Goldschmidt, Hartmut

Abstract Introduction Over the last 15 years gene expression profiling (GEP) has been used to define myeloma molecular subgroups and to determine clinical prognosis. Two major molecular subgroup classifications have been used: the UAMS which determines 7 subgroups and the TC classification based on the presence of IgH translocations and expression of D group cyclins. For prognosis, although a number of different GEP signatures have been defined, the widely used GEP70 identifies 15% of patients with high risk (HR) disease who have a median PFS and OS of 1.75 and 2.83 years. An ideal classification system would identify clinically relevant subgroups with distinct etiology and biology using standardized techniques. We have examined a large group of patients characterized at multiple genetic levels to optimize the diagnostic approach of newly diagnosed patients going forward. Materials and methods Study subjects included 1349 cases enrolled in Total Therapy trials (median follow up 7.5 years). Gene expression profiling was used to determine GEP70 risk status, molecular subgroup by UAMS and TC classifications, and to devise a new and extended TC classification (TC10). Interphase FISH associated with IgH translocations and 1q+ and 17p- were used to build GEP proxies. Data from mutational analysis generated by the FoundationOne targeted sequence panel was also incorporated. Results were validated on the UK MRC MyelomaIX and Hovon65/GMMG-4 studies. Results An initial agnostic analysis of GEP data using sparse k-means clustering verified the existence of TC based groups. Six groups were identified that corresponded overwhelmingly with known TC subgroups; CCND1-t(11;14), D1-HRD, D2-HRD, MMSET, MAF/CCND2, and CCND3. Further comparisons between the molecular subgroup and TC classifier revealed that the UAMS 7 subgroups clustered strongly within one predominant TC group: CD-1 and CD-2 to t(11;14), HY to D1, LB and PR to D2, MF to t(14;16) or t(14;20), and MS to t(4;14). As the UAMS molecular subgroups are largely contained within the TC framework, we aimed to extend the TC by developing the TC10. To extend the known TC subgroups, unsupervised clustering was applied to the 3 largest subgroups [t(11;14), D1, and D2] to determine the strongest single divisor within each respective subgroup. The dominant feature within the t(11;14) cases was CD20 expression, while the D1 and D2 subgroups both split according to RRAS2. CD20 is associated with PAX5 and VPREB3 expression, and RRAS2 is associated with decreased PTP4A3 and increased TNFAIP3 and BIRC3 expression. RRAS2 activation within D1 subgroup and CD20 activation within t(11;14) cases corresponds to an increased time to response to induction therapy suggesting they constitute important biological subgroups. The TC10 combines the known etiologic subgroups of the TC with functionally relevant subdivisions to create 10 novel subgroups: t(11;14) CD20+/-, D1: RRAS2+/-, D2: RRAS2+/-, t(4;14), t(14;16), t(14;20), and t(6;14). Analysis of mutational data revealed that RRAS2 and CD20 activation within the D1, D2, and t(11;14) subgroups reduced the number of mutations in the MAPK pathway. Further mutational analysis revealed that median mutational load was highest in t(14;16) and lowest in D2: RRAS2+ subgroups. The GEP70 score identifies 15% of patients with HR disease and is specific for this purpose. In an analysis of risk assessment methods, we compared GEP detected adverse lesions [t(4;14), t(14;16), t(14;20), 17p- and 1q+] with the GEP70 and revealed that GEP70 HR identified samples have lower OS rates than cases with more than one adverse lesion (validated in external sets). GEP70 HR segregates non-uniformly across molecular subgroups as over 40% of all HR cases are found in the TC10 t(4;14), t(14;16), and t(14;20) subgroups. GEP70 HR cases also have a higher mutational load than low risk cases. Furthermore, GEP70 HR is uniquely associated with 1q+ and 17p- as cases with at least one of these adverse lesions are 4.9 times as likely to be GEP70 HR as cases with neither. Conclusion GEP profiling has a central role in simplifying and standardizing the molecular subgroup designation and risk stratifying of MM patients. The GEP70 risk score reliably identifies HR cases and outperforms FISH in risk assessment, even in validation data sets. The TC10 provides a classification system that improves upon previous methods by defining both etiological and functionally meaningful subgroups. Disclosures Stein: University of Arkansas for Medical Sciences: Employment. Davies:University of Arkansas for Medical Sciences: Employment; Celgene: Consultancy; Janssen: Consultancy; Millenium: Consultancy; Onyx: Consultancy. Heuck:University of Arkansas for Medical Sciences: Employment; Celgene: Consultancy; Janssen: Other: Advisory Board; Millenium: Other: Advisory Board; Foundation Medicine: Honoraria. Weinhold:University of Arkansas for Medical Sciences: Employment; Janssen Cilag: Other: Advisory Board. Chavan:University of Arkansas for Medical Sciences: Employment. Thanendrarajan:University of Arkansas for Medical Sciences: Employment. Epstein:University of Arkansas for Medical Sciences: Employment. Yaccoby:University of Arkansas for Medical Sciences: Employment. Zangari:University of Arkansas for Medical Sciences: Employment; Novartis: Research Funding; Onyx: Research Funding; Millennium: Research Funding. van Rhee:University of Arkansa for Medical Sciences: Employment. Kaiser:Janssen: Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; BristolMyerSquibb: Consultancy; Chugai: Consultancy. Sonneveld:Janssen-Cilag, Celgene, Onyx, Karyopharm: Honoraria, Research Funding; novartis: Honoraria. Goldschmidt:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Millenium: Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai: Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Barlogie:University of Arkansas for Medical Sciences: Employment. Morgan:Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; MMRF: Honoraria; CancerNet: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; University of Arkansas for Medical Sciences: Employment; Weismann Institute: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Introduction: Customized gene panel sequencing is an attractive approach to genomic tumor characterization in clinical care. Based on published MM exome data we developed a MM Mutation Panel (M3 P) that includes the most commonly mutated genes, actionable drug targets, genes targeted by current standard of care (SOC) therapies and which allows tracking of clonal evolution, copy number and sample purity. Methods and Material: M3 P (v3.0) covers 88 genes (1327 amplicons, 181kb). MM samples from 504 patients (pts) have been analyzed (corresponding germline in 81%) through collaborations between Mayo Clinic and Hospital-12-de-Octubre (Madrid, Spain), the DSMM and GMMG (Würzburg, Ulm, Freiburg and Heidelberg, Germany) and the HOVON trial groups (Rotterdam, The Netherlands). The investigated cohort includes 410 untreated pts (81%), which includes a high risk cohort of 72 pts with del17p, 25 paired samples with later follow up from the same cohort, and 94 relapsed patients, of which 50 were relapsed and refractory. Results: Overall coverage per mutation averaged >500x depth. We identified 945 variants (1.9 per pt) and in 83% of the pts a mutation was found. Clonal heterogeneity was assessed with mutations ranging from 3%-100% variant reads suggesting the presence of a significant number of subclones (e.g. 21% of mutations were in < 10% of reads). The mutation incidence was compared with and closely resembles the most recent MM comprehensive genomic data from the MMRF CoMMpass study: We compare here all pts sequenced by M3 P, untreated pts sequenced by M3 P and CoMMpass: KRAS (24%/23%/24%), NRAS (20%/20%/18%), DIS3 (13%/14%/10%), BRAF (9%/7%/6%), FAM46C (6%/6%/8%) and TRAF3 (6%/6%/7%). TP53 mutation incidence, however, was significantly increased in our cohort (14%/12%/4.2%), a difference explained by the inclusion of del17p (untreated) and relapsed refractory MM in panel sequenced pts, cohorts with elevated incidences of TP53 mutations (32% / 26% respectively). Potentially actionable targets include BRAF mutationsin 43 patients (9%), with druggable p.V600E in 19 or 5%, 8 pts (2%) with FGFR3 (p.R248C and p.G375C one patient each), p.R132 mutation in 4 out of 5 IDH1 (1%) and p.R172K IDH2 mutation in 1 of 3 (1%) pts. Mutations in the MAPK pathway (NRAS, KRAS, BRAF) were detected in 59% of pts, ranging from 36% untreated MM to 72% in refractory MM. Similarly, the CRBN/CUL4B/IKZF1/IKZF3/IRF4 pathway, important for IMiD function, harbored a significant enrichment of mutations in advanced disease (6% untreated vs 17% relapsed), including CRBN mutations (0.5% vs 7%). Nine of 17 IRF4 mutations were located at the p.K123R hotspot, with minor difference between early or late disease (1% vs 3%). Notably, in 8 of 9 pts with CRBN mutation and clinical information, all were unresponsive to IMiD therapy, supporting association of these mutations with resistance to IMiDs. Conversely, M3 P genes related to other SOC therapies, including NR3C1 (targeted by steroids) and 5 proteasome subunit genes (proteasome inhibitors), were rarely mutated across the cohorts not exceeding 1% mutation incidence for each gene. Significant differences in DIS3 and FAM46C mutation incidences were observed across cohorts: DIS3 mutations are more common in untreated pts with a 1.7 fold increased predominance (14% untreated and 8% treated). FAM46C has an expected incidence of 8% but was rarely mutated in untreated del17p high risk disease with only one of 100 patients harboring both mutations. The significance of this finding needs to be determined but implies a possible overlap in function. Finally we assessed impact on survival of the mutation variants identified in 142 untreated Mayo patients and found STAT3 mutations negatively impacting PFS (p=0.034) and OS (p=0.001). This gene is rarely mutated in MM (2% of the total cohort) thus the sample size was small and this finding needs further validation. Conclusion: We here describe 504 MM patients sequenced using the M3 P gene panel, which identified mutations in >80% of investigated patients, overlaps well with published whole exome sequence data and provides clinically relevant information. New findings were the high frequency of minor clones, the relative lack of overlap of del17 and FAM46C mutation, a higher frequency of DIS3 mutation at diagnosis compared to relapse, the prognostic significance of STAT3 mutation and the frequent presence of CRBN pathway mutation in drug resistant relapsed patients. Disclosures Sonneveld: Janssen-Cilag, Celgene, Onyx, Karyopharm: Honoraria, Research Funding; novartis: Honoraria. Mai:Janssen-Cilag: Other: Travel Grant; Onyx: Other: Travel Grant; Mundipharma: Other: Travel Grant; Celgene: Other: Travel Grant. Goldschmidt:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Onyx: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millenium: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Chugai: Honoraria, Research Funding, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Knop:Celgene Corporation: Consultancy. Kull:Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Martinez-Lopez:Novartis: Honoraria, Research Funding; Bristol-Meyer Squibb: Honoraria; Celgene: Honoraria; Janssen: Honoraria. Einsele:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau; Amgen/Onyx: Consultancy, Honoraria, Speakers Bureau. Raab:Novartis: Research Funding. Stewart:Oncospire Inc.: Equity Ownership; Celgene: Consultancy; Novartis: Consultancy; BMS: Membership on an entity's Board of Directors or advisory committees.

Abstract We have taken a genetic strategy to define the mechanisms underlying the increased risk of VTE in myeloma patient treated with thalidomide using clinical trial data derived from the MRC, ECOG, Little Rock and HOVON trial groups. Baseline VTE rates in the MRC IX study, (CTD vs CVAD; n=748 no prophylactic anticoagulation), were 14%. Rates in both arms were equal but in the thalidomide arm, thrombotic events were all DVT’s or PE’s, whereas in the CVAD arm they split equally between line related and VTE’s. In the other comparison (CTD vs MP; n=542), the VTE rate was 17%, all in the thalidomide arm. Rates were similar or higher (30%) in the other trials depending on the intensity of treatment used. We carried out a nested case control on DNA from MRC IX on 90 VTE (45 thalidomide, 45 non-thalidomide related), matched to 180 controls. SNPlex analysis for 60 SNPs in the coagulation cascade, DNA repair, thalidomide, metabolism and myeloma specific pathways, identified 7 genes which affected risk (NBS1, MTHFR, Ku80, Cyp3A5, LGAL52 and IL12B). This suggests three major pathways contribute to the risk of thalidomide related VTE, metabolism of thalidomide, tumour responsiveness and some pro-thrombotic factors. These factors differ from non-thalidomide related risk where a strong pro-inflammatory response is most relevant. We tested this hypothesis further using an expanded panel of 3,404 SNPs (BOAC panel), using the Megalle system. Statistical analysis of this data defined the top 20 thalidomide and non-thalidomide associated SNPs, which were consistent with the initial hypothesis, the results of which exclude variation in the coagulation cascade as being a significant risk factor. We explored this hypothesis further using pathway-based analysis focussing on the MTHFR, DNA repair and WNT pathways on data from the ECOG, HOVON and Little Rock data sets. The biological relevance of the SNPs and genes identified was validated by correlating the level of expression using the Affymetrix U133 CHIP with genetic variation at the DNA level. To verify the relevance of DNA repair variability to tumour response further, we correlated gene expression profiling with response and again Ku80 was identified as one of a cluster of genes defining increased risk. The data suggests that the risk of thalidomide related VTE relates to rapid tumour lysis combined with a prothrombotic tendency, whereas in line related thrombosis, risk is dependent upon a strong proinflammatory response. We are building this genetic data into a clinical risk model in order to allow us to develop a rationale for intervention strategies.

Abstract Purpose: Deep vein thrombosis (DVT) is increasingly recognized as a major complication of thalidomide (T; Thal) and lenalidomide (R; Rev) based therapy for multiple myeloma. Estimated incidence varies widely in the literature. There is no consensus on specific risk factors, indications for thromboprophylaxis or the agent of choice for DVT prophylaxis. The purpose of this study was to develop a consensus among members of the IMWG. Patients and Methods: A survey was electronically mailed to 67 IMWG members on July 21, 2006 and consisted of 24 multiple-choice questions. Results: Twenty-three IMWG members (34%) sent in their responses by the cut-off date. All (100%) felt that DVT was an important question, but most (95%) did not avoid Thal/Rev based therapy because of the DVT risk. Overall results are summarized in the Table below. A majority of physicians felt that concomitant therapy with high dose dexamethasone (90% of physicians), alkylators (55%), doxorubicin/liposomal doxorubicin (90%), and erythropoietin (75%) increase the risk of DVT associated with Thal or Rev based therapy. Aspirin (81 mg or 325 mg per day) was the preferred choice of prophylaxis when necessary. However, 65% of respondents preferred warfarin to a therapeutic INR or LMW heparin if either doxorubicin or liposomal doxorubicin was added to the regimens. Most (95–100%) felt that DVT prophylaxis was not indicated for: VAD, MP, bortezomib +/− dexamethasone regimens. Seventy-five percent felt it to be safe to resume therapy with Thal/Rev after therapeutic anticoagulation. Most (95%) believed randomized trials were needed. Conclusion: DVT is recognized as a major clinical problem associated with Thal/Rev containing regimens. Most respondents felt that the DVT risk did not warrant any prophylaxis when either Thal or Rev were used as single agents. Aspirin was the preferred form of DVT prophylaxis for most Thal/Rev containing regimens, except when doxorubicin/liposomal doxorubicin or melphalan were added. Additional responses will be analyzed both electronically and by conference call prior to the meeting. Therapy Estimated incidence of DVT (% respondents) Choice of thromboprophylaxis (% respondents) Single agent thal <5% (61%) None (65%) Single agent Rev <5% (80%) None (65%) Thal-Dex 10–20% (52%) Aspirin (60%) Rev-Dex 10–20% (48%) Aspirin (60%) MPT 10–20% (65%) Aspirin (40%) R-MP 5–10% (57%) Aspirin (70%)

Abstract Background: Treatment of multiple myeloma has evolved considerably in the past few years with availability of several news drugs as well as increasing use of multidrug combinations. These changes have no doubt led to the improved survival seen among patients with MM. We have previously shown that outcomes of patients intolerant or refractory to one of the IMiDs and bortezomib had a poor outcome. Since that time, other drugs of the same class as well as new classes of drugs have been introduced for the treatment of MM. We designed this retrospective study to estimate the outcomes in patients with relapsed myeloma, who have become refractory to the current generation IMiDs and proteasome inhibitors. Patients and Methods: Patients with relapsed multiple myeloma who have received at least 3 prior lines of therapy, is refractory to both an IMiD (lenalidomide or pomalidomide) AND a proteasome inhibitor (bortezomib or carfilzomib), and has been exposed to an alkylating agent were identified from multiple centers. The time patients met the above criteria was defined as T0, and details of all treatment regimens before and after T0 were collected using electronic CRFs. The study was approved by the IRB at the respective centers. Results: 543 patients were enrolled in this study; median age was 62 years (31-87) and 61% were males. Patients were enrolled from centers in North America (n=181), Europe (n=318), and Asia Pacific (n=44). Patients were diagnosed between 2006 and 2014, the median duration between diagnosis of myeloma and study entry (T0) was 3.1 years (0.3 to 9). The median (95% CI) estimated follow up from diagnosis and from T0 were 61 (57, 66) months and 13 (11, 15) months respectively. The median number of lines of therapy prior to T0 was 4 (3-13), 48% had a prior transplant. The median OS from T0 for the entire cohort was 13 (11, 15) months. For these 462 patients, the median number of recorded regimens was 2 (1-9). The overall response and the depth of response to each line of treatment following T0 are as shown in the table. The median (95% CI) PFS and OS from T0 was 5 (4, 6), and 15.2 (13, 17), respectively. The overall survival for the 81 patients with no treatment post T0 was only 2.1 months. In a multivariate analysis, duration from diagnosis to T0, ISS stage III and number of lines of therapy were all associated with inferior PFS, as well as OS, and in addition, serum creatinine>2 mg/dL at T0 also predicted inferior OS. Conclusions: The study provides the expected outcome following development of myeloma that is refractory to a PI and an IMiD. The outcomes of these patients appear to be better than we had seen historically in patients refractory/ intolerant to bortezomib and IMiDs, highlighting the increased treatment options available for these patients. However, there is decreasing response rate to sequential regimens highlighting the development of drug resistance. The data provides a bench mark for comparison of new therapies that are being evaluated in this disease. Table Table. Disclosures Dimopoulos: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genesis: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Kastritis:Takeda: Consultancy, Honoraria; Genesis: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Terpos:BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Other: Travel expenses, Research Funding; Celgene: Honoraria; Takeda: Consultancy, Honoraria; Genesis: Consultancy, Honoraria, Other: Travel expenses; Amgen: Consultancy, Honoraria, Other: Travel expenses, Research Funding; Novartis: Honoraria. Hillengass:Sanofi: Research Funding; Novartis: Research Funding; Amgen: Consultancy, Honoraria; BMS: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria. Leleu:TEVA: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria; LeoPharma: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Pierre Fabre: Honoraria; Celgene: Honoraria; Novartis: Honoraria; Takeda: Honoraria. Oriol:Janssen: Honoraria, Other: Expert board committee; Amgen: Honoraria, Other: Expert board committee. Cavo:Celgene: Consultancy, Honoraria; Millennium: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Mateos:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees. Vij:Shire: Consultancy; Takeda: Consultancy, Research Funding; Jazz: Consultancy; Karyopharma: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Celgene: Consultancy; Bristol-Myers Squibb: Consultancy; Amgen: Consultancy, Research Funding. Lokhorst:Genmab: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. van de Donk:Amgen: Research Funding; Janssen: Research Funding; BMS: Research Funding; Celgene: Research Funding. Mark:Onyx: Research Funding, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Ludwig:Amgen: Research Funding, Speakers Bureau; Takeda: Research Funding, Speakers Bureau; BMS: Speakers Bureau; Janssen: Speakers Bureau. Jagannath:Novartis: Consultancy; Janssen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy; Merck: Consultancy. Usmani:Array: Research Funding; Britsol-Myers Squibb: Consultancy, Research Funding; Skyline: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; BioPharma: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Onyx: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Research Funding, Speakers Bureau; Millenium: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Speakers Bureau. Dytfeld:Janssen Poland: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees. Moreau:Novartis: Honoraria; Amgen: Honoraria; Celgene: Honoraria; Bristol-Myers Squibb: Honoraria; Takeda: Honoraria; Janssen: Honoraria, Speakers Bureau. Lee:Amgen: Membership on an entity's Board of Directors or advisory committees. Shustik:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. de la Rubia:Celgene: Consultancy; Bristol Myers: Consultancy; Amgen,: Consultancy; Janssen: Consultancy. Durie:Takeda: Consultancy; Amgen: Consultancy; Janssen: Consultancy.

Abstract Introduction: For decades conventional skeletal survey (CSS) has been the standard imaging technique for the detection of bone impairment caused by Multiple Myeloma (MM). The development of cross-sectional imaging techniques like Whole Body Computed Tomography (WBCT) with or without Positron Emission Tomography (PET/PET-CT) and magnetic resonance imaging (MRI) led to the use of these techniques in several centers worldwide and to the implementation of their findings into the revised diagnostic criteria of MM. The aim of the current multicenter study was to compare sensitivity and prognostic significance of WBCT and CSS in patients with monoclonal plasma disorders. Methods: For the current retrospective analysis 308 patients with different stages of monoclonal plasma cell disorders from 8 centers were included. Compact discs with pseudonymized imaging data of WBCT and CSS were sent to the organizing center and uploaded to the picture archiving and communication system. In addition, questionnaires were completed by each center to collect clinical data of the patients. Image analysis was performed in consensus reading by three experienced radiologists (LAM, SD, VK) blinded to the clinical data of the patients. Osteolytic lesions in 19 pre-specified anatomic regions were characterized as "definitely present", "probably present", "probably absent" and "definitely absent". For the analysis only "definitely present" and "probably present" entries were counted as myeloma lesions. To define symptomatic or active versus smoldering myeloma based on the presence of bone lesions, findings of CSS were used to simulate the situation before the introduction of WBCT. For comparison of WBCT and CSS only those anatomic regions having valid measurements from both methods performed within 30 days without treatment in the meantime were considered. WBCT and CSS were tested for differences in detection sensitivity with the exact McNemar test. Results: Of 308 submitted datasets; 160 patients were without prior treatment and 56 of them had smoldering myeloma. Of 160 patients 80 (50%) had no osteolytic lesions on either CSS or WBCT and 33 (20.6%) showed osteolyses on both techniques. In 9 patients (5.6%) osteolyses were found on CSS but not in WBCT while 38 patients (23.8%) were positive on CT alone. Of note is that for some CT-scans, the upper extremities were not evaluable due to positioning during the examination. Odds ratio for osteolyses on WBCT compared to CSS was 4.22 (P < 0.0001). The regions where WBCT was most significantly superior in detecting osteolyses were the iliac bone, thoracic and lumbar spine as well as the ribs. CSS compared to WBCT revealed osteolyses in more patients only in the proximal extremities: for left humerus 10 (6.5%) versus 3 (1.9%), right humerus 12 (7.7%) versus 4 (2.6%), left femur 11 (7.1%) versus 7 (4.5%) and right femur 10 (6.5%) versus 8 (5.2%) respectively. Of 157 evaluable patients 63 (40.1%) showed osteoporosis (defined by radiological criteria) on both techniques while 29 (18.5%) had osteoporosis on WBCT only and 10 (6.4%) on CSS only (OR 2.90, P = 0.003). In the 56 patients with smoldering myeloma, with bone disease being defined according to the findings of CSS 12 (21.4%), were positive for osteolyses on WBCT (P = 0.0005). Conclusion: WBCT shows significantly more sites of bone destruction compared to conventional X-ray imaging particularly in skeletal regions composed primarily of trabecular bone while CSS shows more osteolyses in the appendicular skeleton - in part due to a limited field of view. More than 20% of patients with smoldering myeloma based on CSS have active disease that needs treatment based on WBCT. Therefore, WBCT is the current standard for the detection of osteolytic lesions in myeloma. The prognostic significance of WBCT and CSS findings for survival and correlation with clinical parameters will be reported at the meeting. Disclosures Hillengass: Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Novartis: Research Funding; Amgen: Consultancy, Honoraria; Sanofi: Research Funding. Plesner:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Dimopoulos:Amgen: 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; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Genesis: Consultancy, Honoraria. Goldschmidt:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Lentzsch:Celgene: Consultancy, Honoraria; BMS: Consultancy. Terpos:Takeda: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Genesis: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Novartis: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Honoraria.

Abstract Abstract LBA-6 Background: Multiple myeloma (MM) patients who have become refractory to bortezomib (BORT) and refractory or otherwise ineligible for thalidomide or lenalidomide (LEN) have a poor prognosis, with a median overall survival (OS) of 9 months (Kumar. Leukemia. 2012). There is no standard treatment available for these patients. Pomalidomide (POM) is a novel immunomodulatory drug that has shown activity in LEN- and BORT-refractory patients (Vij. ASCO 2012). MM-003 is an open-label, multicenter, phase 3 trial designed to compare the efficacy and safety of POM + low-dose dexamethasone (LoDEX) vs high-dose dexamethasone (HiDEX) in a population of patients who are refractory to both LEN and BORT. Here we present the final progression-free survival (PFS) and interim OS analysis of MM-003. Methods: Eligible patients with primary refractory or relapsed and refractory disease were enrolled. All patients with documented disease progression during treatment or within 60 days of completing their last myeloma therapy (including ≥ 2 consecutive cycles of LEN and BORT either alone or in combination), were randomized 2:1 to receive either POM + LoDEX (arm A) or HiDEX alone (arm B). Patients progressing on HiDEX had the opportunity to receive POM in the companion trial, MM-003C. Patients in arm A received POM 4 mg on days 1–21 and DEX 40 mg (20 mg for patients > 75 years of age) on days 1, 8, 15, and 22 in a 28-day cycle. Patients in arm B received DEX 40 mg (20 mg for patients > 75 years of age) on days 1–4, 9–12, and 17–20 in a 28-day cycle. Treatment was continued until progressive disease or unacceptable toxicity. Patients were stratified by age (≤ 75 vs > 75 years), disease population (refractory vs refractory and relapsed vs refractory and intolerant [intolerant to BORT only]), and number of prior therapies (2 vs > 2). The primary endpoint was PFS; secondary endpoints included safety, OS, overall response rate (ORR; ≥ partial response) by IMWG and EBMT criteria, duration of response, time to progression, and quality of life. OS was to be tested only if PFS would be statistically significant; therefore, alpha was controlled at 0.05 2-sided for both PFS and OS. Results: The Data and Safety Monitoring Board (DSMB) reviewed the protocol-specified final analysis results. 455 patients were randomized from March 2011 to Sept 2012. 302 patients received POM + LoDEX, and 153 patients received HiDEX. At the time of analysis, 45% of patients in arm A and 25% of patients in arm B remained on study. The median number of prior therapies was 5 (range, 1–17). 72% of patients were refractory to both LEN and BORT. At the PFS final analysis, with a median follow-up of 18 weeks, PFS was significantly longer with POM + LoDEX vs HiDEX alone (median 15.7 vs 8.0 weeks; 267 total events; hazard ratio [HR], 0.45; P <.001). OS interim analysis was performed as planned; OS also was significantly longer with POM + LoDEX vs HiDEX alone (median not reached vs 34 weeks; 134 events; HR, 0.53; P<.001), crossing the prespecified O’brien-Fleming superiority boundary. This includes 45 pts who received POM after progressing on HiDEX. Median duration of treatment was 12.4 weeks in arm A and 8 weeks in arm B. Following DSMB review of the data, immediate crossover of arm B patients to arm A was recommended. Overall, 25% of patients in arm A and 38% in arm B died, with progressive disease and infections as the primary reasons. Frequent grade 3/4 hematologic toxicities included neutropenia (42% in arm A vs 15% in arm B), thrombocytopenia (21% vs 24%), and febrile neutropenia (7% vs 0%). Other toxicities (grade 3/4) were predominantly infections (24% vs 23%), hemorrhage (3% vs 5%), glucose intolerance (3% vs 7%), neuropathy (1% vs 1%), and venous thromboembolism (1% vs 0%). The primary reason for discontinuation was progressive disease: 35% arm A and 49% arm B. Complete results will be presented at the meeting. Conclusions: POM + LoDEX significantly increased PFS and OS compared with HiDEX in patients who are refractory to LEN and BORT, a population with limited treatment options. The OS superiority boundary was crossed. Based on these data, POM + LoDEX should become the new standard of care in patients who have exhausted the novel agents, LEN and BORT. Disclosures: Dimopoulos: Celgene: Honoraria. Off Label Use: Pomalidomide is an investigational drug and is not approved for the treatment of patients with any condition. Lacy:Celgene: Research Funding. Moreau:Celgene: Honoraria, Speakers Bureau. Weisel:Celgene: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding. Song:Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Delforge:Celgene: Consultancy, Honoraria, Speakers Bureau; Janssen-Cilag: Consultancy, Honoraria; OrthoBiotech: Consultancy, Honoraria, Speakers Bureau. Karlin:Celgene: Consultancy. Goldschmidt:Novartis: Honoraria, Speakers Bureau; Janssen: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau. Yu:Celgene: Employment. Sternas:Celgene: Employment, Equity Ownership. Jacques:Celgene: Employment, Equity Ownership. Zaki:Celgene: Employment, Equity Ownership. San Miguel:Onyx: Membership on an entity’s Board of Directors or advisory committees; Janssen: Membership on an entity’s Board of Directors or advisory committees; Millennium: Membership on an entity’s Board of Directors or advisory committees; Celgene: Membership on an entity’s Board of Directors or advisory committees; Novartis: Membership on an entity’s Board of Directors or advisory committees.

Abstract Introduction Lenalidomide-based therapies are a standard of care for patients with newly diagnosed, transplant-ineligible MM. Daratumumab (DARA) is a human, CD38-targeted, IgG1κ monoclonal antibody which has single-agent activity in heavily pretreated MM patients. As previously reported in 3 phase 3 studies, the addition of DARA to standards of care in both relapsed refractory (D-Rd, DARA plus bortezomib and dexamethasone [D-Vd]) or transplant-ineligible NDMM (DARA plus bortezomib, melphalan, and prednisone [D-VMP]) resulted in a ≥50% reduction in the risk of disease progression or death (Palumbo A, et al. N Engl J Med 2016;375:754-766; Dimopoulos MA, et al. N Engl J Med 2016;375:1319-1331; Mateos MV, et al. N Engl J Med 2018;378:518-528). Of these, the POLLUX study with D-Rd showed the greatest benefit with a 63% reduction in risk of disease progression or death in patients with MM who had at least one prior line of therapy. Based on the efficacy and tolerable safety profile of D-Rd, we conducted a phase 3 study (MAIA) to evaluate D-Rd vs Rd in transplant-ineligible NDMM. Here we report the prespecified interim analysis of the MAIA study. Methods Patients ineligible for high-dose chemotherapy with autologous stem cell transplantation due to age ≥65 years or comorbidities were randomized 1:1 to Rd ± DARA. Stratification was based on International Staging System stage (ISS [I, II, III]), region (North America vs other), and age (<75 vs ≥75 years). All patients received 28-day cycles of treatment with Rd ± DARA. R: 25 mg (oral) QD on Days 1-21; d: 40 mg (oral) on Days 1, 8, 15 and 22. In the D-Rd arm, DARA was given at 16 mg/kg (intravenously) QW for Cycles 1-2, Q2W for Cycles 3-6, and Q4W thereafter. In both arms, patients were treated until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Key secondary endpoints included overall response rate (ORR), minimal residual disease (MRD)-negativity rate (10-5 sensitivity, clonoSEQ® version 2.0), and safety. Results This international study randomized 737 patients (368 to D-Rd; 369 to Rd) from 14 countries. Key baseline characteristics were well balanced between the two arms. The median (range) age was 73 (45-90) years with 44% of patients ≥75 years, and 52% were male. Two thirds of patients had ECOG scores ≥1: ECOG score 0, 34%; 1, 50%; ≥2, 17%. Overall, 27%, 43%, and 29% were ISS stage I, II, and III, respectively. Of 642 patients evaluable for FISH/karyotyping analysis, 86% and 14% were standard and high cytogenetic risk, respectively. The prespecified interim analysis occurred after 239 PFS events on 24 September 2018 with a median follow up of 28 months. For the primary endpoint, the hazard ratio was 0.55 (95% CI, 0.43 to 0.72; P <0.0001), representing a 45% reduction in the risk of progression or death in patients treated with D-Rd (Figure). The median PFS for the Rd arm was 31.9 months and not reached for the D-Rd arm. Adding DARA to Rd resulted in deeper responses with a complete response (CR) or better rate of 47.6% in the D-Rd arm compared with 24.7% in the Rd arm (odds ratio [OR] 2.75, 95% CI, 2.01 to 3.76; P <0.0001). The very good partial response (VGPR) or better rate was 79.3% in the D-Rd arm compared with 53.1% in the Rd arm (OR 3.4, 95% CI, 2.45 to 4.72; P <0.0001). A total of 19% of patients have died and the HR for OS was 0.78 (95% CI, 0.56 to 1.1); follow-up is ongoing. Higher rates (5% or more difference) of grade 3/4 pneumonia, neutropenia, and leukopenia were observed in the D-Rd arm. The safety profile is consistent with previously reported DARA studies. The complete topline data set will be presented with additional efficacy endpoints, including MRD negativity rate. Conclusion The addition of DARA to Rd in patients with transplant-ineligible NDMM significantly reduced the risk of progression or death by 45%. There are no new safety signals using DARA plus Rd in NDMM. These data together with the phase 3 ALCYONE study (D-VMP vs VMP) support the addition of DARA to standard of care combinations in patients with NDMM ineligible for transplant. Disclosures Facon: 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; Amgen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees. Kumar:KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding. Plesner:Celgene: Other: Independent Response Assessment Comittee; Janssen: Consultancy. Orlowski:Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi-Aventis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BioTheryX: Research Funding; Spectrum Pharma: Research Funding. Moreau:Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Bahlis:Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Hulin:Celgene: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria; Janssen: Honoraria, Research Funding. Goldschmidt:Adaptive Biotechnology: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Chugai: Honoraria, Research Funding; Mundipharma: Research Funding; Novartis: Honoraria, Research Funding; ArtTempi: Honoraria. O'Dwyer:Janssen: Consultancy. Perrot:Janssen: Consultancy, Equity Ownership, Honoraria. Venner:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria. Weisel:Celgene: Consultancy; Angeb: Consultancy, Honoraria, Research Funding; Juno: Consultancy; Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Research Funding; Bristol Myers SquibbMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Ahmadi:Genmab: Employment, Equity Ownership. Chiu:Janssen Research & Development, LLC: Employment, Equity Ownership. Wang:Janssen Research & Development, LLC: Employment. Van Rampelbergh:Janssen: Employment. Uhlar:Janssen: Employment. Kobos:Janssen Research & Development: Employment. Qi:Janssen Research & Development, LLC: Employment. Usmani:Abbvie, Amgen, Celgene, Genmab, Merck, MundiPharma, Janssen, Seattle Genetics: Consultancy; Amgen, BMS, Celgene, Janssen, Merck, Pharmacyclics,Sanofi, Seattle Genetics, Takeda: Research Funding.

Background:Maintenance therapy (MT) in NDMM has been increasingly used to prolong duration of response achieved by ASCT. TOURMALINE‐MM3 is a phase 3, double‐blind, placebo‐controlled study, where ixazomib improved PFS, and is the first study to evaluate the impact of MT on HRQoL post ASCT in NDMM (Dimopoulos et al., Lancet 2019;393:253). HRQoL is an important consideration during MT in NDMM patients with minimal disease burden post ASCT (Anderson et al., Leukemia 2008;22:231).Aims:To assess HRQoL in patients randomized to ixazomib vs. placebo MT in TOURMALINE‐MM3.Methods:In TOURMALINE‐MM3, NDMM patients post ASCT were randomly assigned in a 3:2 ratio to oral ixazomib or matching placebo. HRQoL was assessed by EORTC QLQ‐C30 (overall/subscale score range, 1–100) at screening, the start of every cycle (1–26), end of treatment, every 4 weeks until start of next line of therapy after progression and twice thereafter. MM‐specific symptoms were assessed by EORTC QLQ‐MY20 (subscale score range, 1–100) at screening, the start of every 3 cycles between cycles 1–25, end of treatment, every 4 weeks until start of next line of therapy after progression and twice thereafter. For both instruments, higher scores for global and functional domains indicate better HRQoL, while higher scores on symptom scales represent higher levels of symptomatology. Change from study entry in subscale scores, defined in terms of 30 four‐week intervals, was analyzed using a linear mixed‐effects model among patients who reported HRQoL outcomes at study entry and completed at least one post‐study entry assessment.Results:Characteristics at study entry were well balanced between ixazomib (n = 386) and placebo (n = 251) arms; median age: 58 years; ECOG performance status 0–1: 97%; 79% had at least a very good partial response post ASCT at study entry. At study entry, least squares (LS) mean scores for ixazomib vs. placebo on the EORTC QLQ‐C30 were: Global Health Status/QoL, 69.8 vs. 69.1; Physical Functioning, 82.1 vs. 82.0; Pain, 25.3 vs. 25.7; Nausea/Vomiting, 2.3 vs. 2.0; Diarrhea, 5.9 vs. 6.0; and on the EORTC QLQ‐MY20 were: Disease Symptoms, 20.3 vs. 19.2; Peripheral Neuropathy, 25.0 vs. 25.6. Compliance with study assessments, averaged across cycles, was high in the treatment phase (≥94%) and similar between treatment groups.Changes in subscale scores across the 4‐week intervals were generally similar between the ixazomib and placebo groups, with treatment differences not reaching the established minimal important difference (MID) of 10 in MM (Kvam et al., Eur J Haematol 2011;87:330). LS mean (95% CI) score changes at interval 24 (week 96) for ixazomib vs. placebo on the EORTC QLQ‐C30 included: Global Health Status/QoL, –0.4 (–3.4, 2.7) vs. 1.8 (–1.7, 5.2); Physical Functioning, 0.7 (–1.8, 3.1) vs. 3.0 (0.3, 5.8); Pain, 4.1 (0.5, 7.7) vs. –1.4 (–5.5, 2.7); and on the EORTC QLQ‐MY20 were: Disease Symptoms, 5.1 (2.4, 7.9) vs. 0.8 (–2.3, 3.8); Peripheral Neuropathy, –0.7 (–5.1, 3.7) vs. –6.2 (–11.1, –1.3). EORTC QLQ‐C30 Nausea/Vomiting and Diarrhea subscales, while consistently worse for ixazomib than placebo (LS mean [95% CI] change at interval 24, 5.0 [3.0, 7.0] vs. 1.0 [–1.3, 3.3] and 4.0 [1.1, 6.8] vs. 0.5 [–2.8, 3.8], respectively), were in line with the ixazomib toxicity profile; treatment differences did not exceed the MID.Summary/Conclusion:In addition to improvements in PFS with ixazomib, HRQoL was maintained during the protocol‐defined treatment period in both arms, and active treatment with ixazomib did not have an adverse impact on HRQoL.

Background:Deepened response has been associated with prolonged progression‐free (PFS) and overall survival in multiple myeloma, including in the maintenance therapy setting. In the Myeloma XI trial, post‐ASCT maintenance with lenalidomide vs observation resulted in improved responses in 15.8% vs 11.0% of patients (pts) and a median PFS of 56.9 vs 30.1 months (Jackson et al, ASH 2017). In the phase 3, double‐blind, placebo‐controlled TOURMALINE‐MM3 study (NCT02181413), post‐ASCT maintenance therapy with the oral proteasome inhibitor (PI) ixazomib vs placebo resulted in a 39% improvement in PFS (median 26.5 vs 21.3 months; HR 0.72; 95% CI: 0.58–0.89; p = 0.002), with a favorable safety profile (Dimopoulos et al, Lancet 2019). We report improvements in depth of response and the impact on outcomes in TOURMALINE‐MM3.Aims:To evaluate the rates and timing of response improvement during ixazomib vs placebo maintenance and the impact on PFS in TOURMALINE‐MM3.Methods:Pts who had achieved ≥partial response (PR) to induction therapy with a PI and/or immunomodulatory drug followed by single ASCT were randomized 3:2 to receive ixazomib (N = 395) or placebo (N = 261) on day 1, 8, and 15 of 28‐d cycles for up to 2 years or until progressive disease or unacceptable toxicity. Randomization was stratified by induction regimen, pre‐induction ISS stage, and post‐ASCT response (complete response [CR] or very good PR [VGPR] vs PR). Ixazomib dose was 3 mg in cycles 1–4 and 4 mg from cycle 5 if tolerated in cycles 1–4. Minimal residual disease (MRD) was assessed at screening by flow cytometry (10–5 sensitivity). The primary endpoint was PFS per independent review committee (IRC). Other endpoints included rate of response improvement in pts enrolled in VGPR or PR.Results:At study entry, 60 (15%), 213 (54%), and 89 (23%) pts in the ixazomib arm and 54 (21%), 152 (58%), and 35 (13%) in the placebo arm had CR, VGPR, and PR, respectively, by IRC. Deepening responses were seen in 139/302 (46%) ixazomib vs 60/187 (32%) placebo pts with VGPR/PR at enrollment (relative risk [RR] 1.41, 95% CI 1.1–1.8, p = 0.004), including 92/213 (43%) vs 48/152 (32%) VGPR to CR (RR 1.37, p = 0.025) and 47/89 (53%) vs 12/35 (34%) PR to VGPR/CR (RR 1.54, p = 0.063). On Kaplan‐Meier analysis of time to best deepened response in VGPR/PR pts (Figure), 24‐month rates of deepening response were 54.2% vs 41.4%, and there was a 38.4% improvement in the chance of deepening response over time with ixazomib vs placebo (HR 1.384, p = 0.034). A pooled analysis across arms among pts enrolled in VGPR/PR showed that deepening response vs no improvement was associated with prolonged PFS (median not reached vs 15.9 months; HR 0.245, 95% CI 0.184–0.325, p < 0.0001). Analysis by treatment arm showed that, in VGPR/PR pts with deepening response, 24‐month PFS rates were 77.4% vs 68.3% with ixazomib vs placebo (medians not reached; HR 0.875; 12.5% risk reduction; 95% CI 0.52–1.47; p = 0.615); in VGPR/PR pts without deepening response 24‐month PFS rates were 33.4% vs 23.6% (median 17.9 vs 14.1 months; HR 0.780; 22% risk reduction; 95% CI 0.59–1.03; p = 0.080). Baseline MRD status was a strong predictor of deepening response; deepening responses were seen in 63% (78/124) vs 32% (94/293) of MRD‐ vs MRD+ pts enrolled in VGPR/PR.Summary/Conclusion:Post‐ASCT maintenance with ixazomib resulted in a significantly higher rate of deepening response vs placebo; deepening response was associated with prolonged PFS. Ixazomib resulted in non‐significant PFS benefit vs placebo in VGPR/PR pts with and without deepening response; prolonged follow‐up would be needed to confirm these results.image