Abstract: In nonurban areas with limited access to thrombectomy-capable centers, optimal prehospital transport strategies in patients with suspected large-vessel occlusion stroke are unknown. Objective To determine whether, in nonurban areas, direct transport to a thrombectomy-capable center is beneficial compared with transport to the closest local stroke center. Design, Setting, and Participants Multicenter, population-based, cluster-randomized trial including 1401 patients with suspected acute large-vessel occlusion stroke attended by emergency medical services in areas where the closest local stroke center was not capable of performing thrombectomy in Catalonia, Spain, between March 2017 and June 2020. The date of final follow-up was September 2020. Interventions Transportation to a thrombectomy-capable center (n = 688) or the closest local stroke center (n = 713). Main Outcomes and Measures The primary outcome was disability at 90 days based on the modified Rankin Scale (mRS; scores range from 0 [no symptoms] to 6 [death] ) in the target population of patients with ischemic stroke. There were 11 secondary outcomes, including rate of intravenous tissue plasminogen activator administration and thrombectomy in the target population and 90-day mortality in the safety population of all randomized patients. Results Enrollment was halted for futility following a second interim analysis. The 1401 enrolled patients were included in the safety analysis, of whom 1369 (98%) consented to participate and were included in the as-randomized analysis (56% men; median age, 75 [IQR, 65-83] years; median National Institutes of Health Stroke Scale score, 17 [IQR, 11-21] ); 949 (69%) comprised the target ischemic stroke population included in the primary analysis. For the primary outcome in the target population, median mRS score was 3 (IQR, 2-5) vs 3 (IQR, 2-5) (adjusted common odds ratio [OR], 1.03; 95% CI, 0.82-1.29). Of 11 reported secondary outcomes, 8 showed no significant difference. Compared with patients first transported to local stroke centers, patients directly transported to thrombectomy-capable centers had significantly lower odds of receiving intravenous tissue plasminogen activator (in the target population, 229/482 [47.5%] vs 282/467 [60.4%]; OR, 0.59; 95% CI, 0.45-0.76) and significantly higher odds of receiving thrombectomy (in the target population, 235/482 [48.8%] vs 184/467 [39.4%]; OR, 1.46; 95% CI, 1.13-1.89). Mortality at 90 days in the safety population was not significantly different between groups (188/688 [27.3%] vs 194/713 [27.2%]; adjusted hazard ratio, 0.97; 95% CI, 0.79-1.18). Conclusions and Relevance In nonurban areas in Catalonia, Spain, there was no significant difference in 90-day neurological outcomes between transportation to a local stroke center vs a thrombectomy-capable referral center in patients with suspected large-vessel occlusion stroke. These findings require replication in other settings. Trial Registration ClinicalTrials.gov Identifier: NCT02795962

Abstract: Background Transformation into aggressive lymphoma (AL) is a rare complication of indolent lymphoproliferative disorders (LPDs) and is characterized by poor outcome. Immunoglobulin M (IgM) gammopathies are a spectrum of conditions, from monoclonal gammopathy of undetermined significance (MGUS) to Asymptomatic Waldenstroem Macroglobulinemia (AWM) and Symptomatic WM (SWM) that can eventually evolve to transformed WM (tWM). Actually, tWM represents a clinical challenge, mainly because of its poor characterization. Aims This registry study aims to better characterize tWM, focusing on prognostic factors heralding transformation to AL. Methods Two registries of IgM-MGUS, AWM and SWM [Owen, Semin Oncol 2003] based in Salamanca and in the region of Castilla and Leon (Spain) were investigated to identify cases with histological transformation. IgM-secreting patients with other LPDs (e.g. chronic lymphocytic leukemia, marginal zone lymphoma, IgM-multiple myeloma) were excluded from the analysis. All patients provided written informed consent in accordance to Helsinki's declaration. Statistical analysis was carried out using R v 3.3.3. tool; survival analyses were performed with Log-Rank method, while group comparison was performed with t-student for continuous variables and Chi-square tests for categorical variables. Results Data from 903 patients with IgM-secreting disorders diagnosed between 1976 and 2019 were analyzed; 587 cases with confirmed diagnosis of IgM-MGUS, AWM or SWM were selected. Out of 587 IgM-gammopathies, 22 cases with histological transformation to AL were identified. Cumulative incidence of tWM was: 1.4% at 5, 3.4% at 10 and 5.3% at 12 years, respectively (figure 1). Clinical features at first diagnosis of patients subsequently developing tWM where then analyzed: 3/22 tWM evolved from previous IgM-MGUS, while the remaining patients originally presented with AWM (6/22) or SWM (13/22). IPSS-WM prognostic score was LR for 5, IR for 12 and HR for 3/20 patients, respectively [Morel, Blood 2009]. Glancing on distributions between groups according to the outcome, tWM differed from not transformed (NT) cases for: lower median age at diagnosis (66 vs 72 years, p=0.018), lower platelets levels (median 188 vs 235 x 10^9/mmc, p=0.017), higher LDH ratio (0.8 vs 0.67, p=0.015), higher incidence of chromosome 6q deletion by FISH (40 vs 14%, p=0.021) and higher clonal B lymphocytes infiltration on marrow aspirate by flow cytometry (15 vs 4.5%, p= 0.022). Moreover, 13/22 patients received anti-WM treatment within 3 months from initial diagnosis, mainly chlorambucil-based; 5/22 patients received rituximab in first line and 13 in second line. From the whole series, after a median follow-up of 80 months, median transformation-free survival was 61 months from initial diagnosis (range: 0-228). Among these, Only 1/22 of tWM patient is still alive; 19/21 deaths were thus related to AL/WM, with a median survival after transformation of 12 months (0-53). In the whole series (n=587 ), median OS from initial diagnosis of IgM gammopathy was 76 months for the tWM group (6-225), that is shorter than the NT group (128 months, p=0.012, figure 2). Focusing only on patients treated at initial diagnosis, median survival after first treatment (SAFTI) was 62 vs 90 months for tWM vs NT (p=0.011, figure 3), and median time to next treatment was 28 vs 46 months, respectively (p=0.13). Overall, 10/22 tWM patients received ≥3 treatment lines, and median number of lines prior to transformation was 2 (0-3). Finally, in the whole series IPSS-WM score at diagnosis confirmed to impact on survival (median OS=151, 119 and 56 months for LR, IR and HR groups, respectively, p 〈 0.001). However, this was not the case for tWM cases only, where OS was no longer different between groups. Conclusions In this retrospective study, we confirmed dismal outcome for tWM patients; incidence of transformation was comparable to expectations at 5 years, but higher at subsequent follow-up. At initial diagnosis of IgM gammopathy, younger age, low platelets level, high LDH ratio, high B lymphocytes infiltration by flow cytometry and presence of 6q deletion were significantly enriched among patients subsequently developing tWM. IPSS-WM score looked less predictive among tWM patients probably given to the limited numbers of tWM series. Novel prognostic tools are eagerly awaited for tWM patients. Figure Disclosures Cavallo: Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Puig:The Binding Site: Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria. Ferrero:Gilead: Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Speakers Bureau; EUSA Pharma: Membership on an entity's Board of Directors or advisory committees. Boccadoro:Celgene: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; Sanofi: Honoraria, Research Funding.

Abstract: Background: Patients with RRMM receive multiple lines of therapy in their disease course and often become refractory to or are intolerant of newer approved therapies (eg, IMiDs, anti-CD38 monoclonal antibody [mAb] therapy, proteasome inhibitors [PIs] ), limiting effective treatment options (Kumar et al. Leukemia. 2017; 31:2443). Efficacy outcomes decrease with each line of therapy, showing a need for agents with novel mechanisms of action to improve treatment responses and survival outcomes (Gandhi et al. Leukemia. 2019;33:2266). Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate (PDC) that targets aminopeptidases and rapidly releases alkylating agents into tumor cells. In the phase 2 HORIZON study (OP-106; NCT02963493), melflufen plus dexamethasone demonstrated encouraging efficacy in heavily pretreated patients with RRMM refractory to pomalidomide and/or an anti-CD38 mAb (overall response rate [ORR], 29%; median progressi on-free survival [PFS], 4.2 months; median overall survival [OS] , 11.6 months) with a clinically manageable safety profile characterized primarily by hematologic adverse events (Richardson et al. EHA 2020. Abs. EP945). A contemporary representative control cohort is often used to indirectly compare outcomes of patients in clinical trials versus real-world data. The retrospective MAMMOTH study investigated the natural history and outcomes of patients with RRMM refractory to anti-CD38 mAb therapy after treatment with conventional agents (Gandhi et al. Leukemia. 2019;33:2266), providing a benchmark for the evolving state of the RRMM treatment landscape. Outcomes in clinical studies of novel agents in RRMM have been compared with MAMMOTH previously (Costa et al. ASH 2019. Abs. 3125), but not specifically in patients with RRMM refractory to anti-CD38 mAb therapy. To contextualize the clinical benefit of melflufen plus dexamethasone compared with conventional agents for patients with RRMM refractory to anti-CD38 mAb therapy, an analysis was conducted evaluating efficacy outcomes in HORIZON versus MAMMOTH. Methods: HORIZON patients with RRMM refractory to anti-CD38 mAb in the last line of therapy in the intention-to-treat population at final analysis (data cutoff date, 14 Jan 2020) were included in this analysis (N=63). Patients received melflufen 40 mg (intravenously on day 1 of each 28-day cycle) plus dexamethasone 40 mg weekly until disease progression or unacceptable toxicity. The MAMMOTH dataset included patients who progressed while on anti-CD38 mAb therapy (N=275) and were subsequently treated (N=249). ORR was assessed by the investigator per the International Myeloma Working Group criteria. PFS was defined as the time between the first dose of therapy and disease progression or death. OS was defined as the time from refractoriness to anti-CD38 mAb therapy to death from any cause in contrast to clinical studies in which OS is generally measured from first dose of subsequent therapy. Results: Patients in HORIZON and MAMMOTH had similar baseline median age and profile of daratumumab and isatuximab refractoriness (Table). Patients in HORIZON were more heavily pretreated than those in MAMMOTH (median number of prior therapies [range], 5 [2-10] versus 4 [1-16]). Patients in MAMMOTH were often treated with triplet therapy as first subsequent therapy after anti-CD38 mAb therapy failure (Table). ORR for HORIZON patients who failed last-line therapy with an anti-CD38 mAb (N=63) was 35% versus 31% for all anti-CD38 mAb therapy-refractory patients who received conventional agents in MAMMOTH. Median PFS was 4.6 months (95% CI, 3.7-6.4) versus 3.4 months (95% CI, 2.8-4.0), and median OS from last line was 15.4 months (95% CI, 12.0-25.6) versus 9.3 months (95% CI, 8.1-10.6) for these patients in HORIZON and MAMMOTH, respectively. Conclusion: This indirect comparison of patients with RRMM refractory to anti-CD38 mAb therapy in HORIZON and MAMMOTH suggests longer survival outcomes with melflufen plus dexamethasone (median PFS and OS of 4.6 and 15.4 months, respectively) versus those with conventional agents, despite HORIZON having more heavily pretreated patients. This analysis underscores the high burden of disease and unmet needs for patients with RRMM and the feasibility of novel combination therapy in this setting. Disclosures Blade Creixenti: Takeda: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Mateos:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: 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; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees. Oriol:GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; Amgen: Consultancy, Speakers Bureau; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Larocca:GSK: Honoraria; Takeda: 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; 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; Amgen: Honoraria. Cavo:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GlaxoSmithKline: Honoraria, Speakers Bureau; Karyopharm: Honoraria; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rodríguez-Otero:Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Abbvie: Consultancy; Kite: Consultancy; Sanofi: Consultancy; Celgene/Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Medscape: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; GlaxoSmithKline: Consultancy, Current Employment, Current equity holder in publicly-traded company; Oncopeptides: Consultancy. Leleu:GSK: Honoraria; Sanofi: Honoraria; Novartis: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; Amgen: Honoraria; Karyopharm: Honoraria; AbbVie: Honoraria; BMS-celgene: Honoraria; Janssen: Honoraria; Oncopeptide: Honoraria. Nadeem:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Adaptive: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, 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, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Janssen: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES. Hassoun:Novartis: Consultancy; Celgene: Research Funding; Takeda: Research Funding. Touzeau:Abbvie: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses, Research Funding; Amgen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; GlaxoSmithKline: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Other: Travel, Accommodations, Expenses; Sanofi: Honoraria, Research Funding. Amor:Amgen: Consultancy, 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; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; GSK: Membership on an entity's Board of Directors or advisory committees. Maisel:Takeda: Honoraria, Speakers Bureau; Incyte: Honoraria, Speakers Bureau; Kite: Honoraria, Speakers Bureau; Texas Oncology: Current Employment; Karyopharm: Honoraria, Speakers Bureau; Incyte: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Karyopharm: Honoraria, Speakers Bureau; Texas Oncology: Current Employment; Celgene: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Kite: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau. Mazumder:The Oncology Institute: Current Employment; Amgen: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau. Raptis:INTEGRA: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; UPMC: Current Employment. Puig:BRISTOL-MYERS SQUIBB: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding, Speakers Bureau; AMGEN: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; CELGENE: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding, Speakers Bureau; JANSSEN: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; TAKEDA: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding; THE BINDING SITE: Consultancy, Honoraria. Zavisic:Oncopeptides AB: Current Employment, Current equity holder in publicly-traded company. Thuresson:Oncopeptides: Consultancy, Current equity holder in publicly-traded company; Statisticon: Current Employment. Harmenberg:Oncopeptides AB: Consultancy, Current equity holder in publicly-traded company, Divested equity in a private or publicly-traded company in the past 24 months, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Medivir AB: Current equity holder in publicly-traded company; Ultupharma AB: Current equity holder in private company. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. OffLabel Disclosure: This is an indirect comparison of clinical studies, including a phase 2 investigational study of melflufen in RRMM

Abstract: Introduction : In patients (pts) with multiple myeloma (MM), next generation flow cytometry (NGF) and next generation sequencing have shown an increased capacity to identify the presence of disease and to anticipate patient's prognosis as compared to serum protein immunofixation (IFE). However, both methods rely on bone marrow (BM) samples and it is important to explore alternative techniques applicable in more accessible samples such as peripheral blood. Patients and Methods: Newly diagnosed MM pts enrolled in the PETHEMA/GEM2012MENOS65 trial received six cycles of induction with bortezomib, lenalidomide and dexamethasone (VRD), intensification with high-dose therapy (melphalan or busulfan and melphalan) followed by autologous stem cell transplantation and consolidation with two more cycles of VRD. At the end of the treatment (post-consolidation), the M-protein (MP) was analyzed in serum by conventional IFE and by EXENT Quantitative Immunoprecipitation Mass Spectrometry using IgG/A/M, κ, λ, free κ and free λ isotypic beads; negative samples by EXENT were re-analyzed by liquid chromatography mass spectrometry (LC-MS). The presence of clonal plasma cells in BM samples was investigated by NGF following the Euroflow guidelines (sensitivity≥10 -5). Samples from the first 164 pts enrolled in the trial were analyzed in this study. Results : After consolidation, persistent disease was detected in 42 (26%) pts by IFE, in 56 (34%) by EXENT and in 72 (44%) by NGF. Surprisingly, the presence or absence of disease by IFE did not discriminate pts with different progression-free survival (PFS), but both EXENT and NGF segregated two cohorts with a significantly different PFS (p=0.0016 and p & lt;0.0001, respectively; fig1A and 1C). Importantly, we observed that among pts in complete response (IFE negative), EXENT and NGF also distinguished two groups with different PFS (p=0.002 and p=0.0001, respectively.) Analyzing the results obtained with EXENT and NGF, we found that 76% were concordant (44 EXENT +/NGF +, 80 EXENT -/NGF -) and 24% discordant (28 EXENT -/NGF + and 12 EXENT +/NGF -). When we compared pts´ PFS according the combined results of both methods (fig 1D), we learnt that the 3 comparisons reaching statistical significance were EXENT +/NGF + vs EXENT -/NGF - (p & lt;0.0001), EXENT +/NGF + vs EXENT +/NGF - (p=0.0394) and EXENT -/NGF - vs EXENT -/NGF + (p=0.0363). Considering NGF as a reference, the negative predictive value (NPV) of EXENT was 74% overall (96% in MRD levels ≥10 -4, p & lt;0.0001; 89% in & lt;10 -4 - ≥10 -5 p & lt;0.0001; and 84% in ≥10 -6 cases, p=0.0524). Samples deemed negative by EXENT were re-analyzed with LC-MS. In 63 of them (58%) the MP was identified using LC-MS and therefore a total of 119 samples (73%) were considered positive with EXENT & LC-MS. We first confirmed that EXENT & LC-MS segregated two cohorts with different PFS (fig 1B, p=0.0193) Then, as earlier, we analyzed the results obtained with EXENT & LC-MS and NGF, finding that 65% were concordant (67 EXENT & LC-MS +/NGF +, 40 EXENT & LC-MS -/NGF -) and 35% discordant (5 EXENT & LC-MS -/NGF + and 52 EXENT & LC +/NGF -). Again, we compared pts´ PFS according the combined results of both methods (fig 1E) learning now that only the comparisons EXENT & LC-MS +/NGF + vs EXENT & LC-MS -/NGF - (p=0.0006) and EXENT & LC-MS +/NGF + vsEXENT & LC-MS +/NGF - (p=0.0006) reached statistical significance. With these results, the NPV of EXENT & LC-MS was 89% overall (100% in MRD levels ≥10 -4 p & lt;0.0001; 100% in & lt;10 -4 - ≥10 -5 p & lt;0.0001; and 89% in ≥10 -6 cases p=0.0914). Finally, we observed that whereas among pts deemed EXENT +, NGF identified 2 cohorts with different PFS (a NGF -group of 12 pts displaying a longer PFS as compared with those NGF +; median PFS: 4 years vs not reached, p=0.039) among EXENT & LC-MS - cases (n=45) NGF was not able to show any added clinical value. Conclusions : The use of IFE post-consolidation in pts with MM, as opposed to EXENT and NGF, did not identify pts with different PFS. When referred to NGF, EXENT provided a similar clinical value and displayed a very high NPV, increased further with the addition of LC-MS; this could be utilised to avoid the performance of a BM aspiration after treatment in pts with undetectable disease. Regarding EXENT + and/or LC-MS + cases future quantitative and sequential studies could reveal whether are due to the long half-lives of the MP or represent quiescent low-level disease. Figure 1 Figure 1. Disclosures Puig: Amgen, Celgene, Janssen, Takeda and The Binding Site: Honoraria; Amgen, Celgene, Janssen, Takeda: Consultancy; Celgene: Speakers Bureau; Celgene, Janssen, Amgen, Takeda: Research Funding. Paiva: Bristol-Myers Squibb-Celgene, Janssen, and Sanofi: Consultancy; Adaptive, Amgen, Bristol-Myers Squibb-Celgene, Janssen, Kite Pharma, Sanofi and Takeda: Honoraria; Celgene, EngMab, Roche, Sanofi, Takeda: Research Funding. Cedena: Janssen, Celgene and Abbvie: Honoraria. Rosinol: Janssen, Celgene, Amgen and Takeda: Honoraria. Martínez-López: Roche, Novartis, Incyte, Astellas, BMS: Research Funding; Janssen, BMS, Novartis, Incyte, Roche, GSK, Pfizer: Consultancy. Oriol: Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: 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. Sureda: Bluebird: Membership on an entity's Board of Directors or advisory committees; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Mundipharma: Consultancy; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Moraleda: Jazz Pharmaceuticals: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Gilead: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Novartis: Consultancy, Honoraria, Other: Educational Grants, Research Funding; Sandoz: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other: Educational Grants, Research Funding; ROCHE: Consultancy, Honoraria, Other: Educational Grants, Research Funding; MSD: Other: Educational Grants, Research Funding; Sanofi: Other: Educational Grants, Research Funding; Pfizer: Other: Educational Grants, Research Funding; NovoNordisk: Other: Educational Grants, Research Funding; Janssen: Other: Educational Grants, Research Funding; Celgene: Other: Educational Grants, Research Funding; Amgen: Other: Educational Grants, Research Funding. Bladé Creixenti: Janssen, Celgene, Takeda, Amgen and Oncopeptides: Honoraria. San-Miguel: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Karyopharm, Merck Sharpe & Dohme, Novartis, Regeneron, Roche, Sanofi, SecuraBio, and Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mateos: Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Adaptive Biotechnologies: 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; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sea-Gen: 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; Celgene - Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: 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; Bluebird bio: Honoraria; GSK: Honoraria; Oncopeptides: Honoraria.

Abstract: Background: Deep understanding of the complexity and diversity of the tumor immune microenvironment (TIME) and its influence on response to therapy is needed to improve the ability to predict, monitor and guide immunotherapeutic responsiveness. Among different cell types in the MM-TIME, granulocytic MDSCs (G-MDSCs) have a prominent role in promoting tumor growth and inducing immune suppression; however, their identification and monitoring is imprecise because the phenotypic profile of MDSCs in the MM-TIME is not well-established. Aim: To provide the detailed phenotypic profile of G-MDSCs based on the immune suppressive potential, gene regulatory network and clinical significance of distinct granulocytic subsets in the MM-TIME. Methods: First, we used multidimensional flow cytometry (MFC) to evaluate the preestablished phenotype of G-MDSCs in bone marrow (BM) samples from controls (n=4) and MM patients (n=5). We then used principal component analysis (PCA) to unbiasedly identify different granulocytic subsets in the MM-TIME, and FACS for in vitro experiments to determine their immune suppressive potential (n=9) and for RNAseq to analyze the molecular profile of G-MDSCs in MM (n=5) vs controls (n=5). Subsequently, the clinical significance of the different granulocytic subsets was investigated by comparing their numbers at diagnosis, in MM patients (n=124) achieving MRD-negativity vs MRD-positivity after treatment with VRD induction (x6) followed by autologous transplant and VRD consolidation (x2) (GEM2012MENOS65 clinical trial). Results: In humans, G-MDSCs have been defined as a unique cluster displaying a CD11b-, CD14-, CD15+, CD33+ and HLADR- phenotype, comprising 1% of total BM nucleated cells in healthy individuals and approximately 25% in MM patients. However, we found that the percentage of cells with a CD11b-CD14-CD15+CD33+HLADR- phenotype was similar in the BM of controls and MM patients (median of 8% in both, P 〉 .99). Since these cells were not expanded in MM and represented only 24% of total neutrophils, we next used MFC and PCA to unbiasedly identify other cell clusters within neutrophils. Accordingly, 3 major subsets were identified in neutrophils from controls and MM patients, based on homogeneous CD14-CD15+CD33+HLADR- expression but differential reactivity against CD11b, CD13 and CD16: CD11b-CD13lo/-CD16- (19% and 24%), CD11b+CD13lo/-CD16- (46% and 47%) and CD11b+CD13+CD16+ (35% and 29%). Afterwards, we used FACSorting to deplete or isolate individually, each of the 3 neutrophil subsets from the BM MM-TIME and determine its immune suppressive potential in 2 functional assays: 1) the proliferation rate of autologous T cells in presence of CD3/CD28 stimulatory beads and, 2) the cytotoxic potential of autologous T-cells against MM cells using a BCMAxCD3 bispecific antibody. Interestingly, we noted a significant decrease in T cell proliferation when these were stimulated in the presence of CD11b+CD13+CD16+ neutrophils (0.5-fold, p =.03) but not the CD11b-CD13lo/-CD16- and CD11b+CD13lo/-CD16- subsets. In addition, we noted that the cytotoxic potential of T cells engaged by the BCMAxCD3 bispecific antibody significantly increased with the depletion of CD11b+CD13lo/-CD16- and CD11b+CD13+CD16+ subsets (3-fold and 4-fold, respectively; p ≤.04) but not CD11b-CD13lo/-CD16- neutrophils. Furthermore, RNAseq of the 3 subsets in controls and MM patients revealed that genes related with the IL-4, IL-10 and IL-13 immunosuppressive pathways were specifically upregulated in the CD11b+CD13+CD16+ subset. Finally, based on the surrogacy between the achievement of MRD-negativity and prolonged survival, we compared the distribution of the 3 granulocytic subsets in the BM-TIME at diagnosis and observed that patients reaching MRD-negativity (n=56) displayed significantly lower percentages of total neutrophils (46% vs 52%, p =.002), particularly of the CD11b+CD13lo/-CD16- (11% vs 15%, p =.003) and CD11b+CD13+CD16+ (31% vs 35%, p =.07) subsets vs MRD-positive cases (n=68). Conclusions: We have determined the correlation between the phenotypic, molecular and immunosuppressive potential of unique granulocytic subsets. Thus, we have identified optimal markers for monitoring G-MDCSs in patients with MM (ie. CD11b, CD13, CD16) and unveiled that, in contrast to previous findings, the more mature granulocytes are the only stages with immunosuppressive potential. Disclosures Puig: Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Martinez Lopez:Celgene: Research Funding, Speakers Bureau; Bristol Myers Squibb: Research Funding, Speakers Bureau; Novartis: Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau. Oriol:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Consultancy, 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, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rios:Amgen, Celgene, Janssen, and Takeda: Consultancy. Rosinol:Janssen, Celgene, Amgen, Takeda: Honoraria. Mateos:Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, 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; 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; Takeda: 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; GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees. Lahuerta: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; Amgen: 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. Bladé:Celgene: Honoraria; Janssen: Honoraria; Amgen: Honoraria. San-Miguel:Janssen: Honoraria; Celgene: Honoraria; Amgen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Roche: Honoraria.

Abstract: Continuous treatment with lenalidomide (R) and dexamethasone (d) is a standard of care for multiple myeloma (MM) patients (pts) not candidates for autologous stem cell transplantation (ASCT). As previously reported, the addition of Clarithromycin (C) to Rd has proven to be safe and effective, and case-control analyses suggested a significant additive value with the combination. C optimizes the therapeutic effect of glucocorticoids by increasing the area under the curve, has immunomodulatory effects and may have direct antineoplastic properties. However, there are not randomized phase III trials confirming these results. GEM-Claridex in an open, randomized, phase III trial for untreated newly diagnosed MM pts ineligible for ASCT. Enrolled pts were randomly assigned 1:1 to receive 28-day cycles of R (25mg po qd days 1-21), d (40mg po [20mg in pts & gt;75 years], days 1, 8, 15 and 22) plus or minus C (500mg po bid) until disease progression or unacceptable toxicity. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall response rate (ORR), overall survival (OS) and minimal residual disease (MRD) negativity rate and safety. MRD was evaluated in 99 pts using Euroflow NGF (limit of detection, 2x10-6). As expected, most pts in CR were tested for MRD whereas the majority of pts with missing MRD data achieved VGPR or less and were thus considered as MRD-positive for intent to treat analyses. Two hundred and eighty-eight pts were included (144 to C-Rd and 144 to Rd). Median age was 76 (range: 65-93), 36.8% of pts had ISS 3 and 15.6% presented with high-risk cytogenetic abnormalities. Key baseline characteristics were well balanced between the two arms. The addition of C to Rd resulted in deeper responses with a ≥ complete response (CR) rate of 20.1% in the C-Rd arm compared to 11.2% in the Rd arm (p = 0.037). Also, the ≥ very good partial response (VGPR) rate was 52.8% in the C-Rd arm as compared to the 37.1% in the Rd arm (p = 0.007). MRD analysis was performed at suspected CR and yearly afterwards. On intent-to-treat, 5/144 (3,5%) and 9/143 (6,2%) of pts achieved undetectable MRD with C-Rd and Rd, respectively (p = 0,7). With a median follow-up of 16 months (range, 1-47), no significant differences were observed in PFS: in the C-Rd arm the median was 23 months and has not been reached in the Rd arm (p = 0.09); furthermore, although disease progression and/or death rate was comparable in both arms (C-Rd: 57/144 [39.6%] vs Rd: 45/144 [31.2%] ), a trend towards shorter PFS was observed in the C-Rd group (Figure 1). This effect was less evident in younger ( & lt;75) pts (median PFS, C-Rd: 24 months vs Rd NR, p = 0,588) but, in older pts (≥ 75), the addition of C to Rd resulted into a significant deleterious effect on PFS (median PFS, C-Rd: 19 vs Rd 28 months, p = 0.03) (Figure 2a and 2b). Irrespectively of treatment arm, pts with MRD negative had significantly longer PFS (NR vs 26 months, p = 0,03). Concerning OS, no differences have been identified (p = 0.41), although median has not been reached yet in any arm. Out of the 33 and 28 deaths documented in the C-Rd and Rd arms respectively, the percentage of pts dying w/o documented PD was significantly higher in the C-Rd group (27/33 [82%] vs 13/27 [48%] , p = 0.004). Furthermore, in the C-Rd arm, the most frequent causes of death were severe infections (14/27 [52%] and cardiovascular events 6/27 [22%] ) the majority of them occurring in older (≥75) pts (20/27, 74%). The most common G3-4 adverse events (AE) in the C-Rd and Rd arms were hematologic (neutropenia: 10,4% vs 16,7% [p = ns] and anemia: 2,1% vs 6,9% [p = 0,04] , respectively). G3-4 infections occurred in 16% of cases in both arms and were the most frequent non-hematological AE. 7% of pts in both arms developed G3-4 GI toxicity and there were no differences between the two arms in G3-4 skin-related AEs (2,8% vs 3,5%). Only one case of invasive SPM (colon cancer) in the C-Rd arm was reported. In conclusion, the addition of C to Rd in transplant ineligible newly diagnosed MM pts significantly increases the rate and depth of responses but it is not associated with an improved PFS and OS due to a higher proportion of deaths in the C-Rd arm, mostly infectious, in pts & gt; 75 years and being early deaths. Overexposure to steroids due to the delayed clearance induced by C in this elderly population could explain our results. Figure Disclosures Puig: The Binding Site: Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding. Rosinol Dachs:Janssen, Celgene, Amgen and Takeda: Honoraria. De Arriba:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Honoraria. Oriol:Celgene Corporation: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Janssen: Consultancy; Amgen: Consultancy, Speakers Bureau. De La Rubia:AbbVie: Consultancy; AMGEN: Consultancy; Celgene Corporation: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Amor:Celgene: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Martín Sánchez:GILEAD SCIENCES: Research Funding. Rossi:BMS: Research Funding; Janssen, Celgene, Amgen: Consultancy. Coleman:Merck: Research Funding; Pharmacyclics: Speakers Bureau; Kite Pharmaceuticals: Equity Ownership; Gilead, Bayer, Celgene: Consultancy, Research Funding, Speakers Bureau. Paiva:Amgen, Bristol-Myers Squibb, Celgene, Janssen, Merck, Novartis, Roche, and Sanofi; unrestricted grants from Celgene, EngMab, Sanofi, and Takeda; and consultancy for Celgene, Janssen, and Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria. Bladé:Jansen, Celgene, Takeda, Amgen and Oncopeptides: Honoraria. Niesvizky:Takeda, Amgen, BMS, Janssen, Celgene: Consultancy, Research Funding. Mateos:EDO: Membership on an entity's Board of Directors or advisory committees; Pharmamar: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; 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; 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; GSK: Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria.

Abstract: Background: Transplant-eligible MM patients are achieving unprecedented CR rates with frontline therapy. This urges the question about what other tests are informative upon a negative immunofixation (IFx-), as well as if patients with short duration CR continue having dismal survival with modern frontline plus salvage therapies and if so, how to predict risk of unsustained CR. Aim: To provide an optimal definition of unsustained CR and biomarkers to predict it in transplant-eligible MM patients treated with optimal therapy. Methods: A total of 262 patients enrolled in the PETHEMA/GEM2012MENOS65 trial and who were in CR after receiving six induction cycles of bortezomib, lenalidomide and dexamethasone (VRD), autologous transplant and two consolidation cycles of VRD, were included in this study. Afterwards, patients were enrolled in the PETHEMA/GEM2014MAIN trial. Median follow-up of the series was 38 months after consolidation (53 months since diagnosis). Serum free light-chains (sFLC) were measured in 252 cases. MRD was assessment with next-generation flow (NGF) in 257 patients (median limit of detection of 2.8x10-6). FISH was performed in CD138-enriched plasma cells (PCs) from 223 patients at diagnosis [high-risk was defined by the presence of t(4;14), t(14;16) and/or del(17p)]. To understand the relationship between duration of CR and outcome, patients were segmented into 6-monht increments (range, 0 - 48 months) in time since response assessment after consolidation and loss of CR. Results: We first investigated what other tests commonly performed upon the achievement of IFx- were informative, particularly those employed to define stringent CR. The median percentage of PCs by morphology, at the time of IFx-, was 1.7% (range 0-5). Only 4 patients out of 266 (1.5%) with a negative immunofixation had & gt;5% BM PCs and therefore, were not classified as in CR. Almost one-fourth of patients in CR display an abnormal sFLC ratio (56/248, 23%), but their PFS was identical to that of cases with normal sFLC ratio (3 years-PFS rates of 70% vs 72%; P=.6). BM biopsies were not performed in this study to evaluate PC clonality by immunohistochemistry but we noted that in CR patients with persistent MRD, the median percentage of clonal and normal PCs among total PCs identified by NGF was of 3% and 97%, respectively. Thus, the median percentage of normal PCs is 24-fold greater than clonal PCs within the PC compartment, and therefore simple κ/λ ratios measured in ≥100 PCs are unable to detect such low-levels of residual disease. Indeed, persistent MRD was detectable by NGF in 73/252 (29%) CR patients at a median level of 0.03% (range 0.0002% - 0.59%), and resulted in significantly inferior PFS (3-year rates of 49% vs 83% in cases with persistent vs undetectable MRD, P & lt; .00001) and OS (3 years-PFS rates of 84% vs 95%; P=.001). Afterwards, we sought to identify the optimal landmark to define unsustained CR and to identify which biomarkers could identify patients at risk. A duration of CR of & lt;24 months emerged as optimal criteria to identify a numerically relevant subset of patients (39/262, 15%) with dismal OS (median of 48 months vs not reached in patients with duration of CR ≥24 months, P & lt; .00001). We then performed a logistic regression to identify biomarkers with independent value to predict unsustained CR. Elevated LDH levels (HR: 2.9 [1.1 - 8.0], P =.038) and & gt;20% PCs (HR: 2.8 [1.2 - 6.7], P =.020) at diagnosis together with persistent MRD (HR: 4.3 [1.9 - 9.6] , P & lt;.001) had independent value to predict unsustained CR in a multivariable analysis. Thus, a scoring system with the three parameters yielded significant stratification of patients in CR into favorable (no risk factors), intermediate (any risk factor) and dismal (all risk factors) PFS (3-year rates of 92%, 67% and 0%, respectively; P & lt;.0001; Figure 1) and OS (3-year rates of 99%, 90% and 83%, respectively; P=.001). Conclusions: This is the first study evaluating which baseline and response assessments are useful to stratify transplant-eligible patients with unsustained CR in the context of modern therapy; a simple model based on LDH levels and PC counts at diagnosis plus MRD status was identified and can be used broadly. These findings are clinically meaningful because patients with unsustained CR remain a high-risk population despite optimal therapy, and those at risk should be offered alternative treatment strategies before insurmountable disease progression occurs. Figure 1 Disclosures Paiva: SkylineDx: Consultancy; Takeda: Consultancy, Honoraria, Research Funding; Roche: Research Funding; Adaptive: Honoraria; Amgen: Honoraria; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Kite: Consultancy; Sanofi: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Oriol:Amgen: Consultancy, Speakers Bureau; Janssen: Consultancy; Celgene: Consultancy, Speakers Bureau. Sureda Balari:Roche: Honoraria; Celgene: Consultancy, Honoraria; BMS: Speakers Bureau; Incyte: Consultancy; Janssen: Consultancy, Honoraria; Gilead/Kite: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Merck Sharpe and Dohme: Consultancy, Honoraria, Speakers Bureau; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau. de la Rubia:Janssen: Consultancy, Other: Expert Testimony; Amgen: Consultancy, Other: Expert Testimony; Celgene: Consultancy, Other: Expert Testimony; Ablynx/Sanofi: Consultancy, Other: Expert Testimony. Moraleda:Takeda: Consultancy, Other: Travel Expenses; Sandoz: Consultancy, Other: Travel Expenses; Novartis: Consultancy, Other: Travel Expenses; Gilead: Consultancy, Other: Travel Expenses; Jazz Pharmaceuticals: Consultancy, Research Funding. Mateos:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Honoraria; Seattle Genetics: 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; Celgene: 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; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees. San-Miguel:GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Roche: 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; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: 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; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Abstract: Background The introduction of multiple novel agents and regimens for NDMM and relapsed/refractory MM (RRMM) has improved outcomes while increasing the complexity of treatment selection and disease management. The real-world effectiveness of many novel-agent-based regimens remains to be elucidated. INSIGHT MM (NCT02761187) is the largest global, prospective, observational MM study to date. It aims to understand global NDMM/RRMM disease and pt characteristics, treatment patterns, and clinical outcomes, as well as regional variations. Here we report data for 1056 NDMM pts enrolled from July 1, 2016 to April 27, 2018. Methods INSIGHT MM is enrolling ~4200 adult pts with NDMM/RRMM (1-3 prior therapies) from 15 countries; 9 in Europe (EU), 3 in Latin America (LA), the United States (US), and 2 in Asia. Pts will be followed prospectively for ≥5 yrs. Data are collected from hospital/clinic records at baseline (MM-specific disease characteristics, prior therapies) and every 3 mos (disease management, effectiveness, safety). Results At data cut-off, 1056 NDMM pts had been enrolled from 14 countries, including 495 (47%) from EU, 361 (34%) from the US, 112 (11%) from LA, and 88 (8%) from Taiwan. Median age at enrollment was 64 (range 32-89) yrs and 139 (13%) pts were aged 〉 75 yrs (14%/12%/11%/13% in EU/US/Taiwan/LA); 57% of pts were male (60%/58%/61%/39% in EU/US/Taiwan/LA); 72%, 13%, and 8% were White/Caucasian, Asian, and Black/African American, respectively. Overall, 62% of pts were treated at academic centers and 38% in community settings. Based on accrual at data cut-off, regional differences were observed, with more pts treated at academic centers in EU/Taiwan (88%/91%) vs the US/LA (30%/25%). 87% of pts were treated outside of clinical trials (88%/82%/95%/98% in EU/US/Taiwan/LA). Bone pain (32%, including 33%/28%/40%/37% in EU/US/Taiwan/LA), weakness/fatigue (anemia; 11%, including 12%/10%/6%/18% in EU/US/Taiwan/LA), and kidney problems (5%, including 3%/3%/17%/2% in EU/US/Taiwan/LA) were the most common reasons for pts seeking care; 32% (36%/32%/22%/24% in EU/US/Taiwan/LA) were asymptomatic at diagnosis. At diagnosis, 27%/26%/31% of pts had physician-reported ISS Stage I/II/III MM, and 88% had ECOG PS 0-1; 8% of pts had hypercalcemia, 34% creatinine clearance 〈 60 ml/min, 56% anemia, and 30% 〉 3 bone lesions. The most common reasons for initiating therapy were the presence of CRAB criteria, e.g. bone involvement (54%) and anemia (37%). At start of treatment, fixed-duration therapy, treat-to-best-response, and treat-to-progression approaches were planned for 38%, 29%, and 31% of pts, respectively. The most frequently administered regimens are shown in the Table; 20%/66% of pts received a doublet/triplet. V-based regimens were the most frequently used. Regional differences in regimen selection are emerging: among IMiDs, T is most commonly prescribed in EU, Taiwan, and LA; R is more common in the US. After a median follow-up of 9.3 mos, 72 (7%) pts had discontinued the study, most often due to death (57%), consent withdrawal (14%), or change of treatment provider (11%). At data cut-off, data for 236 (22%) pts who received 1st-line ASCT were available (median age 60 yrs; 12%/63%/25% of pts aged 〈 50/50-65/ 〉 65 yrs). Of these, 64% received ASCT at academic centers; 42% of pts each in EU and the US received ASCT vs 11% in Taiwan and 4% in LA. The most frequently administered regimens in ASCT-eligible (n=429) vs ASCT-ineligible (n=571) pts were VC±d (21% vs 21%), VR±d (19% vs 17%) and VT±d (17% vs 10%). At data cut-off, 115 NDMM pts had progressed to 2nd-line therapy; 99 pts received a PI with 1st-line therapy, of whom 33 (33%) then received a PI-based regimen in 2nd line; 61 pts received an IMiD with 1st-line therapy, of whom 35 (57%) then received an IMiD-based regimen in 2nd line. Among 1st/2nd-line pts, 2%/12% received monoclonal antibody therapy. Conclusions PIs and IMiDs remain the global backbones of MM therapy, with V-based regimens most commonly used in NDMM pts, regardless of intended transplant status. These data from INSIGHT MM are beginning to elucidate regional differences in disease presentation and treatment selection, including higher numbers of pts receiving ASCT in the US/EU vs Taiwan/LA, which are likely reflective of differences in healthcare systems and access to MM treatments in the participating countries. Future studies will evaluate the impact of these regional variations on outcomes. Table. Table. Disclosures Usmani: Abbvie, Amgen, Celgene, Genmab, Merck, MundiPharma, Janssen, Seattle Genetics: Consultancy; Amgen, BMS, Celgene, Janssen, Merck, Pharmacyclics,Sanofi, Seattle Genetics, Takeda: Research Funding. Hungria:Celgene: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Leleu:Karyopharm: Honoraria; Incyte: Honoraria, Other: steering committee membership ; Celgene: Honoraria, Other: steering committee membership ; Janssen: Honoraria, Other; BMS: Honoraria, Other: steering committee membership ; Merk: Honoraria, Other: steering committee membership ; Takeda: Honoraria, Other: steering committee membership ; Amgen: Honoraria, Other: steering committee membership ; Sanofi: Honoraria, Other: steering committee membership steering committee membership ; Novartis: Honoraria, Other: steering committee membership ; Roche: Honoraria; Gilead: Honoraria. Lee:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies Corporation: Consultancy; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Chugai Biopharmaceuticals: Consultancy; Takeda Oncology: 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. Davies:Abbvie: Consultancy; Janssen: Consultancy, Honoraria; Takeda: Consultancy, 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; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; TRM Oncology: Honoraria; ASH: Honoraria; MMRF: Honoraria. Costello:Poseida Therapeutics, Inc.: Research Funding; Takeda: Consultancy; Celgene: Consultancy. Rifkin:Takeda: Consultancy; EMD Serono: Consultancy; McKesson: Equity Ownership; Celgene: Consultancy; Amgen: Consultancy; Sandoz: Consultancy; Boehringer Ingelheim: Consultancy. Weisel:Amgen, BMS, Celgene, Janssen, and Takeda: Honoraria; Amgen, BMS, Celgene, Janssen, Juno, Sanofi, and Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen, Celgene, Janssen, and Sanofi: Research Funding. Chari:Adaptive Biotechnology: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: 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; The Binding Site: Consultancy; Pharmacyclics: Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Array Biopharma: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Puig:Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Boccadoro:Amgen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; AbbVie: Honoraria; Mundipharma: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding. Cook:Bristol-Myers Squibb: Consultancy, Honoraria; Glycomimetics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene Corporation: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Takeda: Consultancy, Honoraria, Research Funding, Speakers Bureau; Seattle Genetics: Honoraria; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Berdeja:Teva: Research Funding; Janssen: Research Funding; Takeda: Research Funding; Amgen: Research Funding; Poseida Therapeutics, Inc.: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Bluebird: Research Funding; Genentech: Research Funding; Glenmark: Research Funding; Novartis: Research Funding; Sanofi: Research Funding. Zonder:Takeda: Honoraria; Coelum: Honoraria; BMS: Research Funding; Celgene: Consultancy, Honoraria; Alnylam: Honoraria; Janssen: Honoraria; Pharmacyclics: Other: DSMC. Abonour:Prothena: Research Funding; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding. Hajek:Takeda: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Spencer:Celgene: Honoraria, Research Funding, Speakers Bureau; Janssen-Cilag: Honoraria, Research Funding, Speakers Bureau; Amgen: Honoraria, Research Funding; BMS: Research Funding; Takeda: Honoraria, Research Funding, Speakers Bureau; STA: Honoraria. Omel:Takeda Oncology: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Honoraria, Membership on an entity's Board of Directors or advisory committees. Demers:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Romanus:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Ren:Takeda Pharmaceuticals International Co.: Employment. Skacel:Department of Hematology, Charles University General Hospital, Prague, Czech Republic: Other: Affiliation; Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Stull:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Terpos:Novartis: Honoraria; 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, Other: Travel Grant, Patents & Royalties; Genesis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant, Patents & Royalties; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Grant, Research Funding.

Abstract: Background: Despite significant improvements in the treatment of MM, the outcome of patients with HR cytogenetics remains poor despite similar complete remission (CR) rates as compared to SR cases. Relapses among patients in CR are attributed to the persistence of MRD, but knowledge about the impact of MRD in patients with SR and HR cytogenetics, treated with modern therapies and monitored with next-generation techniques, is limited. Similarly, there is virtually no data about in vivo mechanisms of resistance in SR and HR MM; however, since MRD represents those very few cells that are resistant to treatment, it could be hypothesized that profiling MRD cells may shed light into the mechanisms of resistance in both SR and HR patients. Aim: To determine the clinical impact of MRD in MM patients with SR vs HR cytogenetics, and to identify transcriptional mechanisms determining MRD resistance by investigating the transcriptome of MRD cells in both patient subgroups. Methods: This study was conducted in a series of 390 patients enrolled in the PETHEMA/GEM2012 trial (6 induction cycles with VRD followed by ASCT and 2 courses of consolidation with VRD). FISH was analyzed on CD138 purified PCs at diagnosis. MRD was predefined to be prospectively assessed following induction, transplant and consolidation, using next-generation flow (NGF) according to EuroFlow. In 40 patients [28 with SR and 12 with HR cytogenetics: i.e., t(4;14), t(14;16) and/or del(17p)], diagnostic and MRD tumor cells persisting after VRD-induction were isolated by FACS according to patient-specific aberrant phenotypes. Due to the small number of sorted MRD cells (median of 25,600) we used a 3' end RNAseq method optimized for generating libraries from low-input starting material (MARSeq). Differential expression analyses were performed with DESeq2 R package. Results: At the latest time-point in which MRD was assessed, MRD-positive rates progressively increased (p =.006) from SR patients (148/300, 49%) to cases with t(4;14) (24/42, 57%) and del(17p) (29/38, 76%). Furthermore, MRD levels were significantly superior in patients with del(17p) compared to SR FISH (0.02% vs 0.006%, p =.009), while MRD levels in patients with t(4;14) (0.004%) were similar to those in SR MM. Only 10 patients had a t(14;16) and 4 were MRD-positive. Among patients achieving MRD-negativity ( 〈 2x10-6), 3-year progression-free survival (PFS) rates were similar for those with SR FISH, t(4;14) and del(17p) (90%, 100% and 89%; p 〉 .05). Conversely, 3-year PFS rates for MRD-positive patients decreased from those having SR FISH to those with t(4;14) and del(17p) (59%, 46% and 24%, respectively), with statistically significant differences between the first and the latest subgroups (p 〈 .001). Since clearance of MRD notably lowered the risk of relapse and persistence of MRD significantly shortened the PFS in each cytogenetic group (p ≤.001), we investigated the unique features of MRD cells persisting after VRD-induction by comparing their transcriptome to that of patient-matched tumor cells at diagnosis (n=40). Accordingly, MRD cells showed 763 genes significantly deregulated (Padj 〈 .05), including a cluster of proteasome subunits and proteasome related genes (i.e. PSMB5, PSMC3IP, BTRC, HUWE1, FBXL20 and TRIM69). Gene set enrichment analysis unveiled biologic determinants of MRD resistance such as the IL6-JAK-STAT signaling pathway in SR patients and the ROS pathway in HR patients (FDR 〈 0.1). Interestingly, the number of genes deregulated in MRD cells of SR patients was 9-fold higher than HR cases suggesting that, whereas in SR MM, a few tumor cells with specific gene regulatory networks may have higher probability to persist VRD induction, the presence of HR cytogenetic alterations is associated per se, with a transcriptional program that allows a few MRD cells to persist treatment. Conclusions: This is one of the largest studies integrating patients' cytogenetics and MRD status. Our results, based on intensive treatment and MRD monitoring using NGF, unveil that achieving MRD-negativity may overcome the poor prognosis of HR cytogenetics. By contrast, persistent MRD significantly reduces PFS rates, particularly in patients with del(17p). Interestingly, MRD cells from SR and HR patients may have different transcriptional mechanisms leading to VRD resistance, and further understanding of these could provide knowledge on how to eradicate MRD in both patient subgroups. Disclosures Puig: Takeda: Consultancy, Honoraria; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Garcia-Sanz:Affimed: Research Funding. Martinez-Lopez:BMS: Research Funding; Pfizer: Research Funding; Vivia: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Research Funding. Oriol:Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Consultancy, 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, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Rios:Amgen, Celgene, Janssen, and Takeda: Consultancy. De La Rubia:Ablynx: Consultancy, Other: Member of Advisory Board. Mateos:GSK: Consultancy, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees; GSK: Consultancy, 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; Celgene: 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; 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. Lahuerta: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; Amgen: 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. Bladé:Janssen: Honoraria. San-Miguel:Amgen: Honoraria; BMS: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Celgene: Honoraria; Roche: Honoraria; Janssen: Honoraria.