janssen, Roche, Gilead, AbbVie, Celgene: Other: medical meetings funding. Pérez Persona: BMS/Celgene: Consultancy, Other: Support for attending meetings and/or travel, Speakers Bureau; Amgen: Consultancy, Other: Support for attending meetings and/or travel, Speakers Bureau; Takeda: Speakers Bureau; AbbVie: Other: Support for attending meetings and/or travel, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; AstraZeneca: Speakers Bureau; GSK: Consultancy; Incyte: Consultancy. Pérez-Encinas: Janssen: Consultancy. Caballero: Celgene, Janssen, Novartis, Abbvie: Speakers Bureau; Celgene, Janssen, Amgen: Consultancy. Ruiz-Zorrilla: Abbvie: Current Employment. Moreno: abbvie: Current Employment. Ferrà: Janssen, Roche, Gilead, Takeda, Abbvie: Consultancy; Janssen, Roche, Gilead, AbbVie: Other: medical meetings funding.

Background: MRD status is an established predictive marker for progression-free survival (PFS) in CLL following chemoimmunotherapy as well as for fixed-duration treatment with venetoclax and an anti-CD20 antibody. To date, this relationship has not been explored for the combination of Ibr+Ven, an all-oral, once-daily, fixed-duration treatment with complementary mechanisms of action that work synergistically to eliminate CLL subpopulations in distinct tumor compartments. In the primary analysis of the phase 3 international GLOW trial, independent review committee (IRC)-assessed PFS for Ibr+Ven was superior to Clb+O (hazard ratio, 0.216; p < 0.0001). Herein we further investigate MRD outcomes at the time of the GLOW primary analysis. Methods: GLOW (NCT03462719) enrolled patients (pts) aged ≥65 years or 18-64 years with cumulative illness rating scale score >6 or creatinine clearance Results: 106 pts were randomized to Ibr+Ven and 105 to Clb+O. Median age was 71.0 years, 51.7% had confirmed unmutated (u)IGHV, 18.0% had del(11q), and 4.3% had a TP53 mutation. Median follow-up was 27.7 (range, 1.7-33.8) months. MRD results are all via NGS and reported for EOT+3 unless otherwise noted. MRD Results at 10 -4: Rate of uMRD was significantly higher for Ibr+Ven vs Clb+O in BM (51.9% vs 17.1%; p < 0.0001) (Fig A) and in PB (54.7% vs 39.0%; p = 0.0259). PB/BM uMRD concordance with Ibr+Ven was 92.9%. In the Ibr+Ven arm, 65.9% (27/41) of pts with a complete response (CR) or CR with incomplete marrow recovery (CRi) and 54.9% (28/51) with a partial response achieved uMRD in BM; rates for Clb+O were 33.3% (4/12) and 16.9% (13/77), respectively. BM uMRD rates were higher for Ibr+Ven vs Clb+O across prespecified subgroups, including bulky disease (≥5 cm), del(11q), and uIGHV . In the Ibr+Ven arm, BM uMRD was higher for uIGHV (58.2%) vs mutated IGHV (44.4%). With Ibr+Ven, 84.5% (49/58) of pts maintained PB uMRD from EOT+3 to EOT+12 vs 29.3% (12/41) with Clb+O. For pts with detectable MRD after Ibr+Ven (n = 30), MRD levels remained stable for most patients from EOT+3 to EOT+12 (Fig B). MRD Results at 10 -5: Rate of uMRD PFS by MRD Status at 10 -4 : In the Ibr+Ven arm, PFS rate during the first 12 months after EOT was >90% for pts with uMRD as well as pts with detectable MRD. In contrast, pts in the Clb+O arm with detectable MRD in PB relapsed more quickly than those with uMRD (Fig C). PFS trends were similar according to MRD status in BM (Fig D). Note that not all pts in the Ibr+Ven arm had 12 months' follow-up post-EOT. Conclusion: All-oral, once-daily, fixed-duration Ibr+Ven demonstrated superior uMRD responses that were deeper and better sustained post-treatment vs Clb+O in elderly or unfit pts with previously untreated CLL. Most pts with uMRD in the Ibr+Ven arm, including those with uIGHV, achieved clearance below 10 -5, and deeper clearance in PB was mirrored in BM. In the Ibr+Ven arm, clinical relapse was infrequent during the first year off treatment for pts with known MRD status at EOT+3 (whether uMRD or detectable MRD), supported by largely sustained uMRD/MRD levels over the same period. Additional follow-up will be important to confirm these early results. Figure 1 Figure 1. Disclosures Munir: Janssen, Abbvie, AstraZeneca, Morphosys, Alexion, Gilead, Novartis: Membership on an entity's Board of Directors or advisory committees; Janssen, Abbvie, AstraZeneca, Alexion, Apellis, Gilead, Novartis: Honoraria. Moreno: Abbvie, Janssen, AstraZeneca, Beigene: Membership on an entity's Board of Directors or advisory committees; Abbvie, Janssen, AstraZeneca: Speakers Bureau; Janssen, Abbvie: Research Funding. Owen: Abbvie, AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen, Roche, Merck, Gilead, Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees. Follows: Roche, Abbvie, Janssen, Takeda, Janpix: Consultancy. Benjamini: AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Janssens: Abbvie, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Trael Grant, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy; Beigene, AstraZeneca: Consultancy, Speakers Bureau. Levin: Roche, Janssen, Abbvie: Other: Travel Expenses, Ad-Board. Robak: AstraZeneca, Abbvie, Janssen, Octapharma, Gilead,Oncopeptides AB, Pharmacyclics, Pfizer, GlaxoSmithKline, Biogen: Research Funding; Biogen, Abbvie, Octapharma, Janssen: Honoraria, Other: Advisory board; Medical University of Lodz: Current Employment. Simkovic: Janssen-Claig, Gilead, Roche, AstraZeneca, Abbvie: Consultancy, Honoraria, Other: Travel Grants, advisiory boards. Voloshin: Janssen, Abbvie, Sanofi, AstraZeneca, Takeda: Other: Clinical Trials, Non-finanfial support, Speakers Bureau; Novartis, Pfizer, MSD, La ROche: Other: Clinical Trials, Non-finanfial support. Vorobyev: Janssen, Roche, Sanofi, Takeda, Biocad, Abbvie: Other: Advisory Boards, Speakers Bureau; Astellas, Novartis, AstraZeneca: Speakers Bureau. Ysebaert: Abbvie, AstraZeneca, Janssen, Roche: Other: Advisory Board, Research Funding. Qi: Janssen: Current Employment. Steele: Janssen: Current Employment. Schuier: Janssen: Current Employment. Baeten: Janssen: Current Employment. Bennett Caces: Janssen: Current Employment. Niemann: Novo Nordisk Foundation: Research Funding; CSL Behring, Genmab, Takeda, Octapharma: Consultancy; Abbvie, AstraZeneca, Janssen: Consultancy, Research Funding. Kater: Abbvie: Honoraria, Other: Ad Board, Research Funding; Genmab, LAVA: Other: Ad Board, Steering Committee; Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding; BMS, Roche/Genentech: Other: Ad Board, , Research Funding.

Ibrutinib, an oral inhibitor of Bruton's tyrosine kinase (BTK), at a once-daily dose of 420 mg achieved BTK active-site occupancy in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) that was maintained at 24 hours. It is unknown if intermittent interruption of ibrutinib therapy contributes to altered clinical outcomes. We therefore evaluated the effect of ibrutinib dose adherence on patient outcomes in the phase 3 RESONATE trial. The overall mean dose intensity (DI) was 95% with median treatment duration of similar to 9 months. Pharmacokinetic assessment of ibrutinib exposure at 420-mg dose suggested similar exposure regardless of patient weight or age. As assessed by independent review committee, patients with higher DI experienced longer median progression-free survival (PFS) compared with those with lower DI regardless of del17p and/or TP53 status. Of 79 patients requiring a drug hold, treatment was restarted at the original dose in 73 (92%) patients. Mean duration of a missed-dose event was 18.7 days (range, 8-56). Patients missing >= 8 consecutive days of ibrutinib had a shorter median PFS vs those missing

Background : Ibrutinib (Ibr) is the only once-daily Bruton's tyrosine kinase (BTK) inhibitor with significant survival benefit vs chemo- and/or immunotherapy in multiple phase 3 studies of patients (pts) with CLL. Ibr in first-line (1L) CLL is associated with lower rates of progressive disease (PD) than in later lines. Acquired mutations in BTK or phospholipase C-γ2 (PLCG2) genes have been shown in ~70-80% of pts with CLL progression on ibr or acalabrutinib. Most studies reporting BTK/PLCG2 mutation rates to date have been conducted in pts with PD. The objective of this study was to systematically evaluate the frequency and time to detection of BTK and PLCG2 mutations in pts who were continuing to respond to ibr (free of PD) in either 1L or R/R treatment. Methods : Peripheral blood samples were prospectively collected from clinical trial pts treated with ibr in 1L (RESONATE-2, iLLUMINATE, and NCT01500733) or R/R settings (RESONATE and RESONATE-17). After CD19 enrichment, established BTK and PLCG2 mutation testing was performed by next-generation sequencing at the last available sample timepoint for pts without PD. Mutation frequencies are summarized using descriptive statistics. For pts with identified BTK mutations, earlier timepoints were assessed by C481x-specific droplet-digital PCR. Prespecified Kaplan-Meier analyses were used to characterize time from ibr initiation to first detection of BTK mutations and to assess differences between specified populations, including 1L or R/R treatment; presence or absence of del(17p)/TP53; and 1 or ≥3 prior therapies. Results : Of 388 pts tested, 238 (61%) were previously untreated and 150 (39%) had R/R disease (del[17p]/TP53 mutations in 49 and 100 pts, respectively). With median testing follow-up on treatment of 35 mo (range 0-72) and 36 mo (range 1-69), the BTK mutation rate was 3% and 30% in previously untreated and R/R pts, respectively. In the 1L and R/R settings the rates of PLCG2 mutations were 2% and 7%, and the rate of co-occurring BTK/PLCG2 mutations were 1% and 5%, respectively. Of the prespecified comparisons, there was superior freedom from detection of BTK mutations (Table) in pts treated with ibr in the 1L vs R/R setting (hazard ratio [HR] 0.09; P Conclusions : In this large study of 388 pts with diverse clinical risk factors and up to 6 years of follow-up, BTK and PLCG2 mutation rates were rare for pts on 1L ibr treatment, consistent with the low frequency of PD in this setting. Detection of BTK mutations was more common in R/R than previously untreated pts (30% vs 3%). These data in pts without PD and with this long-term follow-up are consistent with consensus guidelines, which recommend that the detection of BTK or PLCG2 mutations does not currently warrant changes in the treatment of pts with CLL. The presence of del(17p)/TP53 increases the risk of mutation development both overall and in R/R pts and is more informative than number of prior lines of therapy. Ongoing analyses will further characterize the time of first detection of BTK and PLCG2 mutations, change in allele frequencies over time, relationship between timing and kinetics of mutations and development of PD, and populations that are at relatively increased risk for mutation development. Disclosures Wiestner: Pharmacyclics LLC, an AbbVie Company, Acerta, Merck, Nurix, Verastem, and Genmab: Research Funding; NIH: Patents & Royalties: NIH. Ghia:Adaptive, Dynamo: Consultancy, Honoraria; Celgene/Juno: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; BeiGene: Consultancy, Honoraria; Acerta/AstraZeneca: Consultancy, Honoraria; ArQule: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Research Funding; MEI: Consultancy, Honoraria; Lilly: Consultancy, Honoraria; Novartis: Research Funding; Sunesis: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding. Byrd:Acerta Pharma: Research Funding; Syndax: Research Funding; Trillium: Research Funding; Kartos Therapeutics: Research Funding; Leukemia and Lymphoma Society: Other; Janssen: Consultancy; Vincera: Research Funding; Novartis: Research Funding; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, BeiGene: Research Funding; Pharmacyclics LLC, an AbbVie Company, Gilead, TG Therapeutics, Novartis, Janssen: Speakers Bureau; Pharmacyclics LLC, an AbbVie Company, Janssen, Novartis, Gilead, TG Therapeutics: Other. Moreno:Janssen: Speakers Bureau; AbbVie and Janssen: Research Funding; Janssen, AbbVie, Sunesis, and AstraZeneca: Consultancy. O'Brien:Kite, Regeneron, Acerta: Research Funding; Amgen, Astellas, Celgene, GlaxoSmithKline, Janssen Oncology, Aptose Biosciences Inc. Vaniam Group, AbbVie, Alexion, Verastem, Eisai, Juno Therapeutics, Vida Ventures: Consultancy; Gilead, Pharmacyclics, TG Therapeutics, Pfizer, Sunesis: Consultancy, Research Funding. Jones:Pharmacyclics LLC, an AbbVie Company: Patents & Royalties: and other intellectual property, Research Funding. Cheung:Pharmacyclics LLC, an AbbVie Company: Current Employment, Patents & Royalties: and other intellectual property; AbbVie and Eli Lilly: Current equity holder in publicly-traded company. Chong:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie: Current equity holder in publicly-traded company. Kwei:AbbVie and Gilead: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment. Dean:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie: Current equity holder in publicly-traded company. James:AbbVie: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment, Other: Leadership, Patents & Royalties: and other intellectual property. Woyach:Pharmacyclics, Janssen, Morphosys, Karyopharm, Verastem, Abbvie, Lox: Research Funding; Pharmacyclics LLC, an AbbVie Company, AbbVie, Janssen, AstraZeneca, ArQule: Honoraria; Janssen, Pharmacyclics, AstraZeneca, Abbvie, Arqule: Consultancy.

Background : Ibr is an established standard of care in CLL and is the only once-daily Bruton tyrosine kinase inhibitor with significant overall survival benefit in randomized phase 3 studies in first-line CLL (RESONATE-2; ECOG1912). The synergistic combination of Ibr + Ven (oral inhibitor of BCL2) has been shown to mobilize and clear CLL cells from multiple disease compartments leading to deep responses, providing a rationale to evaluate time-limited treatment (Jain et al. NEJM 2019). CAPTIVATE (PCYC-1142) is a multicenter phase 2 study (NCT02910583) of first-line Ibr + Ven with 2 cohorts: Minimal Residual Disease (MRD) and Fixed-Duration (FD). For both cohorts, patients (pts) received 3 cycles of Ibr lead-in followed by 12 cycles of combined Ibr + Ven. Pts in the MRD cohort were randomized by MRD status to placebo or further treatment. In the pre-randomization phase of the MRD cohort, Ibr + Ven resulted in high rates of undetectable MRD (uMRD) in both peripheral blood (PB; 75%) and bone marrow (BM; 72%), with concordant uMRD results in 93% of pts with matched samples (Tam, ASH 2019). We present primary results from the MRD-guided randomization phase of the MRD cohort, evaluating whether this regimen allows for treatment-free remission in the setting of uMRD. Methods : Pts Results : 164 pts were enrolled in the MRD cohort. Median age was 58 years (range, 28-69); baseline high-risk features included del(17p) in 16% and del(11q) in 17%; del(17p) or TP53 mutation in 20%; complex karyotype in 19%; and unmutated IGHV in 60%. Median time on study was 31.3 mo (range, 15.0-41.0). 90% of pts completed planned treatment with 3 cycles of Ibr lead-in followed by 12 cycles of combined Ibr + Ven. Of 149 randomized patients, 86 (58%) with Confirmed uMRD (100% uMRD in PB and BM) were randomized to placebo (n=43) or Ibr (n=43). 63 of 149 pts (42%) did not achieve Confirmed uMRD as defined above and were randomized to Ibr (n=31) or Ibr + Ven (n=32); uMRD rates at randomization in this group were 48% in PB and 32% in BM. In the Confirmed uMRD group, 1-year DFS rate was not significantly different for pts randomized to placebo (95.3%; 95% CI 82.7-98.8) versus Ibr (100%; 95% CI 100-100) (P=0.1475; Figure). In the group without Confirmed uMRD who were randomized to continue Ibr or Ibr + Ven, uMRD rates improved to 57% in PB and 54% in BM during the overall study period. 30-mo PFS rates were >95% across all randomized arms (Table). Full results of endpoints by randomized arms will be presented. The median duration of treatment was 28.6 mo (range, 0.5-39.8) with Ibr and 12.0 mo (range, 0.8-34.1) with Ven. AEs were primarily grade 1/2 and mostly occurred in early cycles of Ibr + Ven, with modest differences by randomized treatment arm. During the overall study period across all-treated pts (with median treatment duration 29 mo), most common grade 3/4 AEs (≥5% of pts) were neutropenia (36%), hypertension (10%), thrombocytopenia (5%), and diarrhea (5%). Conclusions : First-line Ibr + Ven treatment is an all-oral, once-daily, chemotherapy-free regimen that confers high rates of PB and BM uMRD in pts with CLL, and a 90% reduction in high-risk TLS monitoring (Siddiqi, EHA 2020). The 1-year DFS in pts randomized to placebo after Ibr + Ven combination was similar to that of pts continuing Ibr, supporting a fixed-duration treatment that offers treatment-free remissions in pts with CLL/SLL. The depth of response achieved with this regimen is reflected in the 30-mo PFS rate of ~95% across all treated pts. The safety profile of Ibr + Ven was consistent with known AEs for Ibr and Ven, and no new safety signals emerged. Disclosures Wierda: Genzyme Corporation: Consultancy; GlaxoSmithKline, Novartis, AbbVie, Genentech, Karyopharm, Pharmacyclics LLC, an AbbVie Company, Acerta Pharma, Gilead Sciences, Juno Therapeutics, KITE Pharma, Sunesis, Miragen, Oncternal Therapeutics, Cyclacel, Loxo Oncology, Janssen, and Xencor: Research Funding. Tam:BeiGene: Honoraria, Research Funding; Pharmacyclics LLC, an AbbVie Company: Honoraria; AbbVie: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Allan:AstraZeneca, Pharmacyclics LLC, an AbbVie Company, Genentech, AbbVie, Ascentage, and Cellectar: Consultancy; Celgene, Genentech, AstraZeneca, TG Therapeutics, and Janssen: Research Funding; Janssen, AbbVie, and AstraZeneca: Other: Travel/accommodations/expenses; Janssen, AstraZeneca, and AbbVie: Honoraria. Siddiqi:Pharmacyclics LLC, an AbbVie Company, Seattle Genetics, Janssen, and AstraZeneca: Speakers Bureau; PCYC: Membership on an entity's Board of Directors or advisory committees; Astrazenca: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics, Pharmacyclics LLC, an AbbVie Company, AstraZeneca, Celgene, Kite Pharma, and BeiGene: Consultancy; AstraZeneca: Other: Travel/accommodations/expenses; Pharmacyclics LLC, an AbbVie Company, Juno Therapeutics, KITE Pharma, AstraZeneca, TG Therapeutics, Celgene, Oncternal, and BeiGene: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; BeiGene: Other: DMC member. Kipps:AbbVie, Celgene, Genentech-Roche, Gilead, and Pharmacyclics LLC, an AbbVie Company: Consultancy; AbbVie, Genentech-Roche, Oncternal, and Pharmacyclics LLC, an AbbVie Company: Research Funding. Opat:Amgen: Research Funding; Epizyme: Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; CSL: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Research Funding; AstraZenca: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Tedeschi:BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen spa: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Department of Hematology Niguarda Hospital Milano: Current Employment; Sunesis: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Badoux:AbbVie: Honoraria, Other: Travel/accommodations/expenses. Kuss:Roche, Janssen, Gilead, and AbbVie: Speakers Bureau; Janssen, AbbVie, Roche, Mundipharma, Takeda, Merck, and Gilead: Consultancy, Honoraria. Jackson:AbbVie: Consultancy; Roche: Other: Travel/accommodations/expenses. Moreno:Janssen, AbbVie, Sunesis, and AstraZeneca: Consultancy; AbbVie and Janssen: Research Funding; Janssen: Speakers Bureau. Jacobs:AbbVie, Pharmacyclics LLC, an AbbVie Company, AstraZeneca, and Verastem: Consultancy; TG Therapeutics and Pharmacyclics LLC, an AbbVie Company: Research Funding; AbbVie, Pharmacyclics LLC, an AbbVie Company, AstraZeneca, Janssen, Sanofi, and Genentech: Speakers Bureau. Pagel:Gilead, Pharmacyclics LLC, an AbbVie Company, and AstraZeneca: Consultancy. Flinn:Curis: Research Funding; Curio Science: Consultancy; Calithera Biosciences: Research Funding; AstraZeneca: Consultancy, Research Funding; Nurix Therapeutics: Consultancy; Celgene: Research Funding; Constellation Pharmaceuticals: Research Funding; MorphoSys: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Iksuda Therapeutics: Consultancy; Gilead Sciences: Consultancy, Research Funding; Merck: Research Funding; Loxo: Research Funding; Forty Seven: Research Funding; Takeda: Consultancy, Research Funding; Karyopharm Therapeutics: Research Funding; Genentech, Inc.: Research Funding; Infinity Pharmaceuticals: Research Funding; Juno Therapeutics: Consultancy, Research Funding; Acerta Pharma: Research Funding; Janssen: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Triphase Research & Development Corp.: Research Funding; Verastem: Consultancy, Research Funding; Yingli Pharmaceuticals ≠: Consultancy, Research Funding; Rhizen Pharmaceuticals: Research Funding; Johnson & Johnson: Other; Roche: Consultancy, Research Funding; Vincera Pharma: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; Portola Pharmaceuticals: Research Funding; Seattle Genetics: Consultancy, Research Funding; Teva: Research Funding; TG Therapeutics: Consultancy, Research Funding; Trillium Therapeutics: Research Funding; Pfizer: Research Funding; Great Point Partners: Consultancy; IGM Biosciences: Research Funding; F. Hoffmann-La Roche: Research Funding; Kite Pharma: Consultancy, Research Funding; ArQule: Research Funding; Incyte: Research Funding; Agios: Research Funding; Forma Therapeutics: Research Funding; Novartis: Research Funding; Unum Therapeutics: Consultancy, Research Funding. Zhou:AbbVie: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment. Szafer-Glusman:Pharmacyclics LLC, an AbbVie Company: Current Employment. Ninomoto:AbbVie, Amgen, and Celgene: Current equity holder in publicly-traded company; AbbVie: Current Employment. Dean:AbbVie: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment. James:Pharmacyclics LLC, an AbbVie Company: Current Employment, Other: Leadership, Patents & Royalties: and other intellectual property; AbbVie: Current equity holder in publicly-traded company. Ghia:ArQule: Consultancy, Honoraria; Acerta/AstraZeneca: Consultancy, Honoraria; BeiGene: Consultancy, Honoraria; Adaptive, Dynamo: Consultancy, Honoraria; Novartis: Research Funding; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Celgene/Juno: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Lilly: Consultancy, Honoraria; MEI: Consultancy, Honoraria; Sunesis: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding. OffLabel Disclosure: Ibrutinib in combination with venetoclax is not approved in any indication.

Background Genomic abnormalities such as del(17p)/TP53 mutation, del(11q), and unmutated IGHV are risk factors that predict inferior outcomes with chemoimmunotherapy (CIT) in patients (pts) with CLL/SLL (Byrd J Clin Oncol 2006). Mutations in BIRC3, NOTCH1, SF3B1, and XPO1 have also been associated with poor outcomes with CIT in pts with CLL (Foa Haematologica 2013; Jain Am J Hematol 2016). Ibrutinib (ibr) is the only once-daily Bruton's tyrosine kinase inhibitor with significant progression-free survival (PFS) and overall survival (OS) benefit shown in multiple randomized phase 3 studies versus established therapies in pts with previously untreated or relapsed/refractory CLL/SLL. Superior outcomes were demonstrated with ibr-based therapy versus comparators in the overall population, and in pts with high-risk disease features, such as TP53 aberrations, del(11q), and/or unmutated IGHV in the RESONATE-2 study of first-line single-agent ibr (Burger Leukemia 2020) and in the iLLUMINATE study of first-line ibr-obinutuzumab (Moreno Lancet Oncol 2019). In pts with relapsed/refractory CLL/SLL who were treated with ibr, mutations in BIRC3, NOTCH1, SF3B1, or XPO1 had no significant impact on the PFS benefit conferred by ibr (Byrd Blood 2019). To better understand outcomes in pts with previously untreated CLL with various high-risk genomic features, including integrated FISH cytogenetics and single gene mutations, we performed a pooled analysis of two phase 3 studies of ibr-based therapy in the first-line treatment of CLL/SLL (RESONATE-2 and iLLUMINATE). Methods In RESONATE-2 (NCT01722487), pts aged ≥65 years without del(17p) were randomized to single-agent ibr or chlorambucil (clb). In iLLUMINATE (NCT02264574), pts aged ≥65 years, or Results The pooled analysis included 498 pts treated with first-line ibr-based or clb-based therapy (n=249 each) with median follow-up of 49.1 mos (range, 0.1-78.7). Ibr-based therapy significantly improved ORR and PFS vs comparator (clb-based) therapy. At 42 mo, PFS rates were significantly higher across high-risk genomic subgroups in ibr-treated pts (63-82%) compared with clb-treated pts (6-34%), and consistent PFS benefit with ibr was observed across all high-risk genomic subgroups (Figure). When comparing ibr-treated pts with specified high-risk genomic features vs those without, PFS and ORR were comparable in the different subgroups, including pts with unmutated vs mutated IGHV (PFS HR, 1.79, 95% CI 0.99-3.24) or mutated vs not mutated NOTCH1 (PFS HR, 1.05, 95% CI 0.65-1.69) (Table). Improved outcome was also noted for pts with del(17p)/TP53 mutated/BIRC3 mutated, the highest risk category per Rossi 2013 (HR 1.05, 95% CI 0.54-2.04). At a median duration of ibr treatment of 35.7-43.8 mo across these high-risk subgroups, there were no meaningful differences in the rates of treatment-emergent adverse events (AEs) of any grade or grade ≥3 AEs compared to those of the overall population. Conclusions This integrated analysis of pts undergoing first-line ibr-based treatment, with up to 79 mo follow up, demonstrated similar PFS and ORR for ibr-treated pts with or without high-risk genomic features, and confirmed significant PFS and ORR benefits with ibr-based therapy versus clb (± obinutuzumab). This analysis across two phase 3 studies demonstrated the efficacy of first-line ibr-based treatment irrespective of cytogenetic and mutational risk features, including those with unmutated IGHV, NOTCH1 mutation, and those with the highest risk classification of del(17p)/TP53 mutation/BIRC3 mutation. Disclosures Burger: Gilead, Janssen, Novartis, TG Therapeutics, and Pharmacyclics LLC, an AbbVie Company: Other: Travel/accomodations/expenses, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding; BeiGene, Gilead, TG Therapeutics, and Pharmacyclics LLC, an AbbVie Company: Research Funding. Robak:BioGene: Honoraria, Research Funding; UCB: Honoraria, Research Funding; UTX-TGR: Research Funding; Bristol Meyers Squibb: Research Funding; Momenta: Consultancy; Medical University of Lodz: Current Employment; Pharmacyclics LLC, an AbbVie Company: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Takeda: Consultancy; Sandoz: Consultancy, Honoraria; Octapharma: Honoraria; Pfizer: Research Funding; GSK: Research Funding; Roche: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Acerta: Research Funding; Morphosys: Research Funding; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding. Demirkan:AbbVie, Amgen, AstraZeneca, and Roche: Consultancy; AbbVie, AstraZeneca, Janssen, and Pharmacyclics LLC, an AbbVie Company: Research Funding; AbbVie, Amgen, and Janssen: Speakers Bureau; AbbVie, Amgen, Janssen, and Pfizer: Other: Travel/accommodations/expenses. Bairey:AbbVie: Consultancy; Janssen: Consultancy, Research Funding. Moreno:Janssen: Speakers Bureau; AbbVie and Janssen: Research Funding; Janssen, AbbVie, Sunesis, and AstraZeneca: Consultancy. Simpson:BeiGene: Current Employment, Current equity holder in publicly-traded company; AbbVie and Janssen: Honoraria, Other: Travel/accommodations/expenses; AbbVie, Acerta, Amgen, BeiGene, Celgene, GlaxoSmithKline, Janssen, Merck Sharp & Dohme, Roche, Sanofi, and Pharmacyclics LLC, an AbbVie Company: Research Funding. Munir:F. Hoffmann-La Roche: Consultancy, Other: Medical writing support, furnished by Scott Battle, PhD, of Health Interactions, was funded by F. Hoffmann-La Roche Ltd, Basel, Switzerland; Alexion: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Dai:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie, Bristol-Myers Squibb, Exelixis, Gilead, GlaxoSmithKline, and Revance: Current equity holder in publicly-traded company. Cheung:Pharmacyclics LLC, an AbbVie Company: Current Employment, Patents & Royalties: and other intellectual property; AbbVie and Eli Lilly: Current equity holder in publicly-traded company. Kwei:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie and Gilead: Current equity holder in publicly-traded company. Lal:Pharmacyclics LLC, an AbbVie Company: Current Employment; The Permanente Medical Group (spouse): Current Employment; AbbVie, Clovis, Gilead Sciences, Infinity, Reviva Pharmaceuticals, and The Permanente Medical Group: Current equity holder in publicly-traded company. Hsu:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie: Current equity holder in publicly-traded company. Kipps:AbbVie, Genentech-Roche, Oncternal, and Pharmacyclics LLC, an AbbVie Company: Research Funding; AbbVie, Celgene, Genentech-Roche, Gilead, and Pharmacyclics LLC, an AbbVie Company: Consultancy. Tedeschi:AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen spa: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Department of Hematology Niguarda Hospital Milano: Current Employment; Sunesis: Consultancy; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BeiGene: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Background : The presence of TP53 aberrations (defined as del(17p) or TP53 gene mutation) is a strong negative predictor of survival in patients (pts) with CLL. First-line chemoimmunotherapy is suboptimal in pts with CLL bearing TP53 aberrations, with 3-year progression-free survival (PFS) and overall survival (OS) rates of only 18% and 38%, respectively, with fludarabine, cyclophosphamide, and rituximab (Hallek, Lancet 2010). Ibrutinib is the only once-daily Bruton's tyrosine kinase (BTK) inhibitor with significant PFS and OS benefit demonstrated in multiple randomized phase 3 studies (eg, RESONATE-2, ECOG1912) in the first-line treatment of CLL/small lymphocytic lymphoma (SLL). Previous reports of single-agent ibrutinib or ibrutinib-based combination treatments have further demonstrated favorable PFS benefit in pts with TP53 aberrations in both the first-line and relapsed/refractory settings. Despite these study-specific subgroup analyses, there are limited data on long-term outcomes in pts with TP53 aberrations treated with first-line BTK inhibitors. We performed a pooled analysis of data across 4 studies to evaluate the long-term efficacy and safety of first-line ibrutinib-based therapy in pts with CLL bearing TP53 aberrations. Methods : Data for first-line ibrutinib treatment in pts with TP53 aberrations were pooled across 4 clinical trials in CLL/SLL: PCYC-1122e (NCT01500733; single-agent ibrutinib; n=34), PCYC-1130 (NCT02264574; ibrutinib + obinutuzumab; n=18), ECOG1912 (NCT02048813; ibrutinib + rituximab; n=26), and RESONATE-2 (NCT01722487; single-agent ibrutinib; n=11). ECOG1912 and RESONATE-2 excluded pts with del(17p) but did not exclude pts with TP53 mutations. Long-term PFS (assessed by investigator), OS, and safety are reported. Results : Eighty-nine pts with TP53 aberrations receiving first-line ibrutinib treatment were included in this pooled analysis. Median age was 65 years (range 33-87), and 69% of pts were male. At baseline, 53% had Rai stage III/IV, 38% had bulky disease (lymph nodes ≥5 cm), and 69% (of 87 evaluable) had unmutated IGHV. All patients had either del(17p) or TP53 mutation; 53% (of 89 evaluable) had del(17p) and 91% (of 58 evaluable) had TP53 mutation. Among 16 pts with del(17p) who had TP53 sequencing results available, 11 (69%) had both del(17p) and TP53 mutation. Forty-five pts received ibrutinib as a single agent and 44 received ibrutinib in combination with an anti-CD20 agent. With a median follow-up of 50 months (range 0.1 to 95.9 months), median PFS was not reached (95% CI: 67 months to not estimable; Figure 1A). At 48 months, the PFS rate was 79% and the OS rate was 88% (Figure 1B). Median duration of ibrutinib treatment was 46 months (range 0.1 to 95.5 months). Reasons for treatment discontinuation were progressive disease (20%), study closure (12%), adverse event (10%), withdrawal by pt (7%), death (3%), and other (physician decision due to scheduled pt surgery; 1%). Grade ≥3 adverse events of clinical interest with up to 8 years of treatment with ibrutinib were infection (22%; most commonly pneumonia in 7%), hypertension (13%), atrial fibrillation (12%), and major hemorrhage (7%). With the current follow-up, 46% of pts with TP53 aberrations remained on ibrutinib treatment. Conclusions : With a median follow-up of 4 years, first-line ibrutinib-based treatment resulted in sustained efficacy with high PFS and OS rates in CLL pts with TP53 aberrations, a population with historically poor outcomes. Although pts with TP53 aberrations remain at risk for progression, first-line treatment with ibrutinib has partially overcome the poor prognosis in this high-risk population with 4-year PFS and OS rates of 79% and 88%, respectively. No new safety signals were identified in this analysis. These results from a large, pooled, multi-study dataset demonstrated the long-term benefit of first-line ibrutinib-based treatment in pts with TP53 aberrations. Disclosures Allan: Janssen, AbbVie, and AstraZeneca: Other: Travel/accommodations/expenses; Celgene, Genentech, AstraZeneca, TG Therapeutics, and Janssen: Research Funding; AstraZeneca, Pharmacyclics LLC, an AbbVie Company, Genentech, AbbVie, Ascentage, and Cellectar: Consultancy; Janssen, AstraZeneca, and AbbVie: Honoraria. Shanafelt:Genentech, Pharmacyclics LLC, an AbbVie Company, AbbVie, GlaxoSmithKline, and Merck: Research Funding; Mayo Clinic: Patents & Royalties: and other intellectual property. Wiestner:Pharmacyclics LLC, an AbbVie Company; Acerta, Merck, Nurix, Verastem, and Genmab: Research Funding; National Institutes of Health: Patents & Royalties: and other intellectual property. Moreno:Janssen, AbbVie, Sunesis, and AstraZeneca: Consultancy; AbbVie and Janssen: Research Funding; Janssen: Speakers Bureau. O'Brien:Eisai: Consultancy; Juno Therapeutics: Consultancy; Aptose Biosciences: Consultancy; GlaxoSmithKline: Consultancy; Sunesis: Research Funding; Acerta: Research Funding; Amgen: Consultancy; Celgene: Consultancy; Pfizer: Research Funding; Pharmacyclics: Research Funding; Astellas: Consultancy; Gilead: Consultancy; TG Therapeutics: Research Funding; Vida Ventures: Consultancy; KITE: Research Funding; Vaniam Group LL: Consultancy; Alexion: Consultancy; Regeneron: Research Funding; AbbVie: Consultancy; Verastem: Consultancy; Janssen Oncology: Consultancy. Braggio:DASA: Consultancy; Bayer: Other: Stock Owner; Acerta Pharma: Research Funding. Liu:AbbVie: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment. Dean:AbbVie: Current equity holder in publicly-traded company; Pharmacyclics LLC, an AbbVie Company: Current Employment. Lai:Pharmacyclics LLC, an AbbVie Company: Current Employment; AbbVie and Bristol-Myers Squibb: Current equity holder in publicly-traded company; AbbVie: Other: Travel/accommodations/expenses.

INTRODUCTION. Chromosome banding analysis (CBA) is the gold standard to identify complex karyotypes (CK; ≥3 chromosomal aberrations in the same clone). CK are predictors of poor prognosis and treatment refractoriness in patients with chronic lymphocytic leukemia (CLL). Patients with CK (15% at diagnosis) constitute a heterogeneous subgroup with highly variable clinical course. Recent studies that aim to refine CK definition in CLL suggest that ≥5 is the number of anomalies detected by CBA that better predicts an impaired outcome (Baliakas et al, 2019). Molecular techniques as genomic microarrays also detect genomic complexity (GC). A recent multicentric ERIC study (Leeksma et al, ASH 2017) identified that patients with ≥5 copy number alterations (CNA) detected by microarrays are associated with an adverse outcome. However, risk stratification regarding genomic complexity assessed by CBA and microarrays has not been compared. OBJECTIVES. 1. To compare genomic complexity in CLL defined by CBA vs microarrays; 2. To compare risk stratification based on genomic complexity measured by both techniques. METHODS. The study cohort included 293 CLL patients from 16 European institutions (67% males) with available CBA result at diagnosis or prior to first treatment. The cohort was enriched in patients with CK (n=153, 52%). Tumor DNA extracted from peripheral blood (n=254) or bone marrow samples (n=39) obtained at the time of CBA was hybridized to CGH-arrays (n=12) and SNP-arrays (n=281) platforms. Clinically relevant aberrations [11q-, +12, 13q-, 17p-] and CNA ≥5Mb were considered for the anomaly count. Three risk groups were defined using previously suggested cut-off points for CBA and microarrays [non-CK/low-GC: 0-2; low/intermediate-CK/GC: 3-4; high-CK/GC: ≥5 (Baliakas et al, Leeksma et al)]. Groups obtained by both methods were compared and correlated with other clinical and biological data. Time to first treatment (TTT) of patients categorized according to the number of alterations detected by CBA and microarrays was analyzed. RESULTS. Median number of abnormalities detected was 3 (range: 0-19) by CBA and 2 (range: 0-18) by microarrays. When stratified according to previously defined criteria, a moderate agreement was observed between both techniques (κ=0.483, p Regarding the prognostic value of genomic complexity and considering the number of abnormalities detected as a continuous variable, CBA and microarrays showed a similar concordance index (C-index) for TTT (0.615 vs 0.609, respectively). When considering all the abnormalities independently of their size or when lowering the cutoff to 1Mb for those non-CLL abnormalities, similar impact on TTT was observed (C-index=0.593 vs 0.616). The three risk groups defined by each method showed significant differences on TTT (Figure 1, p CONCLUSIONS. 1. CBA and microarrays are helpful techniques for assessing genomic complexity in CLL patients; 2. Risk categories established by both methods have a significant impact on TTT although they show a moderate agreement; 3. Discordant cases are being investigated to refine genomic complexity criteria equivalent by both techniques. ACKNOWLEDGEMENTS. 17SGR437, GLD17/00282, FPU17/00361 Disclosures Rigolin: AbbVie: Speakers Bureau; Gilead: Speakers Bureau; Gilead: Research Funding. Gimeno:JANSSEN: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau. Bosch:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AstraZeneca: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; F. Hoffmann-La Roche Ltd/Genentech, Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding. Cuneo:Amgen: Honoraria; Abbvie: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Roche: Honoraria, Speakers Bureau. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

Introduction In CLL, the timing and selection of therapy is largely informed by disease stage, prognostic molecular features, tumor load, and patient (pt) performance status. Duvelisib (DUV) is a novel, oral, dual PI3K-δ,γ inhibitor in clinical development for the treatment of CLL/SLL, FL, and other hematologic malignancies. Results from the Phase 3 DUO study (NCT02004522) for relapsed/refractory CLL/SLL showed that DUV monotherapy resulted in statistically significant improvement over ofatumumab (OFA) monotherapy for median progression-free survival (mPFS; 13.3 vs 9.9 months (mo); p Methods Of the 319 pts enrolled in the DUO study, 158 were treated with DUV and 155 with OFA. Tumor burden was assessed at baseline using target lymph node diameter and absolute lymphocyte count. Baseline blood samples from Cycle1 Day1 were analyzed for cytogenetic abnormalities (17p, 11q, 6q deletions; trisomy 12); immune cell counts by flow cytometry; and serum chemokine, cytokine, and serum factor levels. Univariate analysis of these markers was conducted for PFS and ORR. The statistically significant univariate markers were tested in a stepwise multivariate regression (MVR) model using binary high [H] or low [L] thresholds based on the median. Results Tumor Burden: The mPFS (in mo) for DUV monotherapy did not appear to be impacted by baseline tumor burden: high (n=20), 16.6; medium (n=88), 12.7; and low (n=47), 15.1. Across these tumor burden levels, DUV maintained its PFS advantage over OFA. Cytogenetics: DUV-treated pts with del(11q), a marker associated with poor CLL outcomes, had a longer mPFS (in mo) and ORR compared to pts without del(11q) (mPFS: 24.8, n=25 vs 12.7, n=81; HR 0.56, 95% CI [0.30,1.06]; ORR: 80.0% vs 69.1%, odds ratio, 0.56). In contrast, mPFS was shorter in OFA-treated del(11q) pts relative to those without this deletion (5.3, n=24 vs 11.3, n=71). Median PFS was significantly extended in the del(17p) subgroup for DUV vs OFA (16.6, n=27 vs 9.2, n=27; HR 0.42, [0.21,0.85]), and, to a lesser degree, in pts without del(17p) (13.1, n=83 vs 11.1, n=74; HR 0.55 [0.37,0.83]). For the 6 DUV pts with del(11q/17p), mPFS was 17.4 mo. A shorter mPFS was observed for DUV-treated pts with trisomy 12 compared with trisomy 12-negative pts (9.1, n=16 vs 16.5, n=73). For the 10 DUV pts with trisomy 12 as well as del(11q/17p), mPFS was more similar to the trisomy 12 group, at 9.1 mo. Immune cell profiles and serum factors: Several immune cell profiles correlated with longer mPFS (in mo) for DUV, including Treg (16.4H vs 12.9L, HR 0.69 [0.43,1.12]) and monocytes (15.1L vs 12.7H, HR 0.82 [0.54,1.24]). Baseline chemokine and serum factor levels associated with longer mPFS with DUV included CCL3 (22.1L vs 12.2H, HR 0.60 [0.37,0.99]), IL2RA (16.3L vs 11.6H, HR 0.73 [0.47,1.14]), and TNFα (16.6L vs 12.2H, HR 0.78 [0.49,1.24]). Multivariate regression model: The MVR model showed that the biomarker profile of trisomy 12-negative (HR -/+, 0.15), CCL22L (HR H/L, 2.23), TNFαL (HR H/L, 3.66), TregH (HR H/L, 0.31), and monocytesL (HR H/L, 2.45), was associated with longer PFS; TNFαL and TregH were the largest associations, with estimated 73% and 69% reductions in risk of progression or death, respectively. Similarly, stepwise models yielded TNFαL (odds ratio H/L, 0.37) and CXCL11H (odds ratio H/L, 2.99) as biomarkers for improvement in ORR. Based on these analyses, pts with TNFαL tend to have better efficacy profiles for PFS and/or ORR. Conclusions: DUV monotherapy was highly efficacious in CLL/SLL pts with markers of poor response, including high tumor burden, del(17p), and del(11q) as shown by univariate analyses of tumor burden, cytogenetics, immune cell profiles, and serum factors. Multivariate analyses revealed a biomarker profile of CCL22L, TNFαL, TregH, monocytesL, and trisomy 12-negative that correlated with improved mPFS and/or ORR. Additional analyses are underway to characterize the predicted PFS for the biomarker profile. Disclosures Brown: Verastem: Consultancy, Research Funding; Janssen: Consultancy; Morphosys: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy; Sun Pharmaceutical Industries: Research Funding; TG Therapeutics: Consultancy; Sunesis: Consultancy; Gilead: Consultancy, Research Funding; Roche/Genentech: Consultancy; Genentech: Consultancy; Celgene: Consultancy; Boehringer: Consultancy; Beigene: Membership on an entity's Board of Directors or advisory committees; Acerta / Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy; Invectys: Membership on an entity's Board of Directors or advisory committees; Loxo: Consultancy. Flinn:Novartis: Research Funding; Merck: Research Funding; Infinity: Research Funding; Forty Seven: Research Funding; Janssen: Research Funding; Trillium: Research Funding; Pharmacyclics: Research Funding; Verastem: Research Funding; Pfizer: Research Funding; Kite: Research Funding; Takeda: Research Funding; Forma: Research Funding; BeiGene: Research Funding; Curis: Research Funding; Seattle Genetics: Research Funding; TG Therapeutics: Research Funding; Verastem: Consultancy, Research Funding; Portola: Research Funding; Calithera: Research Funding; ArQule: Research Funding; Celgene: Research Funding; Constellation: Research Funding; Genentech: Research Funding; Incyte: Research Funding; Gilead: Research Funding; Agios: Research Funding. Davids:Surface Oncology: Research Funding; Merck: Consultancy; Roche/Genentech: Consultancy, 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; AbbVie, Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; MEI Pharma: Consultancy, Research Funding; Verastem: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hillmen:F. Hoffmann-La Roche Ltd: Research Funding; Celgene: Research Funding; Alexion Pharmaceuticals, Inc: Consultancy, Honoraria; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc.: Honoraria, Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees. Montillo:Gilead: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Speakers Bureau. Tam:Janssen: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BeiGene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jaeger:GSK: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP Orphan: Membership on an entity's Board of Directors or advisory committees; Bioverativ: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda-Millenium: 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; Takeda-Millenium: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Infinity: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; MSD: Research Funding. Ghia:Sunesis: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; BeiGene: Honoraria, Research Funding; Acerta: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; AbbVie, Inc: Honoraria, Research Funding. Stilgenbauer:Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Moreno:Janssen: Consultancy; AbbVie: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy. Le:Verastem Oncology: Employment. Lustgarten:Verastem Oncology: Employment. Sprott:Verastem Oncology: Employment. Pachter:Verastem Inc: Employment, Other: Stockholder. Weaver:Agios Pharmaceuticals: Employment; Verastem Oncology: Employment, Other: Stockholder; Femto Dx: Equity Ownership.

Background : Ibrutinib (ibr), a first-in-class, once-daily inhibitor of Bruton's tyrosine kinase, is approved in the US and EU for patients (pts) with CLL and allows for treatment without chemotherapy. Standard of care for first-line CLL in older pts or those with comorbidities includes single-agent ibr or chemoimmunotherapy (CIT) with chlorambucil (clb) plus anti-CD20 therapy. As no data were available from phase 3 studies directly comparing single-agent ibr with CIT, we performed a cross-trial analysis using data from two phase 3 studies to assess single-agent ibr vs clb plus obinutuzumab (G) in first-line CLL. Methods : In the ongoing PCYC-1115/1116 (RESONATE-2), pts with previously untreated CLL/SLL aged ≥65 years without del(17p) were randomized to receive ibr (420 mg once daily continuously) or clb. In PCYC-1130 (iLLUMINATE), pts with untreated CLL/SLL aged ≥65 years or Results : Primary analysis included 136 pts treated with single-agent ibr and 98 pts treated with clb-G. Median age was 73 years in both groups. High-risk genomic features were generally well balanced (54% and 58% of pts, respectively), including del(11q) (21% and 22%), TP53 mutations (9% and 5%), and unmutated IGHV (43% and 46%). Bulky disease (≥5 cm) was present in 40% and 37% of pts, respectively. Median follow-up was 48.8 mo for ibr and 31.3 mo for clb-G. Single-agent ibr significantly prolonged PFS compared with clb-G (median not reached [NR] vs 22.2 mo), with an 82% reduction in risk of progression or death (HR 0.184; P Conclusions : Despite limitations of this cross-trial analysis, results suggest that PFS with single-agent ibr was superior to clb-G, including, importantly, in patients with high-risk genomic characteristics or bulky disease. In a time-matched analysis, AE profile with single-agent ibr appeared favorable to clb-G. In comparing ibr and ibr-G, lymphocytosis was more common with ibr than ibr-G but resolved in almost all pts, and ORR was similar for ibr and ibr-G. While CR rate was higher for ibr-G vs ibr, CR was not needed to achieve long-term PFS benefit with single-agent ibr. Disclosures Tedeschi: AbbVie: Consultancy; Gilead: Consultancy; Janssen: Consultancy, Speakers Bureau. Greil:Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; Astra Zeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sandoz: Honoraria, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Honoraria, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; MSD: Honoraria, Research Funding. Demirkan:AbbVie: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; Amgen: Consultancy, Research Funding; Janssen: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding. Robak:Janssen: Consultancy, Honoraria; AbbVie, Inc: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria; Gilead: Consultancy. Moreno:AbbVie: Consultancy; Janssen: Consultancy; Pharmacyclics LLC, an AbbVie Company: Consultancy. Barr:AbbVie, Gilead: Consultancy. Simpson:Acerta: Research Funding; Merck: Honoraria, Research Funding; BeiGene: Research Funding; Sanofi: Research Funding; Bristol-Myers Squibb: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Novartis: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; MSD: Honoraria; Pharmacyclics LLC, an AbbVie Company: Research Funding; Roche: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Amgen: Research Funding, TRAVEL, ACCOMMODATIONS, EXPENSES; Janssen: Honoraria, Research Funding. Gaidano:Morphosys: Honoraria; Amgen: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Bairey:Jansen: Research Funding; AbbVie: Consultancy; ROCHE: Research Funding. Stevens:Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees. Gill:Janssen: Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau. Flinn:Takeda: Research Funding; Calithera: Research Funding; Agios: Research Funding; Forma: Research Funding; Trillium: Research Funding; Infinity: Research Funding; ArQule: Research Funding; Gilead: Research Funding; TG Therapeutics: Research Funding; Incyte: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding; Verastem: Research Funding; Genentech: Research Funding; Kite: Research Funding; Curis: Research Funding; Portola: Research Funding; Novartis: Research Funding; Verastem: Consultancy, Research Funding; Merck: Research Funding; BeiGene: Research Funding; Celgene: Research Funding; Pfizer: Research Funding; Forty Seven: Research Funding; Constellation: Research Funding; Seattle Genetics: Research Funding. Kipps:Verastem: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; F. Hoffmann-La Roche Ltd: Consultancy, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech Inc: Consultancy, Research Funding; Verastem: Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Lin:Pharmacyclics LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Webb:Janssen: Employment; Johnson & Johnson: Equity Ownership. Fedorov:Pharmacyclics LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Styles:Pharmacyclics LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Gribben:TG Therapeutics: Honoraria; Pharmacyclics: Honoraria; NIH: Research Funding; Novartis: Honoraria; Acerta Pharma: Honoraria, Research Funding; Abbvie: Honoraria; Kite: Honoraria; Roche: Honoraria; Unum: Equity Ownership; Wellcome Trust: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Cancer Research UK: Research Funding; Medical Research Council: Research Funding.

We analyzed prevalence, characteristics, clinical correlates, and prognostic significance of autoimmune cytopenia in patients with chronic lymphocytic leukemia. Seventy of 960 unselected patients (7%) had autoimmune cytopenia, of whom 19 were detected at diagnosis, 3 before diagnosis, and 48 during the course of the disease. Forty-nine patients had autoimmune hemolytic anemia, 20 had immune thrombocytopenic purpura, and 1 had both conditions. A clear association was observed between autoimmune cytopenia and poor prognostic variables (ie, high blood lymphocyte count, rapid blood lymphocyte doubling time, increased serum β-2 microglobulin level, and high expression of ζ-associated protein 70 and CD38). Nevertheless, the outcome of patients with autoimmune cytopenia as a whole was not significantly different from that of patients without this complication. Furthermore, no differences were observed according to time at which cytopenia was detected (ie, at diagnosis, during course of disease). Importantly, patients with advanced (Binet stage C) disease because of an autoimmune mechanism had a significantly better survival than patients in advanced stage related to a massive bone marrow infiltration (median survivals: 7.4 years vs 3.7 years; P = .02). These results emphasize the importance of determining the origin of cytopenia in patients with chronic lymphocytic leukemia for both treatment and prognostic purposes.

Clonal evolution and outgrowth of cellular variants with additional chromosomal abnormalities are major causes of disease progression in chronic lymphocytic leukemia (CLL). Because new DNA lesions occur during S phase, proliferating cells are at the core of this problem. In this study, we used in vivo deuterium (2H) labeling of CLL cells to better understand the phenotype of proliferating cells in 13 leukemic clones. In each case, there was heterogeneity in cellular proliferation, with a higher fraction of newly produced CD38+ cells compared with CD38− counterparts. On average, there were 2-fold higher percentages of newly born cells in the CD38+ fraction than in CD38− cells; when analyzed on an individual patient basis, CD38+2H-labeled cells ranged from 6.6% to 73%. Based on distinct kinetic patterns, interclonal heterogeneity was also observed. Specifically, 4 patients exhibited a delayed appearance of newly produced CD38+ cells in the blood, higher leukemic cell CXC chemokine receptor 4 (CXCR4) levels, and increased risk for lymphoid organ infiltration and poor outcome. Our data refine the proliferative compartment in CLL based on CD38 expression and suggest a relationship between in vivo kinetics, expression of a protein involved in CLL cell retention and trafficking to solid tissues, and clinical outcome.

Whether advances in treatment are prolonging survival of patients with chronic lymphocytic leukemia (CLL) is unclear. We analyzed presentation patterns and survival over time in 929 patients followed from 1980 to 2008 at the Hospital Clinic of Barcelona. The 5- and 10-year relative survival (adjusted for the expected survival in the general population) was estimated in patients seen in 2 periods of time: 1980-1994 (n = 451) and 1995-2004 (n = 365). We found that CLL shortens life expectancy in all age groups independently of clinical features at diagnosis. Nevertheless, survival is improving, particularly in some groups of patients. Thus, relative survival was significantly higher in the 1995-2004 cohort than in the 1980-1994 group both at 5 years (incidence rate ratio [IRR] = 0.46; P = .004) and 10 years (IRR = 0.65; P = .007) from diagnosis. The improved survival was largely due to a decrease in CLL-attributable mortality in patients younger than 70 years in Binet stage B or C at diagnosis (IRR = 0.40; P = .001 at 5 years; IRR = 0.33; P < .001 at 10 years). These results suggest that newer treatments are changing the prognosis of CLL, particularly in younger patients with advanced disease, whereas no improvement is yet observed in older subjects or those with lower-risk disease.

Somatic hypermutation (SHM) features in a series of 1967 immunoglobulin heavy chain gene (IGH) rearrangements obtained from patients with chronic lymphocytic leukemia (CLL) were examined and compared with IGH sequences from non-CLL B cells available in public databases. SHM analysis was performed for all 1290 CLL sequences in this cohort with less than 100% identity to germ line. At the cohort level, SHM patterns were typical of a canonical SHM process. However, important differences emerged from the analysis of certain subgroups of CLL sequences defined by: (1) IGHV gene usage, (2) presence of stereotyped heavy chain complementarity-determining region 3 (HCDR3) sequences, and (3) mutational load. Recurrent, “stereotyped” amino acid changes occurred across the entire IGHV region in CLL subsets carrying stereotyped HCDR3 sequences, especially those expressing the IGHV3-21 and IGHV4-34 genes. These mutations are underrepresented among non-CLL sequences and thus can be considered as CLL-biased. Furthermore, it was shown that even a low level of mutations may be functionally relevant, given that stereotyped amino acid changes can be found in subsets of minimally mutated cases. The precise targeting and distinctive features of somatic hypermutation (SHM) in selected subgroups of CLL patients provide further evidence for selection by specific antigenic element(s).

We analyzed minimal residual disease (MRD) by consensus polymerase chain reaction (PCR), quantitative PCR (qPCR), and flow cytometry in 40 patients with chronic lymphocytic leukemia (CLL) who underwent stem cell transplantation; 97.4%, 89%, and 100% of the patients could be studied by consensus PCR, qPCR, and flow cytometry, respectively. Overall, 164 of 248 samples were negative for MRD by consensus PCR. Among those, CLL cells were detected by qPCR and by flow cytometry in 77 (47%) and 39 (23%) of the 164 samples, respectively. All 84 samples positive on PCR had detectable CLL cells by qPCR and flow cytometry. A good correlation was seen between MRD levels by flow cytometry and by qPCR (n = 254; r = 0.826; P < .001). Fifteen of 25 patients receiving autografts suffered a relapse, with increasing levels of MRD being observed before relapse in all of them. MRD detection within the first 6 months after autologous transplantation identified patients with a high relapse risk. In contrast, in allografted patients (n = 15) MRD did not correlate with outcome. In conclusion, quantitative methods to assess MRD (flow cytometry and qPCR) are more accurate than consensus PCR to predict clinical evolution. These results might be useful to investigate treatments aimed at preventing relapse in patients with CLL who have received an autograft.

Therapy for patients with chronic lymphocytic leukemia (CLL) has greatly changed over the past few years. After years of stagnation, with treatment revolving around the use of rather ineffective drugs such as alkylators, many patients are now being treated with more effective agents such as purine analogs either alone or combined with other drugs and/or monoclonal antibodies. Treatment of patients refractory to these treatments is particularly challenging and should be decided only upon a careful evaluation of the disease, patient characteristics, and prognostic factors. Refractory disease should be clearly separated from relapsing disease. The only curative therapy for patients with CLL, including those with refractory disease, is allogeneic stem cell transplantation. However, the use of allogeneic transplantation is limited because of the advanced age of most patients and the high transplant-related mortality (TRM). Transplants with nonmyeloablative regimens may reduce TRM and allow more patients to receive transplants more safely. For patients in whom an allogeneic transplantation is not feasible or in whom it is deemed inappropriate, participation in phase 2 trials should be encouraged. Finally, to investigate mechanisms to overcome resistance to therapy in CLL and to identify patients that might gain benefit from early, intensive therapies (eg, based on biologic markers) constitute a challenge that needs active investigation.

Introduction: Allogeneic hematopoietic stem cell transplantation (HCT) is a treatment for CLL that can give long disease control. Even with the availability of kinase and BCL2 inhibitors, HCT is still performed in fit patients (pts) with high-risk CLL. Almost exclusively, outcomes on matched related and unrelated donor transplantations in CLL have been published. Recently, mismatched related donors are gaining interest because of the better outcome of haploidentical HCT with post-transplantation cyclophosphamide (PTCY). Methods: All pts with CLL who received a first allogeneic HCT with a mismatched related donor and whose data were available in the EBMT registry were analyzed. Median values and ranges are reported for continuous variables and percentages for categorical variables. The probabilities of overall survival (OS) and progression-free survival (PFS) were calculated using the Kaplan-Meier method and the log-rank test for univariate comparisons. Relapse/progression and nonrelapse mortality (NRM) were analyzed together in a competing risk framework. Statistical analyses were performed using SPSS and R. Results: One-hundred-seventeen pts with CLL (74% males) underwent a mismatched related donor transplantation between 1984 and 2015 (1984-1999: 10, 2000-2004: 18, 2005-2009: 23, 2010-2016: 66). Median follow-up after HCT was 8 months (range 0-187 months). Median age at transplantation was 54 years (yrs) (range 27-71 yrs). Median time from diagnosis to HCT was 67 months (range 4-207 months). Eighteen pts (17%) had previously undergone autologous stem cell transplantation (ASCT). Disease status at HCT was CR in 16% of pts, PR in 39% and SD/PD in 45%. The Karnofsky score was known for 98 pts; 96% had a score of 70% or more at the time of HCT. Fifty-eight percent of pts received reduced-intensity conditioning, 42% myeloablative conditioning. Peripheral blood stem cells were used in 68% of pts, bone marrow in 32%. The HCT was sex matched in 41% of recipient-donor pairs. The relationship of the donor to the patient was known for 34 pts; in 53% the donor was a child, in 38% a sibling and in 6% a parent. Forty pts (38%) received PTCY as GVHD prophylaxis. In the other 77 pts various methods of T-cell depletion (TCD) were used, but not all methods were specified. At least 56% of those pts had in vivo TCD. For the whole cohort of pts OS at 2 and 5 yrs was 46% and 37%, respectively. PFS at 2 and 5 yrs was 38% and 30%, respectively. The use of PTCY did not have a significant impact on OS (49% vs. 42% at 2 yrs, 44% vs. 33% at 5 yrs, p=0.35) and PFS (45% vs. 31% at 2 yrs, 40% vs. 22% at 5 yrs, p=0.15). CI of NRM in the whole group at 2 and 5 yrs were 41% and 45%, respectively. CI of relapse at 2 and 5 yrs were 21% and 25%, respectively. The CI of NRM and relapse at 2 and 5 yrs were not statistically different in pts who received PTCY compared to other types of TCD (NRM: 38% vs. 45% at 2 yrs, 43% vs. 49% at 5 yrs, p=0.45; relapse: 17% vs. 25% at 2 yrs, 17% vs. 29% at 5 yrs, p=0.33). For the whole cohort, the incidence of acute graft-versus-host disease (aGVHD) at 100 days was 34% for grade II-IV and 16% for grade III-IV with a median time of onset of 23 days (range 4-57 days). Conclusions: Mismatched related donor HCT resulted in a 5-year PFS in 30% of the pts. This result seems only slightly inferior to matched donor transplant (5 yrs PFS 37%1). NRM was higher than expected in this cohort, but comparable to other studies on haploSCT with in vivo T-cell depleted grafts. In conclusion, a mismatched related donor HCT may be considered for high-risk chemoimmunotherapy-refractory or 17p deleted/TP53 mutated CLL pts without options for kinase and BCL2 inhibitor therapy. More data are needed to assess the value of PTCY for GVHD prophylaxis in this specific context. References: 1. Schetelig J, de Wreede L, Moreno C, et al. Risk factors for adverse outcome in patients with Chronic Lymphocytic Leukemia (CLL) undergoing Allogeneic Hematopoietic Cell transplantation (alloSCT): a Retrospective EBMT Analysis. Abstract WP024, EBMT meeting 2015. Figure 1 Figure 1. Disclosures Ciceri: MolMed SpA: Consultancy. Foà:Ariad: Speakers Bureau; Pfizer: Speakers Bureau; BMS: Consultancy; Celgene: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Janssen-Cilag: Consultancy, Speakers Bureau; Genetech: Consultancy; Roche: Consultancy, Speakers Bureau. Hallek:Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding, Speakers Bureau. Schetelig:Sanofi: Honoraria. Kröger:Sanofi: Honoraria, Research Funding; Neovii: Honoraria, Research Funding; Riemser: Honoraria, Research Funding; Novartis: Honoraria, Research Funding.

Background: In CLL/SLL, the iwCLL PR category is heterogeneous and complex to evaluate. Changes in clinical staging (Binet, Rai) have been proposed as a method to evaluate response in CLL (Montserrat, Cancer 1985; iwCLL, Ann Intern Med 1989). Ibrutinib (ibr), a first-in-class, once-daily inhibitor of Bruton's tyrosine kinase, is indicated by the FDA for the treatment of pts with CLL/SLL and allows for treatment without chemotherapy. Robust improvements in progression-free survival (PFS) and overall survival (OS) among ibr-treated pts in the phase 3 RESONATE trial demonstrated superiority of ibr over ofatumumab (ofa) in heavily pretreated CLL, regardless of prognostic features. As the majority of ibr pts achieved iwCLL PR or PR-L manifested by improved hematologic function and/or disease burden, we analyzed RESONATE pts with PR or PR-L by Binet stage to determine if clinical downstaging captures different, clinically meaningful subgroups among patients in iwCLL PR/PR-L. Methods: Among 391 previously treated CLL pts randomized to receive oral ibr (n=195) or intravenous ofa (n=196), those who achieved a best overall response of PR or PR-L were assessed for Binet Stage at time of first response. Stage A was defined as no anemia or thrombocytopenia and Results: A total of 162 (83%) ibr pts and 45 (23%) ofa pts achieved PR/PR-L as best overall response as assessed by investigator; 53% of ibr responders were PR and 46% were PR-L at first response. Baseline characteristics (age, prior therapy, marrow infiltration, unmutated IGHV) were balanced between arms. A majority of PR/PR-L ibr pts were downstaged to Stage A reflecting improvement in lymphadenopathy/organomegaly and/or cytopenias with treatment. At time of first PR/PR-L, the proportion of Stage C pts decreased from 44% (n=72) at baseline to 27% (n=44) for the ibr arm and from 42% (n=19) to 33% (n=15) for the ofa arm. While maintaining PR/PR-L, 48% of ibr-treated and 40% of ofa-treated pts shifted from Stage C to A (or to B/A). The efficacy of ibr over ofa in PR/PR-L pts was similar to that observed in the intent-to-treat population for median PFS (not reached [NR] for ibr vs. 8.48 mo for ofa, P Conclusions: This ad-hoc analysis shows that changes in clinical stage break down the PR/PR-L (iwCLL) category into different, clinically meaningful subgroups, and reinforces the notion that improving cytopenias is a desirable goal of CLL therapy with ibrutinib (Barrientos, ASH 2014). Altogether, this study demonstrates that changes in clinical stage could be a useful and non-costly method to evaluate treatment response at different time points over the course of the disease, a concept with potential clinical implications that requires validation in prospective clinical trials. Disclosures Delgado: Janssen: Consultancy, Honoraria; Novartis/GSK: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Research Funding; Infinity: Research Funding. Suzuki:AbbVie: Equity Ownership; Pharmacyclics, LLC, an Abbie Company: Employment, Other: Leadership, travel, accommodations, expenses. Hsu:AbbVie: Equity Ownership; Pharmacyclics, LLC, an Abbie Company: Employment. James:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Montserrat:Vivia Biotech: Equity Ownership; Pharmacyclics: Consultancy; Janssen: Honoraria, Other: travel, accommodations, expenses; Morphosys: Other: Expert Testimony; Gilead: Consultancy, Other: Expert Testimony.

Background: Ibrutinib (ibr), a first-in-class, oral once-daily inhibitor of Bruton's tyrosine kinase, is indicated by the US FDA for the treatment of pts with CLL/SLL and allows for treatment without chemotherapy. Unlike chemotherapy that is given for a finite number of cycles, ibr is continued until progressive disease (PD) or unacceptable toxicity, leading to extended ibr treatment duration in many patients. The objective was to examine safety and tolerability of ibr therapy in pts with treatment-naïve (TN) or relapsed/refractory (R/R) CLL/SLL using an integrated safety analysis approach, and conduct an analysis of long-term safety. Methods: In study PCYC-1112 (RESONATE), pts with R/R CLL/SLL received ibr 420 mg orally once-daily vs. ofatumumab (Byrd, N Engl J Med 2015). In study PCYC-1115 (RESONATE-2), pts age ≥65 years with TN CLL/SLL received ibr 420 mg orally once-daily vs. chlorambucil (Burger, N Engl J Med 2015). Progressing pts could enroll in the extension study PCYC-1116 for next line therapy (including ibr). Data from ibr-treated pts from the above randomized controlled studies were pooled for an integrated safety analysis. In study PCYC-1102, pts with TN or R/R CLL/SLL received ibr 420 mg or 840 mg orally once-daily (Byrd, N Engl J Med 2013; O'Brien, Lancet Oncol 2014). Pts could continue receiving ibr in the long-term extension study PCYC-1103 where adverse event (AE) collection was limited to grade ≥3 AEs, major hemorrhage, or AEs leading to ibr dose modification. Only data from pts treated with ibr 420 mg daily were examined herein. Results: The integrated analysis included 330 pts; 51% Rai III/IV, 54% bulky disease ≥5 cm, 28% del11q, and 37% CrCl 1 year, 193 (58%) for >2-3 years, and 53 (16%) for >3 years. Concomitant medications included 50% antiplatelet agents, 28% anticoagulants, 3% granulocyte growth factors, and 2% IVIG. The most common AEs were diarrhea (53%) and fatigue (36%). Other AEs experienced by ≥25% of pts were upper respiratory tract infection (30%), nausea (29%), pyrexia (28%), and anemia (27%). Grade ≥3 AEs reported in ≥5% of pts were neutropenia (18%), pneumonia (12%), anemia (7%), and hypertension (HT, 6%). AEs of interest were primarily grade 1/2 (Table). AEs of any grade that led to dose reductions and discontinuation were reported in 13% and 19% of pts, respectively. AEs leading to discontinuation in >1 pt were pneumonia (n=4), anemia (n=3), atrial fibrillation (AFib, n=3), diarrhea (n=2), subdural hematoma (n=2), and thrombocytopenia (n=2). 29 pts died (9%), the most common causes of death were PD (n=8), and pneumonia/lung infection (n=7). In PCYC-1102/1103, 94 pts were treated with ibr for a median of 47.9 mo (max 67.4 mo). The most frequent grade ≥3 AEs were similar to those observed in PCYC-1112 or PCYC-1115/1116, and at times, reflect higher cumulative rates given the median 19 additional months of treatment and follow-up; grade ≥3 AEs reported in ≥5% of pts were hypertension (30%), pneumonia (17%), neutropenia (15%) atrial fibrillation (11%), diarrhea (9%), cellulitis (7%), thrombocytopenia (7%), hyperglycemia (7%), fatigue (6%), decrease in lymphocyte count (6%), and sepsis (5%). Most frequent malignancies included basal cell carcinoma (n=4), squamous cell carcinoma (n=4), and myelodysplastic syndromes (n=2). In 7 of 15 pts, the malignancy AE was diagnosed during the first year, while others occurred over time throughout the ongoing follow-up of >4 years. Overall survival for R/R pts was 74% at 36 mo in PCYC-1112, and 62% at 60 mo in PCYC-1102/1103. Survival of TN pts was 95% at 24 mo in PCYC-1115/1116, and 91% at 60 mo in PCYC-1102/1103 (Kaplan-Meier estimates). Conclusions: In these analyses, which included up to 5 years of follow up in TN and R/R CLL treated with single agent ibr, AEs were primarily grade 1/2 and were manageable with prolonged treatment. Disclosures Coutre: Janssen: Consultancy; Pharmacylics, LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Research Funding. Hillmen:Pharmacyclics: Research Funding; Janssen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Research Funding. Barr:Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; AbbVie: Consultancy. Devereux:Roche: Consultancy, Other: Travel, Accommodations, Expenses ; Gilead: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau; Janssen: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau; GSK: Consultancy. Robak:Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Kipps:Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria. Schuh:Roche: Consultancy, Honoraria; GSK: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria. Furman:Genentech: Consultancy; Janssen: Consultancy; Abbvie: Consultancy, Honoraria; Gilead Sciences: Consultancy; Pharmacyclics: Consultancy, Speakers Bureau. Burger:Janssen: Consultancy, Other: Travel, Accommodations, Expenses; Roche: Other: Travel, Accommodations, Expenses; Gilead: Research Funding; Pharmacyclics, LLC, an AbbVie Company: Research Funding; Portola: Consultancy. O'Dwyer:Roche: Other: Travel, accommodations, expenses; Novartis: Consultancy; Glycomimetics: Consultancy; Amgen: Consultancy, Other: Travel, Accommodations, Expenses ; BMS: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Equity Ownership, Honoraria, Research Funding; NUI Galway: Patents & Royalties. Ghia:Abbvie: Consultancy, Honoraria; Adaptive: Consultancy; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Roche: Honoraria, Research Funding. Valentino:Gilead: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment, Other: Travel, accommodations, and expenses; AbbVie: Equity Ownership; Corvus: Equity Ownership; Johnson and Johnson: Equity Ownership, Other: Travel, accommodations, and expenses. Suzuki:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment, Other: Leadership; Travel, Accommodations, Expenses. Ninomoto:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment; Amgen: Equity Ownership. James:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment. O'Brien:Janssen: Consultancy, Honoraria; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding.

Background: Chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) occurs primarily in older patients (pts) who often have increased comorbidities and cannot tolerate aggressive treatments, which leads to poorer outcomes (Balducci, Cancer Control 2015; Thurmes, Leuk Lymphoma 2008). Alkylating agents, such as chlorambucil (clb), have been commonly used to treat these pts (Eichhorst, Blood 2009). Ibrutinib (ibr), a first-in-class, once-daily, inhibitor of Bruton's tyrosine kinase, is indicated by the US FDA for the treatment of pts with CLL/SLL and allows for treatment without chemotherapy. RESONATE-2 (PCYC-1115) is a randomized phase 3 trial designed to compare the efficacy and safety of ibr vs clb in pts with treatment-naïve (TN) CLL/SLL (Tedeschi, ASH 2015). Primary results, as assessed by an independent review committee (IRC), demonstrated with a median follow-up of 18.4 mo that ibr significantly reduced the risk of progression or death by 84% (P Methods: Eligible pts with TN CLL/SLL aged ≥65 y were randomized 1:1 to receive 420 mg ibr daily until progression or 0.5 mg/kg clb (max 0.8 mg/kg) on days 1 and 15 of a 28-d cycle for up to 12 cycles. Pts with del17p were excluded. Pts were stratified by ECOG status and Rai stage. The primary endpoint was PFS per iwCLL 2008 criteria, with 2012 clarification for treatment related lymphocytosis. Secondary endpoints included OS, ORR, rate of hematologic improvement, and safety; longer term follow-up safety data focused on ibr. Pts in the 1115 study with progressive disease (PD) were enrolled in the PCYC-1116 extension study. At 1115 study closure, all pts in 1115 rolled over to 1116. Pts on the clb arm with PD could cross-over to ibr or investigator's choice. Results: Median age of the 269 pts was 73 y (70% ≥70 y). Baseline characteristics were balanced between arms; 45% had advanced Rai stage, 20% had del11q, and 69% had comorbidities at baseline, including CIRS score >6, reduced creatinine clearance, or ECOG performance status of 2. With a median follow-up of 28.6 mo, prolongation of PFS for ibr vs clb was sustained (89% vs 34% at 24-mo; HR, 0.121; 95% CI 0.074-0.198; P Conclusions: With a median time on study of 28.6 mo, ibr continued to have substantial efficacy, with 88% reduction in risk of progression or death. Furthermore, the quality of responses has improved over time, with 18% of CLL/SLL pts achieving a CR/CRi with single agent ibr. Treatment limiting AEs decreased in frequency with longer follow-up, with 79% of this elderly pt population continues daily ibr. Lastly, even with a high rate of cross-over in the clb arm, OS remains significantly improved for pts randomized to ibr. Disclosures Barr: AbbVie: Consultancy; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Research Funding. Robak:AbbVie: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Owen:Gilead: Honoraria, Research Funding; Janssen: Honoraria; Lundbeck: Honoraria; Roche: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria; Celgene: Honoraria; Pharmacyclics, LLC, an AbbVie Company: Research Funding. Bairey:Janssen: Consultancy. Bartlett:Gilead: Consultancy. Burger:Janssen: Consultancy, Other: Travel, Accommodations, Expenses; Portola: Consultancy; Pharmacyclics, LLC, an AbbVie Company: Research Funding; Gilead: Research Funding; Roche: Other: Travel, Accommodations, Expenses. Hillmen:Pharmacyclics: Research Funding; Janssen: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Research Funding. Coutre:AbbVie: Research Funding; Pharmacylics, LLC, an AbbVie Company: Consultancy, Research Funding; Janssen: Consultancy. Devereux:Roche: Consultancy, Other: Travel, Accommodations, Expenses ; Gilead: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau; GSK: Consultancy; Janssen: Consultancy, Other: Travel, Accommodations, Expenses, Speakers Bureau. McCarthy:Roche: Consultancy, Other: Travel, Accomodations, Expenses; Chugai: Other: Travel, Accomodations, Expenses; Celgene: Other: Travel, Accomodations, Expenses. Simpson:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees. Offner:Novartis: Consultancy; GSK: Consultancy. Zhou:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment. Styles:AbbVie: Equity Ownership; Pharmacyclics, LLC, an AbbVie Company: Employment. James:Pharmacyclics, LLC, an AbbVie Company: Employment; AbbVie: Equity Ownership. Kipps:Roche: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Pharmacyclics, LLC, an AbbVie Company: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau. Ghia:Janssen: Consultancy; Pharmacyclics, LLC, an AbbVie Company: Consultancy; Roche: Consultancy, Research Funding; GSK: Research Funding; AbbVie: Consultancy; Adaptive: Consultancy; Gilead: Consultancy, Research Funding, Speakers Bureau.

In this issue of Blood, Jitschin et al demonstrate a microenvironmental glycolytic shift in chronic lymphocytic leukemia (CLL) cells mediated by Notch-c-Myc signaling. Interfering in the Notch-c-Myc pathway and reprogramming glycolytic metabolism could contribute to overcoming drug resistance in CLL.

BACKGROUND The Fcγ receptor IIb (FcγRIIb) is an inhibitory Fcγ receptor that suppresses B-cell activation when coligated with B-cell antigen receptor (BCR). Previous studies from our group indicate that the ability of the FcγRIIb to inhibit BCR signaling after coligation is attenuated in Chronic Lymphocytic Leukemia (CLL). Furthermore, in contrast to what has been described in normal murine B-cells, stimulation of the FcγRIIb alone induces proliferation of CLL cells. However, the correlation between FcγRIIb expression, immunophenotypic characteristics, and clinical variables in patients with CLL has not been studied. AIM The aim of this study was to correlate the expression of FcγRIIb on leukemic cells from previously untreated CLL patients and its immunophenotypic features and clinical parameters. METHODS The study population included 112 patients with untreated CLL for whom cryopreserved peripheral blood samples were available before treatment. The diagnosis was based on IWCLL 2008 criteria. The median patients' follow up was 57.92 months (range: 2.23-439.78 months). FcγRIIb expression levels were determined by flow cytometry on CD5+/CD19+ CLL cells using a specific Alexa488-conjugated murine mAb specific for human FcγRIIb. The following combinations were assessed: FcγRIIb/CD38/CD19/CD5, FcγRIIb/CD49d/CD19/CD5, and FcγRIIb/CD69/CD19/CD5. Results were expressed as the ratio between the MFI for FcγRIIb and the MFI for the corresponding isotype (MFIR). FcγRIIb expression levels were correlated with: i) expression of CD49d, CD38 and CD69, ii) clinico-biological characteristics, and iii) clinical outcome. Differences of FcγRIIb expression on dichotomized clinicopathological variables were assessed with Mann Whitney test. Kaplan-Meier survival and Cox regression analysis were performed to evaluate the correlation of FcγRIIb expression with clinical outcome. Best cut-offs for overall survival (OS) and treatment-free survival (TFS) were determined by ROC curves. RESULTS All CD5+CD19+ leukemic cells samples expressed FcγRIIb. However, FcγRIIb expression levels markedly varied between patients (median MFIR: 45.8; interquartile range: 14.9-76.6; 5th -95th percentile: 17.15-111.4). FcγRIIb expression was significantly higher in patients who had high (≥30%) CD49d expression than in those with low ( In univariate analysis, low FcγRIIb expression levels (MFIR< 26.67) were associated with shorter OS (HR 4.01, 95%CI 1.15-13.90, p=0.029), together with older age, advanced stage, and expression of CD38 and CD49d. Advanced stage, unmutated IGHV, and CD38, CD49d and ZAP-70 expression were also associated significantly with shorter TFS. Thus, patients with higher levels of FcγRIIb had better survival than those with lower levels (Log rank test, p = 0.018). A multivariate analysis adjusted for FcγRIIb expression, age, disease stage, CD38, and CD49d identified older age (≥65 yrs) (HR 150.76, 95%CI 5.39-4212.42, p =0.003), low FcγRIIb expression (HR 111.91, 95%CI 6.71-1866.97, p =0.001), advanced stage (B/C) (HR 17.44, 95%CI 1.45-210.24, p =0.024) and CD38 expression (HR 5.02, 95%CI 1.01-25.18, p =0.050) as independent predictors for shorter OS. CONCLUSIONS In this study, FcγRIIb expression on leukemic cells from untreated patients with CLL was found to be an independent prognostic marker for OS, overcoming the prognostic value of CD49d, which is consistent with the key role of the FcγRIIb in the pathogenesis of CLL. Further analysis aimed at validating this observation and to better understand the functional cooperation of FcγRIIb with other molecules, particularly CD49d, are warranted. These studies could open a new venue in CLL treatment. Disclosures Gorlatov: MacroGenics: Employment. Sierra:Novartis: Research Funding; Celgene: Research Funding; Amgen: Research Funding.

Despite a wealth of information about the structure of surface membrane immunoglobulin (smIg) on chronic lymphocytic leukemia (CLL) cells, little is known about epitopes reacting with their binding sites. Probing phage-displayed peptide libraries, we identified and characterized mimetopes for Igs of 4 patients with IGHV mutated CLL (M-CLL) and 4 with IGHV unmutated CLL (U-CLL). Six of these mAbs were representatives of stereotyped B-cell receptors characteristic of CLL. We found that mimetic epitopes for U- and M-CLL Igs differed significantly. M-CLL–derived peptides exhibited better amino acid motifs, were more similar to each other, aligned more easily, and formed tighter clusters than U-CLL–derived peptides. Mono-, oligo-, and polyreactivity of peptides correlated with structural changes within antigen-binding sites of selecting M-CLL mAbs. Although M-CLL–isolated peptides and certain U-CLL mAbs bound more effectively to the selecting mAb, others were not as specific, reacting with M-CLL and U-CLL mAbs; these data suggest that in vivo structurally diverse epitopes could bind smIgs of distinct CLL clones, thereby altering survival and growth. Finally, an M-CLL–derived peptide inhibited, in a dose-dependent manner, binding of its homologous mAb to human B lymphocytes; therefore peptides that inhibit or alter the consequences of antigen-smIg interactions may represent therapeutic modalities in CLL.

Background. Fludarabine, cyclophosphamide, and rituximab (FCR) has represented a significant advancement in the treatment of patients with chronic lymphocytic leukemia (CLL) and has the potential of inducing durable remissions of the disease. In the new scenario of targeted agents for CLL, there is an increasing interest in identifying patients who may gain the maximum benefit in terms of disease control by a single shot of FCR chemo-immunotherapy. Purpose. Here we aimed at identifying predictors of durable remission after first line FCR treatment. Methods. The study was based on 405 progressive and previously untreated CLL patients who consecutively received standard FCR (up to 6 cycles) as first line therapy in 19 hematologic centers between 2001 and 2010. According to an intention to treat approach, all patients who received at least one FCR cycle were registered in the study. This series was representative of a FCR treated CLL cohort with respect to baseline characteristics, including age (median: 61 years; >65 years in 33% of patients), gender (male in 68% of patients), stage (progressive Binet A in 11% of patients; Binet B in 59%; Binet C in 30%) and number of FCR courses (median: 6; Results. After a median follow-up of five years, 159 patients have progressed and 72 have died, accounting for a 5-year progression free survival (PFS) according to the IWCLL criteria of 47% (median: 58 months) and for a 5-year overall survival (OS) of 81% (median: not reached). When the demographic effects of age, gender and year of treatment were compensated, the 5-year and 10-year survival of the whole CLL cohort were 85% and 68%, respectively, of those expected in the matched normal general population (p Conclusions. The combination of three biomarkers that are routinely tested at treatment allows to segregate a subgroup of CLL (IGHV mutated without 17p or 11q deletion) that may achieve a durable remission after first line FCR treatment and experience an expected survival similar to that of the general population. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

BACKGROUND. The detection of minimal residual disease (MRD) at the level of 0.01%/10-4 or above is a strong independent predictor of reduced progression-free (PFS) and overall survival (OS) in patients with CLL treated with chemoimmunotherapy. Although newer agents such as B-cell receptor pathway inhibitors can result in prolonged survival without achieving complete response, there remains a important role for MRD analysis in assessing therapeutic strategies aimed at disease eradication and cure. This is particularly important in front-line trials for fit patients which now require at least five years of follow-up if PFS is used as an endpoint. The feasibility of using MRD as a surrogate or intermediate endpoint for accelerated approval of new treatments is under review by regulatory agencies but further prospective validation is required. At the same time technology is rapidly evolving and high-throughput sequencing (HTS) technologies now detect MRD at the 0.0001%/10-6 level. It is therefore important to determine the most effective approaches for quantifying MRD that are compatible with previous studies but sufficiently sensitive for current treatments. AIMS. This collaborative project had two objectives. First, to identify the simplest and most flexible flow cytometry panel capable of detecting MRD at the 0.01%/10-4 or lower, that is compatible with published data and independent of instrument/reagent manufacturer. Second, to compare the flow cytometry approach with HTS analysis using the ClonoSEQ assay (Adaptive Biotechnologies, Seattle, WA). METHODS AND RESULTS. A core panel of antibodies for MRD detection was identified by testing an 8-marker combination in 52 samples (27 post-treatment and 25 dilution study) and re-analysing data with serial exclusion of single markers to determine redundancy. A 1-tube core panel of CD19, CD20, CD5, CD43, CD79b, and CD81 was identified and validated against the previously published 2-tube 6-marker and 4-tube 4-marker ERIC panels in 76 samples (19 post-treatment and 57 dilution study). The results showed good concordance (for log-transformed data above the LoQ, linearity=0.977, Pearson correlation co-efficient=0.983, average difference=0.026 log, 95% limit of agreement 0.20log) and a limit of detection of 0.001%/10-5 for the 1-tube core panel. Inter-operator variation was similar to CML MRD monitoring with both experienced operators, or inexperienced cytometrists after ~1 hour of specific education, achieving a 95% limit of agreement less than 0.3log in samples with MRD levels ranging from 0.0001 – 100%. The flow cytometry approach was compared with the ClonoSEQ HTS assay in 109 samples (21 dilution study and 88 post-treatment samples, complete data currently available on 13/88). The assay was applicable to the vast majority CLL patients, often with two clonal markers. There was 94% concordance at the 0.01% (10-4) threshold (15 samples with ≥0.01% CLL by both methods, 14 samples with CONCLUSIONS. The 1-tube 6-marker flow cytometry core panel is compatible with published studies, manufacturer-independent and flexible, providing directly quantitative results to 0.001%/10-5 without requiring a pre-treatment sample. HTS requires further work to standardise the quantitative analysis and prospective validation but the ClonoSEQ assay is applicable to >95% of CLL patients, does not require viable cells and is extremely sensitive, detecting residual disease in a significant proportion of cases with Disclosures Rawstron: Roche: Honoraria; Biogen Idec: Consultancy; Gilead: Consultancy, Honoraria; Abbvie: Honoraria; BD Biosciences: Intrasure reagent Patents & Royalties; Celgene: Honoraria; GSK: Honoraria. Williamson:Adaptive Biotechnologies: Employment, Equity Ownership. Sanders:Adaptive Biotechnologies: Employment, Equity Ownership. Robins:Adaptive Biotechnologies: Consultancy, Equity Ownership, Patents & Royalties. Hallek:Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; GSK: Honoraria; Gilead: Honoraria. Hillmen:Roche: Honoraria, Research Funding; GSK: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Pharmacyclics: Honoraria, Research Funding; Gilead: Honoraria, Research Funding.

Introduction: The role of various prognostic factors in CLL/SLL is not yet fully understood, including the implications of new genetic markers associated with high risk. Ibrutinib (Imbruvica®), a first-in-class Bruton’s tyrosine kinase inhibitor, is a once-daily single agent approved by the US FDA for CLL patients (pts) who have received ≥ 1 prior therapy, and for pts with 17p deletion CLL. We report updated efficacy results for the phase 3 RESONATETM(PCYC-1112) study of ibrutinib (ibr) vs ofatumumab (ofa), relative to genetic features and prior treatment exposure, and provide updated adverse event (AE) data. Methods: Pts received 420 mg oral ibr daily until disease progression or unacceptable toxicity or IV ofa for up to 24 weeks. Primary endpoint was IRC-assessed PFS with secondary endpoints OS and IRC ORR (Byrd et al, NEJM 2014). At interim analysis, with median follow-up of 9.4 months, the Independent Data Monitoring Committee recommended pts in the ofa arm be provided access to ibr. Additional endpoints including investigator-assessed efficacy, investigation of potential predictive biomarkers, and safety with longer follow-up are reported. Results: The 391 pts were randomized to ibr (n=195) or ofa (n=196). Median age was 67 years, with 40% ≥70 years, 57% Rai stage III/IV disease. Median number of prior therapies was 3 (ibr) vs 2 (ofa) with 23% having 1, 28% with 2, and 49% ≥ 3 prior therapies. Approximately 32% had del(17p) and 32% (122/381) del(11q). 72 of 300 pts had complex cytogenetics (≥3 abnormalities) and 68% (181/266) unmutated IGHV. With outcome analyses pending, preliminary analysis revealed that 19% of pts had NOTCH1, 23% SF3B1, 36% TP53, and 1% MYD88 gene mutations at baseline. With median follow-up of 16 months, investigator-assessed PFS was significantly longer for ibr vs ofa (median NR vs 8.1 months, [HR 0.106, 95%CI 0.073-0.153, P Conclusions: Ibr significantly improved investigator-assessed PFS, OS, and ORR relative to ofa in pts with CLL/SLL who had received ≥ 1 prior therapy. The updated results are consistent with previously published phase 2 single-agent results (Byrd et al. NEJM 2013). Pts in the ibr arm treated in the second line experienced better outcomes than those salvaged in later lines of therapy. These results provide further evidence of ibrutinib’s robust clinical activity in CLL pts regardless of high-risk baseline genetics or number of prior therapies. Figure 1 Progression-Free Survival Figure 1. Progression-Free Survival Table. Investigator-assessed Efficacy Outcomes Table. Investigator-assessed Efficacy Outcomes Disclosures Brown: Sanofi, Onyx, Vertex, Novartis, Boehringer, GSK, Roche/Genentech, Emergent, Morphosys, Celgene, Janssen, Pharmacyclics, Gilead: Consultancy. Hillmen:Pharmacyclics, Janssen, Gilead, Roche: Honoraria, Research Funding. O'Brien:Amgen, Celgene, GSK: Consultancy; CLL Global Research Foundation: Membership on an entity's Board of Directors or advisory committees; Emergent, Genentech, Gilead, Infinity, Pharmacyclics, Spectrum: Consultancy, Research Funding; MorphoSys, Acerta, TG Therapeutics: Research Funding. Barrientos:Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Coutre:Janssen, Pharmacyclics: Honoraria, Research Funding. Tam:Pharmacyclics and Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Mulligan:Roche, Abbvie: Consultancy, Honoraria. Jaeger:Janssen Cilag: Honoraria. Barr:Pharmacyclics: Research Funding. Furman:Pharmacyclics: Consultancy, Speakers Bureau. Kipps:Pharmacyclics: Research Funding. Cymbalista:Janssen, Roche, GSK, Gilead, Mundipharma: Honoraria. Delgado:Roche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria; Celgene: Honoraria; Novartis: Consultancy, Honoraria. Montillo:Janssen: Honoraria. Burger:Pharmacyclics: Consultancy, Honoraria, Research Funding. Chung:Pharmacyclics: Employment. Lin:Pharmacyclics: Employment. Gau:Pharmacyclics: Employment. Chang:Pharmacyclics: Employment. McGreivy:Pharmacyclics: Employment. James:Pharmacyclics: Employment. Byrd:Pharmacyclics: Research Funding.

Introduction : Ibrutinib (Imbruvica®), an oral, first-in-class covalent BTK inhibitor, is a new treatment option approved by FDA for chronic lymphocytic leukemia (CLL) patients (pts) with ≥1 prior therapy. We previously reported results from the phase III trial, in which ibrutinib (ibr) significantly improved progression-free and overall survival vs ofatumumab (ofa) in pts with relapsed/refractory CLL or small lymphocytic lymphoma (SLL) (Byrd et al. NEJM, 2014). Here, we report measures of patient well-being, including hematologic, immunologic, and quality of-life parameters, at interim analysis (IA). Methods : Pts with CLL/SLL after ≥1 prior therapy were randomized 1:1 to ibr 420 mg/day until progression or unacceptable toxicity, or to ofa for up to 24 weeks. At IA, secondary efficacy endpoints of hematologic improvement (sustained improvement ≥56 days without transfusions or growth factors) and FACiT-Fatigue (FACiT-F) outcomes were analyzed, along with exploratory endpoints assessing disease-related symptoms (DRS), serum immunoglobulin, patient-reported outcomes (PROs) by EORTC QLQ-C30, and medical resource utilization (MRU). Results : Of 391 enrolled pts (ibr n=195; ofa n=196), 63% had cytopenia(s) at baseline: 45% had anemia (hemoglobin ≤11 g/dL), 35% thrombocytopenia (platelets ≤100×109/L), and 20% neutropenia (absolute neutrophil counts [ANC] ≤1.5×109/L). On the ibr arm, 69% of pts with baseline cytopenias experienced sustained improvement in blood counts compared to 43% on ofa ( P

Introduction Follicular lymphoma (FL) is the most frequent indolent lymphoma. Autologous hematopoietic stem cell transplantation (ASCT) allows durable progression-free survival in selected relapsed patients. Recently, the EBMT lymphoma working party has published the recommendations for ASCT and allogeneic hematopoietic transplantation (alloTPH) in FL. For those high-risk young patients relapsing after ASCT, alloTPH is a valid therapeutic option; the majority being done with reduced intensity conditioning (alloRIC). Aims Our aim is to describe the outcome of patients with FL who underwent an alloTPH in our cente. Factors potentially influencing outcome such us age, sex, FLIPI at diagnosis, disease status prior alloTPH, EBMT risk score, type of donor, graft vs host disease (GVHD) prophylaxis and development of GVHD were also analized. Methods Actuarial estimates of OS and PFS rates were calculated using the Kaplan-Meier method. OS was estimated from the date of transplantation to the date of death or last follow-up. PFS was defined as the time from transplantation until progression or death from any cause. Patients We retrospectively found 26 alloTPH in the period 1999 - 2013. Two alloTPH were conditioned with a myeloablative regimen. Patients who underwent an alloRIC (n=24) were all conditioned with Fludarabine 30 mg/m2/5 days and Melphalan 70 mg/m2/1 day. Results AlloTPH was from a matched related donor in 70.8% of cases, from a mismatched related donor in 4.2%, matched unrelated donor in 8.3% and from a mismatched unrelated donor in 16.7%. The median age was 49.5 years (range 35-61). The median time from diagnosis to alloTPH was 48 months (range 9 – 190), male: female ratio was 2:1. FLIPI at diagnosis was 0 in 16.7%, FLIPI 1 in 25%, FLIPI 2 in 33.3%, FLIPI 3 in 8.3% and FLIPI 4 in 16.7. Mean number of treatment pre alloTPH was 4.5 (range 2-6). Ten patients (41.7%) had previously received an ASTC. Response before alloTPH was complete response in 54.2%, partial response in 37.5% and stable disease in 8.4%. The majority of patients (95.8%) had an EBMT risk score higher than 3. Graft vs host disease prophylaxis consisted on cyclosporine + short course of methotrexate in 54.2%, cyclosporine + micophenolate in 41.7% and sirolimus + tacrolimus in 4.2%. In vivo T-cell depletion was done in 4 patients receiving grafts from a mismatched unrelated donor (ATG or alemtuzumab, 2 patients each). Mean CD34 cells/Kg infused was 6.45 x106/kg (range 1.92 – 15.6). The median time to granulocyte recovery (>0.5x109/L) was 15 days (range 11-19) and the median time to platelets recovery (>50x109/L) was 14 days (range 6-56). Acute GVHD was developed in 45.8% of patients; it was global grade 1-2 in 36.4% ,and grade 3-4 in 63.6%. Chronic GVHD was present in 58.3% of patients. The median time of chronic GVHD presentation was 196 days after alloTPH (range 101 – 569 days). Regarding opportunistic infections, 20.8% of patients reactivated CMV with no disease, 16.7% had intestinal disease due to CMV. Thirteen per cent of patients developed pulmonary fungal infection (i.e Aspergillus sp). With a median follow up of 48.50 months (range 0-161), the 5 years OS was 66.1% (CI 95% 43.76 - 88.44) and the 5 years PFS was 63.8% (CI 95% 43.22 - 84.4). Overall morbidity at 3, 6 and 12 months after alloTPH was 5%, 5% and 10.3% respectively. Only 1 patient relapsed at 38 months after alloTPH but is still alive. Causes of death were refractory GVHD (n=5), sepsis (n=3) and acute renal failure due to microangiopathy (n=1). Survival was influenced by GVHD prophylaxis. At the median time of follow up (48.50 months) patients receiving cyclosporine-methotrexate had an OS of 82.5% vs 30% for patients receiving cyclosporine-MMF (p Other variables (FLIPI at diagnosis, sex, age older than 60 years, the EBMT risk score pre alloTPH and disease status) had no influence on survival. Conclusions AlloTPH for high risk FL patients seems to overcome the negative effect of FL prognostic factors at diagnosis. This strategy shows an excellent disease control with a low transplant-related mortality. Disclosures: No relevant conflicts of interest to declare.

Background Although recommendations for assessing prognosis in patients with CLL have been formulated (IWCLL, 2008; ESMO, 2013; NCCN, 2013), the actual use of prognostic and predictive markers in patients with CLL seen in daily practice is unknown. Study objectives To ascertain the use of prognostic and predictive markers in patients with CLL not included in trials. Methods Three-hundred and eighty-two members included in the ERIC database were invited to participate in a survey which included a comprehensive list of parameters potentially useful to evaluate patients with CLL at three different steps: 1. At diagnosis; 2. During clinical course; 3. Before therapy. Results One-hundred sixteen out of the 382 ERIC members (30%), mainly from academic institutions (91%), participated in the survey. Here we present a summary of this study which can be seen at its full length at www.ericll.org Prognostic factors at diagnosis The most frequently evaluated parameters (by > 80% of the participants) are: age, disease stage, ECOG, B-symptoms, WBC count, LDT, tumor bulk, DAT, LDH and B2M; CIRS is evaluated by 45% and only 7% measure sTK routinely. CD38 is assessed by virtually all investigators, but not ZAP-70 (58%) nor CD49d (24%). Imaging studies are frequently employed: ultrasonography (US) (51%), CT (21%). PET/CT is never investigated at diagnosis. FISH for 13q-, 11q-, 17p-, and +12 is required by > 70%. Among biomarkers, those more frequently used are IGHV mutational status (54%) and TP53 mutations (25%). As per the newly described gene mutations around 20% of the participants would like to determine mutations of NOTCH1, SF3B1, MYD88, and BIRC3 should they be available. Prognostic factors over the course of the disease Sixty percent of participants re-assess prognostic parameters over the course of the disease. Bone marrow (aspirate/biopsy), lymph node biopsy and imaging studies are performed in subjects with progressive disease. However, 72% of the participants never use PET/CT, which does not seem to be related to the technique availability since only 3% of the participants would use PET/CT if available. Parameters studied before initiating treatment Beside standard clinical parameters, other features frequently evaluated include ECOG (96%), DAT (77%), CIRS (66%) and bone marrow (45%). US, CT scans, and PET/CT are routinely (or occasionally) assessed by 45% (52%), 39% (42%), and 3% (42%) of the investigators, respectively. IGHV mutational status is repeated by a few participants (19%). 17p- and 11q- are studied by 79% and 68% of the investigators, respectively. Likewise, TP53 mutations are routinely (or occasionally) investigated by 40% (27%), NOTCH1 by 6% (13%), SF3B1 by 6% (12%), MYD88 by 4% (10%), and BIRC3 by 4% (9%). Most (89%) investigators consider pre-treatment findings to select therapy, the clinical parameters frequently considered toward that end being age (80% of investigators), ECOG (43%) and CIRS (37%). Biologically, 17p- (79%) and TP53 mutations (40%) along with 11q- (48%) and 13q- (26%) are the most frequently investigated markers. Novel mutations are investigated by 9%-15% of participants and around 20% would use them if possible. Conclusions Although international recommendations are generally followed, the evaluation of patients with CLL at diagnosis includes in many cases parameters (e.g., 17p-, TP53 mutations) more useful as predictive (i.e., predicting response to therapy) than prognostic (i.e., predicting disease progression) factors, as well as ancillary studies (e.g., imaging studies) only recommended within clinical studies. In many instances prognostic markers are repeated over the course of the disease. Finally, treatment decisions are mainly based on clinical features and consolidated biomarkers (i.e., FISH cytogenetics, TP53 mutations). The results of this study need to be taken cautiously because of potential investigator-related biases and its relatively small sample size. However, it could be useful as a basis for refining, based on what is actually done in daily practice, recommendations about evaluation and prognostication of patients with CLL. Disclosures: Montillo: Roche: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; GSK: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Mundipharma: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.

2744 The current standard of care for fit patients (pts) with chronic lymphocytic leukemia (CLL) is rituximab (R) in combination with fludarabine and cyclophosphamide; however, many pts with CLL are elderly and have comorbidities that render them ineligible for fludarabine treatment. Two common treatment options for fludarabine-ineligible pts are bendamustine (B) or chlorambucil (Clb). A further promising treatment option, following the success of the combination of R with fludarabine and cyclophosphamide, might be to combine B or Clb with R. The following study aims to assess the responses of pts to a combination of R and either B or Clb in first-line (1L) or second-line (2L) pts with CLL, with the primary objective being to compare the confirmed complete response (CR) rate (assessed according to Hallek et al. Blood 2008) after 6 cycles of treatment between the two treatment arms for the pooled 1L and 2L pts. Pts (aged ≥ 18 years) who were ineligible for fludarabine treatment, as a result of age or a greater number of comorbidities, were randomized to either the R-B or R-Clb arm. Pts were 1L or 2L, where relapse had occurred no earlier than 12 months since their last dose of 1L treatment. Pts in the R-B arm were treated with six 28-day cycles of B (1L: 90 mg/m2 Days 1 and 2; 2L: 70 mg/m2 Days 1 and 2) with R administered on Day 1 of cycle 1 (375 mg/m2) and cycles 2–6 (500 mg/m2). Pts in the R-Clb arm received the same dose of R but in place of B they received Clb (10 mg/m2Days 1–7, cycles 1–6), and those pts in the R-Clb arm that had not achieved a CR after 6 cycles continued to receive Clb monotherapy for up to 6 further cycles. Tumor assessments were made after cycles 3, 6 and 12 and then 3-monthly for at least a year. Enrollment and randomization are ongoing and, at present, a total of 339 pts have been randomized between the two treatment arms, 126 of whom are included in this interim analysis with the remaining pts continuing on the study. Of these 126 pts, 58 were randomized into the R-B arm and 68 the R-Clb arm. Patient characteristics between the two treatment arms were well balanced (Table). The median age of pts was 74 years (75 years for the R-B arm and 73 years for the R-Clb arm) and the majority of pts were taking concomitant medication (57/58 pts [98%] in the R-B arm; 64/68 pts [94%] in the R-Clb arm). Compared with previous clinical trials in CLL where pts are usually younger and fitter, this patient population is closer in age and fitness to pts presenting in the clinic. A total of 85 pts were previously untreated, with the remaining 41 having received one line of previous treatment. 2L pts had received a median of 6 prior cycles of treatment. The safety population was made up of 124 pts (R-B: n = 57; R-Clb: n = 67) who had received at least one dose of the study medication; 104/124 pts completed all 6 cycles of rituximab treatment. After 6 cycles of treatment, 14/58 pts (24%) in the R-B arm had a confirmed CR compared with 7/68 pts (10%) in the R-Clb arm (p = 0.033). For 1L pts the corresponding CR rates were 30% in the R-B arm vs 13% in the R-Clb arm (p = 0.054) and 2L pts exhibited CR rates of 11% in the R-B arm vs 4% in the R-Clb arm (p = 0.413). At the end of treatment, the overall response rate (ORR) was not different between the R-B and the R-Clb arms (88% and 81%, respectively [p = 0.404]). ORRs for 1L pts were 88% in the R-B arm vs 80% in the R-Clb arm and for 2L pts were 89% in the R-B arm vs 83% in the R-Clb arm. Safety was similar between the two treatment arms with the most common adverse events (AEs) (any grade) being neutropenia (R-B: 42% vs R-Clb: 46%) followed by nausea (R-B: 26% vs R-Clb: 22%). The most common AE at ≥ grade 3 was neutropenia (R-B: 32% vs R-Clb: 34%). Serious AEs were experienced by 20 pts (35%) in the R-B arm and 23 pts (34%) in the R-Clb arm; the most frequent serious AE was pneumonia (R-B: 7% vs R-Clb: 2%). 5/57 pts (9%) in the R-B arm and 8/67 pts (12%) in the R-Clb arm withdrew from the study prematurely due to AEs. R-B or R-Clb could provide useful treatment options for pts with CLL who are ineligible for the current fludarabine-containing standard of care. Interim results from this study have indicated that R-B shows a trend towards higher CR rates compared with R-Clb. | Characteristic | R-bendamustine (n = 58) | R-chlorambucil (n = 68) | |:-------------------------:| ----------------------- | ----------------------- | | Median age, years (range) | 75 (49–87) | 73 (44–91) | | Sex, % | - | - | | Male | 60 | 65 | | Female | 40 | 35 | | Binet stage, % | - | - | | A | 5 | | | B | 55 | 59 | | C | 33 | 37 | | Not reported | 7 | 4 | | 17p/11q del, % | 12 | 4 | | IGVH status, % | - | - | | Mutated | 41 | 52 | | Unmutated | 53 | 38 | | Other | 5 | 10 | | Line of treatment, % | - | - | | 1L | 69 | 66 | | 2L | 31 | 34 | Table: Baseline patient characteristics Disclosures: Leblond: Roche: Advisory Board Other, Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Mundipharma: Honoraria; Janssen-Cilag: Honoraria. Off Label Use: Rituximab in Combination with Bendamustine or Chlorambucil for Treating Patients with Chronic Lymphocytic Leukemia. Rassam: Johnson and Johnson: Unrestricted research grant Other; ROCHE: Honoraria; BMS: Honoraria. Raposo: Roche: Consultancy. Oertel: Roche: Employment, Equity Ownership.

Abstract 3897 Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune hemolytic anemia (AIHA). However, the mechanisms governing the association between CLL and AIHA are poorly understood. MicroRNAs (miRNAs) are small 18–22 nucleotide long RNA molecules that regulate gene expression and play a key role in several biological processes. Importantly, deregulated miRNA expression has been implicated both in CLL and autoimmunity. This led us to speculate that patients with CLL who develop AIHA might have a different miRNA expression pattern as compared to those in whom this complication is not observed. We report here the first results of this study. We have evaluated the miRNA expression in purified CLL cells (CD19+, CD5+) from 14 patients who developed AIHA over the course of their disease and 19 sex-, age-, and clinical stage-matched controls who, after a comparable follow up time, did not develop this complication. The expression of 377 mature miRNAs was analyzed using TaqMan Human MicroRNA Arrays A v2.0 (Applied Biosystems) in an ABI 7900 HT sequence detection system. miRNA expression data was analyzed by the 2–ΔΔCt method, using RNU48 as endogenous control. Statistical analyses were performed with TiGR MultiExperiment Viewer, BRB-ArrayTools and R software. The unsupervised hierarchical cluster analysis identified two groups (CLL AIHA+ and CLL AIHA-). The supervised analysis revealed 7 miRNAs that were down-regulated in CLL AIHA+ patients compared to CLL AIHA- patients: miR-19a, miR-20a, miR-29c, miR-146b-5p, miR-324-3p, miR-340, miR-660. Interestingly, miR-146, which has previously been related to autoimmunity, regulates IL-1 receptor-associated kinase 1 and TNF receptor-associated factor 6, two key adapter molecules downstream of Toll-like and cytokine receptors. The prediction analysis of microarrays (PAM) was used to determine a set of miRNAs able to classify the samples into CLL AIHA+ and CLL AIHA-. We obtained a 122-miRNA model that classified CLL AIHA+ patients with a sensitivity of 69.4% and specificity of 68.4%. This model correctly classified 67% of the analyzed samples. In summary, CLL AIHA+ samples were characterized by a distinctive signature of 7 down-regulated miRNAs, one of which (miR-146) has previously been related to autoimmunity. Moreover, we identified 122 miRNAs that are able to predict AIHA in CLL patients. This is the first study establishing a relationship with CLL associated with AIHA and a distinctive miRNA signature, which should be useful for further studies aimed at unfolding the biologic complexity of AIHA in CLL. Disclosures: No relevant conflicts of interest to declare.

Abstract 1366 Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune phenomena, particularly autoimmune hemolytic anemia (AIHA). However, there are very few studies analyzing autoimmune cytopenias and its clinical implications in large, unselected series of patients with CLL. We investigated the prevalence, characteristics, and prognostic significance of autoimmune cytopenias in 960 patients with CLL diagnosed at the Hospital Clínic of Barcelona between January 1980 and December 2008. Seventy of 960 (7%) patients presented autoimmune cytopenias, of whom nineteen were detected at diagnosis, three prior to diagnosis and 48 during the course of the disease. Forty-nine patients had AIHA, 20 immune thrombocytopenic purpura (ITP) and one both AIHA and ITP. A clear association was observed between autoimmune cytopenias and poor prognostic variables such as high blood lymphocyte count (p= 0.004), blood lymphocyte doubling time less than 12 months (p= 0.01), increased serum beta-2 microglobulin (p= 0.02), and high expression of ZAP-70 (p=0.02) and CD38 (p=0.07). No statistically significant differences were found in the incidence of AIHA based on treatment modality: fludarabine-based 8/204 (4%) vs. alkylating agents-based 12/231 (5%). The outcome of patients with autoimmune cytopenias was not significantly different from that of patients without this complication (median survival: 8 years vs. 9 years; p=ns). Furthermore, no significant differences were observed according to the time at which cytopenia was detected (i.e., before, at diagnosis or after the diagnosis of CLL). Importantly, significant differences in the response rate were observed in the 73 patients with advanced (Binet C stage) disease based on the origin of cytopenia. Whereas 16 of the 19 patients with stage C “immune” disease responded to corticosteroids and as a result switched from stage C to stage A, only 9 of 54 patients with stage C “infiltrative” responded to therapy (p In conclusion, in this large, unselected and single institution series of patients with CLL autoimmune cytopenias correlated with well-known poor prognostic variables but not with treatment modality (i.e. purine analogs vs. alkylating agents). From the prognostic point of view, autoimmune cytopenias did not significantly influenced prognosis in the whole group of patients. Moreover, patients presenting with advanced disease related to an immune mechanism had better prognosis than those in whom advanced stage reflected a high tumor burden only. These results emphasize the importance of determining the origin of cytopenias in patients with CLL for both treatment and prognostic purposes. Disclosures: No relevant conflicts of interest to declare.

Abstract 1389 Although chronic lymphocytic leukemia (CLL) is considered incurable, a proportion of patients treated with modern therapy achieve complete remission (CR) with minimal residual disease (MRD) negative status, which translates into a better outcome. In addition, survival curves for allogeneic stem cell transplant (alloSCT) appear to plateau, suggesting possible cure. Profound immune disturbances are a major cause of morbidity and mortality in CLL and can be exacerbated by therapy. We studied the immune status of 26 patients with CLL with a sustained (median 8 years, range 2.2 to 17) CR following treatment (4 patients received fludarabine, cyclophosphamide and mitoxantrone [FCM], 6 autologous SCT [autoSCT]) and 16 allogeneic stem cell transplantation [alloSCT]. Lymphocyte subsets were studied using multiparameter flow cytometry and compared to healthy controls. CD8+ T cell response to cytomegalovirus (CMV) was assessed using a pentameric HLA-A2 binding CMV pp65-derived peptide and functionality was confirmed by interferon gamma (IFNγ) ELISPOT. Immunoglobulin subtypes, complement proteins, and β2-microglobulin (B2M) were quantified by standard techniques, interleukin 10 (IL-10) and vascular endothelial growth factor (VEGF) by flow-based cytometric bead array technology, and B cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) serum levels by commercial ELISA. Median age at the time of study was 57 years (55 for the alloSCT, 54 for the autoSCT and 63 for the FCM patients). Two alloSCT patients had chronic graft-versus host disease (cGVHD) at sample collection and were receiving immunosuppression. In addition, three patients experienced autoimmune cytopenia after alloSCT, but had responded to therapy at the time of the study. Detectable residual CLL cells (> 10-4) in peripheral blood were found in six patients (3 alloSCT, 3 FCM). The 20 patients in MRD negative CR had a significantly higher absolute B cell count compared to normal controls comprised of both CD19+CD5- cells (154 cells/mm3vs. 76 cells/mm3, p=0.005) and CD19+CD5+ cells (22 cells/mm3vs. 1 cell/mm3, p=0.002). Normal serum levels of immunoglobulin were present in 17 patients whereas 9 had persistent hypogammaglobulinemia (4 were MRD positive, 2 were on immunosuppression for cGVHD and 1 patient had received rituximab). Thus only 2 patients had unexplained hypogammaglobulinemia despite being in MRD negative-CR. T cell abnormalities were also common in these patients. An abnormal CD4:CD8 ratio was present in 9 patients, and CD4+ cells had failed to recover to >400 cells/mm3 in an additional 5 patients. An increase in CD8+ cells (620 cells/mm3vs. 379 cells/mm3 in normal controls) was mostly comprised of cells with a chronically activated phenotype, CD8+DR+ (220 cells/mm3vs. 78 cells/mm3 in normal controls, p=0.062). Furthermore, in CMV+/HLA-A2 patients, an elevated cytotoxic CD3+CD8+CD45RA population was seen (200 cells/mm3vs. 51 cells/mm3, p=0.037). In all cases, cytotoxic T cells expansions secrete IFNγ in response to pp65. As regards T regulatory cells, CD4+CD25+FOXP3+ cells were significantly increased in patients after alloSCT compared to normal controls (4.1% of CD4+ cells vs. 2.05% in normal, p=0.023). In contrast, patients who received either FCM or autoSCT had Treg levels equivalent to our normal samples (2.45% of CD4+ cells), including the three patients who were MRD positive after FCM. B2M was elevated in 7 patients. No differences were found in levels of complement proteins C3 and C4, direct Coombs test, IL-10 and VEGF. Nevertheless, patients showed median BAFF serum levels significantly higher than healthy controls, even when those patients with conditions considered likely to elevate BAFF and APRIL were excluded (cGVHD, autoimmune cytopenia) (p Disclosures: No relevant conflicts of interest to declare.

Abstract 4649 Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of monoclonal CD5+ B lymphocytes. In addition, immune disturbances are commonly present. Although CLL is still considered incurable, long term remissions can be observed after allogeneic stem cell transplantation (SCT). Whether immune function is restored in patients responding to treatment is largely unknown. We report on the immune status in 19 patients with CLL in long-lasting complete remission (CR) after SCT (13 allogeneic, 6 autologous). Median age was 51 (range, 33- 64) and median follow-up since transplantation was 6 years (range, 2-17). Three patients had chronic graft-versus host disease at sample collection, two of whom were receiving immunosuppression. Lymphocyte subsets were studied using multiparameter flow cytometry and compared to healthy controls. We quantified immunoglobulin subtypes, complement proteins, and β2-microglobulin (B2M) by standard techniques and IL-10 and VEGF by using flow-based cytometric bead array technology. CD8+ T cell response to CMV was assessed using a pentameric HLA-A2 binding CMV pp65-derived peptide. Three patients (all following allogeneic SCT) had detectable residual CLL cells (> 10-4) in peripheral blood at the time of the analysis. In the remaining 16 patients with no detectable minimal residual disease (MRD) normal CD19+CD5- and CD19+CD5+ B cell populations were lower than in healthy individuals (10.5% vs. 14.5%; p=0.02 and 1.6% vs. 3.9 %; p=0.002 respectively). A significant increase in the proportion of CD8+ T cells (median 28.1% vs. 18.7%, p=0.03), particularly those with a chronically activated phenotype CD3+CD8+DR+ (10.2% of CD3+ cells vs. 4.9% in controls), was observed (p=0.013). The nine CMV+/HLA-A2 patients all showed specific cytotoxic CD8+ T cells which exhibit predominantly a CD45RA+CD27- phenotype, being better preserved in autologous SCT than in allogeneic SCT patients. Also, higher numbers of CD8+CD45RA+CD27- T cells were observed in patients with a longer follow-up. CD4+ T cell count was < 400/mm3 in 4 patients. An abnormal CD4:CD8 ratio was seen in 7 out of 19 patients. Interestingly, a significant increase of double positive CD4 and CD8 T cells was detected in most patients comprising 2.6% vs.1.6% of lymphocytes in normal subjects (p=0.02). There were no quantitative abnormalities in CD3-CD56+ cells. Not surprisingly, hypogammaglobulinemia was present in all but four patients immediately prior to transplant. Whereas IgM levels normalized in all patients, 4 and 6 patients respectively still had low IgG and IgA levels more than two years after transplantation. Of note, low serum immunoglobulin levels were seen in 6 out of 14 MRD negative-CR patients and all three MRD positive-CR patients, including one who had normal immunoglobulin levels at the time of transplant. Complement proteins C3 and C4 were within the normal range in all cases. The direct Coombs test (DCT) was also negative in all patients although one patient had indirect signs of hemolysis. Regarding serum markers, B2M was increased (>2.5mg/dl) in 5 out of 19 patients. No significant differences were found in IL-10 and VEGF levels between patients and normal controls (median levels, 2.14 vs. 1.06 pg/ml and 156.88 vs. 104.14 pg/ml), but there were 2 patients with markedly elevated IL-10. In summary, these data demonstrate that immune defects persist over time in CLL patients with a long lasting CR (including MRD-negative CRs) after SCT. Disclosures: No relevant conflicts of interest to declare.

Abstract 1235 Poster Board I-257 BAFF (B-cell activating factor) and APRIL (a proliferation-inducing ligand) are TNF family proteins that upregulate anti-apoptotic genes through the NF-kB pathway. Studies in vitro suggest that BAFF and APRIL protect neoplastic B cells from apoptosis in chronic lymphoproliferative disorders (CLPD) including chronic lymphocytic leukemia (CLL). Serum BAFF levels have been previously shown to be lower in CLL than in other CLPD or normal subjects. To contribute to a better understanding of their role in CLL, we analyzed BAFF and APRIL at mRNA and protein serum levels and their receptors [transmembrane activator and CAML interactor (TACI), B-cell maturation antigen (BCMA) and BAFF receptor (BAFF-R)] by flow cytometry, in 82 patients with CLL, 36 with other CLPD and 35 age- and sex-matched controls. mRNA BAFF and APRIL levels were calculated as a the percentage of expression referred to an internal control and the receptor expression as the ratio between the mean fluorescence intensity (MFI) of the receptor antibody and the MFI of the isotype control. Patients with CLL showed significantly lower median BAFF and APRIL levels (0.63 μg/ml and 3.18 μg/ml) than those with other CLPD (1.27 μg/ml and 5.51 μg/ml) (p Disclosures No relevant conflicts of interest to declare.

Abstract 1244 Poster Board I-266 Allogeneic stem cell transplantation (SCT) is the only curative treatment for chronic lymphocytic leukemia (CLL). Advanced age, extensive prior therapy, lack of response to treatment, and T-cell depletion of the graft are poor prognostic factors which have been identified in many studies. Beta-2 microglobulin (B2M) has important prognostic value in patients treated with chemotherapy or chemoimmunotherapy, but has been scarcely investigated in the context of allogeneic SCT. In two studies (Khouri et al. Cytotherapy 2002; Sorror et al. J Clin Oncol 2008) no correlation was found between B2M and transplant outcome. Against this background, we analyzed the influence of B2M and other prognostic parameters in 32 patients (median age 50 yrs [range, 29-63], 20 males) who received an allogeneic SCT in our institution between 1991 and 2006. Interval between diagnosis and transplantation was 44 months (range, 6-116). Median number of prior therapies was 2 (range, 1-6). Six patients had previously received an autologous SCT. Most patients had adverse biologic features (high ZAP-70 expression, unmutated IGHV, poor cytogenetics). Serum B2M was increased (≥2.5 mg/L) in 13 out of 29 patients prior to transplant. Creatinine levels and glomerular filtration rate were normal. Median follow-up after transplantation was 7 years (range, 1.8- 16.9). The relapse risk (RR) at 5 and 10 years was 5 % (95% CI, 0-14%) and 23% (95% CI, 2-44), respectively. At one and 10 years the cumulative non-relapse mortality (NRM) was 34% (95% CI, 17-51) and 38% (95% CI, 20-55), respectively. Five and 10-year progression free survival (PFS), event free survival (EFS) and overall survival (OS) were 85% (CI, 66-100) and 65% (CI, 35-94), 58% (CI, 40-76) and 40% (CI, 19-62), and 62% (CI, 45-79) and 57% (CI, 38-75). In the univariate analysis, factors associated with a higher NRM were prior autologous SCT (p=0.006), chemorefractory disease (p=0.04), and high serum B2M levels at the time of SCT (p=0.03). Parameters associated with EFS and OS were high B2M levels (p=0.001 and p=0.002), prior autologous SCT (p In contrast, IGHV mutational status, high ZAP-70 expression, > 30% bone marrow infiltration, and disease status (CR vs. no CR) at the time of SCT were not associated with outcome. In summary, this study indicates that, as in patients treated with chemo or chemoimmunotherapy, B2M is a strong predictor of clinical outcome in patients with CLL submitted to allogeneic SCT. Disclosures No relevant conflicts of interest to declare.

Abstract 2361 Poster Board II-338 Clinical staging systems are the backbone for assessing prognosis in patients with chronic lymphocytic leukemia (CLL). Clinical stages, however, are assigned without taking into consideration the mechanisms of the disease. In this regard, the prognosis of patients with advanced (Binet C, Rai III, IV) stage due to immune cytopenia is controversial. To address the prognosis of patients with CLL in advanced clinical stage due to immune mechanisms, we studied two groups of patients with and without autoimmune cytopenia. The first group consisted of 62 patients (39 men, median age 65 yrs; range 33-89) with advanced stage due to autoimmune cytopenia (stage C “immune”). Autoimmune hemolytic anemia (AIHA) was defined as a hemoglobin level Disclosures: No relevant conflicts of interest to declare.

The immunoglobulin heavy chain variable (IGHV) gene repertoire in CLL is biased and uniquely characterized by the existence of subsets of cases with “stereotyped” heavy chain complementarity-determining region 3 (HCDR3) sequences. As previously shown, HCDR3 stereotypy may have important pathogenetic and clinical implications, at least for certain subsets of CLL patients. However, the detection of stereotypy has so far been hindered, mainly due to the lack of suitable computational tools. We developed new methods for identification of sequence patterns within HCDR3 amino acid (AA) sequences using a sophisticated combinatorial pattern discovery algorithm. Included in the analysis were HCDR3 sequences from 2,845 CLL patients from our collaborating institutions, as well as 5,344 non-CLL sequences from public databases, for a total of 8,189. The identified patterns were subjected to a multiple and strict filtering process, based on the following criteria: sequence relatedness; location (offset) within HCDR3; and HCDR3 AA length. Clustering of sequences based on the filtered HCDR3 patterns revealed that the CLL IG repertoire can be distinguished in two broad categories: the first includes cases with heterogeneous B cell receptors (BCRs) (non-clustered cases) while the second is characterized by remarkable BCR stereotypy (clustered cases). In particular, 783/2,845 CLL sequences (27.5%) were placed in 339 ground-level clusters. Common sequences among these ground-level clusters allowed their progressive grouping in clusters at higher levels of hierarchy. High-level clusters were characterized by striking IGHV repertoire restriction, with only six IGHV genes (1–69, 1–3, 1–2, 3–21, 4–34, 4–39) accounting for >80% (382/459) of cases. While ground-level clusters provided a high-resolution picture of HCDR3 stereotypy, high-level clusters were considerably larger in size (up to 86 sequences each) and able to capture and describe more distant sequence relationships in the form of more widely shared sequence patterns. In particular, they were defined by patterns characterized by just a few critically positioned residues, reminiscent of the receptors expressed by cells participating in innate immune responses: due to this remarkable structural conservation, we consider them to be BCR “archetypes”. To test the hypothesis that sequence relatedness between IGHV genes may have structural and functional meaning for the IGHV repertoire in CLL, we also constructed sequence distance trees of functional human IGHV genes. Examination of the tree for the IGHV3 gene subgroup revealed a branching that was reflected in the repertoires of clustered vs. non-clustered CLL sequences. In particular, IGHV3-21, the foremost example of a gene with a propensity to be used in clustered rearrangements in CLL, belongs to a branch clearly distinct from other branches that include, for instance, the IGHV3-23, IGHV3-30, IGHV3-33 and IGHV3-7 genes, which were essentially absent from the repertoire of CLL sequences in high-level clusters; a similar case was also evident among IGHV1 subgroup genes. On these grounds, we argue that CLL cases with clustered (i.e. stereotyped) vs. non-clustered (i.e. heterogeneous) BCRs could derive from different progenitor cell populations evolutionarily adapted to particular antigenic challenges. In particular, prompted by the fact that clustered cases were found to express a limited set of highly conserved BCRs, we propose that in such cases the clonogenic progenitors may originate from a B cell population intermediate between a true innate immune system and the conventional adaptive B cell immune system, similar to what has been previously suggested for mouse B1 cells.

The Fcgamma receptors (FcγRs) are a family of molecules that modulate immune responses. FcγRIIb is an inhibitory FcγR that bears immunoreceptor tyrosine-based inhibitory motifs which transduce inhibitory signals on coligation with the surface membrane Ig of the B-cell antigen receptor (BCR). The role of FcγRIIb in controlling B cell activation through inhibition of BCR signaling has been extensively studied in animal models. Nevertheless, data on FcγRIIb are scant in human normal and neoplastic B cells, this being due to the lack of a specific antibody for human FcγRIIb. Consequently, there is little information on this receptor in chronic lymphocytic leukemia (CLL). Considering the activated nature of CLL cells and the central role of the BCR in the biology of the disease, studies of FcγRs are warranted. We used a novel specific mAb directly conjugated with Alexa 488 fluorophore that solely reacts with the human FcγRIIb (MacroGenics, Inc.) to investigate the receptors expression on CLL and normal human B cells. The study population included 84 patients with CLL and 24 age- and sex-matched controls. FcγRIIb expression was assessed as the mean fluorescence intensity (MFI) of surface membrane staining. In CLL cells, FcγRIIb was measured on CD19+CD5+ cells in combination with CD38, CD49d or CD69. Normal B cells were immunostained for CD19, CD5, IgD and CD38 expression and B cell subsets: naïve (IgD+CD38−), activated (IgD+CD38+) and memory B cells (IgD−CD38−) were studied for their relative expression of FcγRIIb. FcγRIIb expression was found significantly higher in naïve B cells compared to activated and memory B cells [median MFI: 17420 (11960–21180) vs. 11.140 (7899–16970) and 11.830 (6984–17100); p Although CD69 and CD38 expression was significantly higher on unmutated IGHV cases, no correlation was found between FcγRIIb levels and IGHV mutational status. Similarly, there was no correlation between FcγRIIb and other poor prognostic variables such as ZAP-70 (≥20%), CD38 (≥ 30%) or high risk cytogenetics. Nevertheless, cases with ≥ 30% CD49d+ cells had higher FcγRIIb expression than those with circulating normal CD5+ B cells > circulating CD5+ CLL B cells. In addition, although FcγRIIb is present on all normal B cell subsets its expression is higher in naïve B cells. Furthermore, in CLL FcγRIIb density is greater in CD38+ and CD49d+ cells within the clone. Although CD49d and FcγRIIb on CLL clones is linked in a direct manner, there is no relationship with FcγRIIb density and IGHV mutations, ZAP-70, CD38 and unfavorable cytogenetic markers. Finally, the relationship between FcγRIIb expression on CLL cells and functional responses to BCR and other receptor-mediated signals deserve further investigation.

Whether recent advances in the understanding and treatment of CLL are changing referral patterns of patients with this disease to specialized centers and their outcome is largely unknown. We analyzed demographics, disease characteristics, treatments administered, and survival over a period of 28 years in a series of 900 patients with CLL separated in three different cohorts based on the year of referral (table). As shown in the table, one of the main differences observed over the years relies on the stage of the disease, with most patients being currently seen in early phase of the disease, reflecting an earlier diagnosis because of analyses performed for routine reasons. In contrast, no differences were observed in patients’ age over the years, in agreement with the stable incidence of CLL in different age groups (SEER). No differences were detected in the proportion of patients developing autoimmune cytopenias, Richter’s syndrome or second neoplasias (data not shown). Not unexpectedly, since 1990 most patients receive purine analogs-based therapies. Importantly, the increasing proportion of patients who remain alive in each time period not only reflects an earlier diagnosis but also improvement in clinical management. Thus, median survivals of patients < 65 with Binet B or C disease are 3.9 yrs (1980–1989), 7.5 yrs (1990–1999) and not reached (2000 onwards), and the proportion of patients alive at 5 years in the same periods of time are 43%, 63% and 72% (figure). Unfortunately survival of patients > 65 yrs has not improved (median survival around 5.5 years across the three groups). Also, survival of patients in early stage (Binet A) has remained basically unchanged. From this large, single-institution study it can be concluded that the outcome of patients with CLL has been steadily improving since 1980. Nevertheless, the most significant progress has been made in younger patients with advanced disease, which constitute a small proportion of subjects with CLL. Besides to improving the outcome of these patients, future efforts should be aimed at prolonging survival of all patients, irrespectively of their age, and seeking the cure for the disease. 1980–1989 1990–1999 > 2000 P Number 254 388 258 Age (yrs). 67 (24–88) 66 (28–96) 67 (34–94) NS < 65 yrs (%) 43 46 45 > 65 yrs (%) 57 54 55 Males (%) 55 55 60 NS Binet A (%) 65 75 85 2 (%) 1.2 1.9 0 NS Treatment No treated (%) 59 37 60 8 NS PA = Purine analogs; Rit. = Rituximab

We examined SHM features in 1967 IGH rearrangements from 1939 patients with CLL. The sequences were divided into four “identity groups”; “truly unmutated” (100% identity to germline; 677 sequences), “minimally mutated” (99–99.9% identity; 133 sequences), “borderline mutated” (98–98.9% identity; 93 sequences) and “mutated” (

B-cell chronic lymphocytic leukemia (CLL), the most common adult leukemia, is a clonal disease manifested by an absolute lymphocytosis. Previously we identified genes capable of sorting and predicting the B-cells of patients with CLL or monoclonal B-cell Lymphocytosis (MBL) from aged matched controls. Using gene expression profiling, we and others have identified genes transcribed at significantly different levels between CLL patients and normal subjects. From these genes RT-QPCR verification was performed, in triplicate or more, on 22 gene candidates. A gene panel of seven genes, significantly different between CLL and normal individuals was chosen: FMOD, CKAP4, PI3Kc2b, LEF1, PFTK1, Bcl2 and GPM6a (in order of Receiver Operating Characteristic [ROC] concordance). This RT-QPCR verification step was based upon the comparison of freshly isolated PBMCs from CLL patients and age matched normal subjects after enriching for B cells with negative selection. The panel was then used to blindly categorize and predict the relationship of RNA from apparently normal subjects, some with and some without MBL, to the mRNA of patients with CLL as well as normal subjects, presumably without MBL. Since the numbers of cells within the expanded clones from individuals with MBL, after positive selection was limiting, RNA was amplified utilizing an RNA whole genome amplification approach and compared to similarly amplified RNA after negative selection; CLL cells, B-cells from normal age matched controls, and cord blood-derived B1 cells, enriched further by CD5 expression with positive selection. Using the Bayesian relevance determination method, a novel computer-learning tool to provide a probabilistic model, 56 samples were identified correctly at the rate of 100%. FMOD and PI3Kc2b were determined to be optimal at predicting blinded samples. In order to make the panel more clinically feasible, a universal reference RNA standard was used as a control, eliminating the need for pairing samples with age-matched controls. Analysis of this new model led to the discovery that a single gene; lymphoid enhancer binding factor 1 (LEF1), was not only capable of sorting CLL B cells from age-matched controls at a 100% rate (n=40) but it was also capable of predicting CLL B cells from other B cell malignancies (n=15). Verification of the protein expression levels for these genes is ongoing. The RNA expression levels of the genes in this panel provides a novel way to identify cell populations and gene expression patterns that change during the transition from B-cell clonal expansions that occur physiologically from those that occur among pre-leukemic and leukemic B-cell populations. The addition of a standard reference RNA enhances the clinical application of this gene panel. These data strongly suggest a unique role for LEF1 in CLL.

The absence of mutations in the VH gene (UM-VH) and the expression of ZAP-70 by leukemic cells are closely related adverse prognostic factors in CLL. Whether ZAP-70 should substitute VH gene analysis as prognostic predictor in patients with CLL is a matter of debate. We and others have shown that allogeneic but not autologous stem-cell transplantation may overcome the negative impact of the UM-VH on the outcome of patients with CLL. Herein we report on transplantation results based on ZAP-70 expression in leukemic cells. Thirty-seven patients (24 M/13 F; median age: 48 years, range: 29-63) received either an autologous (auto-SCT) (n=22) or an allogeneic (allo-SCT) (n=15) transplant. ZAP-70 was assessed by flow cytometry (19 cases), lymph node immunohistochemistry (10 cases) or both (8 cases). No discrepancies were observed in those cases in which both peripheral blood and lymph nodes were analyzed. Thirty-one patients were ZAP-70 positive and 6 ZAP-70 negative. ZAP-70 was positive in all UM-VH (n=24) and in 4 of 8 mutated VH patients. After a median follow-up of 62 months (range: 4 – 142), 5-year survival is 86% (66% to 100%) for allo-SCT and 50% (28% to 72%) for auto-SCT (p=NS), whereas 5-year disease-free survival (DFS) is 80% (54% to 100%) for allo-SCT and 37% (15% to 59%) for auto-SCT (p=0.03). Seventeen patients have relapsed: 16 of 31 of those being ZAP-70 positive and 1 of 6 of those ZAP-70 negative. In ZAP-70 positive patients the cumulative relapse rate at 5 years is 10% (2% to 65%) in the allo-SCT group and 53% (35% to 81%) in the auto-SCT group (p=0.04) (figure 1a). In addition, ZAP-70 positive patients submitted to allo-SCT have a trend for a longer DFS (76% at 5 years; 46% to 100%) than those receiving an auto-SCT (39% at 5 years; 15% to 63%) (p=0.07) (figure 1b). In summary, among transplanted patients those with ZAP-70 positive CLL have a better relapse rate and DFS if submitted to allo-SCT. Figure Figure

Insertions/duplications and deletions (I/D/Ds) in IG variable region genes are infrequent sequelae of the somatic hypermutation process. In the present study, we document the occurrence of nucleotide I/D/Ds in rearranged IGHV genes in CLL patients. Among 809 IGHV-D-J sequences amplified in 760 CLL cases, 9 (1.11%) and 15 (1.85%) sequences exhibited IGHV sequence changes consistent with nucleotide insertions/duplications or deletions, respectively. I/D/Ds were found in genes of the IGHV1, IGHV3 and IGHV4 subgroups, always within mutated IGHV-D-J rearrangements. In 21/24 cases, the inserted/duplicated or lost nucleotides occurred in multiples of 3; therefore, the original reading frame was maintained and a potentially intact receptor was coded. I/D/Ds were located completely or in part within CDRs in 21/24 cases; sequence motifs (AGY, AGA, AAC trinucleotides) that resemble intrinsic hotspots for somatic hypermutation were identified in 21/24 sequences. Short stretches with high homology (misalignment feet) that would offer the DNA polymerase an alternative template for re-annealing in cases of replication slippage were identified in all CLL sequences carrying I/D/Ds. I/D/Ds were generated somatically since (i) they always occurred in cases with somatic mutations, (ii) they could not be found on sequencing analysis of the corresponding germline IGHV genes amplified on DNA isolated from selected patients’ neutrophils, thus excluding a possible genetic polymorphism. The incidence of I/D/Ds in CLL is consistent with previous reports in normal, autoreactive and neoplastic human B cells, thus seemingly indicating that these modifications generally arise without any particular disease-specific associations. A striking exception to this rule was identified in the case of CLL IGHV3-21 expressing cases: one aminoacid was deleted from the CDR2 region in 16/74 (21.6%) IGHV3-21 CLL sequences (database-derived IGHV3-21 CLL cases + present series) vs. only 2/340 (0.59%) non-CLL IGHV3-21 sequences; 15/16 CLL IGHV3-21 sequences carrying this deletion belonged to a subset with unique, shared HCDR3s and light chain CDR3 motifs. The effect of the CDR2 deletion on the structure of the IG molecules in this subset of CLL patients was studied with molecular modelling and dynamics simulations. The models suggested that the deletion could be accommodated without significantly affecting the local structure. The close association of deletions in CDR2 with the homologous subset of IGHV3-21 expressing CLL cases provides further evidence for the importance of an antigenic drive in malignant transformation and/or maintenance of the neoplastic clone in at least some CLL cases.

MRD detection has been associated with a higher relapse risk in patients with CLL having achieved complete response (CR) by conventional NCI-WG criteria. Although there are a number of techniques to evaluate MRD, their respective clinical value is still controversial. Against this background, we analyzed MRD, as assessed by consensus PCR, real time quantitative PCR (qPCR), and flow cytometry, in peripheral blood (PB) and/or bone marrow (BM) in 40 patients with CLL submitted to SCT (25 autologous and 15 allogeneic). Patients were considered MRD positive if a monoclonal pattern was obtained by consensus PCR, qPCR MRD levels were ≥ 10−5 or flow cytometry MRD levels were ≥ 10−4. 97.4%, 89% and 100% of the patients could be studied by consensus PCR, qPCR, and flow cytometry, respectively. One hundred sixty-four of 248 samples were MRD negative by consensus PCR. Among those, CLL cells were detected by qPCR and by flow cytometry in 47% (77/164) and 23% (39/164) of the cases, respectively, whereas all 84 PCR positive samples had detectable CLL cells by qPCR and flow cytometry. A good correlation was seen between MRD levels detected by flow cytometry and by qPCR (n: 254, r: 0.826; p