Citations

Abstract Introduction: Depth of response is associated with long-term outcomes in multiple myeloma (MM); however, the effect of response kinetics on outcomes in NDMM is variable and less clear. Although some studies have shown that achieving a ≥very good partial response (VGPR) at 4 months (mos) from diagnosis is associated with increased overall survival (Garderet Leukemia 2018), other reports have shown worse outcomes in pts with early vs late responses (Yan Blood Adv 2019). The double-blind, randomized TOURMALINE-MM2 (NCT01850524) trial (Facon Blood 2021) showed a clinical meaningful progression-free survival (PFS) benefit with IRd vs pbo-Rd (median 35.3 vs 21.8 mos; hazard ratio, 0.830; 95% confidence interval, 0.676-1.018; P=0.073; median follow-up, 53.3 and 55.8 mos, respectively) in NDMM pts. Safety data were consistent with the established toxicity profile of IRd. We evaluated PFS and duration of response (DOR) by depth of best confirmed response and time to best response in TOURMALINE-MM2. Methods: Pts were randomized to receive oral ixazomib 4 mg (n=351) or placebo (n=354) on days 1, 8, and 15, plus oral lenalidomide 25 mg (10 mg if creatinine clearance ≤60 mL/min) on days 1-21 and oral dexamethasone 40 mg (20 mg in pts aged >75 years) on days 1, 8, 15, and 22 in 28-day cycles. After 18 cycles, treatment was continued without dexamethasone and reduced doses of ixazomib (3 mg) and lenalidomide (10 mg) until progressive disease (PD)/toxicity. Response assessments were performed every cycle until PD, or every 4 weeks in pts who discontinued treatment prior to PD. PFS and DOR were analyzed post-hoc in subgroups defined by depth of response and in subgroups defined by time to best confirmed response; 'early' and 'late' responses were defined by time to best confirmed response of 0-4 and >4 mos, respectively (additional analyses were performed by time to best confirmed response of 0-6 and >6 mos). Pts in either subgroup could have recorded an initial response prior to their best response. PFS and DOR were evaluated from randomization to progression and time of initial response to progression, respectively. To address potential guarantee-time bias in the PFS analysis, and to eliminate potential bias due to transient responses in DOR analysis, sensitivity analyses were conducted in pts with PFS / DOR of ≥6 mos. Results: Among the 705 pts in the intention-to-treat (ITT) population, 20% (26% IRd vs 14% placebo-Rd) had a best confirmed response of complete response (CR) or stringent CR, 35% (37 vs 34%) had VGPR, 26% (19 vs 32%) had PR, 10% (9 vs 10%) had stable disease (SD), 3% (1 vs 4%) had PD. 7% (8 vs 6%) of pts were not evaluable. In a pooled analysis of both arms, achieving a deeper response was associated with longer PFS (Figure, A) and DOR (median not reached [NR], 42.8, and 15.0 mos for pts with ≥CR, VGPR, and PR, respectively). In 570 pts with ≥PR (288 IRd; 282 pbo-Rd), 152 (53%) and 136 (47%) in the IRd arm and 143 (51%) and 139 (49%) pts in the pbo-Rd arm were defined as early (0-4 mos) and late (>4 mos) responders, respectively. For early vs late responders, 46% vs 40% were aged ≥75 years, 21% vs 12% had International Staging System stage III MM, and 44% vs 33% had expanded high-risk cytogenetic abnormalities. Median PFS was prolonged among late vs early responders with IRd (65.7 vs 21.2 mos) and pbo-Rd (62.6 vs 18.2 mos), as was median DOR (IRd, NR vs 22.6 mos; pbo-Rd, 64.1 vs 17.2 mos). The PFS sensitivity analysis among pts with PFS of ≥6 mos confirmed the association of late response with improved outcomes; among late vs early responders achieving ≥PR, median PFS was 65.7 vs 23.9 mos with IRd and 62.6 vs 18.4 mos with pbo-Rd (Figure, B), and among late vs early responders achieving ≥VGPR, median PFS was 65.7 vs 35.3 mos with IRd and 64.4 vs 21.7 with pbo-Rd. Conclusions: Achieving a deeper response was associated with prolonged PFS and DOR in NDMM patients in TOURMALINE-MM2. PFS benefit on the ITT analysis was driven by the higher rates of deep responses (≥VGPR) with IRd vs pbo-Rd. PFS and DOR were also longer in pts achieving a late vs early best confirmed response of ≥PR or ≥VGPR. Consistent with results from a similar analysis in relapsed/refractory MM in the TOURMALINE-MM1 trial (Garderet Leukemia 2018), our findings support the continuation of therapy with the aim of achieving a deeper response over time. Additional sensitivity analyses will be presented. Figure 1 Figure 1. Disclosures Richardson: Sanofi: Consultancy; AstraZeneca: Consultancy; Celgene/BMS: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; Regeneron: Consultancy; Oncopeptides: Consultancy, Research Funding; Protocol Intelligence: Consultancy; Secura Bio: Consultancy; Janssen: Consultancy; Takeda: Consultancy, Research Funding; AbbVie: Consultancy; Karyopharm: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding. Venner: Takeda: Honoraria; BMS: Honoraria; Janssen: Honoraria; Pfizer: Honoraria; Sanofi: Honoraria; GSK: Honoraria. Bahlis: GlaxoSmithKline: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Genentech: Consultancy; Sanofi: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. White: Amgen: Consultancy, Honoraria; Antengene: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Forus: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria. Karlin: Celgene-BMS: Honoraria, Other: member of advisory board; Sanofi: Honoraria; oncopeptide: Honoraria; Janssen: Honoraria, Other: member of advisory board, travel support; Abbvie: Honoraria; GSK: Honoraria, Other: member of advisory board; Amgen: Honoraria, Other: travel support and advisory board ; Takeda: Honoraria, Other: member of advisory board. Rigaudeau: Takeda: Membership on an entity's Board of Directors or advisory committees. Suzuki: Bristol-Myers Squibb: Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria; ONO: Honoraria; Novartis: Honoraria; Sanofi: Honoraria; Abie: Honoraria; Janssen: Consultancy, Honoraria. Shibayama: Mundi Pharma: Honoraria; Otsuka: Honoraria; Pfizer: Honoraria; Bristol-Myers Squibb: Honoraria; Sanofi: Honoraria; Nippon Shinyaku: Honoraria; Fujimoto: Honoraria; Daiichi Sankyo: Honoraria; AstraZeneca: Honoraria, Membership on an entity's Board of Directors or advisory committees; Essentia Pharma Japan: Research Funding; Chugai: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Eisai: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Avvie: Honoraria, Research Funding; Takeda: Honoraria, Research Funding; Ono: Honoraria, Research Funding; Celgene: Research Funding. Zhang: Takeda: Current Employment. Kumar: Takeda: Current Employment, Current holder of stock options in a privately-held company. Twumasi-Ankrah: Takeda: Current Employment. Labotka: Takeda: Current Employment. Rifkin: Takeda: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Fresenius-Kabi: Membership on an entity's Board of Directors or advisory committees; Coherus: Membership on an entity's Board of Directors or advisory committees; McKesson: Current Employment, Current equity holder in publicly-traded company; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb (Celgene): Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees. Lonial: AMGEN: Consultancy, Honoraria; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Merck: Honoraria. Kumar: Antengene: Consultancy, Honoraria; Carsgen: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Beigene: Consultancy; Tenebio: Research Funding; Roche-Genentech: Consultancy, Research Funding; Novartis: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Moreau: Amgen: Honoraria; Oncopeptides: Honoraria; Janssen: Honoraria; Celgene BMS: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria. OffLabel Disclosure: Use of the oral proteasome inhibitor ixazomib in newly diagnosed multiple myeloma patients who are ineligible for transplant.

Abstract Introduction: Renal light chain (AL) amyloidosis typically manifests as proteinuria with or without renal failure and is associated with a risk of progression to renal replacement therapy (RRT). A significant reduction in circulating amyloidogenic light chain is needed to achieve a renal response. Current renal response criteria are binary defining a renal response as >30% reduction in 24-h proteinuria without worsening estimated glomerular filtration rate (eGFR). Several studies suggest that greater reduction in proteinuria following successful therapy improves renal and overall survival. Methods: AL amyloidosis patients diagnosed between 2010 to 2015, achieving at least hematological partial response (hemPR) to therapy and with renal involvement (defined as 24-h non-selective proteinuria >0.5 g/24-h) were included. Four predefined renal response categories were formulated based on reduction level in pretreatment 24-h proteinuria in the absence of renal progression (≥25% decrease in eGFR): renal complete response (renCR, 24-h proteinuria ≤200 mg/24-h); renal very good partial response (renVGPR, >60% reduction in 24-h proteinuria); renal partial response (renPR, 31-60% reduction in 24-proteinuria); and renal no response (renNR, 30% or less reduction). Renal response was assessed at landmark (6-, 12-, and 24 months from treatment initiation) and as best renal response. Graded renal responses were assessed as predictors for time from diagnosis to RRT and overall survival. Results: Seven hundred and thirty-seven patients were included. The median age was 63. The breakdown of renal stage was: I, 34%; II, 52%; and III, 14%. Eighty percent of patients received 1 line of therapy within 12 months of their diagnosis. Bortezomib-based therapy was given to 60% of the patients; 28% received autologous stem cell transplantation (ASCT) as their first line therapy. Hematological CR was achieved in 44% of patients, followed by hematological very good partial response (38%) and hemPR (18%). RRT was required during follow-up in 15% of patients (n=108) with a median time from diagnosis to RRT of 18 (IQR 6-43) months. Twenty-eight percent of the patients died. The median follow-up of the surviving patients was 69 months (IQR 56-86). Reduction in 24-h proteinuria from baseline improved over time with a median reduction of 34%, 50% and 71% at 6-month, 12-month, and 24-months, respectively. At best response, renCR, renVGPR, renPR and renNR were achieved in 27% (n=199), 34% (n=247), 15% (n=112) and 24% (n=179) of patients, respectively. The median time to best renal response among renal responders was 17 (IQR 8-31) months, longer for renCR (23 months, IQR 10-40) compared to renVGPR (16 months, IQR 9-27) or renPR (11 months, IQR 6-19). A renal response as early as 6 months after therapy initiation was able to predict time to RRT with an increase in RRT risk with lower level of renal response at that time point (5-year RRT risk 0%, 3%, 9% and 16% for renCR, renVGPR, renPR and renNR, respectively, P<0.001, Figure 1A). Prediction of risk for RRT based on renal response depth improved at 12- and 24-months (Figure 1B-C) and at best renal response (Figure 1D). Overall survival discrimination based on renal response depth was noted as early as 12 months from therapy initiation and improved with time. Renal response criteria as best response were tested in a univariate analysis and multivariable proportional hazard models for time to RRT and OS. The graded renal response criteria demonstrated an independent prognostic role for time to RRT and OS. Along with renal stage, graded renal responses were the strongest predictors for time to RRT. Conclusions: We validated new graded renal response criteria based on reduction in 24-h proteinuria. These 4-level renal response criteria highlight the importance of achieving a deep renal response to improve renal and overall survival. These findings will allow clinicians to make decisions on therapy changes or augmentation based on response depth as early as 6-months, before irreversible renal failure develops. Figure 1 Figure 1. Disclosures Palladini: Janssen Global Services: Honoraria, Other: advisory board fees; Siemens: Honoraria; Pfizer: Honoraria. Milani: Celgene: Other: Travel support; Janssen-Cilag: Honoraria. Schönland: Sanofi: Research Funding; Prothena: Honoraria, Other: Travel grants; Janssen: Honoraria, Other: Travel grants, Research Funding; Takeda: Honoraria, Other: Travel grants; Pfizer: Honoraria. Hegenbart: Akcea: Honoraria; Alnylam: Honoraria; Janssen: Consultancy, Research Funding; Prothena: Research Funding; Pfizer: Consultancy, Honoraria. Dispenzieri: Oncopeptides: Consultancy; Alnylam: Research Funding; Sorrento Therapeutics: Consultancy; Pfizer: Research Funding; Takeda: Research Funding; Janssen: Consultancy, Research Funding. Kumar: Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Carsgen: Research Funding; Beigene: Consultancy; Novartis: Research Funding; Bluebird Bio: Consultancy; Amgen: Consultancy, Research Funding; Roche-Genentech: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Antengene: Consultancy, Honoraria; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Kastritis: Amgen: Consultancy, Honoraria, Research Funding; Genesis Pharma: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria; Pfizer: Consultancy, Honoraria, Research Funding. Dimopoulos: Takeda: Honoraria; Janssen: Honoraria; Beigene: Honoraria; BMS: Honoraria; Amgen: Honoraria. Liedtke: Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Alnylam: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Witteles: Pfizer: Honoraria, Research Funding; Alnylam: Honoraria, Research Funding; Eidos: Research Funding. Sanchorawala: Pfizer: Honoraria; Takeda: Research Funding; Celgene: Research Funding; Prothena: 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; Regeneron: Membership on an entity's Board of Directors or advisory committees; Proclara: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptide: Research Funding; Karyopharm: Research Funding; Sorrento: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding. Landau: Takeda, Janssen, Caelum Biosciences, Celgene, Pfizer, Genzyme: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Genzyme: Honoraria. Cibeira: Celgene: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Akcea: 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. Wechalekar: Caelum Biosciences: Other: Clinical Trial Funding; Amgen: Research Funding; Janssen: Consultancy; Celgene: Honoraria; Takeda: Honoraria; Alexion, AstraZeneca Rare Disease: Consultancy. Gertz: Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; Aurora Biopharma: Other: Stock option; Ionis Pharmaceuticals: Other: Advisory Board; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria.

Abstract Introduction: Binary cardiac response assessment using NT-proBNP is prognostic in light chain (AL) amyloidosis. Previous studies suggested that refining the criteria to multi-level cardiac responses improves prognostic prediction. We validate a graded cardiac response assessment tool in AL amyloidosis using NT-proBNP or BNP. Methods: In this retrospective, multicenter study AL amyloidosis patients who were diagnosed between 2010 and 2015, achieving at least a hematological partial response (PR) within 12 months of diagnosis and were evaluable for cardiac response (defined as baseline NT-proBNP >650 pg/mL or BNP >150 pg/mL) were included. The following response criteria were tested: cardiac complete response (carCR, nadir NT-proBNP≤350 pg/mL or BNP≤80 pg/mL); cardiac very good partial response (carVGPR, >60% reduction in NT-proBNP/BNP); Cardiac PR (carPR 31-60% reduction); and cardiac non response (carNR, ≤30% reduction). Response was assessed at fixed time points (6, 12 and 24 months from therapy initiation) and at best response. The primary outcome was overall survival based on depth of cardiac response. Multivariate Cox proportional models were analyzed to determine independent prognostic factors for OS and time to cardiac progression using variables with p-value <0.1 in a univariate analysis. Results: Six hundred and fifty-one patients were included. The median age was 64 years. Mayo 2004 cardiac stage II, IIIA and IIIB was present in 47.5%, 38% and 14.5% of patients, respectively (by definition, patients with Mayo stage I do not have cardiac amyloidosis evaluable for response). Seventy-six percent of patients received only one line of therapy within the initial 12 months of diagnosis. Bortezomib-based therapy was the most common (70.2% of patients) followed by autologous stem cell transplantation (ASCT) in 15.7% of patients. Hematological CR, hematological VGPR and hematological PR as best response was achieved in 38%, 39% and 23% of patients, respectively. Forty-three percent of the patients have died, with 36% of the patients dying within 5-years of diagnosis. The median follow-up of the surviving patients is 70 months (IQR 56-84). Cardiac response was evaluable using NT-proBNP in 494 patients (75.9%), BNP in 109 patients (16.7%) and both NT-proBNP and BNP in 48 patients (7.4%). The latter two were grouped together for further analysis. The median time to best cardiac response among responders was 12 months (IQR 7-21 months; 18 months for carCR, 11.5 months for carVGPR and 9.5 months for carPR). Cardiac response improved over time with a median percentage reduction in NT-proBNP/BNP compared to baseline of 15%, 37% and 54%, at 6, 12 and 24 months respectively. Cardiac responses at 6-, 12- and 24-months are depicted in Figure 1A. At best cardiac response, carCR, carVGPR, carPR and carNR were achieved in 16%, 26%, 23% and 35% of patients, respectively. Patients who achieved a carCR had lower cardiac stage at diagnosis compared to patients who achieved carVGPR or carPR (stage II 65% vs 47% vs 47%, respectively; P<0.001). At least carPR at 6 and 12 months and at least carVGPR at 24-months was associated with better survival compared with a lower depth of response. At best cardiac response, deeper cardiac response was associated with a longer survival (5-year OS 93%, 80%, 62% and 35% for carCR, carVGPR, carPR and carNR, respectively; P<0.001, Figure 1B). A 2-year landmark analysis (excluding early deaths not evaluable for cardiac response depth) confirmed improved survival with a deeper cardiac response (5-year OS 93%, 82%, 70% and 58%, P<0.001; Figure 1C). These cardiac response criteria were independent predictors of survival and time to cardiac progression (>30% rise in NT-proBNP/BNP) in multivariate analysis that included age, type of first line therapy, light chain burden, cardiac stage, and hematological response. Conclusions: We validated the prognostic value of graded cardiac response. These response criteria allow better discrimination of patient populations and assessment of treatment effectiveness in an era of improved therapies for AL amyloidosis. The study emphasizes the importance of early diagnosis which increases the likelihood of deep and durable cardiac responses. Figure 1 Figure 1. Disclosures Dispenzieri: Oncopeptides: Consultancy; Pfizer: Research Funding; Sorrento Therapeutics: Consultancy; Takeda: Research Funding; Alnylam: Research Funding; Janssen: Consultancy, Research Funding. Palladini: Siemens: Honoraria; Pfizer: Honoraria; Janssen Global Services: Honoraria, Other: advisory board fees. Schönland: Janssen: Honoraria, Other: Travel grants, Research Funding; Takeda: Honoraria, Other: Travel grants; Sanofi: Research Funding; Pfizer: Honoraria; Prothena: Honoraria, Other: Travel grants. Hegenbart: Alnylam: Honoraria; Janssen: Consultancy, Research Funding; Prothena: Research Funding; Pfizer: Consultancy, Honoraria; Akcea: Honoraria. Kumar: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Novartis: Research Funding; Merck: Research Funding; Tenebio: Research Funding; Bluebird Bio: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Antengene: Consultancy, Honoraria; Oncopeptides: Consultancy; Amgen: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Kastritis: Genesis Pharma: Honoraria; Takeda: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Dimopoulos: Beigene: Honoraria; Takeda: Honoraria; BMS: Honoraria; Janssen: Honoraria; Amgen: Honoraria. Liedtke: GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria; Sanofi: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees. Witteles: Eidos: Research Funding; Alnylam: Honoraria, Research Funding; Pfizer: Honoraria, Research Funding. Sanchorawala: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding; Proclara: Membership on an entity's Board of Directors or advisory committees; Prothena: 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; Caelum: Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron: Membership on an entity's Board of Directors or advisory committees; Takeda: Research Funding; Karyopharm: Research Funding; Oncopeptide: Research Funding; Pfizer: Honoraria; Sorrento: Research Funding. Landau: Genzyme: Honoraria; Takeda: Research Funding; Takeda, Janssen, Caelum Biosciences, Celgene, Pfizer, Genzyme: Membership on an entity's Board of Directors or advisory committees. Cibeira: Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Akcea: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Gertz: Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring; Ionis Pharmaceuticals: Other: Advisory Board; Aurora Biopharma: Other: Stock option.

Abstract Introduction: Daratumumab is approved across lines of therapy for multiple myeloma (MM) by subcutaneous administration (DARA SC) or by intravenous administration (DARA IV). In clinical studies, the administration time ranges from 3-5 minutes for DARA SC versus 3-7 hours for DARA IV, and DARA SC is associated with reduced rates of administration-related reactions (ARRs). These characteristics of DARA SC are associated with benefits for clinics in terms of safety and clinic time. We previously reported DARA administration characteristics at Mayo Clinic infusion centers: DARA SC had shorter total clinic and total chair times compared with DARA IV, and DARA SC was associated with very low rates of ARR-related events (Soefje S, et al. EHA Library. 2021). Based upon this analysis, the treatment plan was modified to reduce the mandated observation time for DARA SC to improve clinic efficiency. Here, we describe updated clinical administration characteristics for DARA SC at Mayo Clinic infusion centers before and after the reduction in procedure-mandated observation time, versus DARA IV, using a novel empirical data extraction approach from Electronic Health Records (EHR). Methods: Patients ≥18 years of age with an ICD-9/10 diagnosis code of MM and a first DARA treatment between April 5, 2017 and June 22, 2021 were identified in Mayo Clinic's EHR database. Data were extracted using a scheduling and pharmacy software that tracked patient movement through appointments at a Mayo Clinic infusion center. On May 3, 2021, the Mayo treatment plan was amended to shorten the mandated post-administration observation time for DARA SC from 4 to 2 hours for Dose 1 and from 1 hour to 30 minutes for Doses 2 and 3, with no mandated observation time for Doses 4+. In this analysis, data were captured for patients initiating DARA IV throughout the defined treatment window. For DARA SC, data were captured for patients starting DARA SC therapy on the initial treatment plan (before May 3, 2021; DARA SC initial) and after the change to shorten the mandated post-administration observation time for DARA SC (after May 3, 2021; DARA SC shortened). Time-based measures included: total clinic time (check-in time through patient check-out); total chair time (time from infusion room entry to infusion room exit or check-out time, including order review, pharmacy preparation time, and post-administration observation time); and observation time (time from the end of medication administration to infusion room exit or patient check-out). The medication administration time documented for DARA SC was 0 minutes due to the default duration for SC injections in the EHR. Results: In total, 755 (DARA IV, n=586; DARA SC initial, n=145; DARA SC shortened, n=24) patients received DARA treatment for MM. For all doses combined, the median total clinic time was 2.9 hours shorter for DARA SC compared with DARA IV (DARA IV, 4.9 hrs; DARA SC initial, 2.0 hrs). The median total clinic time for DARA SC and DARA IV was highest at Dose 1 (DARA IV, 9.5 hrs; DARA SC initial, 6.1 hrs; DARA SC shortened, 4.4 hrs) and lower for subsequent doses (Dose 4+: DARA IV, 4.6 hrs; DARA SC initial, 1.7 hrs; DARA SC shortened, 1.6 hrs; Figure). Similarly, the median total chair time was 2.7 hours shorter in the DARA SC group compared with the DARA IV group for all doses combined (DARA IV, 4.1 hrs; DARA SC initial, 1.4 hrs). The median total chair time for DARA SC and DARA IV was highest at Dose 1 (DARA IV, 8.8 hrs; DARA SC initial, 5.6 hrs; DARA SC shortened, 3.9) and lower for subsequent doses (Dose 4+: DARA IV, 3.7 hrs; DARA SC initial, 1.1 hrs; DARA SC shortened, 1.1 hrs). Conclusion: Marked reductions in the amount of time spent both in clinic and in chair were observed with DARA SC compared with DARA IV, with additional time savings observed following the Mayo procedure change to reduce the DARA SC mandated observation time. These favorable DARA SC administration characteristics may indicate a reduction in the burden on both clinical resources and patients in Mayo Clinic infusion centers. These results add to the growing body of evidence supporting the use of DARA SC as an efficient and convenient treatment administration option for patients with MM. Figure 1 Figure 1. Disclosures Soefje: Beigene: Consultancy; Pfizer: Speakers Bureau; Janssen: Consultancy, Research Funding. Carpenter: nference Inc.: Current Employment; Janssen: Consultancy. Carlson: nference Inc.: Current Employment; Janssen: Consultancy. Awasthi: nference Inc.: Current Employment, Current holder of individual stocks in a privately-held company; Janssen: Consultancy. Lin: Janssen: Current Employment. Kaila: Janssen Scientific Affairs, LLC: Current Employment. Kayal: nference Inc.: Current Employment; Janssen: Consultancy. Kirkup: nference Inc.: Current holder of individual stocks in a privately-held company, Ended employment in the past 24 months; Path AI: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Wagner: nference Inc.: Current Employment; Janssen: Consultancy. Gray: Janssen Scientific Affairs, LLC: Current Employment, Current holder of individual stocks in a privately-held company. Kumar: Oncopeptides: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Antengene: Consultancy, Honoraria; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Bluebird Bio: Consultancy; Beigene: Consultancy; Tenebio: Research Funding; Roche-Genentech: Consultancy, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Abstract Background: Initial studies with venetoclax, a BCL-2 inhibitor, alone or in combination with either dexamethasone or bortezomib and dexamethasone has shown considerable anti-tumor activity in t(11;14) MM with relapsed disease. Based on preclinical studies suggesting synergy when combined with bortezomib and phase 1 data showing efficacy for venetoclax, this combination was compared with bortezomib and dexamethasone (BortDex) in relapsed MM. While the BELLINI (NCT02755597) trial did demonstrate improved PFS with the combination, there were limited number of patients with t(11;14) treated with BortDex. The objective of this study was to assess real-world effectiveness of BortDex in patients with t(11;14) positive relapsed/refractory MM. Patients and methods: This non-interventional, retrospective observational cohort study included patients with t(11;14) MM from the International Myeloma Working Group (IMWG) retrospective study of t(11;14) MM. From the overall cohort, patients with t(11;14) MM receiving BortDex in ≥2 nd and ≤4 th line were initially selected. The cohort was further limited to patients with no evidence of allogeneic SCT within 16 weeks or autologous SCT within 12 weeks prior to BortDex initiation. Finally, patients non-refractory to prior PI regimen and not receiving BortDex regimen as part of a clinical trial were included in the study. Patient demographic and clinical characteristics along with real-world effectiveness outcomes including best response, overall survival (OS), and time to next therapy (TTNT) as a surrogate measure for progression-free survival (PFS) were assessed. All analyses were descriptive in nature and were conducted using the SAS 9.4 (SAS Institute Inc., Cary, NC, USA). Results: Overall, 144 patients who met the inclusion criteria were analyzed. Median age was 62.5 years, 62% were male. Patients had a median of 1 prior line (range 1-3) at start of BortDex, at a median of 18.4 months (range, 1-100) from diagnosis; 29% had a prior transplant. A PR or better was observed in 53% of patients with BortDex. The median TTNT for this cohort was 8.4 months and median OS was 46.1 months. Conclusions: This retrospective study of non-trial patients with t(11;14) MM provides a benchmark for newer therapies in this patient population for comparison with both venetoclax dexamethasone as well as combinations using the -BortDex backbone. Disclosures Emechebe: AbbVie: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company; Pharmaceutical/Biotech Companies: Current holder of stock options in a privately-held company. Kumar: Tenebio: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Beigene: Consultancy; Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Merck: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Goldschmidt: Takeda: Consultancy, Research Funding; Novartis: Honoraria, Research Funding; Mundipharma: Research Funding; MSD: Research Funding; Molecular Partners: Research Funding; Dietmar-Hopp-Foundation: Other: Grant; Sanofi: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Janssen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Incyte: Research Funding; GSK: Honoraria; Chugai: Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; BMS: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Celgene: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Adaptive Biotechnology: Consultancy; Amgen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Johns Hopkins University: Other: Grant. Mateos: Takeda: 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; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Sea-Gen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: 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; Roche: 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; Bluebird bio: Honoraria; Amgen: 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; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria; Oncopeptides: Honoraria. Kim: Janssen, BMS: Research Funding. Dimopoulos: Janssen: Honoraria; Takeda: Honoraria; Beigene: Honoraria; BMS: Honoraria; Amgen: Honoraria. Ludwig: Janssen, Celgene-BMS, Sanofi, Seattle Genetics: Consultancy, Speakers Bureau; Amgen, Takeda: Consultancy, Research Funding, Speakers Bureau. Handa: Kyowa Kirin: Research Funding; Chugai: Research Funding; Celgene: Honoraria, Research Funding; Daiichi Sankyo: Research Funding; Janssen: Honoraria; BMS: Honoraria; Ono: Honoraria; Sanofi: Honoraria, Research Funding; Abbvie: Honoraria; MSD: Research Funding; Shionogi: Research Funding; Takeda: Honoraria, Research Funding. Fernandez de Larrea: Janssen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Honoraria, Research Funding; GSK: Honoraria; Sanofi: Consultancy. Reece: Amgen: Consultancy, Honoraria; GSK: Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Honoraria; Millennium: Research Funding; Karyopharm: Consultancy, Research Funding; BMS: Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding. Raje: Celgene, Amgen, Bluebird Bio, Janssen, Caribou, and BMS: Other. Karve: AbbVie: Current Employment, Current equity holder in publicly-traded company. Arriola: AbbVie: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Ross: AbbVie: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company. Durie: Amgen: Other: fees from non-CME/CE services ; Amgen, Celgene/Bristol-Myers Squibb, Janssen, and Takeda: Consultancy.

Abstract Background: Real-world data (RWD) derived from electronic health records are becoming increasingly important for deriving insights from clinical practice to complement findings from clinical trials. Response to treatment in multiple myeloma (MM) is assessed using the International Myeloma Working Group (IMWG) response criteria based on MM-specific laboratory measures (i.e. monoclonal [M] protein in serum and urine, free light chain [FLC] levels), as well as radiological images and bone marrow (BM) investigations when appropriate. As healthcare providers do not routinely collect all the information required by the IMWG response criteria, RWD data are often incomplete. Here, we present a derived real-world response (dR) algorithm based on IMWG criteria that accounts for lab measures routinely collected in the clinical care of MM patients and evaluate its ability to accurately assess response to treatment using clinical trial patient-level data. Methods: Treatment response is assessed using a rule-based algorithm integrating longitudinal laboratory measures routinely captured in RWD (Xu et al. Pharmacoepidemiol Drug Saf 2021) as e.g. by the Flatiron MM database. The rules are based on 'relaxed' IMWG criteria, which entail exclusion of BM biopsies data and of imaging results, and reduction in either serum or urine M protein levels (rather than both) to assign partial response. This algorithm was applied to patient-level clinical trial data from the Bellini trial (Kumar et al. Lancet Oncol 2020) with response assignment made by an independent review committee (IRC) in the trial used as the 'ground truth'. Agreement between the IRC's and algorithm's assignments of response was estimated using Cohen's Kappa statistic. Differences in overall response rate (ORR) between treatment and placebo arms were calculated using stratified Cochran-Mantel-Haenszel tests based on strata at randomization with number of prior lines of therapy and previous proteasome inhibitor treatment status variables used for stratification. Results: The Bellini trial is a Phase 3 clinical trial with 2:1 design enrolling 194 and 97 patients in its treatment and placebo arms, respectively (291 patients in total). Regular assessments of M protein and FLC levels were performed (median 13 or 14 measurements), providing detailed trajectory of patient response (Table 1). Comparison between the IRC's and algorithm's assignments of responders classified as Partial Response or better (PR+) resulted in almost perfect agreement with Cohen's Kappa 0.82 (274/291 assignments in agreement). It is worth noting that the Cohen's Kappa between the IRC's and Investigator's assessments is 0.85, indicating that the algorithm's error is within some expected uncertainty. Due to the exclusion of BM information, agreement decreased to 0.56 when depths of response were considered separately as opposed to grouping PR+ patients together with most cases being overestimated as complete response (CR) or stringent CR. In assessing treatment effect, differences in ORR between the intervention and placebo arms in the trial based on IRC's assessment could be accurately recapitulated (68% [66/97] vs 71% [69/97] responders in the placebo arm and 82% [159/194] vs 87% [169/194] in the intervention arm for IRC's and algorithm's assessment, respectively). Based on these results, algorithm response assignment led to consistent conclusions about treatment efficacy in the Bellini trial. Implementation of criteria to characterize very good partial response or better (VGPR+) also led to a conclusion consistent with the Bellini trial IRC's assessment, while implementation of criteria of CR+ resulted in estimates of treatment efficacy that were higher, but directionally consonant (Table 2). Conclusions: We present a fully automated rule-based algorithm for response assessment in MM relying on longitudinal lab measurements during treatment. The algorithm uses 'relaxed' IMWG criteria to account for routine clinical practice settings and demonstrates very high agreement with the assessment of trained clinicians, while reliably reproducing the efficacy analysis in the Bellini trial when ORR and VGPR+ are considered. We envision that, if the concordance observed here is confirmed in other independent cohorts, this algorithm can be used in the assessment of response in RWD and can facilitate response assessment when suboptimal amounts of data are available. Figure 1 Figure 1. Disclosures Tyanova: F. Hoffmann-La Roche: Current Employment. Xu: F. Hoffmann-La Roche AG: Current Employment. Williamson: Amgen: Current equity holder in publicly-traded company; Genentech: Current Employment, Current equity holder in publicly-traded company. Rocci: Novartis: Other: Wife is and employee of Novartis and holds Novartis stocks; Sanofi Aventis: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Received travel sponsorship ; Janssen-Cilag Ltd: Honoraria, Speakers Bureau; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Other: Received travel sponsorship ; Owner of 100% stocks of Harlock Healthcare Consulting Ltd (UK privately-held company currently not active).: Current holder of individual stocks in a privately-held company; Roche: Current equity holder in publicly-traded company; Takeda: Consultancy, Honoraria, Other: Received travel sponsorship , Speakers Bureau; Sanofi: Consultancy; NHS: Ended employment in the past 24 months; F. Hoffmann-La Roche Ltd.: Current Employment; AbbVie: Other: Received travel sponsorship . Hong: Imago BioSciences: Current Employment; Genentech, Inc.: Ended employment in the past 24 months; Stock options in Imago BioSciences: Current equity holder in publicly-traded company. Jin: Genentech Inc: Current Employment; Roche: Current equity holder in publicly-traded company. Karve: AbbVie: Current Employment, Current equity holder in publicly-traded company. Roose: Flatiron Health, Inc.: Current Employment; Roche: Current equity holder in publicly-traded company. Sawas: Seattle Genetics: Honoraria; Affimed: Research Funding; Roche: Current equity holder in publicly-traded company; Flat Iron Health: Current Employment; Acrotech: Honoraria; Daiichi-Sankyo: Speakers Bureau; Seattle Genetics: Speakers Bureau; Gilead: Speakers Bureau. Kumar: Antengene: Consultancy, Honoraria; Novartis: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Tenebio: Research Funding; Beigene: Consultancy; Oncopeptides: Consultancy; KITE: Consultancy, 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; Merck: Research Funding; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Janssen: 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; Amgen: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Abstract Background: Multiple myeloma (MM) is a heterogenous cancer of terminally differentiated plasma cells that typically express elevated levels of antiapoptotic proteins, such as BCL-2. Venetoclax (Ven), a highly selective, potent, oral BCL-2 inhibitor, induces apoptosis in MM cells, and when combined with bortezomib and dexamethasone showed promising efficacy in patients (pts) with relapsed/refractory MM (RRMM; Moreau et al. Blood. 2017;130:2392-2400). The Phase 3 BELLINI study primary analysis showed significantly improved response rates and progression-free survival (PFS) in pts with RRMM treated with Ven added to bortezomib and dexamethasone versus placebo (Pbo); however, increased mortality was observed in the Ven group (Kumar et al. Lancet Oncol. 2020;21:1630-1642). At the initial data cutoff (November 26, 2018), the PFS hazard ratio (HR) was 0.63 (95% CI, 0.44-0.90) and overall survival (OS) HR was 2.03 (95% CI, 1.04-3.95). Pts with t(11;14) translocation or high BCL2 expression showed improved responses and PFS without increased mortality. Here, we present updated safety and efficacy data from the prespecified final OS analysis. Methods: BELLINI (NCT02755597) is a Phase 3, randomized, double-blind, multicenter study of Ven or Pbo combined with bortezomib and dexamethasone in pts with RRMM who had received 1-3 prior lines of therapy and were either sensitive or naïve to proteasome inhibitors. Pts were randomized 2:1 to receive Ven 800 mg/day or Pbo plus bortezomib and dexamethasone. Cycles 1-8 were 21-day cycles with bortezomib 1.3 mg/m 2 on Days 1, 4, 8, and 11 and dexamethasone 20 mg on Days 1, 2, 4, 5, 8, 9, 11, and 12. Cycles 9 and beyond were 35-day cycles with bortezomib 1.3 mg/m 2 on Days 1, 8, 15, and 22 and dexamethasone 20 mg on Days 1, 2, 8, 9, 15, 16, 22, and 23. The primary endpoint was PFS assessed by independent review committee. Key secondary endpoints included overall response rate and OS. BCL2 expression was measured by quantitative polymerase chain reaction with the cutoff for high BCL2 determined using bootstrapping and aggregating thresholds from trees. Results: Of 291 randomized pts (194 to Ven and 97 to Pbo), 33 pts were receiving ongoing treatment (28 with Ven and 5 with Pbo) as of the final OS analysis data cutoff (March 15, 2021). At a median follow-up of 45.6 months, there were 78 (40%) deaths in the Ven arm versus 36 (37%) in the Pbo arm. Updated PFS and OS among all pts and those with t(11;14) or high BCL2 expression are shown in the Table. Among all pts, the median PFS per investigator was 23.4 months in the Ven arm versus 11.4 months in the Pbo arm (HR, 0.58 [95% CI, 0.43-0.78]). In pts with t(11;14), the median PFS was 36.8 months in the Ven arm versus 9.3 months in the Pbo arm (HR, 0.12 [95% CI, 0.03-0.44]). In pts with high BCL2, the median PFS was 30.1 months in the Ven arm versus 9.9 months in the Pbo arm (HR, 0.37 [95% CI, 0.21-0.64]). Median OS was not reached in the Ven or Pbo arm among all pts (HR, 1.19 [95% CI, 0.80-1.77]), pts with t(11;14) (HR, 0.61 [95% CI, 0.16-2.32]), pts with high BCL2 (HR, 0.70 [95% CI, 0.32-1.51]), and pts with t(11;14) or high BCL2 (HR, 0.82 [95% CI, 0.40-1.70]). The most common treatment-emergent adverse events (AEs) with Ven (versus Pbo) were diarrhea (60% versus 50%), nausea (38% versus 23%), and constipation (35% versus 31%). The most common Grade 3/4 AEs (Ven versus Pbo) were thrombocytopenia (16% versus 30%), neutropenia (23% versus 8%), pneumonia (19% versus 13%), anemia (16% versus 15%), and diarrhea (15% versus 11%). Serious AEs occurred in 57% of Ven- and 55% of Pbo-treated pts, with serious infections and infestations occurring in 35% and 29% of pts, respectively. Overall, 26% of pts in the Ven arm and 11% of pts in the Pbo arm experienced an AE leading to Ven or Pbo discontinuation. AEs led to 12 deaths in the Ven arm, with 9 of these deaths due to serious infection; an AE led to 1 death in the Pbo arm. A total of 16 (6%) treatment-emergent deaths occurred (14 [7%] with Ven and 2 [2%] with Pbo), with 3 of these deaths due to disease progression (2 [1%] with Ven and 1 [1%] with Pbo). Conclusion: In the final OS analysis, the addition of Ven to bortezomib and dexamethasone showed significantly improved PFS but resulted in increased mortality versus Pbo in the total population. Consistent with results from previous analyses, Ven added to bortezomib and dexamethasone showed the greatest PFS improvement in pts with t(11;14) or high BCL2, with a favorable benefit-risk profile. Figure 1 Figure 1. Disclosures Kumar: Beigene: Consultancy; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Merck: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Tenebio: Research Funding; BMS: Consultancy, Research Funding; Antengene: Consultancy, Honoraria; Roche-Genentech: Consultancy, Research Funding; Novartis: Research Funding; Abbvie: 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; Oncopeptides: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Harrison: Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene/ Juno/ BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Roche/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Haemalogix: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Eusa: Consultancy, Honoraria, Speakers Bureau; Terumo BCT: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Cavo: Novartis: Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: 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, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Bristol-Myers Squib: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. de la Rubia: Ablynx/Sanofi: Consultancy; Amgen, Bristol Myers Squibb,: Honoraria, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celgene, Takeda, Janssen, Sanofi: Honoraria; AbbVie: Consultancy; Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Accommodations; GSK: Consultancy; Takeda: Consultancy; Sanofi: Membership on an entity's Board of Directors or advisory committees. Popat: Abbvie, Takeda, Janssen, and Celgene: Consultancy; AbbVie, BMS, Janssen, Oncopeptides, and Amgen: Honoraria; Takeda: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Janssen and BMS: Other: travel expenses. Gasparetto: Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm Therapeutics Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Oncopeptite: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Connect Registry: 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, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding, Speakers Bureau. Hungria: Sanofi: Honoraria, Other: Support for attending meetings/travel ; Takeda: Honoraria; Abbvie: Honoraria; Amgen, BMS, Celgene, Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings/travel . Salwender: Oncopeptides: Honoraria; GlaxoSmithKline: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Sanofi: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Takeda: Honoraria; Pfizer: Honoraria; Amgen: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Chugai: Honoraria; AbbVie: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Janssen-Cilag: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Bristol-Myers Squibb/Celgene: Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES. Suzuki: Japanese Red Cross Medical Center: Current Employment; Janssen: Honoraria; AbbVie: Honoraria; Sanofi: Honoraria; Bristol-Myers Squibb: Honoraria, Research Funding; Takeda: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; ONO: Honoraria; Novartis: Honoraria. Kim: Seoul National University Hospital: Current Employment. Onishi: Roche: Current Employment, Current equity holder in publicly-traded company; Genentech: Current Employment. Ku: Roche: Current Employment, Current equity holder in publicly-traded company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Genentech: Current Employment, Other: TRAVEL, ACCOMMODATIONS, EXPENSES. Pothacamury: AbbVie: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company. Sehgal: AbbVie: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company. Masud: AbbVie: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company. Ross: AbbVie: Current Employment, Current equity holder in publicly-traded company, Current holder of individual stocks in a privately-held company. Dobkowska: AbbVie: Current Employment, Current equity holder in publicly-traded company, Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Pharmacyclics: Current Employment. Moreau: Celgene BMS: Honoraria; Amgen: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; Oncopeptides: Honoraria.

Abstract Purpose: Multiple myeloma (MM) is a plasma cell (PC) malignancy with an increasing incidence in the United States. Fluorescence in situ hybridization (FISH) is currently the gold-standard diagnostic assay to detect recurrent genomic abnormalities of prognostic and therapeutic significance in MM. Hyperdiploid MM, a standard risk abnormality, is characterized by gains of odd-numbered chromosomes including chromosome 15. While gains of chromosome 15 have been reported in approximately 53% of standard risk MM patients (Chretien, Blood, 2015), losses of chromosome 15 are rarely reported. Enumeration of chromosome 15 centromere is detected using the alpha satellite FISH probe. We previously discovered ~9% of cases had false-negative chromosome 15 FISH results when compared to Mate Pair Sequencing (MPseq) (Smadbeck, BCJ, 2019). To our knowledge, no previous studies have reported a reduced performance of the alpha satellite D15Z4 FISH probe in PC FISH studies. A false-negative result for D15Z4 could result in an underreporting of trisomy 15 and overreporting of monosomy 15. Here, we investigated the incidence of false-negative D15Z4 FISH results by examining the presence of monosomy 15 from patients with a monoclonal gammopathy. Methods: We identified 1231 samples from patients with a monoclonal gammopathy who had undergone uniform testing to identify MM-specific cytogenetic abnormalities. DNA from bone marrow samples was genotyped on the Precision Medicine Research Array and biogeographical ancestry was assessed using the Geographic Population Structure Origins tool (Elhaik, Nat Commun, 2014; Home DNA 2016). FISH of immunoglobulin (cIg)-stained PCs was performed as described (Baughn, BCJ, 2018). Chromosome 15 centromere probe (Vysis CEP 15 D15Z4, Abbott Molecular, Abbott Park, IL) was used for chromosome 15 enumeration. Samples were divided into two groups: Cases with or without evidence of monosomy 15 by FISH. Mann-Whitney U test was applied to compare difference between groups for data deviating from normal distribution. A Chi-squared test evaluating the differences across these two groups was used. Results: We identified monosomy 15 in 31 cases (2.5% of cohort). Monosomy 15 was observed in nearly 100% of both the PC (cIg+) and non-PC (cIg-) populations, by contrast to the other recurrent PC-specific genomic abnormalities which were restricted to only the PC population. All samples with a banded analysis revealed most metaphases had two normal chromosome 15s demonstrating that the D15Z4 FISH probe failed to correctly enumerate the number of chromosome 15 centromere signals. Of the samples with a monosomy 15 result, the median African ancestry was 76.2% (95% percentiles: 77.5%-89.0%), while the median African ancestry of the non-monosomy 15 cohort was 2.3% (95% percentiles: 0%-87.7%) (). Although not all patients with >50% African ancestry had evidence of monosomy 15, 26/31 (83.9%) of patients with monosomy 15 had >50% African ancestry. Accordingly, patients with African ancestry (similarity ≥ 0.70) had 8.02-fold (95% confidence interval: 3.73-17.25, P = 9.92 X10 -8) increased possibility to have monosomy 15. Of cases with monosomy 15, 22 (71.0%) had an IGH rearrangement with the most prevalent IGH partner being CCND1. The incidence of t(11;14) was greater in the monosomy 15 group (13/31:41.9%), in contrast to the non-monosomy 15 group (330/1200=27.5%) (P = 0.12). Conclusions: We report a polymorphic variant of the chromosome 15 centromere resulting in a false-negative FISH result using the D15Z4 FISH probe. Surprisingly, the false-negative FISH result was not uniformly distributed among patients and was highly enriched in individuals of African ancestry. This may be due to a variation of the chromosome 15 alpha satellite in some individuals that prevents the D15Z4 FISH probe from sufficiently binding (O'Keefe, Genome Research, 2000). Although this study focused on identification of monosomy 15, the incidence of a false-negative result is likely greater than we have reported in this study since we did not evaluate cases that had a true trisomy 15 that was reported as normal chromosome 15 enumeration by FISH. This study highlights a critical need to ensure diagnostic reagents have equal performance for all patients independent of their ancestry. Evaluation of genomic events using unbiased approaches such as whole genome sequencing may circumvent some of these limitations. Disclosures Elhaik: DDC: Consultancy. Baird: DDC: Current Employment. Kumar: Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Beigene: Consultancy; BMS: Consultancy, Research Funding; Tenebio: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy; Carsgen: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding.

Abstract Introduction: In oncology clinical trials, overall survival (OS) is considered the gold standard efficacy endpoint. However, in multiple myeloma, the prolonged survival times and availability of multiple salvage therapies render it difficult to rely on OS as a primary endpoint. Instead, progression-free survival (PFS) or clinical response can be a relevant biomarker. At the same time, some health technology assessment bodies will only consider evidence based on patient-relevant endpoints, such as morbidity, mortality, and health-related quality of life (HRQoL), within their benefit assessments. Patient-reported outcomes (PROs) provide insights into how a treatment affects HRQoL, including symptoms and functioning. In the phase 3 MAIA trial, daratumumab, lenalidomide, and dexamethasone (D-Rd) demonstrated a significantly prolonged PFS and rapid and sustained improvements in PROs compared with lenalidomide and dexamethasone (Rd) alone at a median follow-up of 28 months. Updated results with longer follow-up confirmed a continued PFS benefit, deepening best clinical responses, and a significant OS benefit with D-Rd. Here, we report the results of analyses exploring the relationship between clinical efficacy endpoints and PROs in the MAIA trial. Methods: In MAIA (NCT02252172), TIE patients with NDMM were randomized to D-Rd or Rd until disease progression (PD) or unacceptable side effects. Clinical response and PD were defined per the International Myeloma Working Group uniform response criteria. PROs were assessed at baseline, on day 1 of cycles 3, 6, 9, and 12 for year 1, every 6 months thereafter until PD, or at end of treatment and at 8 and 16 weeks post-progression using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30-item (EORTC QLQ-C30). The current analyses were conducted on patients with a baseline PRO assessment and ≥1 post-baseline PRO assessment using a clinical cutoff date of February 19, 2021. Patients from both treatment groups were pooled and stratified by best clinical response. For PROs, the threshold for clinically meaningful change from baseline was defined a priori as ≥10 points based on published literature. Analyses were conducted for the global health status (GHS), fatigue, and pain scales of the EORTC QLQ-C30. The proportions of patients with clinically meaningful improvement in these PROs from baseline at any time while on treatment were calculated for and compared across best clinical response subgroups. For this analysis, patients were censored at the time of PD or discontinuation of therapy. Results were summarized with odds ratios and 95% confidence intervals. Additionally, the proportions of patients with clinically meaningful worsening in PROs from baseline at the time of and post-progression were also calculated for those who had PD. No adjustments were made for multiplicity. Nominal P-values are presented. Results: Best clinical response at a median follow-up of 56.2 months for the 710 patients included in this analysis is shown in the Table. For GHS, fatigue, and pain, the proportion of patients who reported clinically meaningful improvement from baseline increased with increasing depth of best clinical response. Odds ratios comparing best clinical response vs stable disease reflect this relationship and are shown in the Figure. Of the 264 patients who experienced PD and had PRO data at the time of or post-progression, 38.6%, 54.9%, and 39.4% reported meaningful worsening of GHS, pain, and fatigue, respectively, at the time of or post-progression. Conclusions: Patients with deeper best clinical response were more likely to report meaningful improvements in PROs. Patients who experienced PD reported worsening of GHS and symptoms at the time of or following progression. These analyses provide evidence of the association between key clinical efficacy endpoints and PROs and demonstrate the patient relevance of these clinical endpoints. Figure 1 Figure 1. Disclosures Perrot: Abbvie: Honoraria; BMS 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; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Kumar: Amgen: Consultancy, Research Funding; BMS: Consultancy, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Bluebird Bio: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Carsgen: Research Funding; Antengene: Consultancy, Honoraria; Oncopeptides: Consultancy; Beigene: Consultancy; Tenebio: Research Funding; Takeda: Consultancy, 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; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Plesner: Takeda: Research Funding; Genentech: Other: Advisor, Research Funding; Oncopeptides: Other: Advisor, Research Funding; AbbVie: Other: Advisor, Research Funding; CSL Behring: Other: Advisor; Janssen: Other: Advisor, Research Funding; Celgene: Other: Advisor, Research Funding; Genmab: Research Funding. Orlowski: Asylia Therapeutics, Inc., BioTheryX, Inc., and Heidelberg Pharma, AG.: Other: Laboratory research funding; CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Other: Clinical research funding; Amgen, Inc., BioTheryX, Inc., Bristol-Myers Squibb, Celgene, EcoR1 Capital LLC, Genzyme, GSK Biologicals, Janssen Biotech, Karyopharm Therapeutics, Inc., Neoleukin Corporation, Oncopeptides AB, Regeneron Pharmaceuticals, Inc., Sanofi-Aventis, and Takeda P: Consultancy, Honoraria; Asylia Therapeutics, Inc.: Current holder of individual stocks in a privately-held company, Patents & Royalties; Amgen, Inc., BioTheryX, Inc., Bristol-Myers Squibb, Celgene, Forma Therapeutics, Genzyme, GSK Biologicals, Janssen Biotech, Juno Therapeutics, Karyopharm Therapeutics, Inc., Kite Pharma, Neoleukin Corporation, Oncopeptides AB, Regeneron Pharmaceuticals, I: Membership on an entity's Board of Directors or advisory committees. Moreau: Abbvie: Honoraria; Oncopeptides: Honoraria; Celgene BMS: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; Janssen: Honoraria. Bahlis: Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Genentech: Consultancy; GlaxoSmithKline: Consultancy, Honoraria. Nahi: XNK Therapeutics AB: Consultancy. Hulin: abbvie: Honoraria; Celgene/BMS: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Janssen: Honoraria. Quach: Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen/Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: 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, Research Funding; Karyopharm: Consultancy, Honoraria, 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; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Goldschmidt: GSK: Honoraria; Incyte: Research Funding; Janssen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Amgen: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; BMS: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Adaptive Biotechnology: Consultancy; Celgene: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Chugai: Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Novartis: Honoraria, Research Funding; Dietmar-Hopp-Foundation: Other: Grant; Sanofi: Consultancy, Honoraria, Other: Grants and/or Provision of Investigational Medicinal Product, Research Funding; Takeda: Consultancy, Research Funding; Johns Hopkins University: Other: Grant; Mundipharma: Research Funding; MSD: Research Funding; Molecular Partners: Research Funding. O'Dwyer: Bristol Myers Squibb: Research Funding; ONK Therapeutics: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Venner: Amgen: Research Funding; Celgene: Research Funding; Takeda: Honoraria; Amgen: Honoraria; Janssen: Honoraria; BMS: Honoraria; Sanofi: Honoraria; Pfizer: Honoraria. Weisel: Adaptive Biotechnologies: Consultancy, Honoraria, 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, Research Funding; Takeda: 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, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: 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; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy; Novartis: Honoraria; Pfizer: Honoraria. Raje: Celgene, Amgen, Bluebird Bio, Janssen, Caribou, and BMS: Other. Macro: Takeda: Honoraria, Other: Travel accomodation, Research Funding; Janssen: Honoraria, Other: Travel accomodation, Research Funding; GSK: Honoraria; Celgen/BMS: Honoraria; Sanofi: Honoraria. Leleu: Sanofi: Honoraria; Roche: Honoraria; Pierre Fabre: Honoraria; Oncopeptides: Honoraria; Novartis: Honoraria; Mundipharma: Honoraria; Merck: Honoraria; Karyopharm Therapeutics: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Carsgen Therapeutics Ltd: Honoraria; Celgene: Honoraria; Gilead Sciences: Honoraria; Janssen-Cilag: Honoraria; AbbVie: Honoraria; Takeda: Honoraria, Other: Non-financial support. Liu: Janssen: Current Employment, Current equity holder in publicly-traded company. Fastenau: Janssen: Current Employment, Current equity holder in publicly-traded company. Gries: Janssen: Current Employment, Current holder of individual stocks in a privately-held company. Ho: DRG Abacus: Consultancy; Emalex Biosciences: Consultancy; Janssen: Consultancy. Mistry: Janssen: Current Employment, Current equity holder in publicly-traded company. Tromp: Janssen: Current Employment, Current equity holder in publicly-traded company. Delioukina: Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company. Usmani: Amgen: Consultancy, Research Funding, Speakers Bureau; Abbvie: Consultancy; Array BioPharma: Consultancy, Research Funding; GSK: Consultancy, Research Funding; EdoPharma: Consultancy; SkylineDX: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; Takeda: Consultancy, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Janssen: Consultancy, Research Funding, Speakers Bureau; Sanofi: Consultancy, Research Funding, Speakers Bureau; Janssen Oncology: Consultancy, Research Funding; Bristol-Myers Squibb: Research Funding.

Abstract Background: Systemic light chain (AL) amyloidosis is a plasma cell disorder characterized by multisystem deposition of misfolded immunoglobulin light chains produced by clonal plasma cells. Hematologic and organ responses with treatment have been shown to correlate with survival as early as 3 months from initiation of first-line treatment. Our group recently developed and validated a model integrating organ and hematologic responses for assessment of treatment outcomes at 6 months. Although current organ response criteria do not consider the depth of organ response, this has been shown to have prognostic utility in newly diagnosed patients. So, we designed this study to evaluate a composite hematologic and organ scoring system that also considers the depth of organ response at 1 to 6 months from initiation of first-line treatment. Methods: We included patients with AL amyloidosis who had at least one major organ involvement (cardiac, renal and/or liver involvement) and who had not started a second line treatment by 6 months from the time of initiating first-line treatment. For each patient, we calculated an organ response score and a hematologic response score at 1, 2, 3, 4, 5, and 6 months from initiation of first-line treatment. A score was assigned for each depth of hematologic response as follows: complete response=0, very good partial response=1, partial response=2, and no response/progressive disease=3). To calculate organ response, a score was assigned to each organ based on the depth of organ response (Muchtar et al. 2018): non-evaluable=0, complete response=1, very good partial response=2, partial response=3, and no response=4. The final organ response score was obtained by calculating the average of the individual involved organ scores. We then calculated the composite hematologic and organ response (HOR) score by adding the organ and hematologic responses at each interval and compared overall survival (OS) between patients with HOR score ≤ 5 (group 1) and those with score > 5 (group 2). Results: The cohort included 730 patients diagnosed with AL amyloidosis between February 10 th, 2006 and July 9 th, 2019. Median age was 63 (IQR: 56-69), and 65% were male. The involved light chain was Lambda in 75% of cases. Cardiac, renal, and liver involvement were found in 81%, 61%, and 17% of patients, respectively. Among all patients, 28% underwent autologous stem cell transplantation during their disease course. The median follow up in the entire cohort was 7.0 (95%CI: 6.4-8.0) years and OS was 3.6 (95%CI: 2.6-4.4) years. At 1 to 4 months, we observed a statistically significant difference in OS between patients with HOR score ≤5 vs. >5. However, there was no difference in OS between the 2 groups at 5 and 6 months. These results are presented in Table 1. Conclusion: A composite hematologic and organ response score that takes into consideration the depth of organ response can discriminate 2 groups of patients with distinct survival outcomes as early as 1 month from treatment initiation and maintains its predictive ability for up to 4 months. The lack of predictive ability beyond 4 months in this study may be due to limited sample size especially in group 2 as more patients achieve deeper responses with time. This approach can provide the basis for early changes in treatment but needs validation in future studies. Figure 1 Figure 1. Disclosures Dispenzieri: Janssen: Consultancy, Research Funding; Takeda: Research Funding; Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Pfizer: Research Funding; Alnylam: Research Funding. Gertz: Ionis Pharmaceuticals: Other: Advisory Board; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring. Kapoor: Ichnos Sciences: Research Funding; Karyopharm: Consultancy; Glaxo SmithKline: Research Funding; Pharmacyclics: Consultancy; Amgen: Research Funding; Cellectar: Consultancy; Sanofi: Consultancy; BeiGene: Consultancy; Regeneron Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Dingli: GSK: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Alexion: Consultancy. Kumar: Oncopeptides: Consultancy; Merck: Research Funding; Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; Carsgen: Research Funding; Tenebio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.