Kurzfassung: Background Lenalidomide is an effective treatment for myeloma and has been studied in a range of combination regimens worldwide. The results of these studies have suggested that prolonged exposure to lenalidomide is important to improve outcomes both as a maintenance agent post-transplant (Attal M et al NEJM 2012, McCarthy et al NEJM 2012) and in the transplant ineligible population (Palumbo A et al NEJM 2012, Benboubker L et al NEJM 2014). In the Myeloma XI study, the largest of its kind, we explored the use of oral lenalidomide continued to disease progression compared to no therapy in both newly diagnosed transplant eligible (TE) and transplant non-eligible (TNE) populations. Here we present the results of this maintenance randomization, which demonstrate the efficacy and safety of maintenance lenalidomide. Methods The Myeloma XI study is a Phase III, UK-based, multicenter, open-label, parallel group, randomized controlled trial for newly diagnosed symptomatic myeloma patients of all ages and includes a maintenance comparison of lenalidomide versus no maintenance. Newly diagnosed symptomatic myeloma patients both TE and TNE were enrolled to the study. Induction treatment in both pathways was with thalidomide or lenalidomide plus cyclophosphamide and dexamethasone, with appropriate dose reductions for TNE patients. TE patients proceded to a standard melphalan 200mg/m2 transplant. Patients were randomized to either maintenance lenalidomide or observation after achieving maximum response (TNE) or at 100 days after transplant (TE). Lenalidomide was administered at a dose of 10mg daily in 21/28 day cycles until disease progression. Dose adjustments for renal impairment and following AEs were permitted. The primary endpoints for the maintenance randomization were progression-free (PFS) and overall survival. Secondary endpoints included response, toxicity and PFS2. Time-to-event endpoints were measured from maintenance randomization. This abstract summarizes a preliminary analysis, final data will be presented at the meeting. The median follow up in this analysis is 26 months [IQR 12-41]. Results A total of 1550 patients, 828 TE and 722 TNE, median age 61 and 74 years, respectively, were randomized between lenalidomide (n=857) and no maintenance (n=693). The arms were well-balanced for clinical features and response to induction therapy (e.g. ISS stage III: 27% vs 23%, VGPR/CR: 73% vs 73%). The maintenance randomization has met its primary endpoint demonstrating a 55% reduction in risk of progression or death for lenalidomide compared to no maintenance (HR 0.45 [95%CI 0.39-0.52], median PFS 37 vs 19 months, p 〈 0.0001) This significant improvement was observed in each pathway TE: HR 0.46 [95%CI 0.36-0.58], median PFS 60 vs 28 months, p 〈 0.0001. TNE: HR 0.44 [95%CI 0.36-0.53], median PFS 26 vs 12 months, p 〈 0.0001. The benefit of lenalidomide maintenance on PFS persisted across risk subgroups and was independent of induction therapy and response. An exploratory analysis of 132 patients stopping lenalidomide treatment for reasons other than disease progression (91 toxicity, 28 patient choice and 13 clinician choice) shows that patients receiving greater than 12 months of treatment have an improved median PFS compared to those stopping earlier (HR 0.35 [95%CI 0.18-0.68], 49 vs 31 months, p 〈 0.0015). At this time 445 patients continue to receive lenalidomide maintenance on study. Of patients who have stopped therapy, only 21.5% did so due to toxicity. Relevant grade 3/4 adverse events were: neutropenia 35%, thrombocytopenia 7.4%, anaemia 4.4%, peripheral neuropathy 1.4%. Venous thromboembolism occurred in 2.3%. Second primary malignancy (SPM) data was collected and the relationship with maintenance therapy reviewed. 72 SPM were observed (24 no maintenance, 48 lenalidomide). Haematologic malignancy crude incidence was 0.3% vs. 0.9%. While we found a slight excess of SPM in older patients these were mostly non-invasive and did not impact the outcome benefit demonstrated. Conclusion The use of maintenance lenalidomide treatment results in highly significant improvements in PFS for patients of all ages and should be standard of care. On behalf of the NCRI Haem-Onc CSG Disclosures Jackson: Amgen: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau. Davies:Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Pawlyn:Takeda Oncology: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel Support. Jones:Celgene: Honoraria, Research Funding. Kishore:celgene: Other: travel grant. Garg:Janssen: Other: Travel support, Research Funding, Speakers Bureau; Takeda: Other: Travel support; Novartis: Other: Travel support, Research Funding. Williams:Takeda: Honoraria, Other: Travel support, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Novartis: Honoraria; Janssen: Honoraria, Other: Travel support, Speakers Bureau; Celgene: Honoraria, Other: Travel support, Speakers Bureau. Karunanithi:Celgene: Other: Travel support, Research Funding; Janssen: Other: Travel support, Research Funding. Lindsay:Janssen: Consultancy; Novartis: Other: Travel support; Takeda: Other: Travel support; BMS: Consultancy, Other: Travel support; Celgene: Honoraria, Other: Travel support. Jenner:Janssen: Consultancy, Honoraria, Other: Travel support, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel support; Amgen: Consultancy, Honoraria, Other: Travel support; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria. Cook:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Glycomimetics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Speakers Bureau. Kaiser:BMS: Consultancy, Other: Travel Support; Takeda: Consultancy, Other: Travel Support; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Chugai: Consultancy. Drayson:Abingdon Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Owen:Takeda: Honoraria, Other: Travel support; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Other: Travel support. Morgan:Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Janssen: Research Funding; Univ of AR for Medical Sciences: Employment; Celgene: Consultancy, Honoraria, Research Funding.

Kurzfassung: Introduction. Minimal residual disease (MRD) is a powerful predictor of outcome in multiple myeloma (MM). We have previously demonstrated, in transplant eligible patients, that the level of MRD as a continuous variable independently predicts both PFS and OS, with approximately a one year median OS benefit per log depletion (J Clin Oncol 2013; 31:2540-7 and Blood 2015; 125:1932-5). The impact of MRD also appears to be independent of therapy received. There is more limited data on the applicability of MRD assessment in transplant ineligible patients, largely as a consequence of low rates of CR historically within this patient cohort. Patients and Methods. In this analysis we have assessed the impact of MRD on PFS amongst patients treated within the non-intensive arm of the NCRI Myeloma XI trial. Patients were randomised between thalidomide (CTDa) and lenalidomide (RCDa) based induction therapies with responding patients being subsequently randomised to maintenance with lenalidomide monotherapy, or no further therapy. Bone marrow aspirates were obtained at the end of induction and this analysis represents a subset of 297 patients (median age 74 years). MRD was assessed using flow cytometry (sensitivity 10-4) with a minimum of 500,000 cells evaluated with six-colour antibody combinations including CD138/CD38/CD45/CD19 with CD56/CD27 in all cases and CD81/CD117 in additional cases as required. Results. Overall MRD-negativity was demonstrated in 41/297 (13.8%). When considered according to induction therapy received 25/154 (16.0%) of patients randomized to RCDa were MRD-negative compared to 16/143 (10.8%) of those randomized to CTDa (p=0.24; Fisher's exact test). MRD-negativity was associated with a significant outcome advantage as the median PFS was 34 months versus 18 months for MRD-positive patients (p 〈 0.0001, HR 0.44 [95% confidence interval (CI 0.29-0.67)]). This effect was noted in both RCDa (median PFS 17m v 32m; p=0.001, HR 0.41 [95%CI 0.23-0.69] ) and CTDa (median PFS 19m v 34m; p=0.03, HR 0.49 [95%CI 0.26-0.95]). When the impact of MRD was assessed according to induction regimen the outcome of MRD-negative and MRD-positive patients was similar with both regimens (see figure). The impact of MRD was also assessed as a continuous variable across 5 logs of residual disease. Sequential improvements in outcome with each log reduction were demonstrable. Median PFS for the following disease levels; 〈 0.01%, 0.01 - 〈 0.1%, 0.1% - 〈 1%, 1% - 〈 10% and 〉 /=10% were 34, 26, 16, 14 and 9 months respectively (p 〈 0.0001). This pattern was demonstrable in both RCDa and CTDa treated patients (p 〈 0.0001 for both). Multivariate analysis confirmed the independent predictive value of MRD both as a qualitative and continuous quantitative variable (p 〈 0.0001 for both). In both instances achieving an immunofixation-negative CR was not a significant prognostic variable when included in the model with MRD. Conclusions. We would conclude that MRD is a powerful predictor of outcome in transplant ineligible patients and is a meaningful therapeutic goal in this patient group. In contrast to conventional CR it retains independent prognostic significance both as a quantitative and qualitative variable. This data further supports the role of MRD as a primary endpoint and surrogate marker for survival in future clinical trials. Figure. Figure. Disclosures Rawstron: Janssen: Research Funding; BD Biosciences: Other: Remuneration; Gilead: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Honoraria; Genzyme: Honoraria; AbbVie: Honoraria; Roche: Honoraria; Celegene: Honoraria. Pawlyn:Celgene: Consultancy, Honoraria, Other: Travel Support; Takeda Oncology: Consultancy. Davies:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Kaiser:Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Takeda: Consultancy; Bristol-Myers Squibb: Consultancy, Other: Travel support; Chugai: Consultancy. Jones:Celgene: Honoraria, Research Funding. Cook:Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Glycomimetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Jenner:Janssen: Consultancy, Honoraria, Other: Travel support, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Other: Travel support; Takeda: Consultancy, Honoraria, Other: Travel support. Drayson:Abingdon Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Jackson:MSD: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Janssen: Research Funding; Univ of AR for Medical Sciences: Employment. Owen:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Honoraria, Other: Travel support; Janssen: Consultancy, Other: Travel support.

Kurzfassung: Introduction With a multifactorial mechanism of action and excellent PFS associated with prolonged exposure, lenalidomide (len) is an attractive candidate for maintenance therapy. Len exerts its action by interaction with cereblon (CRBN) which forms a ubiquitin ligase complex with cullin-4A (CUL4), damaged DNA binding protein 1 (DDB1) and regulator of cullins 1 (ROC1). Downstream effects are mediated via Ikaros, Aiolos, MYC, IRF4, basigin (BSG) and solute carrier family 16 member 1 (SLC16A1). The impact of selective pressure on MM clonal architecture and mutational load has not been assessed. Although not a DNA damaging agent there is an apparent effect of maintenance len increasing the risk of second cancers and a suggestion that it could select for aggressive clones in high risk disease. We addressed the hypothesis that len may increase the rate of mutation at relapse by performing whole exome sequencing (WES) on 70 paired presentation/relapse samples from patients enrolled to the Myeloma XI trial (MXI), 35 of whom received maintenance Len and 35 not. Methods WES was performed to a median depth of 125x on 70 presentation/relapse pairs from patients enrolled to the MXI trial. MXI is a phase III study comparing thalidomide, len and bortezomib induction combinations and len vs observation maintenance treatment in both transplant eligible (TE) and transplant non-eligible (TNE) NDMM patients. We selected patients who had completed induction +/- ASCT and been randomised to receive maintenance therapy with len or observation. All patients had disease progression determined by IMWG criteria at the time of the relapse sample. Of the 70 patients, 30 were enrolled in the TE pathway and 40 in the TNE pathway. The median time to relapse following maintenance randomisation was 323 days (296 len vs 325 observation). 35 patients (50%) achieved a CR as their best response, 26 (37%) a VGPR and 9 (13%) a PR. The median age was 66 and 69 for those receiving len and those being observed respectively. High risk disease status was confirmed in 33 (47%) patients at presentation (≥ 1of t(4;14), t(14;16), t(14;20), +1q, -17p, -1p). Results The median number of non-silent mutations (NSM) found at presentation and relapse was 37 and 41 respectively (p=0.25). In patients receiving len maintenance the median number of NSM at presentation was 37 vs 34 at relapse (p=0.69). In those being observed the median number of NSM at presentation was 42 vs 52 at relapse (p=0.21). Mutations in genes important in myeloma pathogenesis seen in more than one patient at presentation included KRAS (16), NRAS (14), DIS3 (6), HIST1H1E (2), RB1 (2), EGR1 (2), TP53 (2) and FAM46C (2). These were seen in a total of 37 (53%) patients. One patient had both an NRAS and KRAS mutation. At relapse 7 patients lost mutations (NRAS (3), KRAS (3), DIS3 (1)) and 6 patients gained mutations (KRAS (2), NRAS (2), TP53 (1), FAM46C(1)). Paired presentation/relapse copy number (CN) data (MLPA) was available for 38 patients (54%). At relapse there was evidence of a change in CN status with 5 (13%) patients gaining CN changes associated with high risk (gain 1q (4), del 17p (1). Six patients (9%) were found to have mutations in genes associated with len action; CRBN (1), IRF4 (1), DDB1 (2), SLC16A1 (2). No mutations were found in Ikaros, Aiolos, ROC1, CUL4 or BSG. The CRBN mutation was found at relapse only, in a patient who had achieved a CR and undergone 232 days of len maintenance. The IRF4 mutation was seen at presentation and relapse in a patient who achieved CR and received 754 days of len prior to relapse. Both patients with DDB1 mutations received len induction, ASCT, achieved CR and were randomised to observation. In one patient the mutation was seen at presentation and relapse whilst in the other only at relapse. Both patients with mutations in SLC16A1 were treated with len induction and ASCT to CR. In one patient, randomised to observation the mutation was seen at both time points and they relapsed after 156 days. The other, with the mutation present at presentation only was randomised to len maintenance and relapsed after 256 days. Conclusions This is the largest study comparing the genetics of presentation/relapse myeloma in a len treated population. Overall, the number of mutations at presentation vs relapse remained stable. We show that len does not affect the mutational load at relapse but may select for mutations conferring len resistance although at present further analysis is required to confirm this. Disclosures Jones: Celgene: Honoraria, Research Funding. Pawlyn:Celgene: Consultancy, Honoraria, Other: Travel Support; Takeda Oncology: Consultancy. Cook:Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Glycomimetics: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Jenner:Amgen: Consultancy, Honoraria, Other: Travel support; Janssen: Consultancy, Honoraria, Other: Travel support, Research Funding; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel support. Drayson:Abingdon Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Davies:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Kaiser:BMS: Consultancy, Other: Travel Support; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Other: Travel Support; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Chugai: Consultancy. Jackson:Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau. Morgan:Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Janssen: Research Funding; Univ of AR for Medical Sciences: Employment.

Kurzfassung: Background: Maximising response in myeloma (MM) patients with effective induction regimens prior to autologous stem cell transplant (ASCT) improves progression-free and overall survival. Triplet regimens combining an immunomodulatory agent (IMiD) and/or proteasome inhibitor (PI) are standard of care, however a more personalised approach is achieved by sequential triplet combinations based on an individual's response. Alternatively, quadruplet regimens may be more effective and new generation PIs such as carfilzomib, with less off-target activity, provide the opportunity to investigate this whilst minimising the risk of increased toxicity. The UK NCRI Myeloma XI trial is a large, phase III study aiming to answer these questions in transplant eligible (TE) patients comparing the quadruplet carfilzomib, cyclophosphamide, lenalidomide and dexamethasone to the sequential strategy of triplet IMiD combinations (with thalidomide or lenalidomide) followed by additional PI triplet therapy for those with a suboptimal response ( 〈 VGPR) prior to ASCT. Methods: In 2013, the TE pathway was amended to include KCRD: carfilzomib 36mg/m2 IV d1-2,8-9,15-16 (20mg/m2 #1d1-2), cyclophosphamide (cyclo) 500mg PO d1,8, lenalidomide (len) 25mg PO d1-21, dexamethasone (dex) 40mg PO d1-4,8-9,15-16). Patients are randomised to this up-front quadruplet or the sequential strategy of CRD: cyclo 500mg PO d1,8, len 25mg PO d1-21 PO daily, dex 40mg PO d1-4, 12-15 or CTD: cyclo 500mg PO d1,8,15 thalidomide 100-200mg PO daily, dex 40mg PO d1-4,12-15 given to max. response - patients with VGPR/CR proceed straight to ASCT, PR/MR are randomised to sequential CVD: cyclo 500mg d1,8,15, bortezomib 1.3mg/m2 IV/SC d1,4,8,11, dex 20mg PO d1,2,4,5,8,9,11,12 or nothing and SD/PD all receive sequential CVD. All treatments are given to max. response prior to ASCT, after which there is a maintenance randomisation. Patients: 1512 patients entered the TE pathway prior to amendment (756 CRD, 756 CTD). Of these, 201 patients with a suboptimal initial response went on to receive CVD, 142 following randomisation (initial response PR/MR) and 59 with NC/PD. 788 (of target n=1036) patients have been randomised post-amendment to date (394 KCRD, 197 CRD, 197 CTD). Results: TE patients receiving treatment prior to the amendment had response rates ≥VGPR: CRD 58% vs CTD 52%. For patients receiving the sequential triplet CVD due to a suboptimal response this was upgraded to ≥VGPR in 49% of those with initial MR/PR, 27% with NC/PD. This suggests the overall ≥VGPR rate to this treatment approach prior to ASCT would be approx. 75%. This now needs to be compared to the alternative approach of an upfront quadruplet. Comparing patients contemporaneously randomised to initial induction the patients receiving KCRD have completed a median 4 cycles (range 1-7), CRD 5 (range 1-10) and CTD 6 (range 1-9). Dose modifications have been required in 62% of patients receiving KCRD (56% to carfilzomib, 42% to lenalidomide) 44% CRD (40% to lenalidomide) and 65% CTD (59% to thalidomide). Data for study drug related toxicity in patients who have completed at least one cycle of initial induction are shown in table 1. Serious adverse events suspected to be due to trial medications have occurred in 37% on KCRD, 32% CRD and 35% CTD. Updated toxicity and preliminary response analysis on 23/09/15 will be presented at the meeting. This will include a response comparison at the end of initial induction regimen i.e. KCRD vs CRD vs CTD for an anticipated 700 contemporaneous patients who will have completed treatment. Updated response to the sequencing approach (with 250 patients having received sequential CVD) will also be presented and compared. Conclusions: In our study KCRD, an outpatient delivered 4-drug regimen combining second generation IMiD and PI drugs, is well-tolerated in TE NDMM patients, comparable to 3-drug regimens. Data will be presented at the meeting to compare the response rates achieved with the different regimens and treatment approaches. On behalf of the NCRI Haemato-oncology CSG Table 1. Comparative toxicities KCRD n=261 CRD n=143 CTD n=142 % (no. of patients) Peripheral neuropathy Sensory Gr II-IV 1.9 (5) 1.4 (2) 8.5 (12) Motor Gr II-IV 3.1 (8) 1 (1) 5.6 (8) VTE all grades 4.2 (11) 4.9 (7) 5.6 (8) Anaemia Gr III-IV 9.2 (24) 4.2 (6) 5.6 (8) Neutropenia Gr III-IV 14.9 (39) 16.1 (22) 13.3 (19) Thrombocytopenia Gr III-IV 8.4 (22) 1.4 (2) 1.4 (2) Infusion reaction Gr III-IV 0.4 (1) - - Disclosures Pawlyn: Celgene: Honoraria, Other: Travel support; The Institute of Cancer Research: Employment. Off Label Use: Carfilzomib as induction treatment for myeloma Lenalidomide and vorinostat as maintenance treatments for myeloma. Davies:University of Arkansas for Medical Sciences: Employment; Celgene: Honoraria; Onyx-Amgen: Honoraria; Takeda-Milenium: Honoraria. Jones:Celgene: Other: Travel support, Research Funding. Kaiser:Janssen: Honoraria; Chugai: Consultancy; Amgen: Consultancy, Honoraria; BristolMyerSquibb: Consultancy; Celgene: Consultancy, Honoraria, Research Funding. Jenner:Takeda: Honoraria; Amgen: Honoraria. Cook:Jazz Pharma: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Chugai: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Russell:Therakos: Other: shares. Owen:Celgene: Honoraria, Research Funding; Janssen: Honoraria. Gregory:Janssen: Honoraria; Celgene: Honoraria. Jackson:Celgene: Honoraria; Amgen: Honoraria; Takeda: Honoraria. Morgan:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda-Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; CancerNet: Honoraria; Weisman Institute: Honoraria; MMRF: Honoraria; MMRF: Honoraria; University of Arkansas for Medical Sciences: Employment; Weisman Institute: Honoraria; CancerNet: Honoraria.

Kurzfassung: Introduction Hyperdiploidy (HRD) comprises the largest pathogenetic subgroup of myeloma. However, its clinical and molecular characterisation is incomplete. Here, we investigate HRD using a novel high-throughput molecular analysis method (MyMaP - Myeloma MLPA and translocation PCR; Kaiser MF et al., Leukemia 2013; Boyle EM et al., Gen Chrom Canc 2015) in a large cohort of 1,036 patients from the UK NCRI Myeloma XI trial. Materials, Methods and Patients Copy number changes, including gain of chromosomes 5, 9 and 15, as well as translocation status were assayed for 1,036 patients enrolled in the UK NCRI Myeloma XI (NCT01554852) trial using CD138+ selected bone marrow myeloma cells taken at diagnosis. HRD was defined by triploidy of at least 2 of analysed chromosomes 5, 9 or 15. Analysis was performed on standard laboratory equipment with MyMaP, a combination of TC-classification based multiplex qRT-PCR and multiplex ligation-dependent probe amplification (MLPA; MRC Holland). The parallel assessment of multiple loci with copy number alteration (CNA) by MLPA allowed unbiased association studies using a Bayesian approach. Semi-quantitative gene expression data for CCND1 and CCND2 was generated as part of the multiplexed qRT-PCR analysis. Median follow up for the analysis was 24 months. Results Of the 1,036 analysed patients, 475 (46%) were HRD. Of these, 325 (68%) had gain(11q25), 141 (29.7%) gain(1q), 43 (9.1%) del(1p32) and 36 (7.5%) del(17p). Gain(11q25) was significantly associated with HRD (Bayes Factor BF01 〈 0.05) in the entire group of 1,036 cases and occurred in only 17% of non-HRD cases, but frequencies of the other copy number alterations (CNA) were similar to entire group. Although gain(1q) was negatively correlated with gain(11q25) within the HRD group (Corr-0.21, BF=0.0004), the two lesions co-occurred in 73 (15.4%) cases. Analysis of other CNA revealed that del(13q) was significantly less frequent (25%) in HRD cases than in non-HRD (56%) cases (BF 〈 0.0001). Interestingly, del(13q) within HRD was highly associated with gain(1q) (BF 〈 0.0001) and negatively correlated with gain(11q25) (BF 〈 0.0001). Thus, CNA status can help discriminate three distinct molecular subgroups of HRD: gain(11q25), gain(11q25)+gain(1q), gain(1q)[+/-del(13q)]. HRD cases were classified as D1, D2 or D1+D2 according to the TC classification based on qPCR CCND1 and CCND2 expression values and expression was correlated with copy number status. An association of the D1 subtype with gain(11q25) and of D2 with gain(1q) was confirmed. CCND1 expression was significantly (P 〈 0.001) higher in cases with gain(11q) [Mean Relative Quantitative (RQ) value 5,466] than in cases with gain(1q) [Mean RQ value 721] . In contrast, CCND2 expression values were significantly higher in cases with gain(1q) [Mean RQ 8,723] than in cases with gain(11q) [mean RQ 1,087] (P 〈 0.001). Co-occurrence of gain(11q) and gain(1q) was associated with intermediate values with CCND1 mean RQ 5,090 and CCND2 mean RQ 2,776, reminiscent of the D1+D2 subtype. HRD was associated with favourable outcome when compared to non-HRD cases with median PFS 28.8 vs. 21.7 months (P 〈 0.0001) and 24-months OS of 83% vs. 77% (median not reached), respectively. However, cases with t(11;14) had a median PFS of 27.0 months and 24-month OS of 80%, combarable to outcome of the HRD group. Within HRD cases, gain(1q) was associated with shorter PFS (P =0.02) and OS (P =0.009), associating the D2 group with inferior outcome. Presence of del(1p32) was associated with inferior PFS (P =0.01) and OS (P =0.0007) in the HRD subgroup and del(17p) was associated with inferior OS (P =0.04) with a trend for PFS. HRD cases with presence of any of the risk factors gain(1q), del(1p32) or del(17p) in comparison to those without had a median PFS of 25.1 vs 35.1 months (P =0.0001) and 24-month OS of 73.8% vs 89.0% (P 〈 0.0001). Conclusion We describe in a large trial cohort an association between gain(11q25) and the D1 hyperdiploid subtype as well as gain(1q) and the D2 subtype, a finding that has so far only been inferred by gene expression array data in the original TC classification. We also find an association with adverse outcome for the D2/gain(1q) subtype. Our findings demonstrate that the novel molecular approach MyMaP allows precise molecular sub-classification of HRD myeloma. Disclosures Kaiser: BristolMyerSquibb: Consultancy; Chugai: Consultancy; Janssen: Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Pawlyn:Celgene: Honoraria, Other: Travel support; The Institute of Cancer Research: Employment. Jones:Celgene: Other: Travel support, Research Funding. Savola:MRC Holland: Employment. Owen:Celgene: Honoraria, Research Funding; Janssen: Honoraria. Cook:Takeda Oncology: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; BMS: Consultancy; Celgene: Consultancy, Research Funding, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau. Gregory:Janssen: Honoraria; Celgene: Honoraria. Davies:Onyx-Amgen: Honoraria; Celgene: Honoraria; University of Arkansas for Medical Sciences: Employment; Takeda-Milenium: Honoraria. Jackson:Amgen: Honoraria; Takeda: Honoraria; Celgene: Honoraria. Morgan:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Weisman Institute: Honoraria; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda-Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; University of Arkansas for Medical Sciences: Employment; CancerNet: Honoraria; MMRF: Honoraria.

Kurzfassung: Background Primary refractory myeloma is an important therapeutic challenge; understanding its clinical course and biology is essential if we are to recognize it early and target it therapeutically. Immunomodulatory (IMiD) drugs are widely used as induction therapy with good response rates but a small proportion of patients are refractory. The mechanism underlying IMiD resistance is poorly defined. Mutations in the cereblon pathway are a clear candidate but have not been widely looked for or reported. An important question is whether the primary refractory clone carries class-specific intrinsic resistance biology, leaving it sensitive to other non-cross reactive drugs, or if it is a universal resistance mechanism. We have examined the clinical course of patients with primary IMiD resistance, and whether they respond adequately to subsequent proteasome inhibition (PI), using the results of the largest clinical study in myeloma to date. Methods Myeloma XI is a UK based, open-label, parallel group, randomized controlled trial for newly diagnosed symptomatic myeloma patients of all ages. Treatment was with a combination of cyclophosphamide and dexamethasone plus either lenalidomide or thalidomide (CRD or CTD) for a minimum of 4 cycles (transplant eligible, TE) or 6 cycles (transplant non-eligible, TNE) or to maximum response. Those patients who had not achieved at least a minimal response or who had progressed during induction (PD) subsequently received a PI triplet (cyclophosphamide, bortezomib and dexamethasone, CVD). This abstract summarizes a preliminary analysis of these primary refractory cases, final data will be presented at the meeting. Results The study randomized 3894 patients of all ages giving adequate numbers to identify clinical/biological features in subgroups. Overall 207/3894 (5.3%) of patients had stable disease (SD) or PD at the end of the IMiD triplet. There was no significant difference between those who received thalidomide compared to lenalidomide (CTD: 110/1945, 5.7% CRD: 97/1949, 5.0%). A higher proportion of patients were refractory in the TNE pathway than TE (TE: 79/2042, 3.9%, TNE: 128/1852, 6.9%) 139 patients in the ITT population went on to receive treatment with bortezomib as part of the CVD regimen. The remainder n=69 were treated off protocol or died prior to treatment. CVD was well-tolerated in these patients with a median of 4 (1-8) cycles delivered. Of these patients 22/139 (16%) were also refractory to PI therapy whilst 57% upgraded their response compared to baseline: 32% [95%CI 24-40] to PR/MR and 25% [95%CI 18-33] to CR/VGPR. Patients with IMiD refractory disease had a significantly shorter PFS than those who responded to initial treatment median 8 vs 27 months, HR 2.10 [95% CI 1.77-2.49], p 〈 0.001. For those who received subsequent CVD (n=139) and responded the median PFS was 19 months vs 7 months for double refractory patients. 32/50 transplant eligible patients who responded to CVD were able to go on and receive a transplant and had a PFS of 27 months. We compared the clinical and biological features of the double-refractory (n=22), IMiD refractory (n=185) and responsive (n=3349) patient groups. There was no significant difference in patient sex or median age (66 [range 41-78], 70 [38-88] and 67 [28-92] respectively). Laboratory measures suggested refractory patients had a higher burden of disease at diagnosis with a lower hemoglobin level and a higher proportion of patients with 〉 20% plasma cells in their bone marrow biopsy. There was a higher proportion of patients with light chain only disease and the percentage of patients with ISS stage III was double-refractory 41%, IMiD refractory 45% and responsive 29%. The proportions of patients with adverse translocations and high-risk copy number abnormalities will be presented at the meeting. Conclusions We present the first detailed analysis of IMiD refractory myeloma patients at diagnosis. There was no difference in the percentage of patients refractory to the different IMiDs thalidomide and lenalidomide. Very few patients were primarily refractory to both IMiDs and proteasome inhibitors, suggesting the mechanisms of primary resistance to IMiDs and PIs do not significantly overlap. However, where this did occur outcomes were poor. The biological mechanisms behind resistance will be further informed by molecular studies of these patients' tumour samples. On behalf of the NCRI Haem Onc CSG Disclosures Pawlyn: Takeda Oncology: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel Support. Davies:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Kaiser:Takeda: Consultancy, Other: Travel Support; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS: Consultancy, Other: Travel Support; Celgene: Consultancy, Honoraria, Research Funding; Chugai: Consultancy. Jones:Celgene: Honoraria, Research Funding. Kishore:celgene: Other: travel grant. Garg:Janssen: Other: Travel support, Research Funding, Speakers Bureau; Takeda: Other: Travel support; Novartis: Other: Travel support, Research Funding. Williams:Novartis: Honoraria; Janssen: Honoraria, Other: Travel support, Speakers Bureau; Celgene: Honoraria, Other: Travel support, Speakers Bureau; Takeda: Honoraria, Other: Travel support, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Karunanithi:Celgene: Other: Travel support, Research Funding; Janssen: Other: Travel support, Research Funding. Lindsay:BMS: Consultancy, Other: Travel support; Novartis: Other: Travel support; Takeda: Other: Travel support; Janssen: Consultancy; Celgene: Honoraria, Other: Travel support. Jenner:Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Other: Travel support; Novartis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel support, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel support. Cook:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Glycomimetics: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria. Drayson:Abingdon Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Owen:Takeda: Honoraria, Other: Travel support; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Other: Travel support. Jackson:Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau. Morgan:Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria; Univ of AR for Medical Sciences: Employment; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding.

Kurzfassung: Introduction Epigenetic dysregulation is a hallmark of cancer and has significant impact on disease biology. The epigenetic structure of myeloma is heterogeneous and we previously demonstrated that gene specific DNA methylation changes are associated with outcome, using low-resolution arrays. We now performed a high-resolution genome wide DNA methylation analysis of a larger group of patients from a UK national phase III study to further define the role of epigenetic modifications in disease behaviour and outcome. Patients and Methods Highly purified ( 〉 95%) CD138+ myeloma bone marrow cells from 465 newly diagnosed patients enrolled in the UK NCRI Myeloma XI study were analysed. The extracted DNA was bisulfite-converted using the EZ DNA methylation kit (Zymo) and hybridized to Infinium HumanMethylation450 BeadChip arrays. Raw data was processed using the R Bioconductor package "minfi". SNP containing probes and probes on the sex chromosomes were removed. 464 samples and 441293 probes were retained following inspection of quality control metrics. Beta values were summarized across functional genomic units or differentially methylated regions (DMRs) that included: gene bodies, promoters, insulators, CpG-islands and enhancers. K-means was applied to each DMR to cluster patients into 2 groups (high or low methylation) per region. Filters were applied to define a clinically meaningful minimum group size and methylation differences between the groups. Overall survival (OS) and progression free survival (PFS) were assessed by a Cox proportional hazards regression model fitted to each DMR with a time-dependent covariate of the trial pathway. Pathway analyses were performed using GREAT (Stanford University) and GSEA (Broad Institute). Results We identified 589 differentially methylated regions that were significantly associated with PFS and OS when using a cut-off of P 〈 0.01 (log-rank). Of these, 114 DMRs were located within 10kb of a gene transcription start site (TSS). Among these, several genes implicated in myeloma disease biology, such as immune cell-cell interaction genes (e.g. CD226) or stemness-associated transcription factors (e.g. PAX4) were identified to be differentially methylated. Using pathway analysis on all 589 DMRs, Gene Ontology biologic groups were enriched for positive regulation of proliferation, cell migration and cytoskeleton organisation (FDR P 〈 0.05). This was further supported by enrichment of proliferative E2F1 transcription factor target structures (FDR P 〈 0.05). Matched gene expression profiles have been generated and integrated analyses correlating epigenetic with GEP and genetic risk data and individual gene level methylation-expression associations will be presented at the meeting. This data is also being integrated with drug resistance profiles from the Cancer Cell Line Encyclopedia (CCLE; Barretina, et al, 2016). Conclusion Epigenetic mechanisms play a significant role in influencing tumour cell behaviour. We have identified here differentially methylated regions that are significantly associated with patient outcome. Pathway analyses suggest an epigenetic regulation of biologic mechanisms involved in high risk disease, such as proliferation and migration. Integration of epigenetic data with matched gene expression profiles is currently ongoing to delineate independent epigenetic biomarkers associated with high risk disease behaviour. Disclosures Jones: Celgene: Honoraria, Research Funding. Pawlyn:Takeda Oncology: Consultancy; Celgene: Consultancy, Honoraria, Other: Travel Support. Jenner:Janssen: Consultancy, Honoraria, Other: Travel support, Research Funding; Novartis: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Other: Travel support; Takeda: Consultancy, Honoraria, Other: Travel support; Celgene: Consultancy, Honoraria, Research Funding. Cook:Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Glycomimetics: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Drayson:Abingdon Health: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Davies:Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Morgan:Univ of AR for Medical Sciences: Employment; Janssen: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Bristol Meyers: Consultancy, Honoraria. Jackson:MSD: Consultancy, Honoraria, Speakers Bureau; Celgene: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau; Roche: Consultancy, Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Travel support, Research Funding, Speakers Bureau. Kaiser:Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Other: Travel Support; BMS: Consultancy, Other: Travel Support; Chugai: Consultancy.