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INTRODUCTION Lymphomas represent the fourth most frequent type of cancer, 90% of them arising from B cell lymphocytes. Despite their high prevalence, around 40% remain incurable because of refractoriness to current chemoimmunotherapy or disease relapse after obtaining response (Li et al., 2018; Meng et al., 2020). The cell of origin is a B lymphocyte with a unique B cell receptor (BCR). The BCR is an immunoglobulin composed of two heavy chains (IgH) and two light chains (IgL) whose genes have multiple coding segments that through rearrangement first and further somatic hypermutation in the germinal center, generate a unique sequence that could be used to monitor the treatment response (Seifert et al., 2019; Wang et al., 2020). This project studies the use of next-generation sequencing (NGS) to characterize and monitor such IgH clonality. The use of liquid biopsy samples would provide a minimally invasive method to identify refractory or relapse-risk patients since all of them will have residual tumor cells after treatment. METHODS The sample size of the study was 53 patients with several types of B-cell lymphomas. The IgH gene of the tumor clone was characterized from DNA of tumor samples at diagnosis by NGS and Sanger. The monitoring of this clone was studied by NGS from DNA and circulating tumor nucleic acids (ctNAs) during and after receiving treatment and at different times after clinical response was stablished (CR or PR). Relapse samples were analyzed by NGS and Sanger. RESULTS Characterization of the tumor clone IgH rearrangement is achieved in 45 of the 53 patients with B-cell lymphoma included in the study. As shown in Figure 1, after the two different amplification PCRs results are similar. In contrast, after sequencing the results obtained by Sanger and NGS are very different. In NGS, thanks to the massive amplification prior to sequencing, it is identify the tumor clone in approximately 80% of the samples. It is shown that the effectiveness in characterization is dependent on the origin of the DNA sample, with fresh material samples being the optimal (Figure 1). In monitoring, samples of different origin are used as shown in Figure 2. About 50% of these samples are plasma ctNAs whose average efficiency in the detection of IgH gene rearrangement is 73.3%, with a clear positive correlation between the sensitivity and the toal volume of plasma processed more starting plasma used (2 mL efficiency of 84.09%). Monitoring makes it possible to classify patients into three different groups (Figure 3): patients with complete remission, patients refractory to the different lines of treatment and patients with apparent complete response and subsequent relapse. In patients with complete response, the tumor clone decreases during treatment and at the end of the line it is no longer detectable, nor in subsequent follow-up samples. With respect to refractory patients, it is observed that the tumor clone remains present despite subsequent lines of treatment. Finally, in patients achieving CR with subsequent relapse, the clone can be detected in a small percentage at the end of the treatment schedule and remains present until relapse. A section of patients under treatment is also shown (Figure 3) to demonstrate the application of the study to clinical practice. Two patients with apparent complete response, one of them in complete remission and the other with a high risk of relapse, requiring a more exhaustive follow-up. The monitoring results obtained by flow cytometry are shown being these, in general, concordant. In some cases NGS shows greater sensitivity. CONCLUSION The use of NGS and liquid biopsy samples provides a minimally invasive method to monitor the IgH gene rearrangement of the tumor clone of patients with B-cell lymphomas. In our experience,, patients in remission can be clearly differentiated from those who are refractory or at risk of relapse. facilitating their treatment strategy and clinical decision making. Figure 1 Figure 1. Disclosures Ferrer Lores: Janssen: Membership on an entity's Board of Directors or advisory committees. Terol: BMS: Consultancy; Hospital Clinico Valencia: Current Employment; Roche: Consultancy; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: 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; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel.

The T-cell non-Hodgkin lymphomas continue to be an area of unmet need for new therapies that offer novel mechanisms of action. Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). Tipifarnib inhibits farnesylation of key regulatory proteins involved in CXCL12 production (Gualberto et al, EHA 2019). CXCL12 is a chemokine that is essential for T-cell homing to lymphoid organs and bone marrow, and for the maintenance of immune cell progenitors via its receptor CXCR4 (Susek et al, Front Immunology, 2018). Angioimmunoblastic T-cell lymphoma (AITL) is associated with high levels of CXCL12 expression, which is also a negative prognostic factor (Witzig et al, Blood, 2019). Additionally, Peripheral T-Cell lymphoma Not Otherwise Specified (PTCL-NOS) patients with the CXCL12 rs2839695 A/A wildtype genotype (PTCL-CXCL12+) have also been found to have elevated levels of CXCL12. Therefore, there is strong rationale for targeting these subsets of PTCL with tipifarnib. This Phase 2 study (NCT02464228) was a multi-institutional, single-arm, open-label trial determining the efficacy, safety, and potential predictive biomarkers for tipifarnib in adult patients with relapsed or refractory (R/R) PTCL. Patients received tipifarnib 300 mg orally twice daily on Days 1-21 of 28-day treatment cycles until progression of disease or unacceptable toxicity. The primary objective of the study was to determine the antitumor activity by overall response rate (ORR) per Lugano Classification. Secondary objectives included safety, duration of response (DoR) and progression-free survival (PFS), and exploratory analyses included overall survival (OS) and identification of potential biomarkers associated with tipifarnib activity. Sixty-five R/R PTCL patients (38 AITL, 14 PTCL-NOS, 11 PTCL-CXCL12+, 2 other (1 ALCL-ALK negative, 1 PTCL-subtype not specified) were treated with tipifarnib. The population was heavily pretreated with a median of 3 prior regimens (range 1-8). All patients had at least one treatment-emergent adverse event (TEAE); most patients (87.7%) had at least one treatment-related TEAE, and 18 (27.7%) patients had at least one treatment-related serious TEAE. The most frequently observed (≥20%) treatment-related TEAEs (all grades) were hematological (neutropenia, thrombocytopenia, anemia,) and gastrointestinal (nausea, diarrhea), as well as fatigue, which is consistent with the known safety profile of tipifarnib. Fifty-eight patients were efficacy evaluable and had an associated ORR of 39.7% (23/58) with most responses observed in the AITL and PTCL-CXCL12+ cohorts. In the 32 patients with AITL, the ORR was 56.3% (18/32), including 9 complete responses (CR) and 9 partial responses (PR). In the 10 patients with PTCL-CXCL12+, the ORR was 40.0% (4/10), including 1 CR and 3 PR. The median OS for patients with AITL was 32.8 months, and the median OS had not been reached for patients with PTCL-CXCL12+. Previously, a strong association between KIR3DL2 C336R/Q386E mutation and the activity of tipifarnib was observed and reported in AITL patients (Witzig et al, EHA 2020). Extensive gene expression and gene variant analyses of samples from the study population is currently ongoing to evaluate this correlation and explore other potential predictors of response. Final data will be presented at the time of the conference. Overall, the results from this Phase 2 study with tipifarnib demonstrated very encouraging efficacy in patients with CXCL12-expressing subtypes of PTCL (AITL and PTCL-CXCL12+) and showed a tolerable safety profile. Disclosures Witzig: Karyopharm Therapeutics, Abbvie/Genentech, Seattle Genetics, Celgene/BMS, Incyte, Epizyme, Cellectar, Tessa Therapeutics, Portola Pharmaceuticals, MorphoSys, ADC Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene/BMS, Acerta Pharma, Kura Oncology, Acrotech Biopharma, Karyopharm Therapeutics: Research Funding. Sokol: Dren Bio: Membership on an entity's Board of Directors or advisory committees; Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees. Kim: IGM Biosciences: Research Funding; Kyowa Kirin: Research Funding; Roche: Research Funding; Sanofi: Research Funding; Celltrion: Research Funding; Dong-A Pharmaceutical: Research Funding; Johnson & Johnson: Research Funding; Eisai: Research Funding. de la Cruz Vicente: Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: 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; Eusapharma: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Advani: Astellas/Agensys: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Bristol Myer Squibb: Membership on an entity's Board of Directors or advisory committees; Cell Medica: Membership on an entity's Board of Directors or advisory committees; Forty Seven: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genetech Inc.: 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; Janssen Pharmaceutical: Research Funding; Juno: Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Millenium: Research Funding; Pharmacyclics: Consultancy, Research Funding; Portola Pharmaceuticals: Consultancy; Regeneron: Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees. Marin Niebla: Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kiowa Kirin: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Consultancy, 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; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Speakers Bureau; Amgen: Speakers Bureau. Terol: BMS: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Hospital Clinico Valencia: Current Employment; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Consultancy; 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. Eva: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bendris: Kura Oncology: Current Employment, Current equity holder in publicly-traded company. Ahsan: Gilead: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Kura Oncology: Current Employment, Current equity holder in publicly-traded company. Leoni: Kura Oncology: Current Employment. Foss: Daiichi Sankyo: Honoraria; Mallinckrodt: Honoraria; Acrotech: Honoraria, Speakers Bureau; Seattle Genetics: Honoraria, Speakers Bureau; Kyowa: Honoraria; Kura: Honoraria.

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.

Introduction: Among the genetic lesions described in chronic lymphocytic leukemia (CLL), TP53 and IGHV mutational status are well-established prognostic biomarkers. While mutations resulting in dysregulation of TP53 are associated with chemo-resistance, mutated IGHV (IGHV-M) identifies a good prognosis and unmutated (IGHV-UM) is associated with an aggressive clinical outcome. Thus, molecular assessment of TP53 and IGHV mutational status is recommended to make treatment decisions. Moreover, 30% of CLL patients have a highly homologous complementarity-determining region 3 (CDR3), allowing their classification in subsets based on the stereotypical B-cell receptor immunoglobulins (BcR IG), which have been associated with different clinical features and outcomes. This study aimed to assess the mutational status of TP53 and IGHV and the frequency of stereotypical BcR IG subsets, including CLL#2 and CLL#4 associated with poor and good prognosis, respectively, in a large series of CLL patients in Spain. Methods: Observational, retrospective, cross-sectional, multicentric study of data from the RED53 project, a collaborative network between the Spanish Group of CLL (GELLC) and Janssen for the characterization of TP53 and IGVH mutational status in naïve CLL candidate patients to receive treatment. Blood samples from 225 institutions were collected between May 2016 and March 2021. Included patients had confirmed diagnosis of CLL and required first-line treatment. Basic demographic variables, leukocyte and lymphocyte counts, and the number of clonal CD5 +/CD19 + lymphocytes were recorded at sample extraction. Clonotypic IGHV-IGHD-IGHJ gene rearrangements and exons 4 to 10 of TP53 were amplified by PCR and sequenced (Sanger). Four analytical reference centers qualified by the European Initiative for CLL (ERIC) determined the mutational status following the ERIC guidelines. Results: A total of 1097 samples from patients with a median (range) age of 70.0 (27-97) years were analyzed. At sample extraction, patients had a median (range) of 54.5 (2-516) x10 9 leukocytes/mL and 46.1 (0-8810) x10 9 lymphocytes/mL, of which a median (range) of 80.0 (1-100) % (n=754) were clonal CD5 +/CD19 + lymphocytes. The most frequent indications for treatment initiation were progressive/tumoral adenopathy (n=525, 50.4%), progressive lymphocytosis (n=429, 41.2%), cytopenia (n=369, 35.4%), and systemic constitutional symptoms (n=252, 24.2%). Median (IQR) age was 63.0 (55.0, 71.0) years at diagnosis and 70.0 (62.0, 77.0) years at treatment onset. Median (range) time from diagnosis to treatment was 2.7 (0.6-6.1) years. Among 1097 patients, 100 (9.2%) had TP53 mutations with 103 variants, of which only 3 (3.0%) had 2 mutations. Of the 103 mutations, 91 (88.3%), 9 (8.7%), and 3 (2.9%) were pathogenic, likely pathogenic, and of uncertain significance, respectively. Fig. 1 shows mutation localization and type. IGHV was UM in 58% (471/812) and M in 33.1% (269/812) of patients, and unknown/undetermined in 1.8% (15/812), non-productive in 3.2% (26/812), and borderline in 3.8% (31/812) of patients. IGHV rearrangements were undetected in 25.6% (279/1091) of patients and 65.7% (717/1091), 8.5% (93/1091), and 0.2% (2/1091) had 1, 2, and 3 rearrangements, respectively . Of the 30 patients with IGHV3-21 rearrangements, 18 had available data, of which all had CLL#2 subset and, of the 15 patients with IGHV-M, 5 (33.3%) had CLL#2. Minor subsets were found in 7 (46.7%) and 17 (33.3%) of IGHV-M and UM, respectively. The most frequent stereotyped BcR IG subsets were CLL#2, CLL#1, and CLL#6, in 24.3% (18/74), 23% (17/74), and 10.8% (8/74) of patients, respectively. Among the 60 patients with mutated TP53 and IGHV mutational study available, 66.7% (40/60) had IGHV-UM. Conclusions: In our real-world experience, results regarding TP53 M and IGHV UM (9.2% and 58.0% of patients, respectively) are similar to those reported in previous series of patients requiring first-line treatment, with a slightly higher predominance of IGHV-UM over IGHV-M cases. Subset CLL#2 was the most frequently identified, whereas the frequency of CLL#6 was higher than that reported before. Considering the difficulties associated with the analysis of TP53 and IGHV mutational status of most laboratories diagnosing CLL, the RED53 network allows access to these determinations to naïve CLL patients with active disease by a simple, fast, and standardized method. Figure 1 Figure 1. Disclosures Terol: Roche: Consultancy; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; 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; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; BMS: Consultancy; Hospital Clinico Valencia: Current Employment. Ferrer Lores: Janssen: Membership on an entity's Board of Directors or advisory committees. Bosch: Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel; TAKEDA: Membership on an entity's Board of Directors or advisory committees, Other: Travel. Gonzalez Diaz: Astra Zeneca: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Lectures; Abbvie: Membership on an entity's Board of Directors or advisory committees, Other: Lectures. Crespo: Janssen: Consultancy; Astra Zeneca: Research Funding; Roche/Genentech: Research Funding. Alcoceba: Janssen: Consultancy. Esteve: Janssen: Current Employment. Loriente: Janssen: Current Employment. Villanueva: Janssen: Current Employment.

Introduction. Patients with relapsed/refractory classical Hodgkin's lymphoma (RRHL) still represent a therapeutic challenge. Consolidation with autologous stem cell transplantation (auto-HCT) is the standard of care in this setting. The achievement of a metabolic complete remission (mCR) with salvage chemotherapy (CT) improves long-term outcome after auto-HCT. The introduction of new drugs has significantly changed the landscape of RRHL. Our cooperative group (GELTAMO) has already demonstrated that brentuximab vedotin (BV) + ESHAP (BRESHAP, García-Sanz R et al, Ann Oncol 2019) is able to achieve a mCR rate of 70% before auto-HCT in patients with RRHL. Nevertheless, the superiority of BV + CT vs CT alone has never been tested in prospective randomized clinical trials. Additionally, it is unknown if consolidation treatment with BV could eventually spare auto-HCT in a good risk group of RRHL patients. Objectives. We have conducted a phase IIb prospective clinical trial (BRESELIBET, ClinicalTrials.gov ID: NCT04378647) that evaluates the efficacy of salvage therapy with BRESHAP vs ESHAP in patients with RRHL, followed by BV consolidation (instead of auto-HCT) in those who attained a mCR after salvage therapy. Methods. 150 adult patients with classical RRHL after one line of therapy were to be included and randomized 1:1 in an open label design to receive either BRESHAP [BV (1.8 mg/m 2 iv, D1), etoposide (40 mg/m 2/day iv, D1-4), Solumedrol (250 mg/day iv, D1-4), Ara-C (2 g/m 2 iv, D5) and cisplatin (25 mg/m 2/day iv, D1-4)] (x3 cycles) or ESHAP (x3 cycles). Primary efficacy endpoint of the trial was mCR [Deauville Score (DS) of 1-2]. Those patients in mCR went on to receive up to a 16 doses of BV (1.8 mg/kg iv every 3 weeks) unless unacceptable toxicity or disease progression. Patients not achieving a mCR went off the trial. Herein we are reporting preliminary results of the first 43 patients treated within the trial. Results. As of June 2021, 47 patients have been enrolled; 3 of them have been screening failures and one patient is still under screening. Among the remaining 43 patients [28 males, age at inclusion of 42 (18-64) years, median (range)], 15 were primary refractory, 15 had an early relapse (1 st CR Conclusions. BRESELIBET trial is a randomized trial that tries to demonstrate the superiority of BRESHAP vs ESHAP in RRHL as well as the feasibility of a non-transplant option in patients achieving a stringent CR assessed by PET-CT. These initial results provide safety data as possible support for these two hypotheses and the trial enrollment continues. Disclosures Sureda: Takeda: Consultancy, Honoraria, Speakers Bureau; BMS: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Gilead Kite: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Amgen: Honoraria; Mundipharma: Consultancy. Núñez: Tekada: Consultancy; Incyte: 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. Eva: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Terol: Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel; Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Travel; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Research Funding; Roche: Consultancy; BMS: Consultancy; Hospital Clinico Valencia: Current Employment. Cordoba: ADCTherapeutics: Membership on an entity's Board of Directors or advisory committees; Kyowa-Kirin: Membership on an entity's Board of Directors or advisory committees; AbbVie: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite: 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; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding. Greil: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Takeda: 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, Other: Travel, Accommodations, Expenses, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Daiichi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Sankyo: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel, Accommodations, Expenses, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Sandoz: Honoraria, Research Funding. Romero: Takeda: Honoraria; Alexion: Honoraria.

Introduction. Ibrutinib is a first-in-class, oral, once-a-day Bruton's tyrosine kinase inhibitor that achieves high overall response rates and durable remissions in patients with chronic lymphocytic leukemia (CLL) including those with high-risk features (unmutated IGHV, TP53 abnormalities, 11q deletion). Survival with continuous single-agent ibrutinib in previously-untreated CLL patients is comparable to an age-matched general population (Figure 1). IBRORS is an observational, retrospective, multicentre study to describe the characteristics and clinical outcomes of patients with CLL treated with single-agent ibrutinib in routine clinical practice in Spain. This present analysis reviews the subset of patients in IBRORS who received ibrutinib as the first-line of treatment. This series includes a significant number of patients with high risk cytogenetic/molecular alterations (del17p/TP53 M), which corresponds with the approved indication for first-line CLL patients in Spain at the time. Methods. Adult patients diagnosed with CLL treated with single-agent ibrutinib in first-line, or at first or second relapse since its commercialization in Spain (between January 2016 to January 2019) were included in the IBRORS study. Clinical characteristics of patients, efficacy and tolerability of ibrutinib as first-line treatment were analyzed here. A Kaplan-Meier analysis was performed for overall survival (OS) and progression-free survival (PFS). Results. 84 patients, from a total of 269 included in IBRORS, received single-agent ibrutinib as first-line treatment. The median age was 71.3 years (range 63-77) at the time of ibrutinib initiation. 56.3% of patients presented with an intermediate/high-risk Rai-Binet stage, and the majority of patients (98.6%) had an ECOG PS of 0-1. 91.7% of patients had at least 1 high risk molecular cytogenetic factor (unmutated IGHV, TP53 abnormalities, 11q deletion or complex karyotype) described in table 1. Baseline comorbidities of patients are described in table 2. Concomitant medication included anticoagulants (9.5% patients; vitamin K antagonist [n=4], Apixaban [n=1] and LMWH [n=3] patients), antiplatelet agents (11.9% patients), and antihypertensives (50% patients). The overall response rate (ORR) was 79.5%; 14/84 (16.6%) achieved a complete response (CR), 14/84 (16.6%) achieved CR unconfirmed, 27/84 (32.14%) achieved a partial response (PR) and 12/84 (14.2%) a PR + lymphocytosis. The median PFS and OS were not reached, and the estimated PFS at 24 months was 84.5% (73.4-95.6%). OS and PFS curves are represented in figure 2. The PFS of each patient subgroup with high-risk cytogenetic characteristics was similar to that of all patients in the first-line cohort: del17p/TP53 mutation (HR = 0.963 [95% CI 0.188-4.928]; p = 0.964), del11q (HR = 0.042 [95% CI 0.000-682.736]; p=0.521), unmutated IGHV (HR = 0.391 [95% CI 0.110-1.394]; p = 0.148). The median duration of exposure to ibrutinib was 17.3 (11.9-25.6) months. Dose reduction of ibrutinib occurred in 17/84 (20.2%) patients, 8/84 (9.52%) due to toxicity (4 hematologic toxicity and 4 non-hematologic toxicity). 27/84 (32.1%) patients had temporary interruption of treatment. 15/84 (17.8%) patients permanently discontinued ibrutinib including 6 (7.14%) patients due to progression, 4 (4.76%) due to toxicity and 5 for other reasons. Safety: 49/84 (58.3%) patients developed at least one adverse event (AE), while 12/84 (14.2%) patients developed at least one serious adverse event (SAE). Twelve (14.3%) patients reported at least one haematological toxicity while 53 patients (63.1%) recorded at least one non-haematological toxicity. Only 1 patient experienced grade 3 atrial fibrillation, which did not lead to discontinuation. The most common AEs are described in table 3. Conclusion. This population of previously-untreated CLL patients, enriched for high-risk genomic features, reflects the initial approval of ibrutinib for the treatment of first-line patients with del17p in Spain. Single-agent Ibrutinib as the first-line treatment in this real world population was effective regardless of risk factors and well tolerated, with a low rate of discontinuation due to toxicity. Findings are consistent with those reported in clinical trials. Disclosures Loscertales: AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria. Arguiñano:AbbVie: Honoraria; Janssen: Honoraria; BMS-Celgene: Honoraria; Novartis: Honoraria. Hernandez-Rivas:Janssen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Membership on an entity's Board of Directors or advisory committees; Rovi: Membership on an entity's Board of Directors or advisory committees. Pérez Persona:Amgen: Consultancy; Celgene: Consultancy, Speakers Bureau; Roche: Consultancy, Speakers Bureau; Jannsen: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Takeda: Consultancy. Loriente:Janssen Cilag: Current Employment. Villanueva:Janssen Cilag: Current Employment.

BACKGROUND Patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL), non-candidates for autologous stem-cell transplantation (ASCT), have few treatment options. Ibrutinib is an oral Bruton's tyrosine kinase inhibitor that has shown increased antitumor activity in patients with DLBCL of different subtype from germinal center B-cell like (non-GCB). In the present phase II clinical trial (NCT02692248), we investigated the efficacy and toxicity of the combination of Ibrutinib with the R-GEMOX-D regimen (rituximab, gemcitabine, oxaliplatin and dexamethasone), in patients with non- GCB DLBCL. METHODS We included patients with histological diagnosis of non-GCB DLBCL (according to Hans algorithm), with relapsed or refractory disease after at least 1 line of immunochemotherapy and non-candidates for ASCT. Patients received an induction treatment consisting of 6 (in case of complete remission [CR] after cycle 4) or 8 (in case of partial response [PR] or stable disease after cycle 4) cycles of R-GEMOX-D at standard doses every 2 weeks, in combination with ibrutinib (560 mg daily), followed by a maintenance treatment with ibrutinib for a maximum of 2 years. The primary objective was to evaluate the overall response rate (ORR) after 4 cycles, and the secondary objectives were: CR rate, progression-free survival (PFS), overall survival (OS) and toxicity. Analyses were performed in the intention to treat population (data cut-off 10th April 2020). RESULTS Sixty-four patients (59.4% male) were included between March 2016 and November 2018. Median age was 67 (25-84) years. Patients had received a median of 2 previous lines of treatment; 56.3% were refractory ( Of the 64 patients who started study treatment, 44 and 35 patients, respectively, were evaluated for response after 4th cycle and at the end of induction. Twenty-four (37%) patients started maintenance with ibrutinib, 7 of whom continue or have completed it. Causes of withdrawal from the trial (n=57) were progression (n=40), adverse event (n=6), transplantation (n=5), withdrawal of consent (n=3) and other causes (n=3). ORR and CR rate after 4th cycle were 53.2% and 35.9%, respectively. Patients with relapsed disease had significantly higher ORR (67.9% vs 41.7%, p=0.037) and CR rate (57.1% vs 19.4%, p=0.002) than patients with refractory disease. At the end of induction, ORR and CR rate were 35.9% and 29.7%, respectively. After a median follow-up of 22 months (range: 1 to 39 months), the estimated 2-year PFS and OS were 21% and 25%, respectively (Figure 1A and 1B), being significantly better in patients with relapsed disease (Figure 1C and 1D). In the multivariate analysis, status of lymphoma at study entry significantly influenced PFS (HR 0.45; 95% CI 0.25-0.82; p=0.009) and OS (HR 0.51; 95% CI 0.27-0.94; p=0.0031) independently from the IPI and the number of previous treatment lines. The most frequent adverse events (AE) (present in at least 20% of patients) were thrombocytopenia (67.2%), diarrhea (51.6%), neutropenia (46.9%), anemia (37.5%), fatigue (34.4%), nausea (29.7%) and paresthesia (20.3%). The most frequent grade 3-5 AE (present in at least 10% of patients) were thrombocytopenia (46.9%), neutropenia (35.9%), diarrhea (15.6%) and anemia (14.1%). Three patients presented a grade 5 AE, two of them related (aspergillosis and pneumonia, respectively) and one unrelated (heart failure). CONCLUSIONS The combination of ibrutinib with R-GEMOX-D as salvage therapy for patients with non-GCB DLBCL is associated with high response rates, especially in relapsed patients. The vast majority of refractory patients progress very early, so this regimen could be considered as a bridge to other consolidation therapies. Biological studies analyzing cell of origin by gene expression profiling, minimal residual disease and mutational spectrum are in progress. Disclosures Abrisqueta: Roche: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Speakers Bureau; AbbVie: Consultancy, Honoraria, Speakers Bureau. Giné:Janssen: Research Funding; Gilead: Research Funding; Roche: Research Funding. Grande:Janssen: Research Funding. Caballero:Roche: Other: travel; Gilead: Other: travel; Celgene: 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; BMS: Other: travel; Takeda: Other: travel; Kite: Membership on an entity's Board of Directors or advisory committees. Martin Garcia-Sancho:Roche, Celgene, Janssen, Servier, Gilead: Honoraria; Celgene, Eusa Pharma, Gilead, iQuone, Kyowa Kirin, Roche, Morphosys: Consultancy. OffLabel Disclosure: Off-label use of a new combination in the context of a clinical trial. New combination (Ibrutinib + R-GEMOX)

Introduction. Despite the high proportion of prolonged remissions obtained with ibrutinib in patients with CLL, complete responses (CR) are rarely observed. For the purpose of increasing the deepness of response, ibrutinib has been tested in combination with other drugs that exert a different mechanism of action. Thus, monoclonal antibodies (mAbs) have been concomitantly combined with ibrutinib in untreated or R/R CLLs. Nonetheless, several data derived from both in vitro and clinical studies do not support a synergistic effect of the concomitant administration of ibrutinib with anti-CD20 mAbs. Herein, we present the preliminary results of a multi-center, non-randomized phase 2 study aimed to determine the efficacy and safety of the sequential treatment of CLL patients with ibrutinib followed, in those not attaining CR, by a consolidation phase with ofatumumab (GELLC-7, EudraCT number 2016-004937-26). Patients and methods. Patients aged ≥18 years, physically fit (CIRS score < 6) with treatment-naïve CLL were enrolled in this study. Patients received an induction phase consisting of 12 cycles (28-day) of ibrutinib in monotherapy at 420 mg once daily. Patients attaining a CR after this induction phase were kept on ibrutinib until progression. In contrast, patients not obtaining a CR also continued on ibrutinib but received a consolidation treatment with 7 doses of ofatumumab (300 mg D1 and 1000mg D8 of C13, 1000 mg D1 of C14-C18). The primary endpoint of the study was the CR rate assessed after 20 cycles of treatment (2 months after completing ofatumumab consolidation). Results. 84 patients with a median age 69 years (range 38-84 yrs), 71% male, were included in this study. At inclusion, 83.3% had Binet stage B/C, 61% unmutated IGHV status, and 19% high risk genetic aberrations (7.6% 17p deletion and/or TP53mut, and 11.4% 11q deletion). At the interim data cut-off (June 2019), 7 patients had discontinued the study (progression to Richter transformation, n=1; patient withdrawal, n=3; adverse events [AE], n=3, including one G5 AE), 5 of them during the first 12 cycles of treatment. Sixty-seven patients received the induction phase with 12 cycles of ibrutinib, whereas 22 patients completed 20 cycles of treatment and were evaluable for the primary endpoint of the study. After 12 cycles of ibrutinib, 3 patients (4.5%) were in CR, 54 patients (80.5%) in PR, 6 patients (9%) in PR with lymphocytosis, and 4 patients (6%) in SD. In 20 patients receiving the consolidation with ofatumumab an improvement in response was observed, with 8/20 patients (40%) attaining a CR (7 patients converted PR to CR, and one patient SD to CR), whereas the remaining 12 patients were classified as PR. Two patients that were already in CR at cycle 12 maintained the CR under ibrutinib monotherapy. MRD was undetectable in blood ( Grade ≥3 adverse events (AEs) were experienced by 26 patients (31%), whilst 22 serious AEs were observed in 16 patients (19%) (14 infections, 1 febrile neutropenia, 3 dyspnoea, 1 anemia, 1 edema/pleural effusion, 1 renal insufficiency, 1 squamous carcinoma). The most common G3/4 AEs were hematological toxicity (neutropenia [7.1%], anemia [4.5%], thrombocytopenia [2.4%]) and infections (8.5%). The Gr 5 AE consisted of a severe peripheral edema and pleural effusion leading to death. The great majority of SAEs (67%) and G3/4 AEs (66%) were observed during the first 12 cycles of treatment with ibrutinib monotherapy. Conclusions. The preliminary analysis of the GELLC7 trial showed that the addition of consolidation with ofatumumab after 12 cycles of prior treatment with ibrutinib was well tolerated and elicited a deeper response. These results support the potential role of a sequential therapeutic strategy in CLL, where the addition of a consolidation with mAbs in patients with low tumor burden might improve the quality of the response. Finally, more mature results will be further presented at the meeting. Disclosures Abrisqueta: Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Celgene: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. González-Barca:Kiowa: Consultancy; Celgene: Consultancy; Takeda: Honoraria; AbbVie: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celtrion: Consultancy. Terol:Roche: Consultancy; Janssen: Consultancy, Research Funding; Abbvie: Consultancy; Astra Zeneca: Consultancy; Gilead: Research Funding. Baltasar Tello:GILEAD: Honoraria; JANSSEN: Consultancy, Honoraria; ABBVIE: Honoraria; ROCHE: Honoraria. de la Serna:Roche, AbbVie, Gilead, Janssen, Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche, AbbVie, Janssen, Gilead: Speakers Bureau. Ramirez Payer:GILEAD SCIENCES: Research Funding. Cordoba:Janssen: Consultancy, Honoraria, Speakers Bureau; Servier: Consultancy, Honoraria, Speakers Bureau; Kyowa-Kirin: Consultancy, Honoraria, Speakers Bureau; Gilead: Consultancy, Research Funding, Speakers Bureau; Roche: Honoraria, Speakers Bureau; FUNDACION JIMENEZ DIAZ UNIVERSITY HOSPITAL: Employment; Celgene: Consultancy, Honoraria, Speakers Bureau; Pfizer: Consultancy. Bosch:AbbVie: 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; Janssen: 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; Celgene: 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; Kyte: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. OffLabel Disclosure: Ibrutinib followed by Ofatumumab Consolidation

Mutations in Toll-like receptor (TLR) and myeloid differentiation primary response 88 (MYD88) genes have been found in chronic lymphocytic leukemia (CLL) at low frequency. We analyzed the incidence, clinicobiological characteristics, and outcome of patients with TLR/MYD88 mutations in 587 CLL patients. Twenty-three patients (3.9%) had mutations, 19 in MYD88 (one with concurrent IRAK1 mutation), 2 TLR2 (one with concomitant TLR6 mutation), 1 IRAK1, and 1 TLR5. No mutations were found in IRAK2 and IRAK4. TLR/MYD88-mutated CLL overexpressed genes of the nuclear factor κB pathway. Patients with TLR/MYD88 mutations were significantly younger (83% age ≤50 years) than those with no mutations. TLR/MYD88 mutations were the most frequent in young patients. Patients with mutated TLR/MYD88 CLL had a higher frequency of mutated IGHV and low expression of CD38 and ZAP-70. Overall survival (OS) was better in TLR/MYD88-mutated than unmutated patients in the whole series (10-year OS, 100% vs 62%; P = .002), and in the subset of patients age ≤50 years (100% vs 70%; P = .02). In addition, relative OS of TLR/MYD88-mutated patients was similar to that in the age- and gender-matched population. In summary, TLR/MYD88 mutations identify a population of young CLL patients with favorable outcome.

Introduction: Genomic studies of chronic lymphocytic leukemia (CLL) have uncovered >80 potential driver mutations. The vast majority of these mutations affect coding regions, and just two potential drivers have been identified in non-coding elements. Aim: To describe the biological and clinical impact of a recurrent A>C mutation at the third base of the small nuclear RNA U1, the non-coding component of the spliceosome involved in the recognition of the 5' splice site (5'SS). Methods: Whole-genome sequencing (WGS) and RNA-seq from 318 CLL patients were used to identify and characterize a highly recurrent A>C point mutation occurring at position 3 of the U1 snRNA gene (g.3A>C mutation). The U1 wild-type and mutant forms were introduced into three CLL cell lines (JVM3, HG3, MEC1) to validate in vitro the predicted effect of this alteration. We screened two independent cohorts including a total of 1,314 CLL patients for the presence of the mutation using the rhAmp SNP genotyping assay, and integrated the U1 mutational status with well-known driver alterations, IGHV and epigenetic subgroups, and clinical parameters. Results: The U1 mutation was found in 8/78 (10.3%) CLL cases analyzed by WGS. Given its role in 5'SS recognition by base-pairing, we reasoned that this mutation was likely to alter the splicing and expression patterns of CLL. We were able to confirm widespread specific alterations in the transcriptome by comparing RNA-seq data between wild-type and g.3A>C mutated samples. Applying this knowledge to an algorithm aimed to infer the U1 mutational status from expression data, we were able to identify 4 mutated cases among 240 additional cases that had RNA-seq but no WGS. In total, 12/318 (3.8%) CLL patients analyzed by WGS and/or RNA-seq harbored this mutation. This g.3A>C U1 mutation changes the preferential A-U base-pairing between U1 and 5'SS to C-G base-pairing, creating novel splice junctions and altering the splicing pattern of 3,193 introns in 1,519 genes. In addition to altered splicing, 869 genes were differentially expressed between mutated and wild-type cases. We identified specific cancer genes (e.g. MSI2, POLD1, or CD44) and pathways (B-cell receptor signaling, promotion of apoptosis, telomere maintenance, among others) altered by the U1 mutation. To confirm a causal link between this mutation and splicing changes, we introduced exogenous U1 genes with or without the mutation into three cell lines. Subsequent RNA-seq of these cell lines recapitulated the altered splicing and expression patterns observed in CLL patients. We next screened for the presence of the U1 mutation 1,057 patients (cohort 1) using the rhAmp assay and it was found in 30 (2.8%) cases. The distribution of the mutation was similar in Binet stages and CLL vs monoclonal B-cell lymphocytosis. However, the U1 mutation was almost always found in IGHV unmutated CLL (29/30, p=9.0e-11) and within the naïve-like CLL epigenetic subgroup (p=3.7e-7). None of the U1 mutated cases had mutations in the SF3B1 splicing factor. Considering only pre-treatment CLL samples, U1 mutation was associated with a shorter time to first treatment independently of the Binet stage, IGHV mutational status, epigenetic subgroups, and mutations in the well-known CLL drivers SF3B1, NOTCH1, ATMor TP53. In cohort 2 (n=257), this mutation was found in 13 (5.1%) patients, confirming its enrichment in IGHV unmutated cases, naïve-like epigenetic subgroup, and splicing modulation. Despite the relatively small number of pre-treatment samples carrying the U1 mutation (7/178) and short follow-up of the patients (median 2.6 years), the effect of this mutation on time to first treatment in cohort 2 was compatible with the one observed in cohort 1. Finally, we screened for the U1 mutation a cohort of diffuse large B-cell lymphoma (n=108), mantle cell lymphoma (n=101), follicular lymphoma (n=87), splenic marginal zone lymphoma (n=12), acute myeloid leukemia (n=52), and myelodysplastic syndrome (n=67). The mutation was not present in any of the samples analyzed. Conclusions: Here we have reported that the third base of the small nuclear RNA U1 is recurrently mutated in CLL, proved its effect in splicing and gene expression, and shown that this mutation is independently associated with faster disease progression. The g.3A>C U1 mutation represents a novel non-coding driver alteration in CLL with potential clinical and therapeutic implications. Disclosures Ramirez Payer: GILEAD SCIENCES: Research Funding. Terol:Astra Zeneca: Consultancy; Gilead: Research Funding; Abbvie: Consultancy; Janssen: Consultancy, Research Funding; Roche: Consultancy. Lopez-Guillermo:Celgene: Consultancy, Research Funding; Janssen: Research Funding; Roche: Consultancy, Research Funding; Gilead: Consultancy, Research Funding.

Background and objective. Specific immunochemotherapy is the standard treatment of patients with Burkitt leukemia or lymphoma (BL/L). The BURKIMAB08 trial showed 3-yr overall survival (OS) probability of 72% (Ribera JM et al, Cancer. 2013; 119:1660-8). However, the toxicity was high, and 11% of patients died in complete response (CR). In the BURKIMAB14 trial, dose-intensity of chemotherapy blocks was reduced in patients ≤55 years who achieved CR, with the aim to decrease the death rate without impact on efficacy. We present the results of this trial in 80 patients with BL/L and compare them with those of the BURKIMAB08 trial. Patients and method. All patients received a pre-phase with cyclophosphamide, prednisone and rituximab. Patients in localized stages (I-II non-bulky) received 4 blocks of immunochemotherapy (A1, B1, C1, A2), with 33% reduction of doses of iphosphamide, methotrexate and ARA-C in patients ≤55 years in CR (assessed by PET-CT) after B1 cycle. Patients in stages III-IV and mature B-ALL received 6 immunochemotherapy blocks (A1, B1, C1, A2, B2, C2), with the same dose reduction in cycles C1, A2, B2, C2 in patients ≤55 years in CR after B1 cycle. Patients >55 years received reduced intensity chemotherapy (as in BURKIMAB08) in both induction and post-induction cycles. The CR rate, cumulated incidence of relapse (CIR) and OS were analyzed and compared with those from the BURKIMAB08 trial. Results. From 2014-2019, 80 patients with BL/L were enrolled. Median age (range): 48 (17-80) years, 57 (71%) ≤55 years, 61 males (76%), 15 (19%) patients in stages I-II non-bulky and 65 (81%) in stages III-IV, 25 of whom (38%) had mature B-ALL. 18 patients (23%) were HIV positive, 13 (17%) showed CNS involvement at diagnosis and 23 (31%) bulky mass (>10 cm). 45 patients (60%) had intermediate-high or high IPI. All patients in stages I-II non-bulky showed CR. 4/65 patients in stages III-IV or mature B-ALL are receiving induction therapy, 1/65 withdrew the trial, 7/60 (12%) died in induction, 2/60 (3%) were resistant and 51/60 (85%) achieved CR. Of them, 6 relapsed, 3 withdrew the trial and 3 died in CR (one in the group of localized stage). OS probability at 3 years was 74% (95%CI: 64%-84%) (localized stages 100% [NE], advanced stages 68% [56%-80%], p=0.047, without difference in patients in stages III-IV vs. mature B-ALL, Figure 1). Patients >55 years showed a significantly lower probability of OS (61% [41%-81%] vs. 80% [68%-92%], p=0.022, Figure 2). A lower but non-statistically significant OS probability was observed in HIV-infected vs. non-HIV-positive patients (61% [36%-86%] vs. 78% [67%-89%], p=0.310). The CIR for patients in advanced stage/mature B-ALL was 13% (3%-28%)A trend for lower death rate in CR was observed in BURKIMAB14 vs. BURKIMAB 08 trial (3/62 vs. 16/151, p=0.180), without differences in CIR (9% [3%-21%] vs. 12% [6%-20%]) or in OS (74% [64%-84%] vs. 72% [65%-79%], respectively). Conclusions. The results of the BURKIMAB14 trial are promising, especially for patients in localized stages and for those Supported in part with the grants PI14/01971 FIS, Instituto Carlos III, SGR 288 (GRC) y Fundación "La Caixa". Figure 1. OS according to stage (I-II, vs. III-IV vs. mature B ALL) Figure 2. OS according to age (≤55 y vs >55 y) Figure 1 Disclosures Abrisqueta: Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau; Roche: Consultancy, Honoraria, Other: Travel, Accommodations, expenses, Speakers Bureau. Fernandez:Teva: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Incyte: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Abbvie: Membership on an entity's Board of Directors or advisory committees; Daiichi Sankyo: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees, Research Funding. Terol:Roche: Consultancy; Abbvie: Consultancy; Astra Zeneca: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Research Funding. Gimeno Vázquez:JANSSEN: Consultancy, Speakers Bureau; Abbvie: Speakers Bureau. Sancho:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: Advisory board; Novartis: Honoraria; Kern Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celltrion: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squib: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Background: MCL is a heterogeneous disease and the existence of indolent clinical forms is increasingly recognized although their biological ground is not fully elucidated. The aim of this study was to propose a frontline tailored treatment for indolent clinical forms with a chemo-free regimen, ibrutinib in combination with rituximab. In addition, an extensive genomic study was associated to gain biological insight into these clinical forms. Methods: This is a multicenter single-arm, open-label, phase II study with a two-stage design conducted in 14 Spanish GELTAMO sites (NCT02682641). Centralized histology, PET-CT review as well as minimal residual disease (MRD) studies (qPCR and NGS in peripheral blood [PB] and bone marrow [BM]) and biological studies are conducted. A total of 50 previously untreated MCL patients with indolent clinical forms are planned to be recruited, defined by the following criteria: no symptoms attributable to MCL, ECOG 0-1, stable disease without therapy need at least for 3 months, non-blastoid variants, Ki-67 Results: Forty patients (Gender M 29/ F 11; median age 65.7 years; low-risk MIPI 22% and intermediate/high MIPI 78%) were enrolled in the study up to data cut-off on 15 MAY 2019 (Consort diagram). The median observation time for the patients before treatment was of 7.6 months (range:3-107) and median follow-up was of 19 months. Efficacy data of the first 33 patients evaluable after 12 cycles of treatment are reported here, including two patients who were discontinued before cycle 12 due to related toxicity. A total of 27 patients achieved a response with an 82% overall response rate (ORR) and 75% CR. Among CR patients with evaluable MRD (N=23), the rate of undetectable MRD achieved after 12 cycles was 87%. Only 1 patient eventually became MRD positive at cycle 24, whereas 12 remained MRD negative and accordingly, nine of them discontinued ibrutinib as per protocol whereas 3 had interrupted treatment earlier because of intolerance. At data cut-off, all responding patients maintained the response with a median follow-up of 25 months (12-35). Only one patient progressed at one year of therapy. This particular case had shown intolerance to full-dose ibrutinib, received different salvage therapies and died of progressive disease. The estimated 15 month progression-free survival was 96% (CI95%: 89-100). Four patients withdrew the study because of serious adverse events, including cutaneous rash, severe aplastic anemia, pancreatic adenocarcinoma and lumbar fractures. Twenty-one additional G3 and G4 AEs related to Ibrutinib have been recorded including hematological toxicity in 7 patients, gastro-intestinal intolerance in 4 patients, arthralgias, atrial fibrillation and asthenia in one patient each. Conclusion: In indolent clinical forms of MCL frontline ibrutinib in combination with rituximab has a high efficacy, including undetectable MRD in the majority of cases, with a predictable toxicity profile. Figure Disclosures Gine: Roche: Other: Travel expenses, Research Funding; Gilead: Other: Travel expenses, Research Funding; Janssen: Other: Travel expenses, Research Funding. Martín:Gilead: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding; Teva: Research Funding; Roche: Consultancy, Honoraria, Other: Travel Expenses; Servier: Honoraria, Other: Travel Expenses; iQone: Consultancy; Janssen: Honoraria, Other: Travel Expenses, Research Funding; Kiowa Kirin: Consultancy. Terol:Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy; Roche: Consultancy; Gilead: Research Funding; Abbvie: Consultancy. González-Barca:AbbVie: Consultancy, Honoraria; Celgene: Consultancy; Janssen: Consultancy, Honoraria; Kiowa: Consultancy; Roche: Consultancy, Honoraria; Celtrion: Consultancy; Takeda: Honoraria. Lopez-Guillermo:Gilead: Consultancy, Research Funding; Janssen: Research Funding; Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding.

Introduction: Determination of the mutational status of rearranged immunoglobulin heavy chain variable (IgHV) genes in patients with Chronic Lymphocytic Leukaemia (CLL), is considered one of the most important prognostic factors: patients with unmutated IgHV (UM; ≥98% of identity to the germline) genes have a more aggressive disease course and develop more frequently unfavourable genetic deletions or mutations than patients with mutated IgHV (M; ≤98%). Mutational status, is currently determined by Sanger sequencing (Sseq) that allows the analysis of the major clone, however, international guidelines recommend caution in assigning mutational status in cases with "Borderline" IgHV identity (97-97.9%), and cases with double rearrangements with discordant mutational status. Objective: Analyze and determine the mutational status of the IgHV locus by High-throughput sequencing (HTS), in a cohort of CLL patients (n=51) with unclassifiable Sseq results: borderline status (n=22); double rearrangements (n=27) with discordant mutational status (n=2). Methods: We included 51 DNA samples extracted from peripheral blood of patients diagnosed of CLL according to the National Cancer Institute Working Group guidelines in our institution between 1986 and 2019 (median absolute lymphocytes 11.4x109/L [2,8-239,5x109/L]). Sseq amplification and analysis of IgHV rearrangements were performed on DNA conforming to the updated ERIC recommendations. In all the cases we were able to determinate the IGVH identity. To switch high-throughput sequencing to the clinical practice, we assessed the reliability of different library preparation methods to sequence IGH locus in patients with CLL. Amplification was performed using the Sequencing Multiplex Kit based on IGH FR (forward primers) and consensus JH (reverse primer) multiplex. PCR products were purified using Magsi-NGS Prep magnetic beads (Magnamedics Diagnostics), normalized and pooled to create a library for sequencing using a MiSeq equipment. To simplify and make automatic the analysis of the same we developed a specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation. The backbone of the analysis includes read preprocessing, mapping against IMGT reference sequences, consensus IgHV reads pairwise alignment to determine mutational status and read classification into rearrangements. Results: This approach led to the identification of a dominant clone IgHV in all cases (n=51). Instead, the percentage of identity calculated by HTS analysis varies in: - 15/22 borderline cases whose mutational status could be recalculated into 10 MM and 5 UM. The rest 7 remaining in borderline group. - We could identify both clones in 29 double rearrangements cases, with concordant mutational status except 2/29 undetermined cases, included in UM group regarding HTS results. Our tool led to the identification of a dominant clonotypic IgHV in all cases, and when compared the HTS sequence/mutational status for the most abundant clone with Sseq and for the IgHV status determination, 15 out of 22 (68,18%), could be reclassified. This case showed a major clone with productive rearrangement mutated by Sseq but unmutated by HTS. Conclusions: Analyze and determine the mutational status of the IgHV locus by HTS, would potentially reveal multiple rearrangements and increase the prognostic precision of IgHV mutation analysis. IgHV-HTS classification is able to precisely classify patients with borderline status or/and multiple IgHV rearrangements for which Sseq is inconclusive. In this case, it has been possible to improved prognostication for 17 out of 24 patients. This is helping us to discover the advantages of the data obtained by HTS compared with current Sseq standard technique. Samples were provided by the INCLIVA Biobank. Funded by Gilead Felowship 257/17 Disclosures Terol: Abbvie: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Research Funding; Roche: Consultancy; Astra Zeneca: Consultancy.

Introduction: The negative minimal residual disease (MRD) after treatment has been recently accepted as endpoint for Chronic Lymphocytic Leukaemia (CLL) clinical trials. Conventionally, MRD can be detected by using multi-color Flow Cytometry (FC) with high sensitivity. Determination of the clonal immunoglobulin gene rearrangement can be a useful monitoring marker in a broad range of B-cell lymphoproliferative neoplasms. Moreover, the mutational status of immunoglobulin heavy chain variable (IgHV) rearrangement is considered one of the most important prognostic factors in CLL. Therefore, the identification of the IgHV rearrangement can be a useful marker both at diagnostic and as monitoring marker for MRD. Nowadays, high-throughput sequencing (HTS) technologies has enabled highly sensitive cancer genomic testing in clinical laboratories. There are same initiatives based on HTS to use IgHV rearrangement as marker for MRD monitoring in Acute lymphoblastic leukemia or multiple myeloma, but it remains unharmonized for application on CLL in the clinical laboratory. Objective: We evaluated the performance and clinical applicability of HTS assay for IgHV rearrangement in CLL MRD monitoring in 69 samples from 19 CLL patients treated. Methods: The libraries including IGH locus were performed using the Sequencing Multiplex Kit on IGH consensus primers. To simplify and make automatic the analysis of the data obtained, we developed a specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation. The backbone of the analysis includes read preprocessing, mapping against IMGT reference sequences, consensus IgHV reads pairwise alignment to determine mutational status and read classification into rearrangements. Assessment of IgHV mutational status by Sseq, genomic DNA (gDNA; 50-100 ng), were used for IgHV analysis. gDNA was amplified using locus-specific primer sets for IgHV designed to allow for the amplification of all known alleles of the germline IgH sequence, as described previously. Inmunophenotypic studies were performed on erythrocyte-lysed whole PB samples according to Euroflow procedures. PB white blood cells (WBC) was systematically stained with the eight color combination panel recently proposed by the ERIC group for MRD detection (Rawstron AC et al. 2016). Data acquisition was performed on a FACSCanto II flow cytometer Becton-Dickinson Biociences using the FACSDiva software (V8.0; BD). For data analysis, the Infinicyt softwareTM (Cytognos SL, Salamanca, Spain) was used. The MRD levels were reported as fraction of CLL cells of all nucleated cells. MRD negativity was define as a fraction Results: Patient demographics and the results of IGH clonality tests are summarized in Table 1. Interpretable results were obtained with higher sensitivity compared with Sseq at diagnosis stage (19/19 samples), and we are able to determine the same clone at subsequent samples. Among 50 follow-up samples, 44 MRD were positive in both techniques (HTS and FC); 3 follow-up samples, were negative in both determinations (HTS and FC); in contrast, 3 follow-up samples, were negative by FC but positive by HTS (8.3, 17.2, 18.2 samples). This is the case of Patient 8, in which the last follow-up sample, the detection of the primary clone is positive by HTS, while by FC is undetected (Figure 1). In addition, it was possible to detect IgHV clone in all Patient 7 samples. It was under long-term monitoring by HTS and FC, and 17 months after initial diagnosis and first line of treatment (7.5 sample), it was detected a loss of response (Figure 2.). Conclusions: We evaluated an HTS IgHV assay using initial and follow-up samples of 19 CLL patients. Using our pre-designed primer set in library preparation, and developed our specific bioinformatic pipeline that covers from preprocessing to final data summarization and interpretation, we were able to demonstrate that our method was more sensitive than FC in detecting positive follow-up samples and could be able to propose it for MRD monitoring in CLL. However, the prognostic impact of these low-level MRD detected by HTS should be validated with further investigations. Samples were provided by the INCLIVA Biobank. Funded by Gilead Felowship 257/17 Disclosures Ortiz: GILEAD SCIENCES: Research Funding. Terol:Abbvie: Consultancy; Gilead: Research Funding; Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy; Roche: Consultancy.

Background Tipifarnib is a potent and selective inhibitor of the enzyme farnesyltransferase (FT). FT catalyzes post-translational attachment of farnesyl groups required for localization of signaling molecules to the inner cell membrane. CXCL12 is a ligand for CXCR4 that is essential for T cell homing to lymphoid organs and the bone marrow, and for the maintenance of immune cell progenitors. We have previously shown that FT inhibition by tipifarnib downregulates CXCL12 secretion. Herein we report preliminary efficacy, safety and biomarker data from a Phase 2 study of tipifarnib in angioimmunoblastic T-cell lymphoma (AITL) and CXCL12+ peripheral T-cell lymphoma (PTCL) patients (pts). Methods This Phase 2 study (NCT02464228) is a multi-institutional, single-arm, open-label trial initially designed as a two-stage (11+7 pts) design to determine the efficacy, safety and biomarkers of tipifarnib in pts with relapsed/refractory (R/R) PTCL age >/=18 years and a performance status of 0-2. Based on initial findings, the study was amended to include a cohort of AITL (n=12) and PTCL (n=12) pts with the CXCL12 rs2839695 A/A genotype (wt CXCL12 3'UTR cohort). Pts received tipifarnib 300 mg administered orally twice daily on days 1-21 of 28-day treatment cycles until progression of disease (PD) or unacceptable toxicity. The primary endpoint of the study is overall response rate (ORR). Tumor Whole Exon Sequencing (WES) was generated by NGS and gene expression data generated by RNA Seq. Ancillary studies also investigated the prognostic value of CXCL12 expression in pts who received standard of care treatment. Results As of 24 May 2019, 50 PTCL pts (23 AITL, 25 PTCL-NOS, 1 ALK- ALCL, 1 gamma-delta TCL) have been treated with tipifarnib, 19 pts in stages 1 and 2, and 31 pts in the ongoing AITL histology and wt CXCL12 3'UTR cohorts. Median number of prior treatment regimens was 3; 19 pts had a prior stem cell transplant. All pts (n=48 with available safety data) had at least one treatment-emergent adverse event (TEAE); 42 (88%) had at least 1 study drug-related TEAE and 13 (27%) at least 1 drug related SAE. The most frequently observed drug-related TEAEs of Grade >3 occurring in 10% or more of pts were blood and lymphatic system disorders, including neutropenia (40%), thrombocytopenia (33%), leukopenia (25%), anemia and febrile neutropenia (19% each). There have been 14 deaths on study; one related to study drug (lung infection). Of 18 evaluable pts enrolled in Stages 1 and 2 of the trial, 3 partial responses (PR), 2 of them in pts with AITL histology, and 5 best responses of stable disease (SD) were observed. In the AITL cohort (11 evaluable of 16 pts enrolled), a 45% ORR and 73% clinical benefit rate (CBR; 3 CR, 2 PR and 3 SD) was observed. In the wt CXCL12 3'UTR cohort (n=12 evaluable pts), a 42% ORR was observed (3 CR, 2 PR), with 2 of the 3 CRs observed in patients of AITL histology (n=4). A total of 23 AITL subjects were enrolled in the overall study of whom 16 had WES data. A strong association with the activity of tipifarnib was observed in 8 of the 16 (50%) carrying KIR3DL2 gene variants C336R/Q386E: 50% CR rate, 75% ORR, 100% clinical benefit rate. These tumors expressed also very low levels of CXCL5, a ligand for CXCR2, that may mediate resistance to tipifarnib. High Allele Frequency of KIR3DL2 variants predicted CR to tipifarnib treatment (ROC AUC=0.94, p Conclusion The AITL and wt CXCL12 3'UTR cohorts met pre-specified statistical hypotheses supporting proof-of-concept for tipifarnib in PTCL. AITL histology, KIR3DL2 and CXCL12 genotype provided robust tools for the selection/stratification of PTCL subjects treated with tipifarnib. Extended enrollment of AITL patients continues and an update on enrollment and outcomes will be provided at the time of the presentation. Disclosures Sokol: EUSA: Consultancy. Foss:Mallinckrodt: Consultancy; Eisai: Consultancy; Spectrum: Other: fees for non-CME/CE services ; Acrotech: Consultancy; Seattle Genetics: Consultancy, Other: fees for non-CME/CE services ; miRagen: Consultancy. Kim:Donga: Research Funding; Celltrion: Research Funding; J&J: Research Funding; Roche: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; Mundipharma: Research Funding. Jacobsen:Kura Oncology: Research Funding. Advani:Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Kura: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding; Agensys: Research Funding; Stanford University: Employment, Equity Ownership; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; Regeneron: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Cell Medica, Ltd: Consultancy; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Infinity Pharma: Research Funding; Millennium: Research Funding. Roncero:Kura Oncology: Research Funding. Terol:Janssen: Consultancy, Research Funding; Roche: Consultancy; Gilead: Research Funding; Astra Zeneca: Consultancy; Abbvie: Consultancy. Domingo-Domenech:Bristol-Myers Squibb: Other: Travel expenses; Roche: Other: Travel expenses; Seattle Genetics: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses. Piris:Millenium/Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansen: Membership on an entity's Board of Directors or advisory committees, Other: Lecture Fees; Nanostring: Membership on an entity's Board of Directors or advisory committees; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding. Rodriguez:Kura Oncology: Research Funding. Bolognese:Kura Oncology: Consultancy. Kessler:Kura Oncology: Employment. Mishra:Kura Oncology: Employment. Curry:Kura Oncology: Employment. Kurman:Kura Oncology: Employment. Scholz:Kura Oncology: Employment, Equity Ownership, Patents & Royalties. Gualberto:Kura Oncology: Employment, Equity Ownership, Patents & Royalties.

CD20-TCB (RG6026) is a novel T-cell-engaging bispecific (TCB) antibody with a '2:1' molecular format that comprises two fragment antigen binding regions that bind CD20 (on the surface of B cells) and one that binds CD3 (on the surface of T cells). CD20-TCB offers the potential for increased tumor antigen avidity, rapid T-cell activation, and enhanced tumor cell killing versus other bispecific formats. CD20-TCB has demonstrated highly promising single-agent activity in relapsed or refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL) patients (pts) (Dickinson et al. ICML 2019). Preclinical data demonstrate CD20-TCB-induced programmed cell death protein 1 (PD-1) and programmed cell death-ligand-1 (PD-L1) upregulation on T cells and tumor cells. We hypothesized that the combination of T-cell engagement by CD20-TCB and PD-L1 inhibition by atezolizumab could lead to additive anti-tumor activity in B-NHL. We report preliminary data from NP39488 (NCT03533283), an ongoing Phase Ib study evaluating the safety, tolerability, pharmacokinetics, and preliminary efficacy (objective response rate [ORR] and complete response [CR] rate per modified Lugano 2014 criteria) of CD20-TCB in combination with atezolizumab in R/R B-NHL pts. A single dose of 1000mg obinutuzumab (G) is administered on Day −7 of Cycle 1 as pretreatment (Gpt) to mitigate for potential cytokine release syndrome (CRS). CD20-TCB is initiated on Day 1 of Cycle 1 and given in a q3w schedule. From Cycle 2 onwards, atezolizumab (1200mg) is added and given on the same day as CD20-TCB. CD20-TCB dose-escalation is ongoing and is guided by the modified continual reassessment method-escalation with overdose control (mCRM-EWOC). As of June 25, 2019, 38 pts with aggressive B-NHL (n=33; diffuse large B-cell lymphoma [DLBCL], transformed [tr] follicular lymphoma [FL], primary mediastinal large B-cell lymphoma, mantle cell lymphoma, tr lymphoplasmacytic lymphoma, tr Waldenstrom`s macroglobulinemia) or indolent B-NHL (n=5; FL) had received CD20-TCB doses from 0.07mg to currently 6mg. Pts (52.6% male) had a median age of 67 years (range: 38-82) and a median of three prior treatment lines (range: 1−10); 84% had refractory B-NHL. Two dose-limiting toxicities (Grade [Gr] 3 tumor flare at 6mg during Cycle 1 and Gr 3 myopathy at 1.8mg during Cycle 2) were transient and resolved completely. The most frequent adverse event (AE) was CRS (42%; 16/38 pts), with 24% Gr 1 (n=9), 18% Gr 2 (n=7), and no Gr ≥3 (according to Lee criteria, Lee et al. Blood 2014;124:188-95). The most common AEs (>20%) were pyrexia (37%), anemia (29%), fatigue (24%), neutropenia (21%), diarrhea (21%), and decreased appetite (21%). The most common Gr ≥3 AEs (>10%) were neutropenia (18%) and anemia (13%), with a single Gr 5 unrelated pneumonia. Three pts experienced a transient Gr ≥3 neurotoxicity (Gr 4 polyneuropathy, Gr 3 trigeminal nerve herpes zoster infection, and Gr 3 post-infection encephalopathy), all of which resolved. Thirty-six pts reached their first response assessment or withdrew early and were eligible for efficacy analysis. Across all doses, ORR and CR rates by investigator assessment were 36% (13/36 pts) and 17% (6/36), respectively (indolent NHL: 4/5 and 3/5 pts; aggressive NHL: 9/31 and 3/31 pts). All CRs are ongoing at the time of abstract submission. CD20-TCB exposure and receptor occupancy (RO%) increased dose-dependently across the dose-range evaluated, and are expected to be further optimized (Djebli et al. ASH 2019). At the higher CD20-TCB doses investigated, a trend towards increased clinical activity was observed (ORR of 60% [9/15 pts] in the 4mg and 6mg cohorts combined). The combination of CD20-TCB and atezolizumab has manageable safety in R/R B-NHL pts. No new safety signals or signs of increased immune-related AEs were detected, and the overall safety profile was consistent with that reported with single-agent CD20-TCB (Dickinson et al. ICML 2019). Dose escalation is ongoing and aims to optimize the dose and schedule of CD20-TCB when combined with atezolizumab using the established exposure-response model for CD20-TCB (Djebli et al. ASH 2019). Updated safety, efficacy, and biomarker data will be presented. Disclosures Hutchings: Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Research Funding; Celgene: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Janssen: Research Funding; Incyte: Research Funding. Gritti:Roche: Other: Not stated; Abbvie: Other: Not stated; Becton Dickinson: Other: Not stated; Autolus Ltd: Honoraria. Sureda:Sanofi: Honoraria; Amgen: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria; Gilead: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; BMS: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Support. Terol:Roche: Consultancy; Abbvie: Consultancy; Astra Zeneca: Consultancy; Janssen: Consultancy, Research Funding; Gilead: Research Funding. Dyer:Roche: Research Funding. Iacoboni:Novartis: Consultancy, Honoraria; Roche: Honoraria; Janssen: Honoraria; Abbvie: Honoraria; Celgene: Honoraria. Townsend:Roche: Consultancy, Honoraria. Bacac:Roche: Employment, Equity Ownership, Patents & Royalties: Patents, including the one on CD20-TCB. Bröske:Roche: Employment, Equity Ownership. Dimier:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Ferlini:Roche: Employment, Equity Ownership. Keelara:F. Hoffmann-La Roche Ltd: Employment, Equity Ownership. Lahr:Roche: Employment, Honoraria. Lechner:Roche: Employment, Other: Roche shareholder. Moore:Roche: Employment, Equity Ownership. Morcos:Roche: Employment, Equity Ownership. Panchal:Roche: Employment. Weisser:Pharma Research and Early Development Roche Innovation Center Munich: Employment, Equity Ownership, Patents & Royalties. OffLabel Disclosure: CD20-TCB (also known as RG6026, RO7082859) is a full-length, fully humanized, immunoglobulin G1 (IgG1), T-cell-engaging bispecific antibody with two fragment antigen binding (Fab) regions that bind to CD20 (on the surface of B cells) and one that binds to CD3 (on the surface of T cells) (2:1 format). The 2:1 molecular format of CD20-TCB, which incorporates bivalent binding to CD20 on B cells and monovalent binding to CD3 on T cells, redirects endogenous non-specific T cells to engage and eliminate malignant B cells. CD20-TCB is an investigational agent.

The effectiveness of rituximab maintenance therapy in the treatment of chronic lymphocytic leukemia has been investigated in a phase 2 clinical trial that included an initial treatment with rituximab 500 mg/m2 on day 1 (375 mg/m2 the first cycle), fludarabine 25 mg/m2 on days 1 to 3, cyclophosphamide 200 mg/m2 on days 1 to 3, and mitoxantrone 6 mg/m2 on day 1 (R-FCM), for 6 cycles, followed by a maintenance phase with rituximab 375 mg/m2 every 3 months for 2 years. Sixty-seven patients having achieved complete response (CR) or partial response (PR) with R-FCM were given maintenance therapy. At the end of maintenance, 40.6% of patients were in CR with negative minimal residual disease (MRD), 40.6% were in CR MRD-positive, 4.8% remained in PR, and 14% were considered failures. Six of 29 patients (21%) who were in CR MRD-positive or in PR after R-FCM improved their response upon rituximab maintenance. The 4-year progression-free survival (PFS) and overall survival rates were 74.8% and 93.7%, respectively. MRD status after R-FCM induction was the strongest predictor of PFS. Maintenance with rituximab after R-FCM improved the quality of the response, particularly in patients MRD-positive after initial treatment, and obtained a prolonged PFS. This trial was registered at www.clinicaltrialsregister.eu as identifier #2005-001569-33.

BACKGROUND Although the overall prognosis of patients with aggressive non-Hodgkin's lymphoma (NHL) has improved, nearly a third of patients will have refractory disease or relapse. Identification of these high-risk patients using traditional prognostic factors is limited. PET is the recommended imaging modality for the staging of FDG-avid lymphoma but the value of a comprehensive new imaging biomarkers analysis applied to PET for the prediction of patients outcome has still not been deeply investigated. New metrics estimating the overall tumor burden such as metabolic tumor volume (MTV) and those that may capture intratumoral biological heterogeneity such as total lesion glycolysis (TLG) have been used to predict progression-free survival. AIM The goal of the present work was to characterize Lymphoma lesions by extracting several metabolic volume and textural properties as radiomics features and evaluate their performance as surrogate indicators of the number of treatment cycles, and treatment response. Materials and methods In this retrospective, observational study, we included aggressive non-Hodgkin's lymphoma patients consecutively diagnosed according to the WHO 2016 between January of 2015 to December of 2017. A diagnostic PET/CT scan were essential. 1 patient without treatment was excluded. Clinical and biological data were extracted from medical records. PET/CT examinations were exported from the PACS and loaded into QUIBIM Precision 2.3 analysis platform (QUIBIM, Valencia, Spain) for the calculation of metabolic volumes and textural properties. The SUV values of the PET images were normalized to the average liver SUV, and the lesions were automatically segmented considering a threshold of 41% of the maximum SUV (SUVmax). Physiological uptakes in organs and tissues like bowel, bladder, brain, among others, were manually removed. In the lesions volumetry analysis, the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were calculated. For the extraction of texture features, first order histogram descriptors (SUV values distribution, skewness, kurtosis) as well as second order descriptors were extracted after computing the Gray-Level Co-Occurrence Matrix (GLCM). For the statistical analysis, the Z-score of all imaging features obtained was calculated and a multi-variate analysis was performed by first calculating the intra-class correlation (ICC) to reduce redundant variables. Second, data hierarchy clustering was applied to automatically obtain patient groups according to different imaging signatures. The prognostic performance of IPI with and without the imaging signature was evaluated by a Discriminant Analysis for the number of treatment cycles and treatment response. Prognostic value of OS was performed through Kaplan-Meier analysis. Results A total of 41 patients were included. The descriptive analysis of patients recruited with demographic and clinical data can be appreciated in Table 1. Radiomics features extracted allowed to clusterize patients in different groups that were later introduced in the classifier (Figure 1). The classifier based on discriminant model including the IPI factors predicted number of treatment cycles with a 65.9% of accuracy, being the age the factor with the highest weight (0.818). Adding information about imaging features from PET increased the accuracy to 86.5%. For the treatment response assessment, the IPI factors predicted response correctly in 71.4% of cases, being ECOG the parameter with the highest weight (0.974). Prediction was fully accurate when adding the imaging features, with a 100% of accuracy. The texture feature with the highest importance was 'dissimilarity' of the pixels (weight of 15.919). Conclusion The addition of radiomics features to the conventional IPI evaluation of patients allows for a significant increase in predictive performance, both for determining which patients will have more than 1 treatment lines and those who will respond to treatment. The results of this study would have an impact in disease management with a combined IPI and radiomics-based prognostic evaluation of patients at diagnosis. Disclosures No relevant conflicts of interest to declare.

Brief Report. Artículo breve., B-cell chronic lymphocytic leukemia (B-CLL) migration involves several molecules, including matrix metalloproteinase–9 (MMP-9) and vascular endothelial growth factor (VEGF). We have studied whether VEGF regulates MMP-9. VEGF significantly reduced MMP-9 protein expression in a dose-dependent manner, measured by gelatin zymography. Blocking the VEGFR2 receptor restored MMP-9 levels, implicating this receptor in the observed effect. Down-regulation of MMP-9 by VEGF resulted in significant inhibition of B-CLL cell migration through Matrigel or human umbilical vein endothelial cells, confirming the crucial role of MMP-9 in these processes. Reverse-transcription polymerase chain reaction analyses revealed that VEGF regulated MMP-9 at the transcriptional level. Indeed, VEGF induced STAT1 tyrosine phosphorylation, and this was blocked by inhibiting VEGFR2. STAT1 was responsible for MMP-9 down-regulation, as STAT1 gene silencing restored MMP-9 production and B-CLL cell migration in the presence of VEGF. Thus, the levels of VEGF and MMP-9 influence B-CLL cell expansion and both molecules could constitute therapeutic targets for this disease., Ministerio de Ciencia e Innovación, Spain (grants PI060400, SAF2009-07035, and RTICC RD06/0020/0011, A.G.-P.; and PI061637 and RTICC RD06/0020/0080, M.J.T.) and by the Fundación de Investigación Médica Mutua Madrileña (A.G.-P.). J.R.-M. was supported by the Fundación Ramón Areces. P.E. was supported by the Ministerio de Ciencia e Innovación.

Brief report., As B-cell chronic lymphocytic leukemia (B-CLL) progresses, malignant cells extravasate and infiltrate lymphoid tissues. Several molecules, including gelatinase B/MMP-9, contribute to these processes. Although mainly a secreted protease, some MMP-9 is present at the B-CLL cell surface and the function, mode of anchoring, and interactions of this MMP-9 are unknown. Here we show that anti–MMP-9 antibodies immunoprecipitated a 190-kDa CD44v isoform and α4β1 integrin from B-CLL cells, but not from normal B cells. Function-blocking antibodies to α4β1 or CD44, or transfection with specific siRNAs, decreased cell-associated proMMP-9 and increased the secreted form. B-CLL cells attached to and bound proMMP-9 and active MMP-9, and this was inhibited by blocking the expression or function of α4β1 or CD44. The MMP-9 hemopexin domain was critical in these interactions. α4β1 and 190-kDa CD44v (but not CD44H) formed a complex at the cell surface, since they both coimmunoprecipitated with anti-α4, anti-β1, or anti-CD44 antibodies. Immunofluorescence analyses confirmed that α4β1 and CD44v colocalized with MMP-9. Binding of proMMP-9 inhibited B-CLL cell migration, and this required MMP-9 proteolytic activity. Thus, we have identified α4β1 and CD44v as a novel proMMP-9 cell surface docking complex and show that cell-associated MMP-9 may regulate B-CLL cell migration and arrest.

4 páginas, 2 figuras -- PAGS nros. 383-386, B-cell chronic lymphocytic leukemia (B-CLL) progression is frequently accompanied by clinical lymphadenopathy, and the CCL21 chemokine may play an important role in this process. Indeed, CCR7 (the CCL21 receptor), as well as matrix metalloproteinase-9 (MMP-9), are overexpressed in infiltrating B-CLL cells. We have studied whether MMP-9 is regulated by CCL21 and participates in CCL21-dependent migration. CCL21 significantly increased B-CLL MMP-9 production, measured by gelatin zymography. This was inhibited by blocking extracellular signal-regulated kinase-1/2 (ERK1/2) activity or by cell transfection with CCR7-siRNA. Accordingly, CCL21/CCR7 interaction activated the ERK1/2/c-Fos pathway and increased MMP-9 mRNA. CCL21-driven B-CLL cell migration through Matrigel or human umbilical vein endothelial cells (HUVEC) was blocked by anti-CCR7 antibodies, CCR7-siRNA transfection, or the ERK1/2 inhibitor U0126, as well as by anti-MMP-9 antibodies or tissue inhibitor of metalloproteinase 1 (TIMP-1). These results strongly suggest that MMP-9 is involved in B-CLL nodal infiltration and expand the roles of MMP-9 and CCR7 in B-CLL progression. Both molecules could thus constitute therapeutic targets for this disease, This work was supported by grants PI060400 (to A.G.P.) and PI061637 (to M.J.T.) from the Ministerio de Sanidad y Consumo, and by the Fundación de Investigación Médica Mutua Madrileña (FMM; to A.G.P.). J.R.M. was supported by FMM and the Fundación Ramón Areces

B-cell chronic lymphocytic leukemia (B-CLL) progression is determined by malignant cell extravasation and lymphoid tissue infiltration. We have studied the role and regulation of matrix metalloproteinase-9 (MMP-9) in B-CLL cell migration and invasion. Adhesion of B-CLL cells to the fibronectin fragment FN-H89, VCAM-1, or TNF-α–activated human umbilical vein endothelial cells (HUVECs) up-regulated MMP-9 production, measured by gelatin zymography. This effect was mediated by α4β1 integrin and required PI3-K/Akt signaling. The chemokine CXCL12 also up-regulated MMP-9, independently of α4β1 and involving ERK1/2 but not Akt activity. Accordingly, α4β1 engagement activated the PI3-K/Akt/NF-κB pathway, while CXCL12/CXCR4 interaction activated ERK1/2/c-Fos signaling. Anti–MMP-9 antibodies, the MMP-9 inhibitor TIMP-1, or transfection with 3 different MMP-9 siRNAs significantly blocked migration through Matrigel or HUVECs. Cell-associated MMP-9 was mainly at the membrane and contained the proactive and mature forms. Moreover, B-CLL cells formed podosomes upon adhesion to FN-H89, VCAM-1, or fibronectin; MMP-9 localized to podosomes in a PI3-K–dependent manner and degraded a fibronectin/gelatin matrix. Our results are the first to show that MMP-9 is physiologically regulated by α4β1 integrin and CXCL12 and plays a key role in cell invasion and transendothelial migration, thus contributing to B-CLL progression. MMP-9 could therefore constitute a target for treatment of this malignancy.

Standard first-line treatment for elderly multiple myeloma (MM) patients ineligible for stem cell transplantation is melphalan plus prednisone (MP). However, complete responses (CRs) are rare. Bortezomib is active in patients with relapsed MM, including elderly patients. This phase 1/2 trial in 60 untreated MM patients aged at least 65 years (half older than 75 years) was designed to determine dosing, safety, and efficacy of bortezomib plus MP (VMP). VMP response rate was 89%, including 32% immunofixation-negative CRs, of whom half of the IF– CR patients analyzed achieved immunophenotypic remission (no detectable plasma cells at 10–4 to 10–5 sensitivity). VMP appeared to overcome the poor prognosis conferred by retinoblastoma gene deletion and IgH translocations. Results compare favorably with our historical control data for MP—notably, response rate (89% versus 42%), event-free survival at 16 months (83% versus 51%), and survival at 16 months (90% versus 62%). Side effects were predictable and manageable; principal toxicities were hematologic, gastrointestinal, and peripheral neuropathy and were more evident during early cycles and in patients aged 75 years or more. In conclusion, in elderly patients ineligible for transplantation, the combination of bortezomib plus MP appears significantly superior to MP, producing very high CR rates, including immunophenotypic CRs, even in patients with poor prognostic features.

To identify recurrent genomic changes in mantle cell lymphoma (MCL), we used high-resolution comparative genomic hybridization (CGH) to bacterial artificial chromosome (BAC) microarrays in 68 patients and 9 MCL-derived cell lines. Array CGH defined an MCL genomic signature distinct from other B-cell lymphomas, including deletions of 1p21 and 11q22.3-ATM gene with coincident 10p12-BMI1 gene amplification and 10p14 deletion, along with a previously unidentified loss within 9q21-q22. Specific genomic alterations were associated with different subgroups of disease. Notably, 11 patients with leukemic MCL showed a different genomic profile than nodal cases, including 8p21.3 deletion at tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor gene cluster (55% versus 19%; P = .01) and gain of 8q24.1 at MYC locus (46% versus 14%; P = .015). Additionally, leukemic MCL exhibited frequent IGVH mutation (64% versus 21%; P = .009) with preferential VH4-39 use (36% versus 4%; P = .005) and followed a more indolent clinical course. Blastoid variants, increased number of genomic gains, and deletions of P16/INK4a and TP53 genes correlated with poorer outcomes, while 1p21 loss was associated with prolonged survival (P = .02). In multivariate analysis, deletion of 9q21-q22 was the strongest predictor for inferior survival (hazard ratio [HR], 6; confidence interval [CI], 2.3 to 15.7). Our study highlights the genomic profile as a predictor for clinical outcome and suggests that "genome scanning" of chromosomes 1p21, 9q21-q22, 9p21.3-P16/INK4a, and 17p13.1-TP53 may be clinically useful in MCL.

Patients with mantle cell lymphoma (MCL) may present with either nodal or leukemic disease. The molecular determinants underlying this different biologic behavior are not known. This study compared the pattern of genetic abnormalities in patients with nodal and leukemic phases of MCL using comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) for specific gene loci. Although both leukemic and nodal MCL showed similar genomic patterns of losses (involving 6q, 11q22-q23, 13q14, and 17p13) and gains (affecting 3q and 8q), genomic loss of chromosome 8p occurred more frequently in patients with leukemic disease (79% versus 11%,P

The hallmark for Chroniclymphocytic leukemia (CLL) is a highly variable clinical course. An international prognostic index (CLL-IPI) is a promising tool to improve the precision of prognostic counseling and to identify patients who deserve closed monitoring. The CLL-IPI is a risk-weighted model comprising the risk factors age, stage, del(17p)/TP53 mutation, IGHV mutation status, and β2-microglobulin (β2-M)(LancetOncol 2016). The aims of the study were 1) to determine the IGHV status as well as the IGHV repertoire 2) to assess/validate the applicability of the CLL-IPI in general practice. We included all patients diagnosed of CLL according to the National Cancer Institute Working Group guidelines in our institution between 1986 and 2014 who had at least a 24 months follow-up. Amplification and sequence analysis of IGH rearrangements were performed on either DNA or cDNAusing the BIOMED-2 protocol. Sequence data were analyzed using the IMGT database and tools. Clinical and biological data were extracted from medical records and included age, stage, CD38 and ZAP-70 expression, serum LDH, β2-M, cytogenetics and lines of treatment. Overall survival (OS) was calculated from diagnosis to last follow-up or death, time to first treatment (TFT) from diagnosis to first treatment administration or last follow-up. 209 CLL patients were originally included but complete data to calculate the CLL-IPI was only available in 176 pts. Median age of the series was 65 years (range, 33 to 92), and a slight male predominance 102 (58.5%). The main clinical characteristics are detailed in Table 1. Median follow-up of patients was 71.5 months (range, 24-315). We identified 105/209 patients (50%) with unmutated IGHV. Somatic mutations among IGHV gene subgroups display a hierarchy of mutations (IGHV3>IGHV1>IGHV4). Among the functional IGHV genes, the most frequently encountered were IGHV1-69 (31; 14.6%). It was the most recurrently used in the unmutated group. The most represented IGHV gene within the mutated subset was IGHV4-34, which was used in 15 cases (7.1%). We have observed 39 IGHV genes. The most frequents are showed in Figure1. As previously described, patients with unmutated status showed a higher expression of CD38 and ZAP-70, unfavorable cytogenetics and a higher proportion of treated patients. The CLL-IPI index identified four groups of patients: low risk (0-1 points) n=74 (42%), intermediate (2-3) 67 (38.1%), high (H) (4-6) 29 (16.5%) and very high (VH) 6 (3.4 %). The 5-year OS and 5-year TFT of the CLL-IPI risk groups differed significantly (p< 0.0001, log-rank test) between the low (OS 92.2%, TFT 74.1%), intermediate (OS 83.2%, TFT 34.6%) and high-very high groups (OS 61.5%, TFT 22.8%). We only identified 6 patients (3.4%) with a VH, with no difference in terms of OS and TFT between the VH and high (H) risk groups, probably due to the small number of patients. When we considered the H and VH altogether, the CLL-IPI identified three groups with significantly different TFT and OS (Figure 2) In summary, in our cohort the frequencies of the IGHV genes used in BCR rearrangements were similar to those described in the Mediterranean area and confirm a geographical-dependent leukaemic repertoire. We confirm that the CLL-IPI is a useful tool for real-life practice as it identifies three risk groups with significantly different time to first treatment and overall survival curves. In our experience, the CLL-IPI applied to the whole CLL population at diagnosis discriminates a smaller proportion of patients in the high (16.4%) and very high groups (3.4 %) compared to the original training cohort based on treated patients included in clinical trials. Our results are closely similar to the MAYO cohort that included patients consecutively diagnosed and observed. Table 1 Patient characteristics at diagnosis included in CLL-IPI analysis (n=176) Table 1. Patient characteristics at diagnosis included in CLL-IPI analysis (n=176) Figure 1 Distribution of rearrangements of the 12 most frequent IGHV genes according to mutational status. Figure 1. Distribution of rearrangements of the 12 most frequent IGHV genes according to mutational status. Figure 2 a) Overall survival b) Time to first chronic lymphocytic leukaemia treatment according to the CLL-IPI risk groups Figure 2. a) Overall survival b) Time to first chronic lymphocytic leukaemia treatment according to the CLL-IPI risk groups Disclosures No relevant conflicts of interest to declare.

Introduction Recent large scale genomic studies have disclosed the heterogeneity of the mutational landscape of chronic lymphocytic leukemia (CLL). The remarkable genomic plasticity of this disease has been further emphasized by the complex subclonal composition recognized in some tumors. Initial studies using high-coverage next generation sequencing (NGS) have revealed the prognostic impact of mutations at very low allelic frequency. The results of these studies have opened a new perspective where the proportion of cells carrying specific driver mutations rather than just the presence or absence of the alterations may be relevant to understand the evolution of this disease. However, the information generated has been limited to a small subset of CLL driver genes. The aims of this study were to define the deep mutational architecture of 28 frequently altered driver genes in CLL and determine the relevance of the subclonal quantitative composition in the progression of the disease. Methods Highly purified tumor samples from 406 untreated CLL patients were included in this study. Ultra-deep NGS of the 28 target genes was performed using the Acces-Array system (Fluidigm) (ATM, TP53, SF3B1, BIRC3, XPO1, RPS15, FBXW7, DDX3X, POT1, KLHL6, MGA, MYD88, IRF4, BRAF, NXF1, BCOR, ZNF292, NRAS, KRAS, CCND2, TRAF3, ZMYM3, MED12) or the Nextera-XT DNA library preparation kit (Illumina) (NOTCH1, NFKBIE, EGR2, PIM1, DTX1) before sequencing in a MiSeq (Illumina). A robust bioinformatic pipeline followed by an extensive verification process allowed the detection of mutations down to 0.3% of variant allele frequency (VAF). Copy number alterations were investigated by high density SNP-arrays in 376 cases. We calculated the cancer cell fraction (CCF) carrying each specific mutation using the PyClone algorithm. The prognostic impact of the mutations was evaluated for time to first treatment (TTFT) and overall survival from the time of sampling. Results The mutational frequency observed for virtually all genes was higher than in similar previous studies of population based CLL at diagnosis. We detected mutations with a VAF below the Sanger sequencing threshold (VAF 80%) mutated clones. Overall, among the 260/406 (64%) cases carrying at least one mutation in any of the genes analyzed, a major mutated clone (CCF >80%) was only identified in half of the patients (127, 49%). Convergent mutational evolution, defined as the acquisition of independent genetic mutations in the same gene, was observed in 19 (68%) of the 28 genes analyzed, being present in 66/260 (25%) mutated cases. The number of cases with convergent evolution was directly related to the global mutational frequency of the gene. The clinical relevance of the mutations appeared to be gene specific and related to the quantitative magnitude of the different subclones. We identified three major patterns of specific gene CCF that influenced the prognosis of the patient: 1) CCF independent pattern in which the mere detection of a mutation at any CCF conferred an adverse prognosis (TP53, ATM, POT1, NFKBIE, XPO1, or RPS15 among others); 2) CCF gradual pattern in which the poor prognostic impact was a continuous variable directly related to the size of the mutated clone (SF3B1); and 3) CCF clonal pattern in which the prognostic impact of the mutations was a categorical variable defined by a certain threshold of the mutated clone (NOTCH1, BIRC3, EGR2, FBXW7). On the other hand, cases with convergent mutational evolution had a tendency to a shorter TTFT when compared to mutated cases without this phenomenon. Conclusions In conclusion, the emergence of subclonal mutations is a general and dynamic phenomenon in CLL that seems to involve virtually all driver genes and occurs at different time points of the disease. The clinical impact of the clonal architecture of the tumor is gene specific and related to the magnitude of the respective subclone. These findings provide new insights on the relevance of the subclonal mutational profile in CLL and the importance of quantitative mutational analyses for the management of the patients. Disclosures No relevant conflicts of interest to declare.

et al. PETHEMA/GEM (Programa para el Estudio de la Terapéutica en Hemopatías Malignas/Grupo Español de Mieloma) Cooperative Study Groups., The achievement of complete response (CR) after high-dose therapy/autologous stem cell transplantation (HDT/ASCT) is a surrogate for prolonged survival in multiple myeloma; however, patients who lose their CR status within 1 year of HDT/ASCT (unsustained CR) have poor prognosis. Thus, the identification of these patients is highly relevant. Here, we investigate which prognostic markers can predict unsustained CR in a series of 241 patients in CR at day +100 after HDT/ASCT who were enrolled in the Spanish GEM2000 (n = 140) and GEM2005 < 65y (n = 101) trials. Twenty-nine (12%) of the 241 patients showed unsustained CR and a dismal outcome (median overall survival 39 months). The presence of baseline high-risk cytogenetics by FISH (hazard ratio 17.3; P = .002) and persistent minimal residual disease by multiparameter flow cytometry at day +100 after HDT/ASCT (hazard ratio 8.0; P = .005) were the only independent factors that predicted unsustained CR. Thus, these 2 parameters may help to identify patients in CR at risk of early progression after HDT/ASCT in whom novel treatments should be investigated., This work was supported by the Cooperative Research Thematic Network (RTICs; RD06/0020/0006, RD06/0020/0005, RD06/0020/0031, RD06/0020/0101, RD06/0020/1056, and G03/136), MM Jevitt, SL Firm, Instituto de Salud Carlos III/Subdirección General de Investigación Sanitaria (FIS: PI060339; 06/1354; 02/0905; 01/0089/01-02; PS09/01 897), and Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain (557/A/10).

Aggressive B-cell Lymphomas are the second most frequent AIDS-defining cancers. Few studies have compared the molecular characteristics of aggressive B-cell lymphomas in patients with and without HIV-infection; and to our knowledge, there are no reports comparing the incidence of gene rearrangements between the two groups and their impact on outcome in series treated with RCHOP. We retrospectively studied two series of patients with (N=32) and without HIV-infection (N=43) with diffuse large B-cell lymphomas (DLBCL) NOS (75% and 70%, respectively), T-rich DLCBL (13% and 5%), transformed DLBCL (3% and 14%) and double-hit (DH) DLCBL (9% and 11%) [defined by translocations affecting MYC (TMYC) concomitantly with translocation affecting BCL2 (TBLC2) and/or BCL6 (TBCL6)]. Tissue microarrays were constructed and translocations were studied by fluorescent in situ hybridization. The germinal center (GC) phenotype was defined according to the Hans' algorithm based on the expression of CD10, MUM1 and BCL6. Clinical data was retrieved from records. Continuous and categorical variables are presented using descriptive statistics and compared using Fisher's exact test, χ 2-test, and Mann-Whitney U-test. Survival analyses were performed using the Kaplan-Meier method. P-valuesof less than 0.05 were considered statistically significant. The median follow-up of HIV-infected patients was 6.9 years and of HIV-uninfected was 5 years. HIV-uninfected patients were older than HIV-infected patients, median age (range) 59 years (25-80) and 45 years (37-68) respectively; (P=0.002). There were differences between HIV-infected and HIV-uninfected patients regarding; male gender (81% vs. 54%, P=0.015), ECOG performance status higher than 2 (56% vs. 26%; P=0.018) and elevated ß-2 microglobulin (82% vs. 47%, P=0.005). On the other hand, the percentage of patients with III and IV Ann Arbor stages, two or more extranodal involvement, elevated LDH, 3 to 5 International Prognostic Index (IPI) scores, B-symptoms and bulky disease were similar in both series. The study of molecular features showed that more HIV-infected cases (57%) tended to have a GC phenotype than HIV-uninfected (35%); P=0.093. Regarding gene rearrangements, there was a trend for more HIV-infected patients (30%) to present TBCL2 than HIV-uninfected patients (11%); P=0.056. Of note, only 2 patients of the HIV-infected series were transformed from follicular lymphoma. The frequency of TMYC, TBCL6 and DH was similar in HIV-infected (24%, 28% and 9%, respectively) and HIV-uninfected (15%, 28% and 11%, respectively). HIV-infected patients were treated with RCHOP (N=27), intensive immunochemotherapy for Burkitt Lymphoma (IICT-BL) (N=4), CHOP (N=1) and HIV-uninfected patients with RCHOP (N=39), IICT-BL (N=2), RCOP (N=1), RESHAP (N=1). The complete response rate was not statistically different in HIV-infected and HIV-uninfected patients neither the relapse rate when considered all treatments given. Only patients treated with RCHOP were considered in survival analyses. The overall survival (OS) of HIV-uninfected patients with high IPI scores (3 to 5) (N=15) tended to be shorter than in patients with low IPI scores (0 to 2) (N=24), (5-y OS 60% [35%-85%] vs. 81% [64%-98%], P=0.089) and the progression free survival (PFS) was clearly inferior (5-y PFS 33% [9%-57%] vs. 73% [54%-92%], P=0.004). HIV-infected patients with high IPI scores presented similar OS and PFS than patients with low IPI scores. Contrary to other reports, TMYC had no statistically significant adverse impact on OS and PFS of HIV-uninfected patients, most probably because of small size of our series. The same reasoning could be applied for HIV-infected patients since both OS and PFS of patients with TMYC (N=5) was shorter than in those without TMYC (N=20) (5-year OS 40% [0%-83%] vs. 65% [44%-86%], P=0.365 and 5-year PFS 40% [0%-83%] vs. 60% [38%-82%], P=0.546). TBCL2, TBCL6 and GC phenotype had no impact on OS and on PFS of both HIV-infected and HIV-uninfected patients. Survival analyses of DH were not performed due to the small number of events. In summary, the frequency of TMYC and TBCL6 in aggressive B-cell lymphomas was similar in HIV-infected and HIV-uninfected patients but TBCL2 was less frequent in HIV-infected patients. Supported in part by grants EC11-041 from ISCIII, Spain. Disclosures No relevant conflicts of interest to declare.

INTRODUCTION Follicular lymphoma (FL) may, over time, transform into an aggressive lymphoma, usually diffuse large B-cell lymphoma (DLBCL). Transformed follicular lymphomas (tFL) have a worse prognosis due to poorer response to treatment than primary DLBCL. The incidence of transformation is estimated in ~3% per year, although it varies largely between different studies (24%-70% overall). These differences are mainly due to different criteria to define tFL, to lack of evidence of tFL by biopsy, absence of clonality studies discarding secondary de novo NHL, studies performed in the pre-Rituximab era, or different follow-up times among studies. With all this pitfalls, the actual incidence of transformation remains an open question. The aim of the present study is to analyse the incidence and prognostic impact of transformation in patients with FL in a large retrospective series of the Spanish group of Lymphomas (GELTAMO). PATIENTS&METHODS A total of 1763 patients from 19 Spanish centres diagnosed of FL between 2000 and 2011 were recruited in the study. Data were obtained from the database of centres willing to participate in this study. True tFL (FL to DLBCL) were recorded. From the original cohort, FL IIIb, composite FL+DLBCL, discordant FL (FL in bone marrow and DLBCL in adenopathy or viceversa), and downgrading tFL (DLBCL at diagnosis and relapse of FL) were excluded. Patients with inadequate follow-up were not considered. Therefore, 1611 patients (grade I, II, and IIIa) were finally included. This study was approved by the Salamanca University Hospital Ethic Committee. RESULTS One hundred and ten patients (median follow up of 6 years) were transformed to DLBCL. Cumulative incidence of transformation at 5, 10, and 15 years was of 5%, 9%, and 14%, respectively. With a median follow up of 75.9 months (2 to 179), median time to transformation was 66 months, ranged 1-179. Considering survival from diagnosis of FL, tFL patients had a shorter OS than non-transformed (19% vs. 69%, p2 (p=0.002, HR: 2,1 95% CI: 1.3-3.4). In the multivariate analysis, factors predicting decreased OS after transformation included non-achievement of CR after first line therapy (p We analyzed separately the role of autologous stem cell transplantation (ASCT) in transformed FL patients. Patients that received ASCT were significantly younger ( CONCLUSIONS In this series, one of the largest reported in the rituximab era, high risk FLIPI (>=2) and non-response to FL first line therapy were associated with a higher risk of transformation.Only non-response to transformed FL treatment therapy and a high LDH at transformation were associated with a worse OS after transformation in the multivariate analysis. Autologous transplantation in transformed patients could have a benefit in terms of OS after transformation, but after the introduction of immunochemotherapy strategies, perhaps patients responding to treatment after transformation do not beneficiate from this strategy. *Equal contribution; ‡Equal senior contribution Disclosures Sancho: CELLTRION, Inc.: Research Funding.

Genomic studies have provided a complete profile of somatic mutations in chronic lymphocytic leukemia (CLL). These comprehensive approaches have revealed a relatively large number of mutated genes, the adverse prognostic value of some of which has been demonstrated in a number of reports. Recent studies have shown the clinical relevance of TP53 mutations at very low allele frequency. The presence and prognostic impact of minor mutated clones of other CLL driver genes and their clonal dynamics in the evolution of the disease is not well known. The goal of this study was to explore the presence of clonal and subclonal mutations of TP53, SF3B1, BIRC3, and ATM using an ultra-deep next-generation sequencing (NGS) strategy, to define the evolution of these subclones in different time-points of the disease, and to determine their influence in the outcome of the patients. Samples from 363 untreated CLL cases were included in this study. Copy number alterations were investigated by high density SNP-arrays or by quantitative PCR in 341 and 16 cases, respectively. Targeted ultra-deep NGS of TP53 (exons 4-10), ATM (exons 2-63), BIRC3 (exons 2-9), and SF3B1 (exons 14-16 and 18), including splicing sites, was performed using the Access-Array system (Fluidigm) and sequenced in a MiSeq equipment (Illumina). This methodology combined with a robust bioinformatic analysis based on well-known available tools allowed the identification of mutations down to 0.3% of variant allele frequency (VAF). Results obtained were fully verified by orthogonal techniques. Twelve per cent of VAF was used as threshold for the classification of clonal or subclonal mutations since 12% was the cut-off for detection of mutations by Sanger sequencing. Deletions of 11q comprising ATM or BIRC3 were found in 7% of the cases and were associated with mutations of the other ATM allele in 19/26 (73%) cases and BIRC3 in 3/23 (13%). Deletions of 17p were found in 19 (5%) cases and co-existed with TP53 mutations in 15 (79%) of them. Regarding the mutational status of the studied genes, TP53 mutations were present in 11.6% of patients (7.2% clonal, 4.4% subclonal), ATM mutations in 10% (7% clonal, 1% subclonal, 2% germline mutations considered pathogenic), SF3B1 mutations in 12% (7% clonal, 5% subclonal), and BIRC3 mutations in 4% (2% clonal, 2% subclonal). These subclonal mutations had similar molecular characteristics to their respective high-allele frequency mutations supporting a comparable pathogenic effect. In this regard, clonal and subclonal SF3B1 mutations were associated with shorter time to first treatment (TTT) independently of IGHV mutations. Clonal and subclonal TP53 mutations predicted for shorter overall survival (OS) together with the IGHV mutational status, although the impact of isolated TP53 mutations (i.e. without 17p deletion) on OS was not so evident, as has been the case in other studies. In addition, the outcome of patients with clonal and subclonal BIRC3 mutations showed a similar significant shorter OS. Regarding ATM, the effect of isolated subclonal ATM mutations could not be evaluated because of their low number, but ATM mutations as a whole had a significant impact on TTT even in the absence of 11q deletions. This study also reinforces the need to study the germline of the patients to fully characterize the ATM mutations observed in the tumors. Of note, germline variants previously described as pathogenic were associated with 11q deletions, confirming the hypothesis already suggested that these germline variants may influence disease progression through loss of the otherallele. Clonal dynamics was examined in longitudinal samples of 45 CLL patients. We confirmed the expansion of most TP53 mutated clones after therapy. However, both TP53 and SF3B1 mutations expanded also before any therapy in some patients, indicating that progressive dynamics of these clones is not only dependent on therapy selection. On the contrary, small ATM mutated clones seemed to be more stable. Although the number of cases is limited, we observed that clonal evolution in longitudinal samples had an unfavorable impact on OS. In conclusion, this study shows the presence of a high number of subclonal mutations of different driver genes in CLL and provides insights on the impact of these mutations on the outcome of the patients. These findings suggest that the characterization of the subclonal architecture may be relevant for a better management of CLL patients. Disclosures No relevant conflicts of interest to declare.

Background. Chronic lymphocytic leukemia (CLL) is a highly heterogeneous disease in which immune evasion of tumoral cells, as well as, an impaired CD4 and CD8 T-cell function have been described. Immunomodulatory drugs, such as lenalidomide, alone or in combination with other treatments are promising strategies for those patients with refractory disease. The combination of lenalidomide with dexamethasone has been investigated in multiple myeloma and has revealed as a highly efficient treatment. Nonetheless, the efficacy and mechanisms of action of this combination in CLL have not been elucidated. Aim. To assess the effect of lenalidomide and dexamethasone combination in gene expression of CLL B cells, as well as CD4+ and CD8+ T cells from CLL patients enrolled in LENDEX-LLC-09 trial. Methods. Four patients included in the LENDEX-LLC-09 trial (NCT01246557) were studied (2M/2F, med age 72). All presented with advanced CLL (2 B and 2 C Binet stages), and were previously treated by a minimum of two chemo-immunotherapy regimens. Peripheral blood samples were taken at the recruitment and the 7th day of the first cycle of lenalidomide (2.5mg/day) and dexamethasone (20mg/day, 4 days). Total RNA was extracted from CLL B cells (CD5+ CD19+) and T cells (CD4+ or CD8+) positively selected by immunomagnetic methods (Miltenyi Biotec). Good quality RNA (RIN>7) was hybridized to Human Gene 2.0 ST array (Affymetrix). Differences between gene expression of pretreated and treated samples were assessed for each cell type using linear models for microarrays. Genes with a |logFC|>1 were considered as potentially relevant. Functional analysis was performed using Ingenuity Pathway Analysis (IPA). Results and discussion. The major effect in the gene expression due to treatment was observed in CD4+ T cells, which presented 290 up-regulated genes and 103 down-regulated. CLL cells showed up-regulation of 189 and down-regulation of 53 genes, while increase and decrease in the expression of 112 and 37 genes, respectively, were found in CD8+ T cells. Globally, the most important involved networks were related to cell-to-cell signaling, cellular growth and proliferation, cell death and survival, as well as inflammatory response and immune cell trafficking. Regarding CLL B cells, TNF-α was the most up-regulated gene, as previously described in lenalidomide treated B cells. Contrarily, we did not observe significant differences in genes involved in the immunologic synapse, as CD80, CD86, CD200, PD-L1, CD276 and CD270, which have been reported as key regulators in lenalidomide mechanism of action. Of note, a general increase of genes associated with binding to cells (CD68, CTLA4, ADAM28, ITGAX, LY96) was detected. In contrast to previous studies that demonstrated a growth arrest and induction of apoptosis by lenalidomide or dexamethasone in monotherapy (Baptista et al, 2012; Fecteau et al, 2014), a global inhibition of the apoptosis (up-regulation of BTK and CD79B and inhibition of SMAD7, among others) were observed when both drugs were combined. Considering CD8+ T cells gene expression, an up-regulation of genes involved in leukocyte activation and cell-to-cell binding was detected. The most remarkable changes were found in TNF-α and IFN-γ induction, as well as in ADAM28, LY96 and CD68. In contrast to CD8+ T cells, an inhibition of CD4+ T cell proliferation was observed after the combined treatment (up-regulation of VSIG4, LILRB4 and down-regulation of ICOS). This observation suggests that dexamethasone administration inhibits the CD4+ activation promoted by lenalidomide, as has been described in multiple myeloma (Hsu et al, 2011). Regarding response to treatment, two patients initially presented a complete response with positive minimal residual disease. However, all patients finally progressed after treatment and one died due to disease progression. No significant differences in gene expression patterns were found among patients. Conclusions. Our results suggest that lenalidomide and dexamethasone combination leads to an anti-tumoral activity displayed by an activation of CD8+ T cells against the tumor, rather than an increase of apoptosis in CLL cells. More studies are needed to confirm these preliminary findings of the combined effect of lenalidomide and dexamethasone in refractory CLL patients. Acknowledgments. This work was funded by Celgene, and supported by PI11/1621, 14SGR585 and Fundació LaCaixa. Disclosures Off Label Use: Lenalidomide and dexamethasone combination in CLL.

INTRODUCTION: High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is the standard treatment for patients with relapsed or refractory aggressive B-cell lymphoma, and is frequently used as part of first-line therapy in patients with peripheral T-cell lymphoma (PTCL). However, long-term remission rates with this strategy are inferior to 50%, so novel approaches are required. We have designed a prospective multicenter phase II study to evaluate the safety and efficacy of bendamustine as part of conditioning regimen in patients with aggressive lymphomas undergoing ASCT. METHODS: Inclusion criteria were: histologic diagnosis of i) relapsed or refractory diffuse large B-cell lymphoma (DLBCL) or grade 3B follicular lymphoma (FL) in partial response (PR) or complete remission (CR) after salvage therapy, or ii) transformed DLBCL or peripheral T-cell lymphoma (PTCL) in first or subsequent PR or CR. Conditioning regimen consisted of bendamustine (200 mg/m2, days -7 and -6), etoposide (200 mg/m2, days -5 to -2), cytarabine (400 mg/m2, days -5 to -2), and melphalan (140 mg/m2, day -1) (BendaEAM regimen). Primary endpoint was progression-free survival (PFS) at 3 years. Secondary endpoints were toxicity, response to transplant at 3 months, and overall survival (OS). This trial was registered at EMEA (EUDRACT number 2010-020926-17). RESULTS: Sixty patients (median age 54 years, range 27-70) from 22 Spanish hospitals were included since May 2011 to November 2012. Histologies were: 40 DLBCL, 3 grade 3B FL, 13 transformed DLBCL, and 7 PTCL. 82% of patients have received ³2 lines of treatment prior to ASCT. 37 patients (62%) were in CR at the time of transplant and 23 (38%) in PR. A median number of 4.05 x 106/Kg (range: 1.69-19.80) CD34+ cells were reinfused. All patients (except one who died early) engrafted after a median of 11 (range: 9 to 72) and 14 (range: 4 to 53) days, respectively, to achieve >0.5 x109/L neutrophils and >20 x109/L platelets. 39 serious adverse events (SAEs) were reported before day +100, including 14 infectious episodes, 2 of them resulting in respiratory failure and death (3.3% of transplant related mortality). Another major SAE was renal toxicity developed by 5 patients (8.3%) after bendamustine administration, reversible in all cases (3 of these patients had developed mild renal failure during previous salvage therapy). Non-relapse mortality after day +100 was 3.3% (1 patient died because of Wernicke's encephalopathy, and 1 patient from infectious complications). Concerning response to transplant, 44 patients (73.3%) achieved CR, 7 (11.7%) PR, and 6 patients (10%) did not respond. Univariate analysis showed that patients who received more than 2 lines of treatment prior to transplant (1 line: 100% of CR post-transplant; 2 lines: 71%; >2 lines: 50%; p=0.013), and those who were in PR at transplant (48% vs 89%, p0.1). At the time of analysis, 13 patients (22%) had disease progression and 8 patients (13%) have died (4 from lymphoma, and 4 from other causes). With a median follow-up of 18.9 (9.5 to 32.3) months, the estimated 2-year PFS and OS were 73% and 88%, respectively. CONCLUSIONS: The BendaEAM conditioning regimen is feasible and active in patients with aggressive lymphomas. Toxicity profile is similar to that commonly observed in the ASCT setting, but renal toxicity can occur and should be carefully monitored, especially in patients with prior history of renal failure. Longer follow-up is needed to assess the long-term toxicity and the efficacy of this regimen, although patients who are not in CR before transplant seem to have poorer outcomes. Disclosures No relevant conflicts of interest to declare.

Patients with FL can have long time of survival, but disease progression typically occurs 3-5 years after initial treatment. Consolidation with Z after initial therapy has shown to improve progression-free survival (PFS) mainly in the pre-R era, whereas maintenance with R also has demonstrated a substantial benefit in terms of PFS in patients treated with immunochemotherapy. In this setting, the Spanish intergroup PETHEMA/GELTAMO/GELCAB started a randomized phase 2 trial in order to compare the use of consolidation with Z vs. R maintenance in patients with FL responding to R-CHOP. From June 2008 to July 2010, 146 patients (66M/80F; median age, 55 years) were enrolled from 25 Spanish institutions in the randomized phase 2 trial ZAR2007 (ClinicalTrials.gov, number NCT00662948). Main inclusion criteria were: FL grade 1, 2 or 3a, age 18-75 years, stages II-IV and need of treatment according to modified GELF criteria. Patients with FL grade 3b or transformed to DLBCL were excluded. In addition, patients with platelet count 25% before randomization were also excluded. Main end-point of the trial was PFS from randomization. The distribution according to the FLIPI score was as follows: low-risk 14%, intermediate 47%, and high 39%. After R-CHOP, 124 patients in CR (n=56), CR[u] (13) or PR (55) were randomized 1:1 (stratified by response) to arm A (90Y ibritumomab tiuxetan 0.4 mCi/kg IV; total dose of 90Y was capped at 32 mCi) vs. arm B (1 infusion of R 375 mg/m2 every 8 weeks for 2 years). Sixty three (51%) patients were assigned to arm A (Z) and 61 (49%) to arm B (R). Twenty two patients were not randomized due to response Disclosures: Lopez-Guillermo: Roche: Membership on an entity’s Board of Directors or advisory committees. Briones:F. Hoffmann-La Roche: Honoraria.

Abstract 3949 Although in MM an optimal response to front-line therapy is a surrogate for extended survival, two class of patients fall outside this paradigm: those that after treatment show unsustained complete remission (CR) and those that not achieving CR, return into an MGUS-like signature and experience nevertheless long term disease control (LTDC). The prospective identification of the later group remains to be accomplished. Herein, we hypothesized that whole BM immunophenotypic profiling by multiparameter flow cytometry (MFC) would help to identify upfront, symptomatic MM patients with an occult MGUS-like signature (from here on named MGUS-like-MM). For this purpose, the relative frequency of plasma cells (plus the balance between clonal and normal PC), precursor and mature B-cells, T- and NK-cells, erythroblasts, monocytes, neutrophils and eosinophils was determined in 698 newly diagnosed, transplant eligible MM patients included in two consecutive GEM/PETHEMA trials: GEM2000 (VBMCP/VBAD; n=486) and GEM2005 Whole BM immunophenotypic profiling identified a cluster of 176 (25%) symptomatic MM patients “assigned as MGUS-like-MM” based on the following phenotypic features: significantly decreased median numbers of myelomatous PC together with a significant increment of eosinophils, neutrophils, monocytes, T- and NK -cells, mature B-cells and particularly normal PC. This subgroup was characterized by a favorable clinical presentation with increased (P Finally, it should be pointed out that this MGUS-like signature was not restricted to symptomatic MM, since we have also found a subset of high-risk smoldering MM patients with the same signature. These later patients showed a significantly lower risk of progression into symptomatic MM as compared to the rest of high-risk smoldering MM patients (data not shown). In summary, whole BM immunophenotypic profiling by MFC is capable to identify a subset of symptomatic MM patients with an occult MGUS-like signature associated with prolonged survival. Given that in this subgroup of patients the value of CR is not as important as in the rest of MM patients, the prospective identification of this signature may contribute to discriminate a sub-optimal response that require additional treatment from a residual “MGUS-like component” that may remain stable without further treatment. Disclosures: Paiva: Celgene: Honoraria; Miellenium: Honoraria; Janssen: Honoraria. Martínez-López:Celgene: Honoraria. Mateos:Celgene: Honoraria; Miellenium: Honoraria; Janssen: Honoraria. De La Rubia:Celgene, Janssen: Consultancy, Speakers Bureau. Lahuerta:Celgene: Honoraria; Millenium: Honoraria. Blade:Celgene: Honoraria; Millenium: Honoraria; Janssen: Honoraria. San Miguel:Celgene: Honoraria; Millenium: Honoraria; Janssen: Honoraria.

Abstract 1639 Objectives To evaluate the efficacy and safety of rituximab-bendamustine-mitoxantrone-dexamethasone (R-BMD) in patients with relapsed or refractory follicular lymphoma, (R/R FL) to first-line therapy with R-chemotherapy (R-ChemoT), followed by maintenance with R. Methods Phase II trial including 61 patients with R/R LF, after a 1st R-ChemoT line. Induction treatment: Rituximab 375 mg/m2 iv, day 1; bendamustine 90 mg/m2 iv, days 1 and 2; mitoxantrone 6 mg/m2/day iv, day 1; oral dexamethasone 20 mg / day, days 1 to 5. Cycles of 28 days. Evaluation of response after 3rd cycle. If stable disease or progression: withdrawal from the study. If complete response (CR) or complete response unconfirmed (CRu): administration of a 4th cycle. If partial response (PR): administration up to 6 cycles. If CR, CRu or PR at the end of induction: patients receive maintenance with R 375 mg/m2/day every 12 weeks for 2 years. Primary objective: Complete responses (CR + CRu). Results are presented as valid % and median [range]. Results Results from 46 patients who completed induction period. 52.2% women, age 63 [32–76] years. Ann Arbor stage III / IV 75.6% (31/41) and III / IV-B 22.6% (7/31). FLIPI: intermediate risk 28.9% (11/38); high-risk 23.7% (9/38). Number of administered cycles: 4 [1–6]. Overall response 93.5% (43/46); CR: see Table 1. Progression Free Survival –median (CI95%)-: 14.5 (11.6-NA) months. The most relevant grade 3/4 toxicity: neutropenia 52% (n = 24; 17 patients received G-CSF) and thrombocytopenia 4.3% (n = 2). Infections grade 3/4: 6.5% (n = 3). One patient died due to CMV reactivation. No skin reactions were reported. There are maintenance available data from 15 patients: 3 patients sustained CR at the end of this period, and 2 patients progressed. Conclusions R-BMD is a treatment schedule effective and a safe alternative for patients with R/R FL, after a 1st line with R-ChemoT. No skin reactions were reported, possibly due to the inclusion of dexamethasone in the treatment scheme. Additional follow up is required to achieve more conclusive findings. Disclosures: No relevant conflicts of interest to declare.

Abstract 1596 Background: The IPI, which takes into consideration both host and tumor factors, is the standard method used to stratify aNHL into different risk categories. The IPI was derived in the pre-rituximab era and confirmed as valid in the Rituximab (R) era. The major mechanism of action of R appears to be through the host's immune system. Host factors related to the immune status have been recently recognized as significant in predicting outcome. The ALC, AMC, and ALC/AMC ratio were identified by Wilcox et al. as having an impact on both progression free survival (PFS) and overall survival (OS) (Leukemia 2011;25:1502-09). In order to confirm these findings in a different population of aNHLs we have studied 402 patients with aNHL treated in the R era at 5 centers: 1 in Puerto Rico, 4 in Spain (1 Barcelona, 2 Madrid, 1 Valencia). Methods: 402 patients diagnosed between December 2000 and April 2011 with aNHL were included. ALC and AMC were obtained from pretreatment CBC. All patients received anthracycline and R based chemotherapy. ALC was divided in quartiles (Q): 1st Q ALC ranged between 277 and 950, 2nd Q ALC 951–1352, 3rd Q ALC 1353–1870, and the 4th Q ALC 1871– 5400. The lower Q ALC of 950 and the median of 1353, as well as the lower Q AMC of 366 and the median AMC of 504 were assessed as cutoffs to divide patients into groups with low or high ALC and AMC. Results: Median age was 64 (17–92) and 55% were females. Median follow up was 50 months. FFS and OS at 4 years were 73% and 79% respectively. FFS was superior for patients with an ALC >950 vs =366 vs =504 and 2) whose 4 yr FFS and OS were 53% and 65% respectively (p950 vs Conclusions: We have confirmed that the ALC is an independent prognostic factor for FFS in aNHL. It can identify patients with an inferior outcome despite having a favorable IPI and its effect seems to be more striking in males than in females. In contrast to Wilcox's findings, the AMC and ALC/AMC ratio was not an important predictor of FFS and OS in our cohort. Improved FFS in patients with higher ALC suggests that the immune system plays an important role inthe outcome of patients treated with R-chemo. Disclosures: No relevant conflicts of interest to declare.

1630 The management of recurrent or refractory Hodgkin's lymphoma (HL) remains challenging. Previous published data have suggested that infiltrating normal B lymphocytes in classic HL lesions may contribute to the survival of Hodgkin and Reed-Sternberg cells in vivo. The objective of this prospective, multicenter, phase II trial was to investigate the activity of an anti-CD20 monoclonal antibody, ofatumumab, in combination to a standard platinum-based salvage regimen, ESHAP (O-ESHAP) followed by high-dose chemotherapy and autologous stem cell transplantation (ASCT) for patients with classical HL failing to first line chemotherapy. Forty- five patients (25 M / 21 F, median age 34 years, range 18–66) were enrolled in the study between June 2010 and June 2012. Treatment consisted on three cycles of ESHAP plus ofatumumab 1,000 mg days 1 and 8 on first cycle and day 1 on second and third cycles. At the time of study entry, 66% of patients had III-IV Ann Arbor stage, 16% bulky disease, 18% B symptoms, 40% extranodal HL and 52% ≥3 involved nodal areas. We respect to response to first-line therapy, 46% patients had achieved a completed response (CR) and then relapsed, 6% had a partial remission (PR), whereas the remaining 48% were primary refractory. Eighty-one percent patients have received 3 cycles of O-ESHAP as scheduled, three patients 2, and five 1 cycle (1 patient due to toxicity, 1 patient's decision, 2 HL progression, and 4 treatments ongoing). Grade 3–4 WHO hematological toxicity was observed in 16%, 19%, and 20% after cycles 1, 2, and 3, respectively. Non-hematological toxicity was reported in 32%, 10%, and 20%, respectively. Overall response (OR) rate was 63% (49% CR and 14% PR). Response to O-ESHAP according to prior response to first-line chemotherapy is shown in [table 1][1]. Adequate PBSCs collection was achieved in 94% mobilized patients. Twenty-six out of 33 patients have already proceeded to ASCT. Two patients died of neutropenic sepsis after ASCT and HL progression, respectively. Preliminary results of this ongoing trial suggest that addition of ofatumumab to ESHAP is safe and has a promising clinical activity in patients with relapsed/refractory HL candidates to ASCT. | | Response to first-line chemotherapy | |:---------------------- | ----------------------------------- | ----------------- | | | Relapsed or partial response (n=17) | Refractory (n=16) | | Response after O-ESHAP | | | | OR | 16 (94%) | 7 (44%) | | CR | 14 (82%) | 3 (22%) | | PR | 2 (12%) | 4 (22%) | | Refractory | 1 (6%) | 9 (56%) | Table 1. Response to O-ESHAP according to previous response to first-line treatment Disclosures: No relevant conflicts of interest to declare. [1]: #T1

Abstract 3917 INTRODUCTION VEGF is an important pro-angiogenic factor involved in survival and dissemination of chronic lymphocytic leukemia cells. At high concentrations such as those present in bone marrow niches, VEGF reduces MMP9 production and favours bone marrow retention. But on the other hand, it is well known that autologous VEGF and CD49d are required for B-CLL cell migration. In other cancer cell lines, this effect seems to be mediated by CXCR4/SDF-1 axis. In this work we studied the role of exogenous VEGF on B-CLL migration as well its relationship with the G-coupled proteins CXCR4, CXCR7 and CD49d. MATERIALS AND METHODS We obtained peripheral blood mononuclear cells from 33 patients diagnosed of CLL according to established clinical and laboratory protocols at our institution after informed consent. We also used the CLL cell line Mec-1. B-lymphocytes were purified by Ficoll-Hypaque density gradient centrifugation anti-CD19 conjugated Dynabeads and stored in liquid nitrogen. Then we analysed by flow cytometry the expression of several chemokines and adhesion molecules, CXCR4, CXCR7 and CD49d before and after exogenous VEGF exposure (50 ng/mL), VEGF-R2 inhibitor (70 nM) or both. In order to evaluate the role of VEGF in the motility of these cells, we performed an in vitro 24-hours transmigration assay towards a media containing (or not) SDF-1. B-CLL (5 × 105 cells) cells were incubated on the upper chamber of transwell filters coated with human umbilical vein endothelial cells in the presence or absence (control) of vascular endothelial growth factor (VEGF) ([50 ng/ml], 24 hours), VEGFR2/KDR inhibitor [70nM] or both simultaneously. We quantified the migration ratio between those stimulated with VEGF compared with non-stimulated controls, inhibitor-treated cells versus control and both (R2-inh plus VEGF) versus inhibitor-treated cells. Migration ratio was given as mean ± SD. Statistical analysis was performed by non-parametric Wilcoxon test using SPSS statistical software (version 19.0). RESULTS Basal CXCR4, CXCR7 and CD49d expression levels of B-CLL cells were highly variable among the 33 patients analyzed. Mean fluorescent intensity (MFI) of CXCR4 expression was significantly higher on cells treated with VEGF versus untreated cells (average increase, 9.64 ± 95, p=0.028). However, we did not detect a significant difference in the percentage of cells expressing this receptor. On the other hand, VEGF treatment did not influence either the mean fluorescent intensity or the number of CXCR7 and CD49d expressing cells. Exposure to a VEGFR2 inhibitor reduced the percentage of cells expressing CXCR4 and CXCR7, suggesting a potential regulatory role of this receptor in the expression of these chemokines. Concerning B-CLL migration, we observed a significant increase in cell migration of cells treated with exogenous VEGF versus the control ones in both the Mec-1 cell line and the primary cells (27.66 ± 69.97 p= 0.03). Furthermore, the treatment with VEGFR2 inhibitor reduced significantly the migration index (−23.18 ± 33.5, p= 0.001) and the motility was restored by the addition of VEGF to the R2-inhibitor treated cells (36.04 ± 39.33, p=0.001). DISCUSSION This preliminary data suggest that VEGF seems to be involved in B-CLL migration through the regulation of CXCR4 expression levels. Detailed molecular mechanisms implicated in this process should be further studied. New therapeutic strategies focussed in blocking both the SDF1-CXCR4 axis and/or VEGF pathway could have a potential therapeutic implication by decreasing B-CLL cell migration into lymph nodes and bone marrow microenvironment. Disclosures: No relevant conflicts of interest to declare.

Abstract 3930 Chemoimmunotherapy combination regimens achieve high rates of negative minimal residual disease responses in CLL, which has been correlated with prolonged PFS and OS. In the present study, we addressed the prognostic value of MRD levels obtained after rituximab, fludarabine, cyclophosphamide, and mitoxantrone (R-FCM) induction treatment in the response duration of patients with CLL included in the GELLC-1 trial and receiving maintenance rituximab treatment (Bosch et al. J Clin Oncol 27:4578–4584, 2009). Patients achieving CR or PR after R-FCM induction received rituximab maintenance consisting of rituximab 375 mg/m2 every three months for two years (up to 8 cycles). MRD was evaluated by four-color flow cytometry assays giving a sensitivity < 10−4 in paired peripheral blood (PB) and bone marrow (BM) samples three months after R-FCM induction therapy, every 6 months during rituximab maintenance, and at the final restaging 3 months after conclusion of treatment. Sixty-seven patients (median age 60 years, 70% male) received a median of 8 cycles of rituximab maintenance (range, 1 to 8), 76% of them completing the entire planned treatment. After R-FCM induction, MRD was considered negative in 45/59 patients (76%) in PB and in 35/63 patients (55%) in BM. Of note, these patients with negative MRD in PB had longer PFS in comparison to those with detectable MRD (at 4 years, 88%, [95%IC 98%-78%] vs 27%, [95%IC 51%-3%] respectively; p10−4 to 10−2, n=8) MRD levels (PFS at 4 years, 84%, 74%, and 25%, respectively, p Figure 1. Figure 1. Figure 2. Figure 2. Disclosures: Off Label Use: Rituximab is currently not approved as maintenance therapy for patients with chronic lymphocytic leukemia. Bosch:Hoffman La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract 3938 The incorporation of high-dose therapy/autologous stem cell transplantation (HDT/ASCT) and novel agents has significantly improved survival of MM young pts; however, the molecular heterogeneity of the disease warrants the investigation if such improvement also benefits patients harboring poor prognostic features such as non hyperdiploid (HY) karyotypes and high proliferation index. Herein, we have analyzed by MFC the DNA ploidy status and proliferation of bone marrow (BM) PC in a total of 595 newly diagnosed MM pts included in two consecutive PETHEMA/GEM trials: GEM2000 (VBMCP/VBAD followed by HDT/ASCT; N=319) and GEM2005 Of the 595 pts, 295 were classified as non-HY (49.6%) and 300 as HY (50.4%). Patients with non-HY vs HY DNA content showed significantly inferior median PFS (34 vs 44 months, P=.004) and OS (67 vs 84, P=.005). Interestingly, we have detected by MFC the presence of two different PC clones (with different DNA ploidy status) in 34 of the 595 (6%) patients, and this subgroup showed a poor outcome (median PFS and OS of 26 and 52 months respectively, P≤.005). Regarding the proliferative index, the median percentage of PCs in S-phase in the whole series was of 1.14% (0%-13%). Accordingly, pts were stratified using a cutoff of ≥1% vs 15% PCs by MFC (HR=1.7;P=.008) and >5% normal PCs within the BM PC compartment (HR=6.6;P=.008) emerged as independent prognostic factors for PFS; in turn, for OS the presence of high-risk cytogenetics (HR=2.3;P After this analysis of the overall population, we investigated whether the incorporation of novel agents in the induction regimen previous to HDT/ASCT could abrogate the poor prognosis of patients classified as non-HY and with ≥1% PCs in S-phase. Patients with non-HY DNA status included in the GEM2005 Finally, we wanted to gain further insight into the potential association between specific cytogenetic abnormalities and PC proliferation, as well as whether there is a difference in the proliferative rate of PCs between diagnosis and disease progression. Interestingly, pts harboring a t(11;14) showed a significantly decreased percentage of PCs in S-phase (0.7% vs 1.2%, P In summary, our results show that the evaluation of PCs DNA content by MFC immunophenotyping provides valuable clinical information, as pts with a non-HY DNA status and high proliferative rate show a poor outcome, which is not yet fully abrogated by the incorporation of novel agents prior to HDT/ASCT. Moreover, pts at relapse show an increased proliferative index; therefore, the precise mechanisms leading to PC proliferation deserves further investigations. Disclosures: Paiva: Celgene: Honoraria; Janssen: Honoraria. Rosiñol:Janssen: Honoraria; Celgene: Honoraria. Mateos:Janssen: Honoraria; Celgene: Honoraria. Alegre:Janssen: Honoraria; Celgene: Honoraria. Lahuerta:Janssen: Honoraria; Celgene: Honoraria. Blade:Janssen: Honoraria; Celgene: Honoraria. San Miguel:Janssen-Cilag: Consultancy; Celgene: Consultancy; Millennium Pharmaceuticals, Inc: Consultancy.

Abstract 293 The effectiveness of rituximab, fludarabine, cyclophosphamide, and mitoxantrone (R-FCM) followed by rituximab maintenance in the treatment of CLL has been investigated in a phase II clinical trial that includes two treatment parts. First, patients were given induction therapy with R-FCM up to 6 cycles, achieving an overall response (OR) rate of 93% and a CR rate of 82% (46% MRD-negative CR) (Bosch et al. J Clin Oncol 27:4578–4584, 2009). Patients achieving CR or PR with the initial part of the treatment received rituximab maintenance. Here we present the final results of the treatment maintenance part, initiated three months after concluding R-FCM, and consisting of rituximab 375 mg/m2 every three months for two years (up to 8 cycles). Sixty-four patients (median age 60 years, 70% male) receiving > 4 cycles of maintenance therapy were evaluated for response, including bone marrow (BM) examination and MRD assessment by four-color flow cytometry of peripheral blood and BM. Patients in whom rituximab maintenance was prematurely interrupted (≤ 4 cycles) due to toxicity were considered as failures. Median number of cycles of maintenance administered was 8 (range, 1 to 8) and 76% of patients completed the entire planned treatment. Treatment was delayed due to insufficient hematological recovery in 9 cycles (2%) and to non-hematological toxicity in 4 cycles (0.8%). Neutropenia was observed in 31.3% of cycles (grade 3&4 in 8.5%), thrombocytopenia in 4.6%, and anemia in 1.2%. At the end of the maintenance therapy, 45% of patients had low IgA serum levels, 37% low IgG, and 66% low IgM. Sixteen patients experienced grade 3&4 infectious episodes, including 9 pneumonia, 2 febrile neutropenia, 1 appendicitis, 1 myositis, 1 herpes zoster, and 1 cerebral abscess. Two patients died, one due to multifocal leukoencephalopathy and the other due to hemophagocytic syndrome. Infectious episodes grade 3&4 were observed in 19.5% of cycles with neutropenia 3&4, but in only 3% of cycles with neutropenia inferior to grade 3 (p Disclosures: Bosch: Hoffman La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Off Label Use: Rituximab is currently not approved as maintenance therapy for patients with chronic lymphocytic leukemia.

Abstract 3896 Chronic lymphocitytic leukaemia/Small lymphocytic lymphoma (CLL/SLL) is a neoplasm composed of monomorphic small neoplastic B cells that usually co-express CD5 and CD23. The current WHO classification considers CLL/SLL as the same entity being SLL the non-leukemic lymphoma presentation of CLL. The criteria for SLL include the presence of lymphadenopathy with less than 5×109/L peripheral blood B cells. Patients with SLL usually develop PB involvement during the evolution of the disease. The aim of this study was to analyze the main clinico-biological features and outcome of a series of SLL patients and compare them with the CLL patients diagnosed in the same period of time.Patients and methods: we have included 588 patients (353M/ 233F; median age 61 years) diagnosed with CLL or SLL according to the WHO classification criteria in the same period of time.The main clinico-biological features and the outcome were recorded and analysed according to the CLL/SLL diagnosis. Results: five hundred forty-five patients (93%) fulfil the criteria for CLL and 43 patients (7%) for SLL. The main clinico-biological variables according to the CLL/SLL criteria are detailed in the table. No differences were observed in gender distribution, age at diagnosis or ECOG. Patients with SLL had more frequently Binet C stage, low haemoglobin levels and platelet counts. 320 patients eventually received therapy, including purine analogues containing regimens (159 patients), chlorambucil (113), CHOP-like regimens (31), and other therapies (17). Sixty-nine patients received rituximab in combination. SLL patients received more frequently CHOP-like regimens than CLL patients, but this difference did not reach statistical significance. During the follow-up, 58% of the SLL patients eventually developed leukemic presentation, after a median time from diagnosis of 4.6 years (0.2–15 years). Patients with SLL not receiving treatment progressed to PB involvement sooner than treated SLL (median time, 1 year vs 6 year, respectively; p=0.06).Twenty four of the 588 patients eventually developed Richter syndrome, with this proportion being higher in the SLL than in CLL patients (13.1% vs 3.5%; p=0.001). Moreover, the proportion of second neoplasm (excluding non melanoma skin cancer) was higher for SLL patients than for CLL patients. After a median follow-up for surviving patients of 7.4 years (range, 0.1 to 28), 207 patients eventually died with no differences in overall survival between the two groups of patients. In addition, the causes of death were also similar (50% in SLL and 43% in CLL due to disease progression). In conclusion, although the outcome is similar in SLL and CLL groups, SLL patients more frequently had cytopenias as well as higher risk to develop Richter syndrome and second neoplasias. Genetic and other biological studies are warranted to elucidate the particular presentation and features of SLL.Patients (n=588)CLL (=545)SLL (n=43)pMedian age (years)6161Gender (Male/female)324/21929/14Binet C27/536 (5%)8/43 (18%) Disclosures: No relevant conflicts of interest to declare.

Abstract 3128 Background: follicular lymphoma is an incurable, long-lasting disease with an heterogeneous outcome. Several prognostic systems have been proposed, and recently a new one, the FLIPI2 score based on five parameters has been published. However, in order to confirm its prognostic utility, further studies at other centers are highly recommendable. Aim: to validate the new FLIPI2 score in independent series of follicular lymphoma patients diagnosed at our institution between February 1990 and July 2010. Patients and methods. We considered 180 patients consecutively diagnosed with follicular diagnosis in the period described and from whom all variables required were available. The variables included were: beta2microglobulin higher than the upper normal value, longest diameter of the largest involved node longer than 6 cm, bone marrow infiltration, hemoglobin level lower than 120 g/L and age older than 60 years (one point if present). Three risk groups were identified: low risk (0 points), intermediate risk (1 -2) and high risk (3 or more) Progression-free survival was measured from date of treatment until date of progression or death from any cause. Continuous variables were summarized as median and range, categorical variables reported as counts, and PFS and OS carried out using the Kaplan-Meier method and curves compared by the log-rank test. Results: median age was 55 years (range, 24 to 77), male sex 92 (51%), Ann Arbor Stage I-II: 32(18%), III-IV: 143 (82%), age > 60 y 70 (39%), Hb < 120 g/L 38 (21%), β2microglobulin > UNV: 45 (25%), LDH > UNV: 34 (19%), bone marrow infiltration 82 (48%), longer diameter of the largest involved node > 6 cm 64 (36%). 47 patients (26%) received rituximab-containing regimens and 124 received conventional chemotherapy regimens (pre-rituximab era). Median follow-up of the series was 66.9 months (range,1.3-221). Using the FLIPI score (n=162) 58 patients (36%) were in the low risk group, 54 (33%) were in the intermediate group and 50 (31%) in the high risk group. Using the FLIPI2 (n=180) 36 patients (20%) were in the low risk group, 103 (57%) in the intermediate group and 41 (23%) in the high risk group. According to FLIPI 5y- PFS rate was 79% for the low risk group, 63% for the intermediate group and 32% for the high risk group, p < 0.001. According to FLIPI2 score, 5y-PFS rate was 82% for the low risk, 54% for the intermediate and 43% for the high risk groups, p=0.017. Concerning OS, applying the FLIPI, 5y-OS rate for the low, intermediate and high risk groups were 94%m 84% and 64%, respectively, p=0.003. Using the FLIPI2, 5y-OS for the low, intermediate and high risk groups were 96%, 80% and 67% respectively, p=0.006. Conclusions: in our experience the FLIPI2 score is a reproducible prognostic index in patients with follicular lymphoma although the FLIPI score seems to discriminate better between groups than the FLIPI2 score. Disclosures: No relevant conflicts of interest to declare.

Abstract 4625 CLL - Therapy, excluding Transplantation Acadesine induces cell death in B-cell chronic lymphocytic leukemia (CLL) cells in a dose-dependent manner. Acadesine enters B-cells where it is phosphorylated to ZMP, which induces apoptosis independently of ATM or p53. It is active in vitro against CLL cells from patients who have not responded to prior treatment with fludarabine and/or chlorambucil. A phase I/II open-labeled clinical study was designed to determine the safety and tolerability of acadesine given intravenously as a 4-hour infusion to patients with CLL. Part I is the dose escalation part of the study where patients receive a single dose of acadesine on Day 1 and are followed up to Day 22. In Part II, patients will receive up to 5 doses of acadesine at the maximum tolerated dose (MTD) identified in Part I over a period of up to 20 days. Patient population includes CLL patients with relapsed/refractory disease who have received one or more prior lines of treatment including either a fludarabine or an alkylator-based regimen. A patient is defined as having refractory disease if they fail to achieve less than a partial response (PR) according to the NCI working group guidelines, or relapse within the first 6 months after treatment after achieving at least partial response. Primary endpoints of the study evaluate the safety and tolerability of acadesine. Secondary endpoints evaluate the pharmacokinetics of acadesine and ZMP, and B and T-cell counts in peripheral blood as efficacy biomarkers. Twenty-one patients have been included to date, eighteen in Part I at doses of 50, 83.5, 139.5, 210 or 315 mg/kg, and three in Part II, with two doses at 210 mg/kg at days 1 and 4. Pharmacokinetic data showed acadesine is rapidly converted into ZMP inside blood cells. In part I, at single acadesine dose, the Cmax levels for ZMP in whole blood obtained at 315 mg/kg were similar to the ones obtained at the previous dose (210 mg/kg), suggesting that the saturation plateau was reached, which was confirmed by the PK modeling. In 5 patients treated with acadesine at 210 mg/kg and 315 mg/kg a decrease in absolute B cell count was observed, ranging from 6% to 54% with respect to the B cell count prior to acadesine administration. Reversible asymptomatic hyperuricaemia was observed in four patients in cohorts 1 to 3, probably due the metabolism of acadesine to ZMP and uric acid. Prophylactic allopurinol was used in cohorts 4 and 5 and it has significantly reduced the incidence of hyperuricaemia. Acadesine 315 mg/kg was the dose limiting toxicity (DLT) dose with 2 of 3 patients having DLTs-Tumour Lysis Syndrome (TLS) and clinically significant acute renal failure (CTCAE V3.0 Grade 3-chronic dialysis not indicated). We started Part II of the study, with two consecutive doses at 210 mg/kg (Optimal Biological Dose). Three patients have been included to date. No DLT nor grade 3 or 4 Adverse Events related to acadesine were observed, and in all of treated patients a decrease in absolute B cell count was observed ranging from 6% to 35% with respect to the B cell count prior to acadesine administration. In the following cohort, we will administer 5 consecutive doses of acadesine at 210 mg/kg, at days 1, 4, 8, 11 and 15. In conclusion, a MTD was found at one single acadesine dose. Two consecutive doses have already been tested without safety concerns and 5 consecutive doses are currently planned in part II of this ongoing study. Results for this cohort and additional safety, pharmacokinetics and efficacy data will be presented at the meeting. Disclosures: Saunders: Advancell: Consultancy. de Frias:Advancell: Employment. Campàs:Advancell: Employment.

Abstract 1382 The effectiveness of rituximab maintenance in the treatment of CLL has been investigated in a phase II clinical trial that includes two treatment parts. First, patients were given R-FCM up to 6 cycles as induction therapy, achieving an overall response rate of 93% and 46% of CR with negative minimal residual disease (MRD) (Bosch et al. JCO, etc). Second, three months after concluding R-FCM, patients having achieved CR or PR receive rituximab maintenance (375 mg/m2) every three months for two years (up to 8 cycles). We present here the preliminary results of the second part of the study, namely the efficacy of rituximab maintenance. Evaluation of response was performed three months after the last cycle of maintenance and included bone marrow (BM) examination, MRD assessment in peripheral blood and BM by four-color flow cytometry. Patients in whom rituximab maintenance was prematurely interrupted due to toxicity were considered as failures. Fifty-six patients (median age 60 years, 70% female) responding to R-FCM were evaluable for response to rituximab maintenance. Median number of cycles of maintenance given was 8 (range, 3 to 8), 77% of patients completed the entire planned treatment, whereas 91% received 6 or more cycles. Treatment was delayed due to insufficient hematological recovery in 12 cycles (2.7%). Toxicity was mainly hematological, with neutropenia being observed in 31.8% of cycles (Grade 3&4 in 8.9%), thrombocytopenia in 3.4% and anemia in 3.9%. Hypogammaglobulinemia occurred in 38% of patients (low levels of IgA in 50%, IgG in 34%, and IgM in 60%). Eight patients, three of them with hypogammaglobulinemia, experienced grade 3&4 infectious episodes (4 pneumonia, 2 gastrointestinal, 1 myositis, and 1 cerebral abscess). Herpes virus (I/VZ) reactivation was observed in 8 patients. Two patients died due to multifocal leukoencephalopathy and hemophagocytic syndrome, respectively. After rituximab maintenance, 44.6% of patients were in CR MRD negative, 41% in CR, 3.6% in PR, and 10.7% failed to treatment. Failures were due to disease progression (two patients), development of severe neutropenia (two patients), and death (two patients). Among 28 patients that were in CR MRD (-) at the onset of the maintenance part, 19 held the MRD negative status at the end of maintenance, 5 (18%) turned negative into positive MRD (probability of conversion, 40% at 30 months), whereas 4 failed to treatment (2 neutropenia, 1 progression, 1 death). Moreover, 5 of 24 patients (22%) in CR MRD(+) after R-FCM became MRD negative after rituximab maintenance, 17 maintained the CR, one patient achieved a PR, and one patient progressed under maintenance (Table 1). In conclusion, rituximab maintenance after chemoimmunotherapy seems to prolong duration of response and, in some cases, improves the quality of response towards a CR with negative MRD. Maintenance with rituximab had the major benefit in patients in CR with positive MRD. The exact role and the best dosage and treatment schedule of rituximab as maintenance therapy in CLL should be now investigated in randomized clinical trials. Disclosures: Bosch: Hoffman La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Off Label Use: Rituximab is currently not approved as maintenance therapy for patients with chronic lymphocytic leukemia. Garcia-Marco:ROCHE: Consultancy, Honoraria, Research Funding.

Abstract 2452 Background. Clinical trials have shown an improved response rate and progression free survival (PFS) among the different treatment options used in the last two decades, specially with rituximab in combination with fludarabine and cyclophosphamide. We wished to analyze, in an unselected community based population, the clinical characteristics and efficacy of first line therapy with several treatment options used throughout a ten-year period. Patients and methods. We included 307 patients diagnosed of CLL and requiring first-line treatment between January 2000 and September 2009. Patients were treated at 20 hospitals placed in the Community of Valencia and Murcia and received first-line therapy according to the clinical guidelines of each hospital. PFS was calculated from date of first treatment to date of progression/relapse. We performed a descriptive analysis of clinical and biological features. The survival curves were built with Kaplan-Meier method and compared with the log rank test. Multivariate analysis for response and PFS were performed by logistic and Cox regression methods respectively, using the statistical package SPSS (v15). Results. Median age at treatment was 67 years (range 28–94) with 58% (n=179) men. 39% (120/305) were in Binet A, 38% (117) in Binet B and 22% (68) in Binet C. 27% (84) were Rai III-IV. B symptoms were present in 25% (77) and fever was a rare symptom 3%. Patients were asymptomatic in 59% (181) of the cases with ECOG performance status 0–1 in 83% (256). Splenomegaly was present in 41% (127) and hepatomegaly only in 8% (24). 42% of the patients (129) had at least three lymph-node areas affected with bulky disease (diameter higher than >5cm) in 10% (32). Median haemoglobin level was 126gr/L (46–169), lymphocyte count 49 x109/L (0,5–613) with lymphocyte doubling time (LDT) Patients receiving rituximab (group 3–4, n=73) achieved a significant higher response rate (CR or PR) than patients without rituximab (93% vs 61%). The main clinical variables with prognosis significance in the univariate analysis for PFS were: lymphocyte count (p=0,026, HR 1.002, CI95% (1.000–1.004)); haemoglobin level (p=0,02, HR 0.890, CI95% (0.826–0.958); b2-microglobulin (p=0,002, HR 1.372, CI95% (1.125–1.672)); bulky mass (p=0,055, HR 1.656, CI95% (0.989–2.775)); CD38 expression (p=0,045, HR 1.005, CI95% (1.000–1.011)); p53 deletion (p=0,014, HR 2,231, CI95% (1,180–4,217)) and 11q23 deletion (p=0,03, HR 2,138, CI95% (1,290–3,542)). The median PFS for patients in the different groups were: G1:26.9 months (22.4–31.3), G2 45.5 months (32.7–58.4), G3: not reached, G4: 20.5 months (29.6–47.3), p < 0.0001. In the multivariate analysis the variables with independent prognostic significance for PFS were: lymphocyte count (p=0.003, HR 1.004, CI 95% (1.001 −1.007)), 17deletion (p=0.01, HR 2.7 CI95% (1.273–5.73)), 11q deletion (p=0.006, HR 2.193 CI95% (1.248–3.852)) and treatment received (G1 as reference): G2 (p=0.005, HR 0.464, CI95% (0.271–0.794)), G3 (p < 0.001, HR 0.179, CI95% (0.083–0.386)), G4 (p=0.223, HR 0.289, CI95% (0.039–2.130)). Conclusion. In this community based population, treatment with rituximab containing regimens results in a higher global and complete response rate and a longer PFS compared with alquilating agents and purine analogs. Fludarabine containing-schedules also achieved a significant higher response rate than alquilating agents. Rituximab in combination with purine analogs provide the better quality of response. These results confirm the data provided by clinical trials and support their use as front-line treatment. Disclosures: Terol: ROCHE: Consultancy.

Abstract 1910 The outcome of multiple myeloma (MM) patients has markedly improved in the last decade. Thus, overall response rates between 85%-95%, with 30%-50% complete remission (CR) rates are now being reported in young patients treated with novel agents plus high-dose therapy/autologous stem cell transplantation (HDT/ASCT). A similar scenario is also emerging in the elderly (non-transplant candidates) population. Accordingly, more sensitive techniques are needed to assess patients’ response; these may contribute to compare the efficacy of different treatment schemas, to monitor minimal residual disease (MRD) and for prognostication. In the present study we have assessed the frequency and the prognostic value of IR by multiparameter flow cytometry in a total of 516 newly diagnosed MM patients included in three consecutive PETHEMA/GEM Spanish trials: two designed for transplant candidate patients - GEM 2000 (n=157) and GEM200565y (n=153). The GEM2000 trial was based on 6 induction cycles of VBMCP/VBAD followed by HDT/ASCT; the GEM200565y compared 6 cycles of Bortezomib/Melphalan/Prednisone -VMP- vs. Bortezomib/Thalidomide/Prednisone -VTP-. All three trials had in common that patients received 6 induction cycles and IR was evaluated at this time point. In addition, IR was assessed on day +100 after HDT/ASCT in the first two trials. Patients were defined to be in IR when myelomatous plasma cells (MM-PCs) were undetectable by MFC or when less than one phenotypically aberrant PC was detected among 104 cells analyzed. Patients were referred for MRD studies if they were mainly in CR or VGPR. The IR rates reported here were calculated on intention to treat analysis. Figure 1 summarizes the IR rates after induction. The lowest IR rates corresponded to the VBMCP/VBAD and TD schemes (5% and 6%, respectively) while with the bortezomib-based regimens an approximately 3-fold increment in the IR rates was observed: VTP (12%), VBMCP/VBAD/Bortezomib (15%), VMP (16%) and VTD (17%). After HDT/ASCT, IR rates were found to be significantly increased (p We further compared the impact of achieving an IR after induction and at day+100 after HDT/ASCT in the progression-free (PFS) and overall survival (OS) within the three protocols. Patients in IR status after an induction regimen according to the GEM2000, GEM200565y protocols showed significantly longer (p65y protocols, respectively). Likewise, an IR vs. no-IR status after HDT/ASCT in both the GEM2000 and GEM05 In summary, this study demonstrates that the achievement of an IR is a strong prognostic factor regardless of the type of treatment; thus, higher IR rates may help to identify optimal therapeutical schemes. In this sense, HDT/ASCT is able to markedly increase IR rates after induction even in the era of novel agents, and this translates into extended survival. Disclosures: Off Label Use: VTP is not approved for the treatment of newly diagnosed myeloma patients and VT and VP are not approved for maintenance therapy. None of the combinations proposed, VBCMP/VBAD plus bortezomib, VT and VTD are approved as induction therapy in newly diagnosed myeloma patients. Mateos:Janssen Cilag: Honoraria; Celgene: Honoraria. Rosiñol:Janssen-Cilag: Honoraria; Celgene: Honoraria. Cibeira:Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Oriol:Janssen-Cilag: Honoraria; Celgene: Honoraria. de Arriba:Janssen-Cilag: Honoraria; Celgene: Honoraria. Palomera:Janssen Cilag: Honoraria. De La Rubia:Janssen-Cilag: Honoraria; Celgene: Honoraria. Díaz-Mediavilla:Janssen-Cilag: Honoraria; Celgene: Honoraria. Garcia-Laraña:Janssen Cilag: Honoraria; Celgene: Honoraria. Sureda:Janssen-Cilag: Honoraria; Celgene: Honoraria. Alegre:Janssen-Cilag: Honoraria; Celgene: Honoraria. Blade:Janssen cilag: Honoraria; Celgene: Honoraria. Lahuerta:Janssen-Cilag: Honoraria; Celgene: Honoraria. San Miguel:Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees.