ALBERT

Description: Introduction: Stratification of multiple myeloma patient responses by reductions in monoclonal component is based upon reliable, historic outcome data. With the introduction of novel agents, a greater number of patients are achieving hitherto unthought-of responses, with many expecting to meet the requirement for VGPR or greater. Multiple factors can impact the quantification and assessment of response in patients achieving deep responses including the influence of IgG recycling, accuracy of quantitation against an increasing polyclonal background and the presence of monoclonal immunotherapies. Alternative strategies for monoclonal protein measurement include heavy+light chain (HLC) immunoassays. Here for the first time we compare the consistency of response assignment between the two methods and evaluate the clinical impact of discordance. Methods: Sera from 509 newly diagnosed intact immunoglobulin multiple myeloma (IIMM) patients enrolled onto IFM-2009 trial were available (median age was 59 (range: 33-66) years, follow-up 30 (3-56) months). Two patients arms were treated with RVDx3+ASCT+RVDx2 or RVDx8, followed by 12 months Lenalidomide maintenance. Responses were assigned at the end of consolidation therapy according to IMWG criteria using changes in monoclonal protein concentrations measured by either SPE or dHLC (clonal - non clonal). Complete response (CR) was assigned by either method by the absence of monoclonal protein on IFE or a normal HLC ratio (HLCr), respectively, and

Description: Background : Free Light Chain (FLC) escape has been described for the first time in 1971 by Hobbs, who reported biochemical relapses of multiple myeloma (MM) with only Bence Jones proteinuria, in patients followed for an intact monoclonal immunoglobulin (Ig) MM. Indeed, FLC escape is defined as an increase of FLC without corresponding increase of the intact monoclonal Ig. In the era of novel-agent based therapy and autologous stem cell transplantation (ASCT), the patterns of disease progression may change, including a potential increased rate of FLC escape. Brioli and al (Blood 2014;123(22):3414-9) reported that 10% of the cases at relapse presented with FLC escape, and that FLC evaluation at relapse could represent an interesting marker of impact from intraclonal heterogeneity on myeloma outcome. We analysed the relapse patterns of patients treated according to the IFM 2009 clinical trial. Methods: Patients treated according to the IFM 2009 clinical trial (Lenalidomide bortezomib dexamethasone RVD + / - ASCT, Attal and al, ASH 2015) were analyzed. In patients presenting with an intact monoclonal Ig at diagnosis, serum and urine electrophoresis + FLC were compared in a central lab at the time of diagnosis and at the time of progression, in order to identify FLC escape. Results: 700 patients with symptomatic de novo MM were enrolled in the IFM DFCI 2009 clinical trial. Among them, 318 had a progressive disease, assessed with a centralized biochemistry analysis and 267 patients of them with an intact monoclonal Ig were included in this study. A vast majority (250 patients, 94%) showed an increase of the initial serum monoclonal component up to 5 g/L or up to 25% from the NADIR (IMWG criteria for progressive disease). 8 patients progressed with new bone lesions or plasmocytoma (3%) without any biological markers of progressive disease... Finally, 9 patients (3%) were identified as FLC escape as they did not exhibit an increased intact monoclonal Ig but they had an increased serum FLC and/or an increased Bence Jones proteinuria. Three of them had a serum and urinary measurable disease on diagnosis and they relapsed with both an increase of FLC and an increase of Bence Jones proteinuria. The six other patients presented at diagnosis only with an urinary measurable disease: 3 of them relapsed with an increase of FLC, without any Bence Jones proteinuria, the three others relapsed both on FLC and urines. Isotype of monoclonal component was IgG (6 patients), IgA (2) or IgD (1); light chain was Kappa for 6 patients and Lambda for the three others. Four patients were treated with RVD alone, and 5 patients with RVD + ASCT. The relapse occurred in a median of 2 years after diagnosis (5 months - 3.5 years). Conclusion: Based on a very large study of patients treated into a phase 3 clinical trial with centralized assessment of response and relapse, we are showing that FLC escape in a very rare phenomenom, observed in 3% of the cases. The low frequency of FLC escape does not lead to a systematic monitoring of intact Ig MM by FLC. Disclosures Attal: amgen: Consultancy, Research Funding; celgene: Consultancy, Research Funding; janssen: Consultancy, Research Funding; sanofi: Consultancy. Avet-Loiseau:sanofi: Consultancy; janssen: Consultancy; amgen: Consultancy; celgene: Consultancy. Moreau:Takeda: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria, Speakers Bureau; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria.

Description: INTRODUCTION: Multiple myeloma (MM) is a biologically and clinically heterogeneous disease. Different recurrent driver genomic events have been reported, but to date no unifying feature has been identified in MM evolution. The recent interest in signatures of mutational processes through analysis of whole-exome sequencing data has led to initial insights into what generates MM mutational repertoire (Bolli et al, Nat Com 2014). Here, taking advantage of the increased power provided by whole genome sequencing (WGS), we analyzed 22 paired samples from 11 patients first at the smoldering (SMM)/MGUS stage and subsequently at the time of progression to symptomatic MM to gain a deeper understanding of the full landscape of mutational processes operative in MM, especially during their evolution over time. MATERIAL AND METHODS: DNA from bone marrow CD138+ cells underwent WGS along with a matched normal sample using HiSeq X Ten machines (Illumina, Inc.). Mutational signature extraction was performed running non-negative matrix factorization (NMF) as previously described (Alexandrov et al, Nature 2013). RESULTS: We have observed and utilized a median number of 5780 (range 2599-7760) substitutions per patient at the asymptomatic stage and 5954 (ranges 2824-8227) at progression to MM stage to extract mutational signatures. NMF extracted 5 main signatures (http://cancer.sanger.ac.uk/cosmic/signatures). Specifically, APOBEC- (signature #2) and age-related signatures (signatures #1 and #5) accounted for 13% (1-21%) and 23% (3.2-40%) of all substitutions, respectively. In addition, we found two known signatures that were not implicated in MM so far: non-canonical AID (Signature #9), contributing to 28% of all substitutions (17-55%); and signature #8, accounting for 28% of all substitutions (13-45%) and pertaining to a yet unknown mutational process. Finally, the fifth signature did not match any of the previously described ones, representing a potential novel process which we defined as MM-1 (7%, range (1-16%). Interestingly, we found a differential contribution of processes in non-coding and intronic regions where AID was more prevalent, while exonic regions where APOBEC and age signatures were more prevalent. In intronic regions we found widespread regions of kataegis (9/11 patients), reflective of localized hypermutation. In our patients, kataegis was associated with rearrangements in 60% of cases, and was present in both the SMM and MM sample in 84% of cases, suggestive of an early event during tumor development. Contrary to what is observed in solid cancers, APOBEC signature was only responsible for 25% of kataegis variants, vs 70% for AID, suggesting a causative role of aberrant AID activity in shaping the early mutational repertoire of neoplastic plasma cells. To confirm this, we looked at serial samples in our cohort. While the percent contribution of each signature varied in each patient, confirming genomic heterogeneity of MM, it did not change when paired SMM and MM samples from the same patient were compared. This shows that mutational processes required for the development of symptomatic MM act early, and have been already operative at the SMM stage. However, by clustering substitutions as clonal (early variants present at the time of tumor initiation) or subclonal (late variants arisen closer to the time of sampling) using a Bayesian hierarchical Dirichlet process (Bolli et al, Nature Comms 2014), we could analyze processes operative before SMM was diagnosed. NMF analysis of these clusters reported striking differences. Specifically, AID and age were the predominant mutational processes in early substitutions in all patients, contributing to a median of 35% (25-54%) and 30% (15-43%) of variants respectively. Conversely the contribution of AID was minimal among late substitutions (5%, 1-22%), where instead APOBEC, Signature #8 and MM-1 activity was prominent [19% (1-43), 38% (8-73%), 16% (2-50%) respectively]. CONCLUSION: WGS data allowed the identification of mutational processes operative well before MM becomes clinically evident. Our observation that all samples have signs of aberrant AID at the time of tumor initiation supports a unifying model where MM precursors are initially transformed with the contribution of AID, providing a fertile ground for other later processes (i.e APOBEC and signature #8) to act and shape the final genomic landscape of overt multiple myeloma. Disclosures No relevant conflicts of interest to declare.

Description: Background: triplet combinations comprising a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD) are current standard induction and consolidation regimens in NDMM. The all-oral combination of weekly ixazomib plus lenalidomide-dexamethasone (IRd) has been evaluated by several groups in NDMM and is approved in relapsed-refractory MM. The IFM 2014-01 phase 2 trial previously studied the weekly IRd regimen as induction and extended consolidation followed by single-agent ixazomib maintenance in frontline transplant eligible patients (Moreau et al ASH meeting 2016): IRd was well tolerated and overall response rate was 81%, including 38% very good partial response or better (≥VGPR) at the completion of induction (3 cycles). Responses further increased at each step of the program and 76% of patients (per protocole analysis) achieved ≥VGPR before maintenance with 6% CR and 38% sCR. To stay in line with current RVd regimen, and to increase dose intensity, we examined the efficacy and safety of twice-weekly ixazomib +Rd as induction prior to transplant, followed by weekly IRd consolidation and single-agent lenalidomide maintenance (NCT02897830). Methods: This is a phase II, single-arm, open-label, multicenter study. During induction, patients received three 21-day cycles of twice-weekly oral IRd: ixazomib (3 mg on days 1, 4, 8 and 11), lenalidomide (25 mg daily, days 1-14), and dexamethasone (40 mg on days 1, 4, 8 and 11) followed by transplant. Patients then received two 28-day cycles of weekly IRd early consolidation followed by 6 additional cycles of IR (no dexamethasone) as late consolidation (ixazomib 4mg on days 1-8 and 15; lenalidomide 25mg daily, days 1-21). Single-agent lenalidomide maintenance was administered for up to 1 year (10 mg daily, days 1-21). The primary endpoint was the stringent complete response (sCR) rate at the completion of consolidation. The secondary endpoints included assessments of overall response rate (ORR) and rates of response categories at each step of the program, progression-free survival (PFS), feasibility and safety. Responses were assessed in accordance with the IMWG uniform criteria. Toxicity was evaluated according to NCI CTCAE, version 4.03. Results Between 07/2016 and 08/2017, 50 patients with NDMM were screened at 10 IFM centers, 46 were enrolled with a median age of 59 years, and 59% were male. The percentages of patients with ISS stage I, II, and III were 41.5%, 41.5%, and 17%, respectively. High-risk cytogenetics, defined as t (4; 14), or del17p (central Lab, H. Avet-Loiseau), was observed in 9% of patients (6.5% FISH failure). As of July 1st 2019 (data cut-off), 10 patients prematurely discontinued therapy. Considering efficacy, 43/46 patients (94%) completed consolidation and 9 achieved sCR (20.9%; 90% CI [11.4 to 33.7]). This result did not meet the minimum efficacy threshold (40%) for the primary efficacy endpoint (p=0.998). Overall, at the completion of consolidation, ORR was 91% including 21% sCR, 30% ≥CR and 58%≥VGPR. Responses at each step of the program are described in the table 1. If we focus on twice-weekly IRd induction, at the completion of 3 cycles, ORR was 74%, including 33% ≥VGPR. The feasibility of the program was good and overall, 39/46 patients (85%) were able to receive maintenance therapy with single-agent lenalidomide. After a median follow-up of 22 months, 7 patients progressed and 3 patients died. Concerning safety: 31 serious treatment emergent AEs were reported in 20 patients (43.5%) comprising infections (8 patients), cardiac disorders (2 patients: ischemic heart disease and aortic valve incompetence), psychiatric, renal and respiratory disorders (2 cases each). No grade 3-4 peripheral neuropathy was described. Conclusions The all-oral Ixazomib-Lenalidomide-Dexamethasone (IRd) induction/consolidation regimen in the transplant setting is convenient, well tolerated, leading to 21% sCR before maintenance. Twice-weekly IRd induction does not seem superior to weekly IRd induction Results on response rates following maintenance and MRD data will be presented during the meeting. Table Disclosures Roussel: Celgene Corporation: Consultancy, Other: travel fees, lecture fees, Research Funding; takeda: Other: travel fees, lecture fees, Research Funding; Amgen: Other: travel fees, lecture fees, Research Funding; Janssen: Honoraria, Other: travel fees, lecture fees, Research Funding. Hebraud:celgene: Other: travel fees, lecture fees; takeda: Other: travel fees, lecture fees. Hulin:Janssen, AbbVie, Celgene, Amgen: Honoraria; celgene: Consultancy, Honoraria. Leleu:Oncopeptide: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Karyopharm: Honoraria; Amgen: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Janssen: Honoraria; BMS: Honoraria; Merck: Honoraria. Facon:Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Touzeau:celgene: Other: travel fees, lecture fees, Research Funding; takeda: Other: travel fees, lecture fees. Perrot:jannsen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; takeda: Honoraria. Stoppa:celgene: Other: travel fees, lecture fees; takeda: Other: travel fees. Moreau:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Avet-Loiseau:takeda: Consultancy, Other: travel fees, lecture fees, Research Funding; celgene: Consultancy, Other: travel fees, lecture fees, Research Funding. Attal:celgene: Consultancy, Other: travel fees, lecture fees, Research Funding; takeda: Consultancy, Other: travel fees, lecture fees, Research Funding. OffLabel Disclosure: Ixazomib is indicated in RRMM in association with Rd

Description: Introduction: Achievement of MRD negativity in MM is associated with prolonged progression-free survival (PFS) and is being investigated as a potential surrogate for established clinical endpoints, such as PFS and overall survival (OS). Here, we evaluated the predictive utility of MRD in patients (pts) with MM for PFS and OS using a systematic literature review (SLR) and meta-analysis, and investigated how hazard ratios (HR) for PFS and OS, stratified by MRD status, changed for various pt subgroups. Methods: A SLR was conducted to identify all studies in MM reporting survival outcomes by MRD status (through 8 June 2019). In these studies, MRD was assessed by various assays (multiparametric flow cytometry [MFC], next generation sequencing [NGS], and polymerase chain reaction [PCR]), sensitivity thresholds (10-4, 10-5, and 10-6), and disease settings (relapsed/refractory MM [RRMM], transplant-eligible [TE] and transplant-ineligible [TIE] newly diagnosed MM [NDMM]). Studies with allogeneic transplant, where MRD was measured in peripheral blood or using PET-CT, or from which PFS and OS data could not be extracted were excluded from the analysis. To obtain a pooled effect estimate of MRD status on PFS and OS HRs, a meta-analysis was performed. Subgroup analyses were performed to adjust for variables expected to impact the association of MRD and PFS/OS outcomes. Variables were selected based on available qualitative evidence from studies. Statistical analyses were performed using the 'metafor' R package for meta-analyses. Results: 143 publications met the inclusion criteria; 86 publications were included in the meta-analysis based on data availability (65 PFS and 28 OS HRs). Outcomes for PFS (N = 8590) and OS (N = 3392) were significantly improved for MRD-negative pts: PFS HR 0.35 (95% confidence interval [CI], 0.31-0.39) and OS HR 0.48 (95% CI, 0.41-0.55; P

Description: Key Points Pom-Dex is active and well tolerated in adverse cytogenetic patients with early RRMM, particularly in those with del(17p). Pom-Dex prolonged OS in adverse cytogenetic patients with early RRMM.

Description: Key Points IRd was associated with a consistent PFS benefit vs placebo-Rd in RRMM patients with high-risk and standard-risk cytogenetics. The addition of ixazomib to Rd overcomes the poor PFS associated with high-risk cytogenetics in patients with RRMM.

Description: Introduction: Daratumumab (DARA) is a human IgGκ mAb targeting CD38 with both direct on-tumor and immunomodulatory mechanisms of action, and has been approved as monotherapy for RRMM and in combination with standard of care (SOC) regimens for RRMM and newly diagnosed MM (NDMM). Across three phase 3 DARA studies in RRMM and NDMM, DARA plus SOC reduced the risk of progression or death by ≥50%, enabled a doubling of CR rates, and elicited a ≥3-fold increase in MRD-negative rates. Among MRD-negative RRMM pts, pts treated with D-Rd or D-Vd rapidly achieved MRD negativity and demonstrated prolonged progression-free survival (PFS) vs MRD-positive pts (Avet-Loiseau H, et al. ASH 2016. Abstract 246). MRD assessment is being investigated as a potential surrogate for established endpoints such as overall survival (OS). When measured sequentially, sustained MRD-negativity provides an index of deep clinical responses that may provide a more robust assessment of disease control (Kumar S, et al. Lancet Oncol 2016. 17[8]:e328-e346). Here, we evaluate sustained MRD negativity with DARA plus SOC regimens and its association with PFS/OS outcomes in RRMM. Methods: Eligible pts in POLLUX and CASTOR received ≥1 prior line of therapy and were randomized (1:1) to receive SOC treatment regimens ± DARA. Pts in the POLLUX study were given lenalidomide (25 mg PO) on Days 1-21 and dexamethasone (40 mg) once per week in each 28-day cycle ± DARA (16 mg/kg IV) given weekly for Cycles 1-2, Q2W for Cycles 3-6, and Q4W thereafter. CASTOR pts received 8 cycles (21 d/cycle) of bortezomib (1.3 mg/m2 SC) on Days 1, 4, 8, and 11 and dexamethasone (20 mg) on Days 1, 2, 4, 5, 8, 9, 11, and 12 ± DARA (16 mg/kg IV) given weekly for Cycles 1-3, Q3W for Cycles 4-8, and Q4W thereafter. MRD was assessed at the time of suspected CR and at 3 and 6 months following confirmed CR in POLLUX, and at time of suspected CR and 6 and 12 months following the first treatment dose in CASTOR. Additional MRD evaluation was required in both studies every 12 months post-CR. MRD was assessed via next generation sequencing using the clonoSEQ® assay V2.0 (Adaptive Biotechnologies, Seattle, WA). Sustained MRD negativity was defined as the maintenance of MRD negativity in the bone marrow confirmed ≥6 or ≥12 months apart and was evaluated in the intent-to-treat (ITT) population. Sustained MRD negativity was also evaluated among ≥CR pts to account for different sustained MRD negativity rates between treatment arms. Results: A total of 569 (D-Rd, n = 286; Rd, n = 283) pts in POLLUX and 498 pts (D-Vd, n = 251; Vd, n = 247) in CASTOR were randomized; median (range) number of prior lines received was 1 (1-11) and 2 (1-10), respectively. Median duration of follow up was 39.5 months in POLLUX and 31.3 months in CASTOR for this analysis. Using the ≥6-month sustained MRD cutoff, a significantly higher proportion of pts achieved sustained MRD negativity for ≥6 months when treated with D-Rd vs Rd (16% vs 0.7%; P