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Purpose: T cells influence outcome in follicular lymphoma, but their contributions seem to be modified by therapy. Their impact in patients receiving rituximab without chemotherapy is unknown.Experimental Design: Using flow cytometry, we evaluated the T cells in tumors and/or blood in a total of 250 follicular lymphoma patients included in two Nordic Lymphoma Group randomized trials that compared single rituximab with IFN-α2a–rituximab combinations.Results: In univariate analysis, higher levels of CD3+, CD4+, and CD8+ T cells in both tumors and blood correlated with superior treatment responses, and in multivariate analysis, tumor-CD3+ (P = 0.011) and blood-CD4+ (P = 0.029) cells were independent. CD4+ cells were favorable regardless of treatment arm, but CD8+ cells were favorable only in patients treated with single rituximab, because IFN-α2a improved responses especially in patients with low CD8+ cell levels. Higher levels of blood-CD3+ (P = 0.003) and blood-CD4+ (P = 0.046) cells predicted longer overall survival, and higher levels of blood-CD8+ cells longer times to next treatment (P = 0.046).Conclusions: We conclude that therapeutic effects of rituximab are augmented by tumor-associated T cells for rapid responses and by systemic T cells for sustained responses. CD4+ and CD8+ cells are both favorable in patients treated with rituximab. IFN-α2a abrogates the negative impact of few CD8+ cells. Clin Cancer Res; 17(12); 4136–44. ©2011 AACR.

Supplementary Materials and Methods from T Cells in Tumors and Blood Predict Outcome in Follicular Lymphoma Treated with Rituximab

Eskelund et al examined clonal hematopoiesis (CH) in a cohort of patients with mantle cell lymphoma (MCL) treated with first-line chemotherapy and autologous stem cell transplantation. In young, good-risk MCL patients, CH after first-line therapy arises almost entirely from preexisting clones, stabilizes after a period of expansion posttransplantation, and does not negatively impact survival.

PURPOSE In an update of the randomized, open-label, phase III European Mantle Cell Lymphoma (MCL) Elderly trial (ClinicalTrials.gov identifier: NCT00209209 ), published in 2012, we aimed to confirm results on long-term outcome focusing on efficacy and safety of long-term use of rituximab maintenance. PATIENTS AND METHODS Five hundred sixty patients with newly diagnosed MCL underwent a first random assignment between rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and rituximab, fludarabine, and cyclophosphamide (R-FC) induction, followed by a second random assignment in 316 responders between rituximab and interferon alfa maintenance, to be continued until progression. We compared progression-free survival from the second randomization and overall survival (OS) from the first or second randomizations. RESULTS After a median follow-up time of 7.6 years, the previously described difference in OS between the induction arms persisted (median, 6.4 years after R-CHOP [n = 280] v 3.9 years after R-FC [n = 280]; P = .0054). Patients responding to R-CHOP had median progression-free survival and OS times of 5.4 and 9.8 years, respectively, when randomly assigned to rituximab (n = 87), compared with 1.9 years ( P < .001) and 7.1 years ( P = .0026), respectively, when randomly assigned to interferon alfa (n = 97). In 58% and 32% of patients treated with R-CHOP, rituximab maintenance was still ongoing 2 and 5 years from start of maintenance, respectively. After R-FC, rituximab maintenance was associated with an unexpectedly high cumulative incidence of death in remission (22% at 5 years). Toxicity of rituximab maintenance was low after R-CHOP (grade 3-4 leukopenia or infection < 5%) but more prominent in patients on rituximab maintenance after R-FC, in whom grade 3-4 leukopenia (up to 40%) and infections were frequent (up to 15%). CONCLUSION The excellent results of R-CHOP followed by rituximab maintenance until progression for older patients with MCL persisted in a mature follow-up. Prolongation of rituximab maintenance beyond 2 years is effective and safe.

Mantle cell lymphoma (MCL) is a rare, often aggressive type of B-cell lymphoma with poor survival and no cure. Cancer and cancer treatment has a negative impact on health-related quality of life (HRQOL) both during active disease and in the long term, and improvement of HRQOL is a crucial objective of cancer therapy in older patients and no curative intent. Baseline HRQOL has in other lymphoma populations been shown to be predictive of outcome. Here, we explored HRQOL, and its association with survival, by the EORTC QLQ-C30 questionnaire, before, during and after chemotherapy in a patient cohort with mantle cell lymphoma, treated within the NLG-MCL4 trial, designed to evaluate the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment. Fifty-one patients were enrolled, median age was 71 years (range 62-84), 37 were men (73%). Pre-treatment HRQOL was similar to scores from the reference population with healthy individuals. During treatment, HRQOL deteriorated, but reverted to the same level as the reference population after treatment. There was a correlation between physical function (p=0.001) and role function (p=0.006) at baseline and WHO performance status, but not with other clinical or genetic prognostic factors. None of the baseline factors were predictive for treatment related to HRQOL in this cohort. Pre-treatment physical (p=0.011) and role function (p=0.032) were independent factors associated with overall survival, and physical function (p=0.002) was also associated with progression free survival. These findings may possibly be used to design support during treatment and improve rehabilitation. Further investigations are needed for assessment of long-term HRQOL. This article is protected by copyright. All rights reserved.

Mantle cell lymphoma (MCL) is characterized by marked differences in outcome, emphasizing the need for strong prognostic biomarkers. Here, we explore expression patterns and prognostic relevance of circular RNAs (circRNAs), a group of endogenous non-coding RNA molecules, in MCL. We profiled the circRNA expression landscape using RNA-sequencing and explored the prognostic potential of 40 abundant circRNAs in samples from the Nordic MCL2 and MCL3 clinical trials, using NanoString nCounter Technology. We report a circRNA-based signature (circSCORE) developed in the training cohort MCL2 that is highly predictive of time to progression (TTP) and lymphoma-specific survival (LSS). The dismal outcome observed in the large proportion of patients assigned to the circSCORE high-risk group was confirmed in the independent validation cohort MCL3, both in terms of TTP (HR 3.0; P = 0.0004) and LSS (HR 3.6; P = 0.001). In Cox multiple regression analysis incorporating MIPI, Ki67 index, blastoid morphology and presence of TP53 mutations, circSCORE retained prognostic significance for TTP (HR 3.2; P = 0.01) and LSS (HR 4.6; P = 0.01). In conclusion, circRNAs are promising prognostic biomarkers in MCL and circSCORE improves identification of high-risk disease among younger patients treated with cytarabine-containing chemoimmunotherapy and autologous stem cell transplant.

Background: For fit CLL patients (pts), continuous BTK inhibitor treatment is replacing CIT as standard of care in frontline setting, particularly in pts with unfavorable prognostic factors. The time limited combinations venetoclax plus obinutuzumab (GVe) and venetoclax plus rituximab (RVe) have produced high rates of undetectable minimal residual disease (uMRD), which strongly associates with long progression-free survival (PFS) both in frontline and relapsed setting. For frontline therapy GVe is approved in this setting based on data from the CLL14 trial in an unfit population. However, data from a fit cohort are not yet available. The GAIA (CLL13) trial evaluated the efficacy and safety of three Ven+CD20 antibody-based regimens in comparison to CIT as a frontline treatment for fit pts with CLL and without TP53 mutation/deletion. Methods: Treatment-naïve fit (CIRS ≤6, normal creatinine clearance with ≥ 70ml/min) CLL pts requiring therapy were eligible. Based on known poor response to CIT, pts with TP53 aberrations were excluded. Pts were randomized in a 1:1:1:1 ratio to receive six courses of CIT (FCR for pt ≤65 years: fludarabine 25 mg/m² d1-3, cyclophosphamide 250 mg/m² d1-3, rituximab 375 mg/m² d1 cycle 1 and 500 mg/m² d1 cycle 2-6; BR for pt >65 years: bendamustine 90mg/m² d1-2, rituximab) or one of three venetoclax (V) combinations (standard ramp-up from cycle 1 d22, 400 mg/d cycle 2-12): V and rituximab (375/500mg/m² d1 cycle 1-6) [RVe], V and obinutuzumab (1000 mg d1, 8, 15 cycle 1 and d1 cycle 2-6) [GVe], or V, obinutuzumab and ibrutinib (420 mg/d cycle 1-12, if MRD-detectable continued until cycle 36) [GIVe] . Pts were stratified according to country, Binet stage and age (≤ 65/> 65 years). The co-primary endpoints of the trial are (1) the rate of uMRD ( Trial is registered at ClinicalTrials.gov (NCT02950051). Results: A total of 926 pts (CIT: 229 (150 FCR, 79 BR), RVe: 237, GVe: 229, GIVe: 231) with a median age of 61 years (range 27-84) were accrued between 12/2016 and 09/2019. The majority of pts were in advanced Binet stage (B: 37.8%, C: 35.6%) and unmutated IGHV status was present in 56%. Fourteen pts did not receive study treatment (13 FCR, 1 GVe) and were not included in the safety population. The data cut for the first co-primary endpoint analysis was February 28, 2021. The median observation time was 27.9 months. The co-primary endpoint uMRD in PB at MO15 was met as the rate of uMRD in ITT population was significantly higher in GVe compared to CIT: 86.5% (97.5% CI 80.6-91.1) vs 52.0% (CI 44.4-59.5; p The most common grade 3-5 treatment-emergent AE were neutropenia (50.5% of all pts), thrombocytopenia (12.2%), tumor lysis syndrome (7.5%), infusion-related reaction (7.2%), febrile neutropenia (6.5%) and pneumonia (5.3%)). Atrial fibrillation and bleeding events occurred more frequently in GIVe while infusion-related reactions were most common in the GVe arm (Table 1). The absolute numbers of second malignancies were 33, 19, 22 and 21 for CIT, RVe, GVe and GIVe. Fatal AEs occurred in 5, 7, 6 and 9 of the patients. Conclusions: The time-limited therapies of GVe and GIVe provided superior uMRD rates in PB at MO 15 compared to CIT. In addition, uMRD rates in BM and CRR were higher in GVe and GIVe in particular than in CIT. All arms showed a good safety profile in this fit pt population. Figure 1 Figure 1. Disclosures Eichhorst: AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AstraZeneca: 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, Other: Travel, accomodation, expenses, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Speakers Bureau; Adaptive Biotechnologies: Speakers Bureau; Hexal: Speakers Bureau; ArQule: Membership on an entity's Board of Directors or advisory committees; Oxford Biomedica (UK): Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Consultant Department I for Internal Medicine: Consultancy; University Hospital of Cologne: Current Employment. Kater: Genmab, LAVA: Other: Ad Board, Steering Committee; Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding; Abbvie: Honoraria, Other: Ad Board, Research Funding; BMS, Roche/Genentech: Other: Ad Board, , Research Funding. Von Tresckow: Celgene: Other: travel grant; AstraZeneca: Honoraria, Other; Roche: Honoraria, Other: Reasearch support, travel grant; Janssen: Honoraria, Other: Reasearch support, travel grant; AbbVie: Honoraria, Other: advisory board, travel grant. Staber: Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; Takeda: Consultancy, Research Funding; MSD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Poulsen: Janssen: Consultancy; Abbvie: Consultancy. Janssens: Sanofi: Consultancy; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Beigene, AstraZeneca: Consultancy, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Trael Grant, Speakers Bureau; Abbvie, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Noesslinger: Roche: Speakers Bureau; Abbvie,: Speakers Bureau; Janssen: Speakers Bureau; AstraZeneca: Honoraria; Gilead: Honoraria; Celgene: Honoraria. Jaeger: Norvartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. Frederiksen: Abbvie: Research Funding; Gilead: Research Funding; Alexion: Research Funding; Novartis: Research Funding; Janssen Pharmaceuticals: Research Funding. Hebart: Roche: Honoraria; BMS: Honoraria; AstraZeneca: Honoraria; AbbVie: Honoraria; Janssen: Honoraria. Simon: Gilead: Other: Travel support. Fink: AbbVie: Other: travel grant; Janssen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Celgene: Research Funding. Fischer: Abbvie: Honoraria; Roche: Honoraria, Other: Travel Grants. Kreuzer: Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Abbvie: Consultancy, Honoraria, Research Funding, Speakers Bureau; Mundipharma: Consultancy, Honoraria, Research Funding, Speakers Bureau. Ritgen: Abbvie: Consultancy, Other: Travel support, Research Funding; Chugai: Consultancy; MSD: Consultancy, Other: Travel support; Roche: Consultancy, Other: Travel support, Research Funding; Celgene: Other: Travel support. Brüggemann: Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau; Incyte: Other: Advisory Board; Janssen: Speakers Bureau. Levin: Roche, Janssen, Abbvie: Other: Travel Expenses, Ad-Board. Stilgenbauer: AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Other: Research Support; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Consultancy; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Honoraria; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Research Funding. Hallek: Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Abbvie: Consultancy, Research Funding, Speakers Bureau. OffLabel Disclosure: Ibrutinib in combaintion with Venetoclax + Obinutuzumab is not approved.

Mantle cell lymphoma (MCL) is an incurable disease with a highly variable clinical course. The prognosis after relapse is generally poor, and no standard of care exists. We investigated the postrelapse outcomes of 149 patients who were initially treated in the Nordic Lymphoma Group trials, MCL2 or MCL3, both representing intensive cytarabine-containing frontline regimens including autologous stem cell transplant. Patients with progression of disease before 24 months (POD24, n = 51, 34%) displayed a median overall survival of 6.6 months compared with 46 months for patients with later POD (n = 98, 66%; P < 0.001). MCL international prognostic index, cell proliferation marker, blastoid morphology, and TP53 mutations showed independent prognostic value irrespective of POD24, and in a combined, exploratory risk score, patients with 0, 1, 2-3, or 4-5 high-risk markers, respectively, displayed a 5-year overall survival of 62%, 39%, 31%, and 0%. By a comparison of median progression-free survival of the different salvage therapies in the relapse setting, bendamustine-rituximab was superior to all other combination chemotherapy regimens; however, it was also associated with longer responses to last line of therapy. Collectively, we confirm the prognostic impact of POD24 and highlight the relevance of other biomarkers, and we emphasize the importance of novel therapies for patients with high-risk features at first POD.

Mantle cell lymphoma (MCL) is characterized by marked differences in outcome, emphasizing the need for strong prognostic biomarkers. Here, we explore expression patterns and prognostic relevance of circular RNAs (circRNAs), a group of endogenous non-coding RNA molecules, in MCL. We profiled the circRNA expression landscape using RNA-sequencing and explored the prognostic potential of 40 abundant circRNAs in samples from the Nordic MCL2 and MCL3 clinical trials, using NanoString nCounter Technology. We report a circRNA-based signature (circSCORE) developed in the training cohort MCL2 that is highly predictive of time to progression (TTP) and lymphoma-specific survival (LSS). The dismal outcome observed in the large proportion of patients assigned to the circSCORE high-risk group was confirmed in the independent validation cohort MCL3, both in terms of TTP (HR 3.0; P = 0.0004) and LSS (HR 3.6; P = 0.001). In Cox multiple regression analysis incorporating MIPI, Ki67 index, blastoid morphology and presence of TP53 mutations, circSCORE retained prognostic significance for TTP (HR 3.2; P = 0.01) and LSS (HR 4.6; P = 0.01). In conclusion, circRNAs are promising prognostic biomarkers in MCL and circSCORE improves identification of high-risk disease among younger patients treated with cytarabine-containing chemoimmunotherapy and autologous stem cell transplant.

Background: In early studies of venetoclax (ven) in CLL, severe tumor lysis syndromes (TLS) were observed leading to the implementation of multiple safety measures including a 5-week ramp up schedule. Since then, studies have consistently reported low rates of TLS in ven-treated patients (pts), most likely as a result of strict prophylactic and laboratory monitoring measures. Various lead-in regimens prior to the administration of ven were shown to be feasible and effective in reducing the risk of TLS in pts with CLL. However, no comparison of different pretreatment regimens has been performed so far in a prospective randomized trial. Using the set-up of the GAIA trial, we compared TLS incidence and formal TLS risk reduction between 3 different ven-based combinations. Methods: The phase 3 GAIA (CLL13) trial compared 3 different time-limited ven-based combinations against standard chemoimmunotherapy (CIT) in fit, treatment-naïve pts with CLL. Pts were randomized to receive CIT (FCR in pts ≤65 years; BR in pts >65 years), ven and rituximab (RVe), ven and obinutuzumab (GVe), or ven, obinutuzumab and ibrutinib (GIVe). In RVe, GVe and GIVe, ven was added at cycle 1 day 22 (ramp up day 1) after a 21-day pretreatment with rituximab (1 dose), obinutuzumab (3 doses) or obinutuzumab (3 doses) plus ibrutinib (continuous) (Figure 1A). The safety population (i.e. all pts who received study treatment) of the ven-containing arms was used for this analysis. TLS was reported according to Cairo-Bishop criteria (Cairo M, Bishop M. Br J Haematol. 2004). For TLS risk evaluation, the most recent available CT/MRI and absolute lymphocyte count (ALC) were used. TLS risk was evaluated at baseline and at ramp up day 1, before the first dose of ven. The patients were categorized retrospectively according to the following TLS risk categories: high (any lymph node [LN] with largest diameter ≥10 cm or any LN with largest diameter ≥5 cm and ALC ≥25 G/L), intermediate (any LN ≥5 cm to Results: The safety population of all ven-containing arms comprised of 696 pts (RVe: 237, GVe: 228, GIVe: 231). Baseline TLS risk was high in 22%, 23% and 19% of pts in the RVe, GVe and GIVe arm, intermediate in 62%, 65%, 67% and low in 10.5%, 14.7% and 12.4% of pts, respectively. After the first 21 days of treatment (i.e. at ramp up day 1), the fraction of pts with a reduction in TLS risk varied between the treatment arms with 31.7% (RVe), 71.4% (GVe) and 47.3% (GIVe) of pts decreasing by at least one TLS risk category (Figure 1B). With regard to TLS risk reduction, GVe was superior to RVe (p In total, 36, 30 and 19 cases of TLS occurred in 29 (12.2%), 26 (11.4%) and 19 (8.2%) pts in the RVe, GVe and GIVe arm. The majority of TLS cases were categorized as CTC grade 3 (28 [RVe], 19 [GVe], 12 [GIVe]), only few CTC grade 4 TLS were reported (1 [RVe], 2 [GVe], 3 [GIVe]). There were no cases of fatal TLS and no pts requiring dialysis due to TLS. In the obinutuzumab arms the majority of TLS cases occurred before ramp up day 1 (GVe: 76.7%, GIVe: 68.4%), i.e. before any venetoclax intake, in contrast 80.6% of TLS cases in the RVe arm were reported during ven ramp up (Figure 2). While there was no significant difference in the cumulative TLS incidence between the treatment arms (p=0.334), there was an increase in TLS occurring after ramp up day 1 in the RVe arm compared to GVe (p Conclusions: This analysis represents the first comparison of the formal TLS risk reduction and actual TLS incidence of different ven-based combinations in a randomized trial. GVe led to the highest TLS risk reduction, while the lowest number of TLS cases occurred in the GIVe arm. Most TLS cases in the GVe and GIVe arms occurred before the start of ven. RVe was least effective in reducing TLS risk and in contrast to the obinutuzumab-containing arms, the vast majority of TLS cases was reported during the ven ramp up. The relatively high incidence of TLS in comparison to other trials might partly be a consequence of using different reporting criteria (Cairo-Bishop vs Howard criteria). No fatal TLS occurred in any of the treatment arms. Figure 1 Figure 1. Disclosures Von Tresckow: AbbVie: Honoraria, Other: advisory board, travel grant; Celgene: Other: travel grant; AstraZeneca: Honoraria, Other; Roche: Honoraria, Other: Reasearch support, travel grant; Janssen: Honoraria, Other: Reasearch support, travel grant. Niemann: Novo Nordisk Foundation: Research Funding; CSL Behring, Genmab, Takeda, Octapharma: Consultancy; Abbvie, AstraZeneca, Janssen: Consultancy, Research Funding. Kater: Abbvie: Honoraria, Other: Ad Board, Research Funding; Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding; Genmab, LAVA: Other: Ad Board, Steering Committee; BMS, Roche/Genentech: Other: Ad Board, , Research Funding. Staber: Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; Takeda: Consultancy, Research Funding; MSD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Levin: Roche, Janssen, Abbvie: Other: Travel Expenses, Ad-Board. Poulsen: Janssen: Consultancy; Abbvie: Consultancy. Janssens: Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Trael Grant, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy; Beigene, AstraZeneca: Consultancy, Speakers Bureau; Abbvie, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Noesslinger: AbbVie: Honoraria; Celgene: Honoraria; Roche: Honoraria; Jansen: Honoraria; AstraZeneca: Honoraria; Gilead: Honoraria. Simon: Gilead: Other: Travel support. Fink: AbbVie: Other: travel grant; Janssen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Celgene: Research Funding. Fischer: Abbvie: Honoraria; Roche: Honoraria, Other: Travel Grants. Wendtner: Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding. Ritgen: MSD: Consultancy, Other: Travel support; Chugai: Consultancy; Abbvie: Consultancy, Other: Travel support, Research Funding; Roche: Consultancy, Other: Travel support, Research Funding; Celgene: Other: Travel support. Brüggemann: Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau; Incyte: Other: Advisory Board; Janssen: Speakers Bureau. Stilgenbauer: AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Honoraria; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Other: Research Support; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Research Funding; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Consultancy. Hallek: Roche: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Mundipharma: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Pharmacyclics: Honoraria, Speakers Bureau. Eichhorst: Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AstraZeneca: 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, Other: Travel, accomodation, expenses, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Speakers Bureau; Adaptive Biotechnologies: Speakers Bureau; Hexal: Speakers Bureau; ArQule: Membership on an entity's Board of Directors or advisory committees; Oxford Biomedica (UK): Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Consultant Department I for Internal Medicine: Consultancy; University Hospital of Cologne: Current Employment. OffLabel Disclosure: The combination of obinutuzumab, venetoclax and ibrutinib is not approved for the treatment of CLL

Background: Venetoclax (ven)-based time-limited combination treatments have yielded high rates of undetectable MRD (uMRD) in patients (pts) with CLL. In correlative analyses, attainment of uMRD status was associated with longer progression-free survival (PFS), making uMRD a robust surrogate parameter for remission duration particularly after time-limited therapy. While MRD is usually assessed by conventional 4-color flow cytometry (FCM) defining uMRD as less than 1 CLL cell in 10 000 leukocytes ( Methods: The phase 3 GAIA (CLL13) trial compared 3 different time-limited ven-based combinations against chemoimmunotherapy (CIT) in fit, treatment-naïve pts with CLL. Pts were randomized to receive CIT for 6 cycles of 28 days each (FCR for pts ≤65 years; BR for pts >65 years), ven and rituximab (RVe), ven and obinutuzumab (GVe), or ven, obinutuzumab and ibrutinib (GIVe), all for 12 cycles with the option for ibrutinib continuation until cycle 36 for pts not obtaining uMRD4. The co-primary endpoints were the rate of uMRD4 at month (MO) 15 (GVe vs CIT) and PFS (GIVe vs CIT). MRD was centrally assessed by FCM at MO2, MO9, MO12 and MO15 in peripheral blood (PB) and at final restaging (RE, two months after the end of treatment) in bone marrow (BM). The following categories were used: high (≥10 -2), intermediate (≥10 -4 to Results: In total, 926 pts were randomized (CIT: 229, RVe: 237, GVe: 229, GIVe: 231). Based on the intention-to-treat (ITT) population, rates of uMRD4 in PB by FCM were 62.0% (CIT), 73.0% (RVe), 88.6% (GVe) and 88.3% (GIVe) at MO9 and 52.0% (CIT), 57.0 (RVe), 86.5% (GVe) and 92.2% (GIVe) at MO15. BM uMRD4 results at RE were 37.1% (CIT), 43.0 (RVe), 72.5% (GVe) and 77.9% (GIVe). HsFCM samples were available for 844 (MO9 PB), 863 (MO15 PB) and 744 (RE BM) pts with median limits of detection (LOD) of 1.6x10 -5 (MO9 PB), 1.4x10 -5 (MO15 PB) and 9.9x10 -6 (RE BM) that were similar between the treatment arms. With hsFCM a lower limit of detection (LOD) of ≤10 -5 was achieved in 364 (MO9) and 477 (MO15) PB samples and in 580 BM samples at RE. 480 (MO9 PB), 386 (MO15 PB) and 164 (RE BM) samples did not reach a LOD of ≤10 -5 and were thus not included in the MRD5-evaluable populations (Figure 1). Among pts with samples evaluable for MRD5 in PB at MO15, 26 of 82 (31.7%, CIT), 45 of 132 (34.1%, RVe), 81 of 131 (61.8%, GVe) and 93 of 132 (70.5%, GIVe) achieved uMRD5. BM uMRD5 rates at RE were 24.2% (23 of 95 pts), 16.1% (27 of 168 pts), 41.7% (65 of 156 pts) and 53.4% (86 of 161 pts), respectively (Figure 2A). The median MRD level at MO9 was lower in CIT, GVe, GIVe (all 1x 10 -5) compared with RVe (2x 10 -5) by hsFCM (Figure 2B). While the obinutuzumab-containing arms stayed at this low level between MO9 and MO15, median MRD levels in CIT and RVe increased to 8.9x 10 -5 (CIT) and 3.1x 10 -5 (RVe) in the same period. The different treatment arms showed distinct patterns of differential clearance of CLL in BM and PB. While the fraction of concordant MRD results between PB and BM at RE was lower in the CIT arm with 14/34 (41.2%), the ven-containing arms showed a similar compartment effect with a proportion of concordant results of 67/108 (62.0%, RVe), 70/101 (69.3%, GVe) and 71/104 (68.3%, GIVe). In 9/16 (56.3%, CIT), 23/36 (63.9%, RVe), 22/63 (34.9%, GVe) and 23/73 (31.5%,GIVe) pts who achieved uMRD5 in PB (RE) MRD was still measurable in BM. More sensitive NGS analyses and detailed correlative analyses are pending and will be presented at the conference. Conclusions: HsFCM improves MRD detection in CLL below 10 -4 in PB and BM by capturing low levels of MRD (≥10 -5 to Figure 1 Figure 1. Disclosures Von Tresckow: Celgene: Other: travel grant; AstraZeneca: Honoraria, Other; Roche: Honoraria, Other: Reasearch support, travel grant; Janssen: Honoraria, Other: Reasearch support, travel grant; AbbVie: Honoraria, Other: advisory board, travel grant. Niemann: CSL Behring, Genmab, Takeda, Octapharma: Consultancy; Abbvie, AstraZeneca, Janssen: Consultancy, Research Funding; Novo Nordisk Foundation: Research Funding. Kater: Genmab, LAVA: Other: Ad Board, Steering Committee; Abbvie: Honoraria, Other: Ad Board, Research Funding; BMS, Roche/Genentech: Other: Ad Board, , Research Funding; Janssen, AstraZeneca: Other: Ad Board, steering committee, Research Funding. Simon: Gilead: Other: Travel support. Fink: AbbVie: Other: travel grant; Janssen: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Research Funding; Celgene: Research Funding. Fischer: Abbvie: Honoraria; Roche: Honoraria, Other: Travel Grants. Wendtner: Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support, Research Funding. Staber: Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria; Takeda: Consultancy, Research Funding; MSD: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Incyte: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Levin: Roche, Janssen, Abbvie: Other: Travel Expenses, Ad-Board. Stilgenbauer: AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Honoraria; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Other: Research Support; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Research Funding; AbbVie, Amgen, AstraZeneca, Celgene, Gilead, GSK, Hoffmann-La Roche, Janssen, Novartis, Sunesis: Consultancy. Brüggemann: Amgen: Other: Advisory Board, Travel support, Research Funding, Speakers Bureau; Incyte: Other: Advisory Board; Janssen: Speakers Bureau. Hallek: Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Gilead: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Research Funding, Speakers Bureau; Abbvie: Consultancy, Research Funding, Speakers Bureau. Ritgen: MSD: Consultancy, Other: Travel support; Chugai: Consultancy; Abbvie: Consultancy, Other: Travel support, Research Funding; Roche: Consultancy, Other: Travel support, Research Funding; Celgene: Other: Travel support. Eichhorst: AbbVie: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; BeiGene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; AstraZeneca: 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, Other: Travel, accomodation, expenses, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Speakers Bureau; Adaptive Biotechnologies: Speakers Bureau; Hexal: Speakers Bureau; ArQule: Membership on an entity's Board of Directors or advisory committees; Oxford Biomedica (UK): Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; F. Hoffmann-La Roche Ltd: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Travel, accomodation, expenses, Research Funding, Speakers Bureau; Consultant Department I for Internal Medicine: Consultancy; University Hospital of Cologne: Current Employment. OffLabel Disclosure: The combination of obinutuzumab, venetoclax and ibrutinib is not approved for treatment of CLL

Background: Mantle cell lymphoma (MCL) is a rare, often aggressive type of B-cell lymphoma with poor survival and no cure. Cancer and cancer treatment has a negative impact on health-related quality of life (HRQOL) both during active disease and in the long term, and improvement of HRQOL may be one of the most important objectives of cancer therapy. In addition, baseline HRQOL has in other lymphoma populations been shown to be predictive of outcome. Hitherto, there are only few reports on HRQOL in MCL. The primary aim of this study was to explore HRQOL before, during and after chemotherapy in an elderly population with MCL. Secondary aims were to identify predictors for HRQOL, information that can be used for improvement in rehabilitation. Methods: The cohort consisted of patients included in the multicenter open-label phase Ib-II NLG-MCL4 trial (LENA-BERIT), designed to evaluate the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment in elderly patients (>65 years) with MCL. The treatment with R-B stopped after six months, LEN continued for six more months. HRQOL was assessed by the EORTC QLQ-C30 questionnaire pre-treatment, and after 6, 12 and 24 months post study inclusion. For the functional scales and the global quality of life scale a higher score represents a better level of functioning. For the symtom scales and single items, a higher score corresponds to a higher level of symtoms. Patient scores were compared to scores from a reference population sample at baseline. Survival was analysed by Kaplan-Meier estimates, and cox regression multivariate analysis was used to assess survival with adjustments for prognostic factors, age, sex and more. Results: Fifty-one patients were enrolled, 1 patient was excluded based on screen failure. Median age was 71 years (range 62-84), 37 were men (73%). Stratified according to Mantle Cell Lymphoma International Prognostic Index (MIPI), 5 (10%) were low-risk, 18 (38%) intermediate and 26 (52%) high-risk. Follow-up time for living patients were 52 months, and for deceased patients 27 months. Median overall survival time were 52 months. The proportion of patients reporting HRQOL data was at baseline; 48 (96%), after 6 months; 33 (83%), after 12 months; 27 (89%), and after 24 months; 12 (75%). During the first six months of treatment, several functional scores deteriorated, and after 12 months it had stabilised at baseline level or better. The global health status (QoL) improved at 12 months after diagnosis, but then dropped to baseline levels after 2 years. Before treatment, patients exhibited levels of the symptom scores, comparable to the reference population. Six months after start of therapy, the scores for pain, dyspnoea and insomnia were improved, while appetite loss and diarrhoea were impaired. After 12 months, the symptom scales improved to a level superior compared both to baseline and the reference population. The population was divided into two groups, with the median as cut-off values. In the multivariate analysis, including MIPI, gender and the presence of TP53 mutation, impaired pre-treatment physical function, role function and elevated pain score were independent prognostic markers for overall survival. Role function and pain were also independent prognostic markers for progression free survival. Conclusion: In this population of elderly patients with MCL, pre-treatment HRQOL was similar to the reference population. During treatment, HRQOL deteriorated, but reverted to the same level as the reference population after treatment. Pre-treatment physical and role function and pain were independent factors associated with overall survival. These novel findings may be used to design support during treatment and improve rehabilitation. Figure Disclosures Jerkeman: Roche: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Gilead: Research Funding; Abbvie: Research Funding.

Despite recent advances in lymphoma treatment, mantle cell lymphoma (MCL) remains incurable, and we are still unable to identify patients who will not benefit from the current standard of care. Here, we explore the prognostic value of recurrent genetic aberrations in diagnostic bone marrow (BM) specimens from 183 younger patients with MCL from the Nordic MCL2 and MCL3 trials, which represent current standard-of-care regimens. In the univariate model, mutations of TP53 (11%) and NOTCH1 (4%), and deletions of TP53 (16%) and CDKN2A (20%), were significantly associated with inferior outcomes (together with MIPI, MIPI-c, blastoid morphology, and Ki67 > 30%); however, in multivariate analyses, only TP53 mutations (HR, 6.2; P 30%, blastoid morphology, MIPI high-risk, and inferior responses to both induction- and high-dose chemotherapy. In conclusion, we show that TP53 mutations identify a phenotypically distinct and highly aggressive form of MCL with poor or no response to regimens including cytarabine, rituximab, and autologous stem-cell transplant (ASCT). We suggest patients with MCL should be stratified according to TP53 status, and that patients with TP53 mutations should be considered for experimental frontline trials exploring novel agents.

In the HOVON68 CLL trial, patients 65 to 75 years of age had no survival benefit from the addition of low-dose alemtuzumab to fludarabine and cyclophosphamide (FC) in contrast to younger patients. The reasons are explored in this 5-year trial update using both survival analysis and competing risk analysis on non-CLL-related mortality. Elderly FCA patients died more frequently from causes not related to CLL, and more often related to comorbidity (mostly cardiovascular) than to infection. In a Cox multivariate analysis, del(17p), performance status >0, and comorbidity were associated with a higher non-CLL-related mortality in the elderly independent of the treatment modality. Thus, while the ‘fit’ elderly with no comorbidity or performance status of 0 might potentially benefit from chemo-immunotherapy with FC, caution is warranted, when considering alemtuzumab treatment in elderly patients with cardiovascular comorbidity.

We report the final analysis of the PROLONG study on ofatumumab maintenance in relapsed chronic lymphocytic leukemia (CLL). In all, 480 patients with CLL in complete or partial remission after second- or third-line treatment were randomized 1:1 to ofatumumab (300 mg first week, followed by 1000 mg every 8 weeks for up to 2 years) or observation. Median follow-up duration was 40.9 months. Median progression-free survival was 34.2 and 16.9 months for ofatumumab and observation arms, respectively, (hazard ratio, 0.55 [95% confidence interval, 0.43–0.70]; P P = 0.0044). Overall survival was similar in both arms; median was not reached (0.99 [0.72–1.37]). Grade ≥ 3 adverse events occurred in 62% and 51% of patients in ofatumumab and observation arms, respectively, the most common being neutropenia (23% and 10%), pneumonia (13% and 12%) and febrile neutropenia (6% and 4%). Up to 60 days after the last treatment, four deaths were reported in the ofatumumab arm versus six in the observation arm, none considered related to ofatumumab. Ofatumumab maintenance significantly prolonged progression-free survival in patients with relapsed CLL and was well tolerated.

Lenalidomide plus bendamustine-rituximab does not overcome the adverse impact of TP53 mutations in mantle cell lymphoma

Introduction: In spite of improvements in treatment of mantle cell lymphoma (MCL), this is still considered an incurable lymphoma entity, and the majority of patients eventually relapse. Ibrutinib is a very active agent in MCL, but in vitro has been shown to partially antagonize the activity of rituximab, by suppression of NK cell activity and subsequent ADCC. Lenalidomide, on the other hand, improves rituximab-induced ADCC. In this multi-centre open-label phase II trial, we evaluated safety and efficacy of this triplet combination in patients with relapsed or refractory MCL. Methods: Patients with MCL, relapsing after or refractory to at least one rituximab-containing chemotherapy regimen, WHO PS 0-3, and measurable disease were eligible. The primary endpoint was maximal overall response rate (ORR) measured with CT and PET/CT. Minimal residual disease (MRD) monitoring by PCR was performed during follow-up, according to EuroMRD criteria. Ion Torrent sequencing of the most frequently mutated genes in MCL was performed on frozen tumor cells from bone marrow at time of relapse. Health-related quality of life was assessed by the EORTC-QLQ C30 questionnaire before and during treatment. Treatment schedule: Induction phase: Up to twelve 28-day cycles with: Lenalidomide 15 mg p o daily, days 1-21, Ibrutinib 560 mg p o days 1-28, Rituximab 375 mg/m2 i v day 1 in cycle 1, then 1400 mg s c (or 375 mg/m2i v) days 8, 15 and 22 in cycle 1, then day 1 in cycles 3, 5, 7, 9 and 11. Maintenance phase: For patients in CR, PR or SD, not in need of other treatment, given until progression, cycle duration 56 days. Ibrutinib: 560 mg p o days 1-56, 2. Rituximab 1400 mg s c (or 375 mg/m2i v) day 1 of each cycle. Results: Accrual of 50 pts was completed in June 2016, at 10 centres in Sweden, Norway, Denmark and Finland. The median age was 69.5 years, with a median MIPI score of 6.2. Patients had received a median of two previous regimens, four had progressed after single agent ibrutinib, and three had received prior allo-SCT. A TP53 mutation was detected in 11 of 49 evaluable cases (22%), 8 cases were of blastoid/pleomorphic histology, and 22 of 40 evaluable cases had a Ki67 >30%. Treatment emergent-AEs of any grade in ≥20% of patients were rash (24%) and fatigue (20%). Five pts (10%) experienced rash grade 3, mainly during cycle 1. Hematological toxicity was generally of low grade, apart from grade 3-4 neutropenia in 5 patients. One patient died due to possible treatment-related toxicity (septic shock). In total, 27 patients achieved CR (54%) and 10 PR (20%). Among evaluable patients with a TP53 mutation, blastoid/pleomorphic histology or Ki67 >30%, the CR rates were 7/11 (64%), 15/8 (62%) and 11/22 (50%), respectively. After a median follow-up of 40 months, the median PFS is 18 months (95% CI 6.5-28), and median OS 47 months (95% CI 30-64). Patients with a detectable TP53 mutation at relapse (n=11) had a median PFS of 13 months (95% CI 4.2-21), whereas pts without a TP53 mutation had a median PFS of 34 months (95% CI 8.3-60). Of the 28 patients evaluable for MRD at 6 months, 15/27 (56%) patients achieved molecular remission in blood and 12/28 (43%) in bone marrow. After 12 months, MRD-negativity in BM was 68% (13/19). Out of 4 patients with TP53-mutated MCL, 2 were MRD-negative in BM after 12 months, as well as 2 out of 4 patients with blastoid/pleomorphic histology. By self-reported HRQOL, a lower level of emotional functioning (EF), as well as a higher level of pain (PA) at baseline, was associated with inferior PFS. In addition, low EF was associated with inferior OS. By a Cox regression multivariable analysis, including MIPI, TP53, histology, Ki67, EF and PA, only MIPI was prognostic for PFS or OS with this regimen. Conclusions: The combination of ibrutinib, lenalidomide and rituximab has been shown to be an active and well tolerated regimen in this cohort of high risk R/R MCL, associated with a high rate of molecular remission. The activity in TP53 mutated MCL is lower than in unmutated disease, but this regimen may still serve as an option for a bridge to an allogeneic transplantation or CAR-T therapy in this category of patients. Disclosures Jerkeman: Roche: Research Funding; Abbvie: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Gilead: Research Funding. Hutchings:Genmab: Honoraria; Genmab: Consultancy; Takeda: Consultancy; Roche: Research Funding; Celgene: Research Funding; Daiichi: Research Funding; Sankyo: Research Funding; Genmab: Research Funding; Janssen: Research Funding; Novartis: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; Roche: Honoraria; Roche: Consultancy; Takeda: Honoraria.

INTRODUCTION: Circular RNAs (circRNAs) are covalently closed endogenous RNA molecules with tissue- and disease specific expression patterns, that are emerging as potential diagnostic and prognostic biomarkers. These molecules exert diverse regulatory functions, and several studies have reported prognostic relevance and functional significance of circRNAs in cancer. However, no studies have yet examined the role of circRNAs in Mantle Cell Lymphoma (MCL). We have previously shown that the Nanostring nCounter technology enables specific, sensitive and accurate quantification of circRNAs in formalin-fixed, paraffin-embedded (FFPE) tissue samples from patients (Dahl et al, 2018). Here, we quantified circRNA expression in MCL tumors to address whether certain circRNAs could serve as prognostic markers in MCL. Samples were obtained from patients treated in the two Nordic clinical trials MCL2 and MCL3, all treated with immuno-chemotherapy and autologous stem cell transplant, which due to the improved prognosis observed with this regimen, remains the current standard of care. MATERIALS AND METHODS: We profiled the genome-wide circRNA expression in MCL using high-throughput RNA-sequencing (RNA-seq) of 14 diagnostic MCL samples, from which high-quality RNA from lymph nodes with MCL tumor infiltration was available. Based on these data, we designed assays for analyses of 41 differentially expressed circRNAs and quantified the expression using the NanoString nCounter technology. We examined the prognostic potential of individual circRNAs in a training cohort of 75 patients (MCL2) and confirmed these results in an independent, but similarly treated, validation cohort of 90 patients (MCL3). RESULTS: The total cohort consisted of 165 previously untreated MCL patients In our training cohort we identified seven circRNAs that were significantly associated with both progression-free survival (PFS), TTP, overall survival (OS) and lymphoma specific survival (LSS). We dichotomized expression values of each individual circRNA and examined the prognostic value in the validation cohort MCL3. Only one (circRAB11FIP1) of the seven circRNAs identified in MCL2 retained prognostic value in MCL3. As shown in Figure 1, univariate analysis revealed that low circRAB11FIP1 expression was significantly associated with TTP in MCL2 (HR=5.1, [2.5;10.4], p Finally, we performed a multivariate cox regression analysis of the entire cohort and found that circRAB11FIP1 was an independent prognostic factor for TTP, even when adjusting for MIPI and ki67-index (HR=2.36[1.3;4.4], p CONCLUSION: Our study showed that low circRAB11FIP1 was significantly associated with shorter TTP, even when adjusting for known prognostic factors, indicating that circRAB11FIP1 could play a specific role in the pathogenesis of MCL. CircRAB11FIP1 originates from exon 2 of the host gene RAB11-Family Interacting Protein 1 located on chromosome 8, and no studies have yet examined the functional role of this circRNA. Interestingly, we found that low circRAB11FIP1 was significantly associated with the presence of TP53 mutations. This warrants future studies to examine whether there is a functional link between circRAB11FIP1 and TP53 in MCL, which may help explain why patients with TP53 mutations have an exceedingly poor prognosis. Figure Disclosures Kolstad: Merck: Research Funding; Nordic Nanovector: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jerkeman:Janssen: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Acerta: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Roche: Honoraria, Research Funding.

In chronic lymphocytic leukemia, TP53 mutations and deletion of chromosome 17p are well-characterized biomarkers associated with poor progression-free and overall survival following chemoimmunotherapy. Patients harboring low burden TP53 mutations with variant allele frequencies of 0.3-15% have been shown to have similar dismal outcome as those with high burden mutations. We here describe a highly sensitive deep targeted next-generation sequencing assay allowing for the detection of TP53 mutations as low as 0.2% variant allele frequency. Within a consecutive, single center cohort of 290 newly diagnosed patients with chronic lymphocytic leukemia, deletion of chromosome 17p was the only TP53 aberration significantly associated with shorter overall survival and treatment-free survival. We were unable to demonstrate any impact of TP53 mutations, whether high burden (variant allele frequency >10%) or low burden (variant allele frequency ≤10%), in the absence of deletion of chromosome 17p. In addition, the impact of high burden TP53 aberration (deletion of chromosome 17p and/or TP53 mutation with variant allele frequency >10%) was only evident for patients with IGHV unmutated status; no impact of TP53 aberrations on outcome was seen for patients with IGHV mutated status. In 61 patients at time of treatment, the prognostic impact of TP53 mutations over 1% variant allele frequency could be confirmed. This study furthers the identification of a clinical significant limit of detection for robust TP53 mutation analysis in chronic lymphocytic leukemia. Multicenter studies are needed for validation of ultra-sensitive TP53 mutation assays in order to define and implement a technical as well as a clinical lower limit of detection.

Background: Regimens based on ibrutinib alone and lenalidomide and rituximab in combination show high activity in patients with relapsed or refractory mantle cell lymphoma. We hypothesised that the combination of all three drugs would improve efficacy compared with previously published data on either regimen alone. Methods: In this multicentre, open-label, single-arm, phase 2 trial, we enrolled patients aged 18 years or older with relapsed or refractory mantle cell lymphoma who had previously been treated with at least one rituximab-containing regimen, an Eastern Cooperative Oncology Group performance status score of 0–3, and at least one site of measurable disease, and who met criteria for several laboratory-assessed parameters. Treatment was divided into an induction phase of 12 cycles of 28 days with all three drugs and a maintenance phase with ibrutinib and rituximab only (cycle duration 56 days), given until disease progression or unacceptable toxicity. In the induction phase, patients received intravenous (375 mg/m2) or subcutaneous (1400 mg) rituximab once a week during cycle 1 and then once every 8 weeks. Oral ibrutinib (560 mg once a day) was given to patients every day in the cycle, whereas oral lenalidomide (15 mg once a day) was given on days 1–21. The primary endpoint was overall response assessed in the intention-to-treat population according to Lugano criteria. Safety analysis included all patients who received the treatment, irrespective of eligibility or duration of treatment. The trial is ongoing, but is no longer accruing patients, and is registered with ClinicalTrials.gov, number NCT02460276. Findings: Between April 30, 2015, and June 1, 2016, we enrolled 50 patients with relapsed or refractory mantle cell lymphoma at ten centres in Sweden, Finland, Norway, and Denmark. At a median follow-up of 17·8 months (IQR 14·7–20·9), 38 (76%, 95% CI 63–86) patients had an overall response, including 28 (56%, 42–69) patients who had a complete response and ten (20%, 11–33) who had a partial response. The most common grade 3–4 adverse events were neutropenia (in 19 [38%] of 50 patients), infections (in 11 [22%] patients), and cutaneous toxicity (in seven [14%] patients). There were three treatment-related deaths during the study, two due to sepsis and one due to embolic stroke. Interpretation: Our results provide preliminary evidence that the triplet combination of ibrutinib, lenalidomide, and rituximab is an active regimen in patients with relapsed or refractory mantle cell lymphoma, and should be evaluated in a prospective randomised controlled trial. Funding: Janssen and Celgene.

Ibrutinib is indicated in Europe for the treatment of several B-cell malignancies, including chronic lymphocytic leukaemia (CLL). However, despite the high efficacy and favourable toxicity profile of ibrutinib, recent data suggest that it is not always administered optimally in clinical practice, with an increased tendency for dose reduction and a higher frequency of discontinuation. An expert panel of European haematologists was convened to identify practical issues pertinent to physicians involved in the therapeutic management of ibrutinib-treated CLL patients and here we outline the findings. Practical management recommendations are given for treating patients with ibrutinib and clinical considerations for the management of adverse events (AEs) that can be associated with ibrutinib treatment are addressed. This article highlights that patients should be monitored for treatment emergent adverse events, most of which are mild, transient and generally occur early in therapy and that, even with more challenging AEs, patients can often be maintained on therapy with minimal disruption through careful management. The necessity to use the correct ibrutinib dose, along with increased awareness, vigilance, mitigation and management of AEs, are all recommended to maximise outcomes for CLL patients treated with ibrutinib.

The safety and efficacy of ibrutinib (420 mg) in chronic lymphocytic leukemia (CLL) were evaluated in a phase 2 study; 51 patients had TP53 aberration (TP53 cohort) and 35 were enrolled because of age 65 years or older (elderly cohort). Both cohorts included patients with treatment-naive (TN) and relapsed/refractory (RR) CLL. With the median follow-up of 4.8 years, 49 (57.0%) of 86 patients remain on study. Treatment was discontinued for progressive disease in 20 (23.3%) patients and for adverse events in 5 (5.8%). Atrial fibrillation occurred in 18 (20.9%) patients for a rate of 6.4 per 100 patient-years. No serious bleeding occurred. The overall response rate at 6 months, the primary study endpoint, was 95.8% for the TP53 cohort (95% confidence interval, 85.7%-99.5%) and 93.9% for the elderly cohort (95% confidence interval, 79.8%-99.3%). Depth of response improved with time: at best response, 14 (29.2%) of 48 patients in the TP53 cohort and 9 (27.3%) of 33 in the elderly cohort achieved a complete response. Median minimal residual disease (MRD) in peripheral blood was 3.8 × 10-2 at 4 years, with MRD-negative (

Recent studies show that mantle cell lymphoma (MCL) express aberrant microRNA (miRNA) profiles; however, the clinical effect of miRNA expression has not previously been examined and validated in large prospective homogenously treated cohorts. We performed genome-wide miRNA microarray profiling of 74 diagnostic MCL samples from the Nordic MCL2 trial (screening cohort). Prognostic miRNAs were validated in diagnostic MCL samples from 94 patients of the independent Nordic MCL3 trial (validation cohort). Three miRNAs (miR-18b, miR-92a, and miR-378d) were significantly differentially expressed in patients who died of MCL in both cohorts. MiR-18b was superior to miR-92a and miR-378d in predicting high risk. Thus, we generated a new biological MCL International Prognostic Index (MIPI-B)-miR prognosticator, combining expression levels of miR-18b with MIPI-B data. Compared to the MIPI-B, this prognosticator improved identification of high-risk patients with regard to cause-specific, overall, and progression-free survival. Transfection of 2 MCL cell lines with miR-18b decreased their proliferation rate without inducing apoptosis, suggesting that miR-18b may render MCL cells resistant to chemotherapy by decelerating cell proliferation. We conclude that overexpression of miR-18b identifies patients with poor prognosis in 2 large prospective MCL cohorts and adds prognostic information to the MIPI-B. MiR-18b may reduce the proliferation rate of MCL cells as a mechanism of chemoresistance.

Aims Manual counting of the fraction of Ki-67-positive cells (the Ki-67 index) in 1000 tumour cells is considered the ‘gold standard’ to predict prognosis in mantle cell lymphoma (MCL). This time-consuming method is replaced by the faster, but less accurate, semiquantitative estimation in routine practice. The aim of this study was to investigate the use of computerized image analysis software for scoring of Ki-67 in MCL. Methods and results We developed an automated method for determining the Ki-67 index by computerized image analysis and tested it using a cohort of 62 MCL patients. The data were compared to Ki-67 scores obtained by semiquantitative estimation and image-based manual counting. When using the Ki-67 index as a continuous parameter, both image-based manual counting and computerized image analysis were related inversely to survival (P = 0.020 and P = 0.025, respectively). Ki-67 index obtained by semiquantitative estimation was not associated significantly with survival (P = 0.093). The results were validated in a second patient cohort with similar results. Conclusion Computerized image analysis of the Ki-67 index in MCL is an attractive alternative to semiquantitative estimation and can be introduced easily in a routine diagnostic setting for risk stratification in MCL.

An unresolved issue in chronic lymphocytic leukemia (CLL) is whether IGHV3-21 gene usage, in general, or the expression of stereotyped B-cell receptor immunoglobulin defining subset # 2 (IGHV3-21/IGLV3-21), in particular, determines outcome for IGHV3-21-utilizing cases. We reappraised this issue in 8593 CLL patients of whom 437 (5%) used the IGHV3-21 gene with 254/437 (58%) classified as subset # 2. Within subset # 2, immunoglobulin heavy variable (IGHV)-mutated cases predominated, whereas non-subset # 2/IGHV3-21 was enriched for IGHV-unmutated cases (P =.002). Subset # 2 exhibited significantly shorter time-to-first-treatment (TTFT) compared with non-subset # 2/IGHV3-21 (22 vs 60 months, P =.001). No such difference was observed between non-subset # 2/IGHV3-21 vs the remaining CLL with similar IGHV mutational status. In conclusion, IGHV3-21 CLL should not be axiomatically considered a homogeneous entity with adverse prognosis, given that only subset # 2 emerges as uniformly aggressive, contrasting non-subset # 2/IGVH3-21 patients whose prognosis depends on IGHV mutational status as the remaining CLL.

Ofatumumab is a human anti-CD20 monoclonal antibody that has proven efficacy as monotherapy in refractory chronic lymphocytic leukaemia. We assessed the efficacy and safety of ofatumumab maintenance treatment versus observation for patients in remission after re-induction treatment for relapsed chronic lymphocytic leukaemia. This open-label, multicentre, randomised phase 3 study enrolled patients aged 18 years or older from 130 centres in 24 countries who had chronic lymphocytic leukaemia in complete or partial remission after second-line or third-line treatment. Eligible patients had a WHO performance status of 0-2, had a response assessment within the previous 3 months, did not have refractory disease, autoimmune haemolytic anaemia requiring treatment, chronic or active infection requiring treatment, and had not previously received maintenance treatment or autologous or allogeneic stem-cell transplant. Using a randomisation list generated by a central computerised system and an interactive voice recognition system, we randomly assigned (1:1) patients to receive ofatumumab (300 mg followed by 1000 mg 1 week later and every 8 weeks for up to 2 years) or undergo observation. Randomisation was stratified by number and type of previous treatment and remission status after induction treatment (block size of four). Treatment assignment was open label. The primary endpoint was investigator-assessed progression-free survival in the intention-to-treat population. We report the results of a prespecified interim analysis after two-thirds of the planned study events (disease progression or death) had happened. This trial is closed to accrual but follow-up is ongoing. This trial is registered with ClinicalTrials.gov, number NCT00802737. Between May 6, 2010, and June 19, 2014, we enrolled 474 patients: 238 patients were randomly assigned to receive ofatumumab maintenance treatment and 236 to undergo observation. One (

In patients with mantle cell lymphoma (MCL) up to 65 years, recommended first-line treatment consists of immuno-chemotherapy including high-dose cytarabine (HA), followed by autologous stem cell transplantation (ASCT) in complete (CR) or partial remission (PR).1 However, it remains unclear whether total body irradiation (TBI) should be part of conditioning before ASCT.1 A large registry study by the European Society for Blood and Marrow Transplantation (EBMT) including 418 MCL patients reported a significantly reduced relapse incidence after TBI in comparison to a non-TBI conditioning (mostly carmustine, etoposide, cytarabine, and melphalan, BEAM), but only for patients transplanted in first PR.2 In contrast, a single-center evaluation of 73 MCL patients who underwent ASCT did not find a significant PFS difference according to the use of TBI vs BEAM.3 A recently published consensus project by EBMT/European MCL Network involving twelve expert clinicians showed that, while consensus was achieved on ASCT as standard first-line consolidation therapy, no consensus was reached on the role of TBI.4 Three recently completed prospective studies including untreated MCL patients up to 65 years investigated the efficacy of HA-containing immuno-chemotherapy followed by ASCT: Nordic MCL2,5, 6 HOVON-45(ref. 7) and European MCL Younger.8, 9 We combined the individual patient data from these studies to compare the long-term clinical outcome of MCL patients transplanted without TBI (Nordic MCL2 and HOVON-45) vs with TBI (MCL Younger, experimental HA-containing arm).

In recent decades, the prognosis of Mantle Cell Lymphoma (MCL) has been significantly improved by intensified first-line regimens containing cytarabine, rituximab and consolidation with high-dose-therapy and autologous stem cell transplantation. One such strategy is the Nordic MCL2 regimen, developed by the Nordic Lymphoma Group. We here present the 15-year updated results of the Nordic MCL2 study after a median follow-up of 114years: For all patients on an intent-to-treat basis, the median overall and progression-free survival was 127 and 85years, respectively. The MCL International Prognostic Index (MIPI), biological MIPI, including Ki67 expression (MIPI-B) and the MIPI-B including mIR-18b expression (MIPI-B-miR), in particular, significantly divided patients into distinct risk groups. Despite very long response durations of the low and intermediate risk groups, we observed a continuous pattern of relapse and the survival curves never reached a plateau. In conclusion, despite half of the patients being still alive and 40% in first remission after more than 12years, we still see an excess disease-related mortality, even among patients experiencing long remissions. Even though we consider the Nordic regimen as a very good choice of regimen, we recommend inclusion in prospective studies to explore the benefit of novel agents in the frontline treatment of MCL.

For elderly patients with mantle cell lymphoma (MCL), there is no defined standard therapy. In this multicenter, open-label phase 1/2 trial, we evaluated the addition of lenalidomide (LEN) to rituximab-bendamustine (R-B) as first-line treatment for elderly patients with MCL. Patients >65 years with untreated MCL, stages II-IV were eligible for inclusion. Primary end points were maximally tolerable dose (MTD) of LEN and progression-free survival (PFS). Patients received 6 cycles every four weeks of L-B-R (L D1-14, B 90 mg/m2 IV, days 1-2 and R 375 mg/m2 IV, day 1) followed by single LEN (days 1-21, every four weeks, cycles 7-13). Fifty-one patients (median age 71 years) were enrolled from 2009 to 2013. In phase 1, the MTD of LEN was defined as 10 mg in cycles 2 through 6, and omitted in cycle 1. After 6 cycles, the complete remission rate (CRR) was 64%, and 36% were MRD negative. At a median follow-up time of 31 months, median PFS was 42 months and 3-year overall survival was 73%. Infection was the most common nonhematologic grade 3 to 5 event and occurred in 21 (42%) patients. Opportunistic infections occurred in 3 patients: 2 Pneumocystis carinii pneumonia and 1 cytomegalovirus retinitis. Second primary malignancies (SPM) were observed in 8 patients (16%). LEN could safely be combined with R-B when added from the second cycle in patients with MCL, and was associated with a high rate of CR and molecular remission. However, we observed a high degree of severe infections and an unexpected high number of SPMs, which may limit its use. This trial is registered at www.Clinicaltrials.gov as #NCT00963534.

Hypogammaglobulinemia is the most common immune deficiency in chronic lymphocytic leukemia (CLL). However, the prognostic significance in terms of morbidity and mortality remains controversial. We here evaluate the significance of hypogammaglobulinemia in terms of infections, treatment-free survival (TFS), and overall survival (OS). A total of 159 consecutive, newly diagnosed patients were included for analysis. Twenty-five patients (16%) had a moderate or severe infection within one year of diagnosis, but no associations were found between low immunoglobulin (Ig) levels and infections. In multivariate analysis, we found age (>65), high Binet stage, high β2-microglobulin, and Ig deficiency to be associated with shorter OS. Decreased levels of IgM, deletion of chromosome 17p and unmutated IGHV status had independent negative impact on TFS. Thus, patients with hypogammaglobulinemia did not suffer more from infections early in the disease course, and decreased Ig had independent negative prognostic impact in CLL.

AIM: In 2008, the Danish National Chronic Lymphocytic Leukemia Registry was founded within the Danish National Hematology Database. The primary aim of the registry is to assure quality of diagnosis and care of patients with chronic lymphocytic leukemia (CLL) in Denmark. Secondarily, to evaluate adherence to national guidelines and to provide source data for research purposes.STUDY POPULATION: All patients diagnosed with CLL in Denmark from 2008 onward are included in the registry. Patients are followed in one of nine hematology centers. All centers participate in the registry and are all obliged to collect data.MAIN VARIABLES: Predefined data are collected at the time of diagnosis, and follow-up at the time of significant events: treatment, progression, transplantation, and death. Parameters included in the International Workshop on Chronic Lymphocytic Leukaemia criteria for diagnosis, and for decision on treatment initiation as well as characteristics included in the CLL International Prognostic Index are collected.DESCRIPTIVE DATA: To ensure full coverage of Danish CLL patients in the registry, both continuous queries in case of missing data, and cross-referencing with the Danish National Patient Registry are performed. Data from the registry are published in an annual report summarizing the collected data, the overall survival for yearly cohorts, and the degree of data coverage. Per year approximately 450 new patients with CLL are registered in the registry, cumulative as of July 1, 2015, 3,082 patients have been registered.CONCLUSION: The Danish National CLL Registry is based within the Danish National Hematology Database. The registry covers a cohort of all patients diagnosed with CLL in Denmark since 2008. It forms the basis for quality assessment of CLL treatment in Denmark and offers a unique opportunity for population-based research.

TPS7582Background: Chemoimmunotherapy (CIT) is still standard of care in first line treatment of fit CLL patients (pts) without del(17p) or TP53 mutation. However, CIT is often associated with side...

7517Background: An interim analysis of the PROLONG phase 3 study in patients (pts) with CLL showed a significant increase in progression free survival (PFS) with OFA maintenance without unexpected ...

We report the largest retrospective, phase IV non-interventional, observational study of ofatumumab therapy in heavily pre-treated patients with poor-prognosis chronic lymphocytic leukemia. Total number of patients was 103; median age was 65 years (range 39–85). Median number of prior lines of therapy was 4 (range 1–13), including, in most cases, rituximab-, fludarabine- and alemtuzumab-based regimens; 13 patients had been allografted. Of 113 adverse events, 28 (29%) were considered to be directly related to ofatumumab. Grade 3–4 toxicities included neutropenia (10%), thrombocytopenia (5%), anemia (3%), pneumonia (17%), and fever (3%). Two heavily pre-treated patients developed progressive multifocal leukoencephalopathy. On an intention-to-treat analysis, the overall response rate was 22% (3 complete response, 1 incomplete complete response). Median progression-free and overall survival times were 5 and 11 months, respectively. This study confirms in a daily-life setting the feasibility and acceptable toxicity of ofatumumab treatment in advanced chronic lymphocytic leukemia. The complete response rate, however, was low. Therefore, treatment with ofatumumab should be moved to earlier phases of the disease. Ideally, this should be done in combination with other agents, as recently approved for ofatumumab plus chlorambucil as front-line treatment for patients unfit for fludarabine. This study is registered at clinicaltrials.gov identifier:01453062.

Mutations or deletions in TP53 or ATM are well-known determinants of poor prognosis in chronic lymphocytic leukemia (CLL), but only account for approximately 40% of chemo-resistant patients. Genome-wide sequencing has uncovered novel mutations in the splicing factor sf3b1, that were in part associated with ATM aberrations, suggesting functional synergy. We first performed detailed genetic analyses in a CLL cohort (n=110) containing ATM, SF3B1 and TP53 gene defects. Next, we applied a newly developed multiplex assay for p53/ATM target gene induction and measured apoptotic responses to DNA damage. Interestingly, SF3B1 mutated samples without concurrent ATM and TP53 aberrations (sole SF3B1) displayed partially defective ATM/p53 transcriptional and apoptotic responses to various DNA-damaging regimens. In contrast, NOTCH1 or K/N-RAS mutated CLL displayed normal responses in p53/ATM target gene induction and apoptosis. In sole SF3B1 mutated cases, ATM kinase function remained intact, and γH2AX formation, a marker for DNA damage, was increased at baseline and upon irradiation. Our data demonstrate that single mutations in sf3b1 are associated with increased DNA damage and/or an aberrant response to DNA damage. Together, our observations may offer an explanation for the poor prognosis associated with SF3B1 mutations.

Summary Background Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53 aberrations. Methods In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until disease progression or the occurrence of limiting toxicities. The primary endpoint was overall response to treatment at 24 weeks in all evaluable patients. This study is registered with ClinicalTrials.gov, number NCT01500733, and is fully enrolled. Findings Between Dec 22, 2011, and Jan 2, 2014, we enrolled 51 patients; 47 had CLL with deletion 17p13.1 and four carried a TP53 mutation in the absence of deletion 17p13.1. All patients had active disease requiring therapy. 35 enrolled patients had previously untreated CLL and 16 had relapsed or refractory disease. Median follow-up was 24 months (IQR 12·9–27·0). 33 previously untreated patients and 15 patients with relapsed or refractory CLL were evaluable for response at 24 weeks. 32 (97%; 95% CI 86–100) of 33 previously untreated patients achieved an objective response, including partial response in 18 patients (55%) and partial response with lymphocytosis in 14 (42%). One patient had progressive disease at 0·4 months. 12 (80%; 95% CI 52–96) of the 15 patients with relapsed or refractory CLL had an objective response: six (40%) achieved a partial response and six (40%) a partial response with lymphocytosis; the remaining three (20%) patients had stable disease. Grade 3 or worse treatment-related adverse events were neutropenia in 12 (24%) patients (grade 4 in one [2%] patient), anaemia in seven (14%) patients, and thrombocytopenia in five (10%) patients (grade 4 in one [2%] patient). Grade 3 pneumonia occurred in three (6%) patients, and grade 3 rash in one (2%) patient. Interpretation The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. Funding Intramural Research Program of the National Heart, Lung, and Blood Institute and the National Cancer Institute, Danish Cancer Society, Novo Nordisk Foundation, National Institutes of Health Medical Research Scholars Program, and Pharmacyclics Inc.

INTRODUCTION: The addition of high-dose cytarabine to mantle cell lymphoma (MCL) treatment regimens has significantly prolonged survival of patient subgroups, but relapses are common and are usually associated with treatment resistance. High-dose cytarabine is effective due to the improved retention of ara-CTP by target cells, but likewise toxic, causing mainly hematological side effects. Thus, understanding the molecular mechanism(s) responsible for resistance and to identify predictive markers for resistance and/or sensitizing agents would be of great clinical value. In an attempt to elucidate those mechanisms and to create a tool for drug discovery investigations, we established a unique and molecularly reproducible cytarabine resistant model from the Z138 MCL cell line. Using molecular profiling, we confirm that down-regulation of the deoxycytidine kinase (dCK) protein is key to development of resistance. The MCL resistance model was carefully characterized by screening with annotated compound libraries focused on (i) chemotherapeutics to identify potential cross-resistance and/or sensitivity, and (ii) epigenetic pathways to investigate sensitivity, but also to select individual candidates for sensitization of cytarabine resistant cells. Furthermore, we investigated the hypothesis that the levels of dCK at diagnosis can be used to predict cytarabine resistance through measurement of event-free survival using the Nordic MCL 2/3 cohort, where patients are treated with a combinatorial protocol including high-dose cytarabine. MATERIAL AND METHODS: The first resistant sub-clone defined as Z138 Cytarabine Resistant (Z138-CytR) was established by continuous exposure of wild type Z138 Cytarabine Naïve Sensitive cells (Z138-CytNS) to increasing concentrations (0.005 - 0.3 µM) of cytarabine. Using this model, we could identify the approximate time to resistance development, and utilize this information for developing a novel highly reproducible time-controlled cytarabine resistant model. Molecular changes were investigated by protein and gene expression analyses. Utilizing drug libraries, the cell model was further used to identify substances with growth reducing effect on cytarabine resistant cells. RESULTS AND CONCLUSION: Gene expression profiling revealed that major transcriptional changes occur during the initial phase of adaptation to cellular growth in cytarabine containing media, and only few genes are deregulated upon development of resistance. Instead, resistance to cytarabine was shown to be mediated by down-regulation of the dCK protein, responsible for activation of nucleoside analogue prodrugs. Consequently, cytarabine resistant cells showed cross-resistance to other nucleoside analogues including gemcitabine, cladribine and fludarabine. Of major importance, using drug libraries, we identify substances with growth reducing effect on cytarabine resistant cells. Further investigations are needed to pinpoint compounds that can prevent the down-regulation, or possibly restore dCK protein levels. The possibility to predict cytarabine resistance in diagnostic samples was assessed, but analysis show that the majority of patients have moderate to high expression of dCK at diagnosis, corresponding well to the initial successful response to cytarabine-containing treatment protocols. Disclosures Geisler: Roche: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy. Jerkeman:Celgene: Research Funding; Gilead: Research Funding; Janssen: Research Funding; Amgen: Research Funding; Mundipharma: Research Funding.

Introduction: In spite of improvements in treatment of mantle cell lymphoma (MCL) over the last 10-15 years, this is still considered an incurable lymphoma entity, and the majority of patients eventually relapse. Ibrutinib is a very active agent in MCL, with an overall response rate (ORR) of 68% as a single agent in the relapse situation. In vitro, ibrutinib has been shown to partially antagonize the activity of rituximab, by suppression of NK cell activity and subsequent ADCC. Lenalidomide, on the other hand, improves rituximab-induced ADCC. In this multi-centre open-label phase II trial, we evaluated safety and efficacy of this triplet combination in patients with relapsed or refractory MCL. A phase I trial with this combination has been performed in 22 patients with untreated follicular lymphoma (Alliance 051103). In this trial, rash was the most common adverse event (AE), occuring in 73% of pts, with grade 3 rash in 32%. Methods: Eligibility criteria were: patients with MCL, relapsing after or refractory to at least one rituximab-containing chemotherapy regimen, WHO PS 0-3, and measurable disease. The primary endpoint was maximal overall response rate (ORR) measured with CT and PET/CT. Minimal residual disease (MRD) monitoring by PCR was performed during follow-up, according to EuroMRD criteria. Ion Torrent sequencing was performed on frozen tumor cells from bone marrow at time of relapse, including the following genes: ATM, CCND1, TP53, KMT2D, NOTCH1, NOTCH2, WHSC1 and BIRC3. Treatment schedule: Induction phase: Up to twelve 28-day cycles with: Lenalidomide 15 mg p o daily, days 1-21, Ibrutinib 560 mg p o days 1-28, Rituximab 375 mg/m2 i v day 1 in cycle 1, then 1400 mg s c (or 375 mg/m2i v) days 8, 15 and 22 in cycle 1, then day 1 in cycles 3, 5, 7, 9 and 11. Maintenance phase: For patients in CR, PR or SD, not in need of other treatment. Given until progression, cycle duration 56 days. Ibrutinib: 560 mg p o days 1-56, 2. Rituximab 1400 mg s c (or 375 mg/m2i v) day 1 of each cycle. Results: Accrual of 50 pts was completed in 12 months, June 2016, at 10 centres in Sweden, Norway, Denmark and Finland. The median age was 69.5 years, with a median MIPI score of 6.2. Patients had received a median of two previous regimens, four had progressed after single agent ibrutinib, and three had received prior allo-SCT. In total, 17/50 pts have discontinued treatment (n=9 due to PD, n=4 due to AE, n=2 withdrew consent, n=1 proceeded to alloSCT and n=1 due to other cause). Treatment emergent-AEs of any grade in ≥20% of patients were rash (24%) and fatigue (20%). Five pts (10%) experienced rash grade 3, mainly during cycle 1. Hematological toxicity was generally of low grade, apart from grade 3-4 neutropenia in 5 patients. One patient died due to possible treatment-related toxicity (septic shock). One event of laboratory tumor lysis syndrome was reported, and two events of atrial fibrillation, without reduction or discontinuation of ibrutinib. With a median follow up time of 7 months, 29 patients were evaluable for efficacy as of July 14, 2016. The ORR to date is 83% with 12 patients achieving CR (41%) and 12 PR (41%). Median duration of response and PFS has not been reached. One of three evaluable patients with progression on single agent ibrutinib responded with a PR, with ongoing response at 9 months. Of the 13 patients evaluable for MRD at 6 months, 7/12 patients have achieved molecular remission in blood and 7/13 in bone marrow. Conclusions: So far, the combination of ibrutinib, lenalidomide and rituximab has been shown to be an active and well tolerated regimen in patients with R/R MCL, associated with molecular remission. Cutaneous toxicity was manageable, in contrast to what has been reported with a similar combination in untreated patients with follicular lymphoma. Up-dated results will be presented at the annual meeting, including data on mutational profile as biomarker for efficacy. This trial was registered at http://clinicaltrials.gov as NCT02460276. Disclosures Jerkeman: Gilead: Research Funding; Mundipharma: Research Funding; Celgene: Research Funding; Amgen: Research Funding; Janssen: Research Funding. Niemann:Abbvie: Research Funding; Roche: Consultancy; Gilead: Consultancy; Abbvie: Consultancy; Janssen: Consultancy. Geisler:Roche: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy.

Background: Minimal residual disease monitoring has been shown to be of relevance in mantle cell lymphoma (MCL) to evaluate quality of remission and predict clinical relapse. The main objectives of the present study were to determine the value of minimal residual disease (MRD) monitoring to guide pre-emptive treatment with rituximab, and to predict clinical relapse in MCL following autologous stem cell transplantation (ASCT) in two prospective trials (MCL2 and MCL3) with long-term follow-up conducted by the Nordic Lymphoma Group. Methods: Patients treated in the two studies received a total of 6 alternating cycles with R-CHOP and R-Ara-C followed by a peripheral blood stem cell harvest and high-dose therapy with ASCT. Additionally, responding patients not in CR before ASCT in the MCL3 trial received yttium-90 ibritumomab tiuxetan (0.4 mCi/kg) as intensification one week prior to the standard conditioning with BEAM/C. Staging included physical examination, blood tests, computed tomography (CT) scans and bone marrow (BM) aspiration and biopsy. Clinical and molecular response evaluation was repeated 2-3 months and 6 months after transplant, and then every 6 months until relapse or 5 years follow-up. A combined standard nested and quantitative real-time PCR assay was used to estimate MRD involvement in consecutive post-transplant BM/PB samples. Molecular relapse after ASCT was defined as; 1. Conversion from standard nested PCR negative to standard nested PCR positive, or 2. For patients who were MRD positive post-ASCT, a significant (>5 fold) increase of the real time quantitative PCR detectable MRD level in two consecutive BM samples. Patients in clinical remission who developed a molecular relapse in both studies received 4 weekly doses of rituximab (375 mg/m2). This treatment could be repeated in case of recurrent molecular relapses. Results: An MRD marker for Bcl-1 or IgH rearrangement was obtained for 94 out of 160 patients (59%) recruited in the Nordic MCL2 trial, and for 121 out of 160 (76%) in the consecutive MCL3 trial. 183 patients, who had completed induction therapy and autologous stem cell transplantation (ASCT) in the two studies and where a PCR marker in blood or bone marrow was obtained, were included in the current analysis. Median follow-up from inclusion was 8.5 years among survivors. Patients who were MRD negative post-ASCT had significantly longer relapse-free survival (RFS) and overall survival (OS) compared to those who were MRD positive (P Conclusion: We observed a continuous pattern of MRD relapses that did not subside even after 5-10 years and included all risk groups. Hence, it is fair to consider MCL as a chronic incurable lymphoma entity and novel approaches will be necessary to change the natural course of this disease. Detection of MRD was shown to be a predictor for clinical relapse and inferior survival. Additionally, the data strongly suggests that pre-emptive rituximab treatment delayed clinical relapse in MCL. We recommend MRD monitoring post-ASCT in MCL as a useful approach to select the MRD positive patients for novel strategies in future trials and as an alternative to maintenance therapy for all patients. The MCL2 and MCL3 trials were registered at www.isrctn.com as ISRCTN 87866680 and at www.clinicaltrials.gov as NTC 00514475, respectively. Disclosures Kolstad: Nordic Nanovector: Other: Membership of Scientific Advisory Board. Jerkeman:Janssen: Research Funding; Celgene: Research Funding; Amgen: Research Funding; Mundipharma: Research Funding; Gilead: Research Funding. Geisler:Roche: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy.

Background The management of chronic lymphocytic leukemia (CLL) is in rapid transition and tailored individual therapy is a likely future scenario for those needing treatment. Previous studies of CLL have revealed an increased risk of second cancers. The underlying mechanisms are unclear, but may involve shared risk factors, weakened immune surveillance, and chemotherapy exposure. However, little is known about the impact of CLL treatment on second cancer risk. We followed Danish population-based cohorts of treated and untreated CLL patients and compared their risk of second cancers with that of matched controls. Methods All patients registered with a diagnosis of CLL in the Danish Cancer Registry 2002-2013 were included in the analyses. For each CLL patient, we randomly selected 50 CLL-free control persons matched on age and gender from the general population. Patients and controls were followed for new cancers registered in the Danish Cancer Registry 2002-2013 using ICD10 codes. Information about CLL treatment was available from The Danish National Patient Registry allowing us to stratify patients accordingly. Follow up of the patients and controls were done separately for each cancer type without competing risk. Adjusted hazard ratios (HR) and 95% confidence intervals (95%CI) for new cancers by time since CLL diagnosis /matching date for controls were calculated using Cox regression analyses. Results Overall, 4,919 CLL patients with a median person-years of follow-up (PYFU) of 3.9 and 245,877 controls with a median PYFU of 4.6 were included. During follow-up, a total of 694 new malignancies, 54 hematological (excluding CLL) and 640 non-hematological, were registered among the CLL patients (eight patients developed both hematological and non-hematological malignancies). This corresponded to increased relative risks for combined groups of hematological (HR, 1.3; 95% CI, 1.0 to 1.7) and of non-hematological (HR, 1.4; 95% CI, 1.3 to 1.5) cancers, respectively, compared to the controls. Chemotherapy treatment was registered for 1,664 (34%) of the CLL patients during follow-up, and this was accompanied by increased relative risks of both hematological cancers excluding CLL (HR, 2.7; 95% CI, 1.9 to 4.1) and non-hematological cancers (HR, 1.8; 95% CI, 1.6 to 2.1). In contrast, risks of hematological cancer were not increased (HR, 0.9; 95% CI, 0.6 to 1.3) and risk of non-hematological cancers only slightly increased (HR, 1.3; 95% CI, 1.1 to 1.4), among untreated CLL patients. In site-specific analyses the increased risk among treated CLL patients pertained to Hodgkin and non-Hodgkin lymphomas, myelodysplastic syndrome, lung, skin, and thyroid cancer with HR's ranging from 1.8 to 13.3. Conclusions CLL patients treated with chemotherapy are at increased risk of other hematological and non-hematological malignancies. Increased awareness and possibly cancer screening programs are warranted for CLL patients receiving chemotherapy. Detailed analyses of the role of different types of CLL specific treatments on risk of second cancers based on the Danish Cancer Registry, the Danish National Patient Registry and the Danish National CLL Registry are ongoing. Disclosures Geisler: Roche: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy. Niemann:Abbvie: Research Funding; Roche: Consultancy; Gilead: Consultancy; Abbvie: Consultancy; Janssen: Consultancy.

INTRODUCTION: During the past decades, the outcome of Mantle Cell Lymphoma (MCL) treatment has improved substantially in younger patients. In a recent update of the Nordic MCL2 trial we show very long response durations after a median follow-up of 11.4 years, but we also observe a continuous pattern of relapses even after 10 years of remission.(Eskelund et al, 2016) The course of this disease remains very heterogeneous, and with the current prognostic indexes we are unable to identify patients who might be cured by the current standard-of-care and others who would possibly benefit from alternative frontline approaches. Recently, next-generation sequencing (NGS) studies have explored the mutational landscape of MCL, however, in inhomogeneous and diversely treated cohorts or with short follow-up. Still, TP53 and NOTCH1/2 mutations have been shown to be prognostic markers. In our current study we examine the prognostic impact of aberrations in the most frequently mutated genes in MCL in a homogenously and optimally treated patient cohort, with a long-term follow-up. MATERIAL AND METHODS: Freshly frozen DNA from diagnostic bone marrow samples from patients included in two prospective Nordic trials, MCL2 and MCL3 were analysed. In both trials patients received intensified first line induction therapy with alternating courses of R-CHOP and R-HD-Cytarabine and consolidation with high-dose therapy and ASCT. All patients signed an informed consent.(Geisler et al, 2008; Kolstad et al, 2014). NGS was performed using the Ion Torrent Technology. A targeted panel of 8 genes frequently mutated in MCL was constructed on the basis of previous NGS studies.(Bea et al, 2013; Zhang et al, 2014) The panel included all coding regions of the following genes: ATM, CCND1, TP53, KMT2D, NOTCH1, NOTCH2, WHSC1 and BIRC3. Cut-off for calling a mutation was set to a variant allele frequency >3%. Mean depth was >1500X in all patients. RESULTS: So far, we have mutational data from 72 patients. Patients were previously untreated and Of the 72 patients, mutations were detected in 33 cases. Twenty-one patients carried 1 mutation and 12 patients had >1 mutation (2-4). Mutations were distributed as follows: ATM 15 (21%), KMT2D 11 (15%), WHSC1 7 (10%), TP53 6 (8%), CCND1 5 (7%), NOTCH2 4 (6%), NOTCH1 3 (4%), BIRC3 2 (3%). In univariate analyses, mutations in TP53 were highly predictive of an inferior outcome (median OS and PFS were 14 and 10 months, respectively; p1 mutations. In multivariate analyses, the only prognostic significant mutations were TP53 (p TP53 mutations were associated with increased Ki67 expression, median 30% (range 20-80%), higher risk MIPI/MIPI-B/MIPI-C, and 4 out of 6 patients had blastoid morphology at diagnosis. All 6 TP53 mutations were found in the DNA-binding domain, and 5 were missense mutations while the last was a frameshift mutation. Patients with missense mutations all died within 3 years (range 6-34 months) due to relapsing or progressive disease, while PFS and OS of the latter patient was 4.6 years and 8.4 years, respectively. We found no predictors for late relapses. CONCLUSION: Here we evaluate the prognostic impact of mutations in eight genes that are commonly involved in MCL in a cohort of 72 younger patients who received intensified induction therapy and ASCT in the Nordic MCL2 trial. In line with previous reports, we demonstrate a negative prognostic impact of TP53 and NOTCH1/2 mutations; however, in multivariate analyses only TP53 and NOTCH1 mutations held significance. Missense mutations in the DNA binding domain of TP53 seem to predict an exceedingly poor short term outcome. At the annual meeting, we will present mutational analyses and long term follow up of >150 patients from the combined MCL2 and MCL3 cohort. Disclosures Jerkeman: Amgen: Research Funding; Gilead: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding. Geisler:Roche: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Sanofi: Consultancy.

Background The treatment of chronic lymphocytic leukemia (CLL) is in rapid transition. As single agents, Fludarabine (F) was shown to be superior to chlorambucil (Rai, NEJM, 2000). Soon after F with Cyclophosphamide (C), showed superiority to F alone (Eichhorst, Blood, 2006; Flinn, JCO, 2007, Catovsky, Lancet, 2007). Subsequently, the addition of CD20 antibody rituximab (R) to FC for the first time showed a survival benefit for fit patients in a clinical trial (Hallek, Lancet, 2010). Likewise, in unfit patients the addition of CD20 antibodies to chlorambucil led to increased overall survival (Goede, NEJM, 2014). Eventually, BCR-targeted treatment for patients harboring TP53 aberrations demonstrated promising results (Farooqui, Lancet Onc, 2015). Here we assess the impact of these successive changes of therapy on the survival of patients with CLL in a Danish population-based cohort. Methods We studied the survival of a population-based cohort of CLL patients reported to the Danish Cancer Registry 1978-2013. Patients were categorized according to year of diagnosis from 1978-1994, 1995-2000, 2001-2005 and 2006-2013. For each CLL patient, we randomly selected 50 controls from the general population matched on age, gender and municipality. Kaplan MeierÕs survival curves and Hazard ratios (HR) and 95% confidence interval (95%CI) for death since time of diagnosis /matching date for controls were calculated. Change in survival probability relative to the controls with stratification on gender, age and calendar period of diagnosis was assessed. Results In total, 10500 patients were diagnosed with CLL in Denmark from 1978 to 2013 as follows: 1978-1994: 4651, 1995-2000: 1622, 2001-2005: 1664 and 2006-2013: 2563. Thus, the reported incidence of CLL increased slightly after year 2000. Overall, we observed a continuously decreasing risk of death for patients with CLL compared to matched controls, with HRs from 3.47 (3.37 - 3.58) to 2.09 (1.96 - 2.24) for patients diagnosed 1978-1994 and 2005-2013, respectively. In inter group analyses, a significant stepwise reduction in risk of death was observed for each period (Figure 1). In all age groups and calendar periods, male patients had an inferior survival compared to female patients and younger patients survived longer than older patients (p Discussion A significant improvement in survival probability for patients with CLL over time was found. This coincides with the introduction of FCR as standard therapy for younger patients with CLL (approval by EMA in 2009, affecting the cohort diagnosed 2006-2013). Significant survival improvement was also observed in the 2001-2005 cohort, possibly due to a shift to combination chemotherapy. Also for elderly patients, otherwise expected to get less intensive treatment in part due to co-morbidities, the survival improved over time. This may be accounted for by the introduction of semi-intensive chemotherapy like bendamustine, reduced intensity FC(R) and more recently chlorambucil combined with CD20-targeting antibodies. For the first time, we here present population-based data showing significant improvement in survival for patients with CLL in parallel with the introduction of new chemo-immunotherapeutic regimens into clinical practice. These data substantiate the reported increased survival for patients treated with chemo-immunotherapy in clinical studies. Further investigation and cross-reference with treatment databases are warranted in order to assess the impact of new targeted treatment options for CLL. Figure 1. Overall survival for patients (70-79 and 50-59 years), lower four curves; upper four curves represent matched controls. Figure 1. Overall survival for patients (70-79 and 50-59 years), lower four curves; upper four curves represent matched controls. Disclosures Geisler: GlaxoSmithKline: Consultancy; Novartis: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Gilead: Consultancy; Roche: Consultancy. Niemann:Novartis: Other: Travel grant; Janssen: Consultancy; Roche: Consultancy; Gilead: Consultancy.

The international Prognostic Index for patients with CLL (CLL-IPI) : An international meta-analysis

Background: Despite encouraging progress in treatment results, CLL remains incurable and patients (pts) eventually relapse. Currently, the effects of maintenance therapy are unknown for CLL. OFA, a human anti-CD20 monoclonal antibody, has proven efficacy as a monotherapy in refractory CLL. PROLONG is an open-label, two-arm randomized study of OFA versus observation (obs) for pts in remission after induction treatment for relapsed CLL. Here, we report interim analysis results for the key primary and secondary endpoints of the study. Methods: Pts in CR or PR after 2nd or 3rd line treatment for CLL were randomized 1:1 to receive OFA (300 mg followed 1 week later by 1000 mg every 8 weeks for up to 2 years) or observation. Pts on OFA received premedication with acetaminophen, antihistamine and glucocorticoid. Pts were stratified by number and type of prior therapy, and remission status (CR or PR) after induction treatment. The primary endpoint was progression free survival (PFS) from randomization as assessed by investigator. The predefined interim analysis of efficacy occurred at 2/3 study events (minimum 187), with a p Results: 474 pts were randomized prior to the interim analysis. Baseline characteristics were similar between arms (Table 1). The median duration of OFA treatment was 12.5 months. The median follow-up was 26.1 months for OFA and 24.0 months for obs. The median PFS was 28.6 months for OFA and 15.2 months for obs (HR=0.48; p Adverse events (AEs) during the study occurred in 87% OFA pts vs. 75% obs pts. OFA pts had 25% Grade 3-4 AEs vs. 17% obs pts. Grade3-4 infections were 18% OFA vs. 13% obs. The most common (>5% of all pts) grade 3-4 AEs that occurred were neutropenia (22% OFA vs. 9% obs) and pneumonia (7% OFA vs. 4% obs). Death rate was similar in both arms (14%). AEs that lead to permanent discontinuation of treatment occurred in 8% OFA pts. Conclusions: OFA maintenance provided significant clinical benefit for pts with relapsed CLL. OFA was well-tolerated with no unexpected toxicities. Additional data analyses are ongoing and efficacy outcomes according to patient subgroups will be presented. Acknowledgments: The authors thank the patients for their participation in the study, the other PROLONG investigators, and the HOVON Committee. Figure 1 Figure 1. Figure: Graph of PFS OFA vs. obs Figure:. Graph of PFS OFA vs. obs Disclosures van Oers: Roche: Consultancy. Off Label Use: Ofatumumab is a human anti-CD20 monoclonal antibody that has proven efficacy as monotherapy in refractory CLL. The purpose of its use in this clinical trial is to investigate its use in a maintenance setting for CLL. . Smolej:GlaxoSmithKline: Consultancy, Honoraria, Travel funds Other; Roche: Consultancy, Honoraria, Travel funds, Travel funds Other; Sanofi: Consultancy, Honoraria, Travel funds, Travel funds Other; Janssen: Consultancy, Honoraria, Travel funds, Travel funds Other. Gupta:GlaxoSmithKline: Employment. Phillips:GlaxoSmithKline: Employment. Williams:GlaxoSmithKline: Employment. Lisby:Genmab: Employment. Geisler:Roche: Consultancy; GlaxoSmithKline: Consultancy; Celgene: Consultancy; Janssen: Consultancy.

The human IGHV4-34 gene encodes antibodies which are intrinsically autoreactive when the VH domain is unmutated. Therefore, B cells expressing IGHV4-34 B-cell receptor immunoglobulins (BcR IG) are normally under close scrutiny in order to avoid unwanted autoreactivity, especially against DNA. The IGHV4-34 gene is frequently utilized in chronic lymphocytic leukemia (CLL), where, typically, it shows a high load of somatic hypermutation (SHM). We have previously reported distinctive SHM patterns amongst IGHV4-34 CLL, especially for subsets with stereotyped BcR IG. However, although a large number of cases (~2000) was previously studied, since even the largest subsets account for only ~3% of CLL, meaningful conclusions could not be reached for smaller subsets. Here we revisit this issue in a series of 16,528 CLL cases and focus on IGHV4-34 expressing subsets: #4 (IGHV4-34/IGHD5-18/IGHJ6 | 156 cases, 0.9%); #11 (IGHV4-34/IGHD3-10/IGHJ4 | 16 cases, 0.1%); #16 (IGHV4-34/IGHD2-15/IGHJ6 | 41 cases, 0.25%); #29 (IGHV4-34/IGHD: unassignable/IGHJ3 | 39 cases, 0.24%); and #201 (IGHV4-34/IGHD: unassignable/IGHJ3 | 43 cases 0.26%). Focusing on codons 27-104 within the VH domain (from CDR1-IMGT to FR3-IMGT), we calculated the sequence distance between subsets and the corresponding IGHV4-34 germline sequence based on a pairwise qualitative and quantitative comparison of the respective amino acid composition. The minimum distance calculated, and hence the greatest identity, was observed between subsets #4 and #16, both concerning IgG-switched cases (IgG-CLL), which is notable given the overall rarity of IgG-CLL. In contrast, the maximum distance, implying the least identity, was between subsets #16 and #201, the latter concerning IgM/D-CLL. Extreme variations between subsets were noted in codons spanning the entire VH domain. This result is consistent with our finding of a subset-biased distribution of mutations over the VH domain. More specifically, while subsets #11, #16, #29 and #201 had a lower frequency of mutations within VH CDR1 compared to VH CDR2, the exact opposite was seen in subset #4, with 40% of mutations in VH CDR1 versus 27% in VH CDR2. In addition, subsets #4, #11, #16 and #29 had a similar distribution of mutations in VH FR2 and VH FR3, in contrast to subset #201 that showed a preference for VH FR3 over VH FR2. Consequently, we noted that certain positions were targeted in a subset-specific manner e.g. codon 28 in VH CDR1 was heavily targeted in subsets #4 (68.6%) and #16 (87.8%), with most cases carrying an acidic amino acid (AA) introduced by SHM, glycine to glutamic acid, G>E: 51.3% for subset #4 and 78% for subset #16. The high prevalence of acidic AA introduced by SHM in these subsets is notable considering the electropositive nature of their VH CDR3 (especially of subset #4), strongly recalling edited anti-DNA antibodies. Interestingly, the G>E change was identified at a much lower frequency in other IGHV4-34 subsets: 18.75% for subset #11; 2.6% for subset #29; 7% for subset #201, all of which carried electronegative VH CDR3. Further, we noted that certain positions were heavily targeted in all subsets e.g. 56-86% targeting for SHM at codon 92 in VH FR3 where serine is encoded by the agc triplet, the ”hottest of hotspots”. This result could be viewed as sequence- rather than subset-dependent and linked to the molecular features of this codon, which is supported by the low targeting of codon 93 (0-6%), also encoding serine by the tct triplet. Other positions were targeted in all subsets but at vastly different frequencies e.g. codon 64 was targeted in 37.8% in subset #4 rising to 100% in subset #29. Finally, positions heavily targeted by SHM in certain subsets were unmutated in other subsets e.g. codon 36 in VH CDR1 remained unmutated in subset #16, in contrast 76.9% of subset #29 were mutated at this position resulting in an AA change. In conclusion, we document different spectra of SHM and AA changes between stereotyped IGHV4-34 CLL subsets. The finding of subset-biased, recurrent AA changes at certain codons indicates that the respective progenitor cells may have responded in a specific manner to the selecting antigen(s), despite expressing the same IGHV gene, indicating a functional purpose for these modifications. This is exemplified by the molecular characteristics of the recurrent AA changes in subset #4, thereby offering interesting pathogenetic hints. Disclosures No relevant conflicts of interest to declare.

Preliminary observations from essentially small patient series indicate that certain recurrent gene mutations may be enriched in subsets of chronic lymphocytic leukemia (CLL) with stereotyped B-cell receptors (BcR). On these grounds, it could be argued that differential modes of immune signaling, in the context of subset-biased antigen-immunoglobulin (IG) interactions, may be associated with the acquisition and/or selection of certain genomic aberrations within various stereotyped CLL subsets. With this in mind, we here sought to explore the genetic background of 10 major stereotyped subsets which collectively account for ~11% of all CLL and represent both IGHV unmutated (U-CLL) and/or mutated (M-CLL) cases. We focused on recurrent mutations within the NOTCH1 (entire exon 34 or targeted analysis for del7544-45), TP53 (exons 4-9), SF3B1 (exons 14-16), BIRC3 (exons 6-9) and MYD88 (exon 5) genes. Overall, 647 cases were analyzed, belonging to the following major subsets: (i) U-CLL: #1 (the largest within U-CLL, clinically aggressive), n=139; #3, n=39; #5, n=22; #6, n=48; #7, n=74; #8, n=46; #59, n=19 and #99, n=18; (ii) M-CLL: #4 (the largest within M-CLL, particularly indolent), n=78; and, (iii) subset #2 (the largest overall, variable mutational status and clinically aggressive), n=164. All cases were devoid of MYD88 mutations, which was not surprising given that our cohort was predominantly composed of U-CLL. Mutations within the BIRC3 gene were either absent (#2, #4, #6 and #59) or rare (#1, #3, #5, #7, #8 and #99; frequency 1.5%-7%) with no clear bias to any subset. BIRC3-mutant cases frequently co-existed with either del(11q) or trisomy 12. NOTCH1 mutations were more frequent in subsets #1, #6, #8, #59 and #99 (frequency, 22%-32%), sharply contrasting subsets #2 or #3 (4% and 7%, respectively) (p Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.