Abstract: Multiple myeloma (MM) shows constitutive activation of canonical and noncanonical nuclear factor κB (NF-κB) signaling via genetic mutations or tumor microenvironment (TME) stimulations. A subset of MM cell lines showed dependency for cell growth and survival on the canonical NF-κB transcription factor RELA alone, suggesting a critical role for a RELA-mediated biological program in MM pathogenesis. Here, we determined the RELA-dependent transcriptional program in MM cell lines and found the expression of the cell surface molecules interleukin-27 receptor-α (IL-27Rα) and the adhesion molecule JAM2 to be responsive to RELA at the messenger RNA and protein levels. IL-27Rα and JAM2 were expressed on primary MM cells at higher levels than on healthy long-lived plasma cells (PCs) in the bone marrow. IL-27 activated STAT1, and to a lesser extent STAT3, in MM cell lines and in PCs generated from memory B cells in an IL-21–dependent in vitro PC differentiation assay. Concomitant activity of IL-21 and IL-27 enhanced differentiation into PCs and increased the cell-surface expression of the known STAT target gene CD38. In accordance, a subset of MM cell lines and primary MM cells cultured with IL-27 upregulated CD38 cell-surface expression, a finding with potential implications for enhancing the efficacy of CD38-directed monoclonal antibody therapies by increasing CD38 expression on tumor cells. The elevated expression of IL-27Rα and JAM2 on MM cells compared with that on healthy PCs may be exploited for the development of targeted therapeutic strategies that modulate the interaction of MM cells with the TME.

Abstract: Background The most common cause of severe renal impairment in myeloma (MM) is the direct effect of a high concentration of nephrotoxic monoclonal free light chains (LC) leading to MM cast nephropathy. Decreasing LC and therefore improving renal function is important for long term outcome. In the UK NCRI Myeloma XI trial the addition of the second generation PI carfilzomib (K) to the immunomodulatory agent (IMiD) lenalidomide, cyclophosphamide and dexamethasone (Rdc) improved progression-free survival (PFS) in newly diagnosed MM patients (NDMM) eligible for autologous stem cell transplant (ASCT) (median PFS KRdc not reached (NR) v Rdc 36 months HR 0.66 (95% CI 0.52, 0.83, P=0.0004). This exploratory subgroup analysis compares PFS and renal recovery between patients receiving KRdc and Rdc within renal function subgroups. Methods Myeloma XI is a phase III, randomized controlled trial with an adaptive design for symptomatic NDMM patients of all ages. This renal analysis is of the transplant eligible (TE) pathway and compares induction treatment with the quadruplet KRdc to triplet Rdc. Patients were randomized contemporaneously 2:1. All patients were randomized to post-ASCT R maintenance or observation. For further exploratory analysis patients randomized earlier in the study to Rdc were also included. Relevant exclusion criteria were acute renal failure non-responsive to 72 hours rehydration (creatinine & gt;500umol/L, urine output & lt;400ml/day or dialysis). The Modification of Diet in Renal Disease formula was used to calculate the baseline estimated glomerular filtration rate (eGFR). Renal function was normal, eGFR & gt;=60 ml/min/1.73m2, moderately impaired 30-59 or severely impaired & lt;30. Potentially nephrotoxic LC were considered those with a difference of & gt;=500mg/L between the involved and uninvolved (dFLC). Renal recovery was defined as an improvement in eGFR of ≥25% at the end of induction therapy. Results 1547 patients were randomized to KRdc n=526 or Rdc n=1021 (265 contemporaneous, 756 not). In the contemporaneous group baseline renal function was normal in 609/791 (77.0%), moderately impaired in 141/791 (17.8%) and severely impaired in 40/791 (5.1%) (data n/a in 1 patient). Patients with moderately or severely impaired renal function had shorter PFS compared to those with normal renal function. Subgroup analysis showed consistent outcomes for KRdc compared to Rdc across all renal subgroups with no evidence of significant heterogeneity (Figure 1, Phet=0.9354). Further exploratory analysis combined patients with moderate or severe renal impairment into one group. Difference in PFS and renal recovery between patients with normal or impaired renal function and high ( & gt;=500) or low ( & lt;500) dFLC were examined. Consistent with the findings in the contemporaneous group, KRdc was associated with a significant improvement in PFS compared to Rdc in both the normal and renal function impaired groups. Within the group of patients with normal renal function at baseline those with high dFLC had shorter PFS than those with low dFLC. KRdc was associated with improved PFS irrespective of LC level: high dFLC KRdc median PFS NR (95% CI 39, NR) v Rdc 34 months (30, 39) and low dFLC KRdc NR (44, NR) v Rdc 41 (37, 47). In the group of patients with renal impairment at baseline KRdc was also associated with an improved PFS irrespective of LC level: high dFLC KRdc median PFS NR (95% CI 29, NR) v Rdc 32 months (28, 42) and low dFLC KRdc 37 (25, NR) v Rdc 27 (24, 33). In contrast to those with normal renal function, however, patients with renal impairment and high dFLC had a longer PFS than those with low dFLC. This observation was apparent whether patients received KRdc or Rdc and suggests that patients with high dFLC may have had reversible renal impairment, improving their ultimate outcomes. Supporting this hypothesis, measurable renal recovery in the renal impaired group at the end of induction was more common in patients with high dFLC (dFLC & gt;=500 68.6% v dFLC & lt;500 53.2%). Interestingly the rate of renal recovery was similar between KRdc and Rdc in the high dFLC group (KRdc 71.1% v Rdc 67.5%) suggesting the improved PFS seen with KRdc in the group with renal impairment is not due to an increased rate of renal recovery. Conclusions KRdc was associated with improved PFS compared to Rdc in NDMM patients across all renal subgroups. Irrespective of treatment, renal function is more likely to improve if attributable to nephrotoxic LC. Disclosures Pawlyn: Janssen: Honoraria, Other: Travel expenses; Celgene: Consultancy, Honoraria, Other: Travel expenses; Amgen: Consultancy, Other: Travel expenses; Takeda: Consultancy, Other: Travel expenses. Menzies:Celgene, Amgen, Merck: Research Funding. Davies:Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotech: Honoraria; Celgene/BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Cook:Celgene, Janssen, Takeda: Research Funding; Amgen, Bristol-Myers Squibb, Celgene, Janssen, Takeda, Roche, Sanofi: Honoraria; Karyopharm: Honoraria. Gregory:Celgene, Amgen, Merck: Research Funding; Janssen: Honoraria; Celgene: Consultancy. Jenner:Amgen, Janssen, Celgene, Takeda, Novartis, Sanofi, GSK: Consultancy; Janssen, Takeda, Amgen, Celgene, Novartis: Honoraria; Janssen, Celgene: Research Funding; Janssen, Takeda, Amgen: Other: Travel expenses. Jones:Celgene: Honoraria, Research Funding. Kaiser:Bristol-Myers Squibb/Celgene, Janssen, Karyopharm: Research Funding; Bristol-Myers Squibb, Chugai, Janssen, Amgen, Takeda, Celgene, AbbVie, Karyopharm, GlaxoSmithKline: Consultancy; Janssen, Amgen, Celgene, Bristol-Myers Squibb, Takeda: Honoraria; Bristol-Myers Squibb, Takeda: Other: Travel expenses. Owen:Takeda: Honoraria, Other: Travel expenses; Janssen: Consultancy, Other: Travel expenses; Celgene: Consultancy, Honoraria, Research Funding. Morgan:Karyopharm: Consultancy, Honoraria; Janssen: Research Funding; GSK: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Jackson:Takeda: Honoraria, Research Funding, Speakers Bureau; Gsk: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau. Cairns:Celgene, Amgen, Merck: Research Funding; Celgene: Other: Travel Support. OffLabel Disclosure: Carfilzomib, lenalidomide, dexamethasone and cyclophosphamide combination induction therapy for newly diagnosed myeloma

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Background: The impact of the selective pressure of maintenance Lenalidomide has the potential to enhance disease aggressiveness at relapse and if this were the case would shorten the time to next therapy. Previously we have shown that Lenalidomide maintenance therapy in myeloma is associated with improved progression-free survival (PFS). This initial analysis defined PFS as the time to biochemical progression but at that time point not all patients will go on to second line treatment, with the time to treatment being variable dependent on the aggressiveness of disease behavior at relapse. We have used time to next treatment as a marker of the impact of maintenance on disease behavior by analyzing long-term follow-up data from 1971 patients in the Myeloma XI trial. Methods: Myeloma XI is a phase III trial with pathways for transplant eligible (TE) and transplant ineligible (TNE) newly diagnosed myeloma patients who, after immunomodulatory agent-based induction therapy +/- autologous stem cell transplant, were randomized between lenalidomide maintenance (Len, 10mg 21/28 days) or observation (Obs). Maintenance Len ceased at the time of biochemical progression; neither the timing of commencement, nor agents used for second line therapy were mandated in the protocol. Taking advantage of the large sample size and median 50 months of follow-up we present updated PFS data, time to next treatment (TTNT) and an exploratory analysis to compare an estimate of the aggressiveness of relapse. We included all patients who progressed on trial excluding that defined by death. From the time of biochemical progression we compared the time to the start of next line of therapy between those patients who had received Len vs observation defining this as Time to Clinical Relapse (TCR). Hazard ratios (HR) were adjusted for induction/consolidation treatment and pathway. Results: Len was associated with a significant improvement in PFS compared to Obs. The median PFS was 41 months [95% CI 38,45] for those allocated to Len and 21 [19,23] for Obs (HR 0.50 [0.44,0.56], P 〈 0.01). This was consistent in both the TE (median PFS Len 64 [54,76] vs Obs 32 [28,36] , HR 0.52 [0.45,0.61] P 〈 0.01) and TNE (median PFS Len 26 [22,31] vs Obs 11 [9,13] , HR 0.47 [0.40,0.55] P 〈 0.01) pathways. TTNT was also significantly longer with Len compared to Obs. The median TTNT was 52 months [95% CI 46,60] for those allocated to Len and 28 [26,32] for Obs (HR 0.55 [0.49, 0.62] P 〈 0.01). This was consistent in both the TE (median TTNT Len 72 [64,NR] vs Obs 43 [38,49] , HR 0.59 [0.49,0.70] P 〈 0.01) and TNE (median TTNT Len 33 [28,38] vs Obs 17 [15,20] , HR 0.51 [0.43,0.60] P 〈 0.01) pathways. At the time of analysis 569 patients had progressed on trial without progression defined by death. Of these 254 (148 TE, 106 TNE) were receiving Len and 315 (189 TE, 126 TNE) Obs. 422 (74.2%) had received a subsequent line of therapy or had died following progression. The most common second line therapy was a bortezomib containing regimen (45.6%). Overall the median TCR was 7.6 months [95%CI 6.4, 8.5]. There was no difference in TCR between patients receiving Len (median 6.3 months [95% CI 5.0, 8.1] ) and Obs (8.1 months [7.0, 9.7]), HR 1.06 [0.87, 1.29] . This was consistent for both the TE and TNE pathways. Conclusions: We found no difference in the aggressiveness of relapse dependent upon whether patients received Lenalidomide maintenance or observation, using long term follow-up data and an exploratory analysis of time to clinical relapse. This is consistent with our data showing an absence of a significant change in mutational landscape between the groups. Further, the data are consistent with results of meta-analyses showing improved PFS and OS providing further support for the use of maintenance strategies with IMiD drugs. on behalf of the NCRI Haematological Oncology Clinical Studies Group Disclosures Pawlyn: Amgen, Celgene, Takeda: Consultancy; Amgen, Celgene, Janssen, Oncopeptides: Honoraria; Amgen, Janssen, Celgene, Takeda: Other: Travel expenses. Davies:Amgen, Celgene, Janssen, Oncopeptides, Roche, Takeda: Membership on an entity's Board of Directors or advisory committees, Other: Consultant/Advisor; Janssen, Celgene: Other: Research Grant, Research Funding. Royle:Celgene, Amgen, Merck, Takeda: Other: Research Funding to Institution. Cairns:Celgene, Amgen, Merck, Takeda: Other: Research Funding to Institution. Cook:Amgen, Bristol-Myers Squib, GlycoMimetics, Seattle Genetics, Sanofi: Honoraria; Celgene, Janssen-Cilag, Takeda: Honoraria, Research Funding; Janssen, Takeda, Sanofi, Karyopharm, Celgene: Consultancy, Honoraria, Speakers Bureau. Drayson:Abingdon Health: Consultancy, Equity Ownership. Gregory:Amgen, Merck: Research Funding; Celgene: Consultancy, Research Funding; Abbvie, Janssen: Honoraria. Jenner:Abbvie, Amgen, Celgene, Novartis, Janssen, Sanofi Genzyme, Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Jones:Celgene: Honoraria, Research Funding. Kaiser:Celgene, Janssen: Research Funding; Abbvie, Celgene, Takeda, Janssen, Amgen, Abbvie, Karyopharm: Consultancy; Takeda, Janssen, Celgene, Amgen: Honoraria, Other: Travel Expenses. Owen:Celgene, Janssen: Honoraria; Celgene: Research Funding; Janssen: Other: Travel expenses; Celgene, Janssen: Consultancy. Russell:Astellas: Consultancy, Honoraria, Speakers Bureau; Jazz: Consultancy, Honoraria, Speakers Bureau; Pfizer Inc: Consultancy, Honoraria, Speakers Bureau; DSI: Consultancy, Honoraria, Speakers Bureau. Morgan:Celgene Corporation, Janssen: Research Funding; Bristol-Myers Squibb, Celgene Corporation, Takeda: Consultancy, Honoraria; Amgen, Janssen, Takeda, Celgene Corporation: Other: Travel expenses. Jackson:Celgene, Amgen, Roche, Janssen, Sanofi: Honoraria. OffLabel Disclosure: Lenalidomide for myeloma as maintenance therapy 10mg 21/28 days

Abstract: 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.