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Vitamin C is an essential vitamin that acts as a co-factor for many enzymes involved in epigenetic regulation in humans. Low vitamin C levels in hematopoietic stem cells (HSC) promote self-renewal and vitamin C supplementation retards leukaemogenesis in vitamin C-deficient mouse models. Studies on vitamin C levels in patients with myeloid malignancies are limited. We thus conducted a retrospective analysis on a prospective cohort of patients with myeloid malignancies on whom plasma vitamin C levels were measured serially at diagnosis and during treatment. Baseline characteristics including hematological indices, cytogenetics, and molecular mutations are described in this cohort. Among 64 patients included in our study, 11 patients (17%) had low vitamin C levels. We noted a younger age at diagnosis for patients with myeloid malignancies who had low plasma vitamin C levels. Patients with low plasma vitamin C levels were more likely to have acute myeloid leukemia compared to other myeloid malignancies. Low vitamin C levels were associated with ASXL1 mutations. Our study calls for further multi-institutional studies to understand the relevance of low plasma vitamin C level in myeloid neoplasms, the role of vitamin C deficiency in leukemogenesis, and the potential benefit of vitamin C supplementation.

BACKGROUND: Bortezomib-based triplet regimens, specifically bortezomib, lenalidomide and dexamethasone (VRD) and bortezomib, cyclophosphamide and dexamethasone (VCD) are the two most common induction regimens used in transplant-eligible patients with NDMM, with conflicting data on comparative efficacy and outcomes in this population. OBJECTIVES: We compared long-term outcomes of multiple myeloma (MM) patients receiving VRD vs. VCD induction prior to autologous stem cell transplant (ASCT). STUDY DESIGN: Patients registered with Center for International Blood and Marrow Transplant Registry were included if they underwent ASCT for MM from 01/2013 to 12/2018 within 6 months of diagnosis, received VRD or VCD induction and achieved pre-transplant ≥ partial response. Of 1,135 patients, 914 received VRD and 221 received VCD. RESULTS: Patients receiving VCD were more likely to have renal impairment and ISS stage III disease and less likely to receive full dose melphalan (200 mg/m(2)) conditioning (69% vs 80%, p

Patients with relapsed and refractory multiple myeloma (RRMM) who are triple-class exposed (to an immunomodulatory agent, proteasome inhibitor, and anti-CD38 antibody) have limited treatment options and there is no standard of care. Idecabtagene vicleucel (ide-cel, bb2121), a BCMA-directed CAR T-cell therapy, demonstrated efficacy in triple-class exposed RRMM patients in the KarMMa trial (NCT03361748). In this retrospective study (KarMMa-RW), patient-level data from triple-class exposed RRMM patients were merged into a single data model and compared with KarMMa using trimmed stabilized inverse probability of treatment weighting. Endpoints included overall response rate (ORR; primary), rate of very good partial response or better (≥VGPR), progression-free survival (PFS), and overall survival (OS). Of 1949 real-world triple-class exposed RRMM patients, 190 received subsequent (index) line of therapy and met KarMMa eligibility criteria (Eligible RRMM cohort). With a median follow-up of 13.3 months in KarMMa and 10.2 months in Eligible RRMM, ORR, and ≥VGPR were significantly improved in KarMMa versus Eligible RRMM (ORR, 76.4% vs 32.2%; ≥VGPR, 57.9% vs 13.7%; both P P = 0.0004) and OS (20.2 vs 14.7 months; P = 0.0006). This study demonstrated that ide-cel significantly improved responses and survival compared with currently available therapies in triple-class exposed RRMM.

Introduction Selinexor is a first-in-class, oral, potent selective inhibitor of nuclear export (SINE) which blocks XPO1, forcing the nuclear retention and activation of tumor suppressor proteins, leading to cancer cell apoptosis. Selinexor has demonstrated antimyeloma activity in triple class refractory multiple myeloma (MM) [Chari et al. NEJM 2019]. Selinexor synergizes with proteasome inhibitors (PIs) in PI-sensitive and -resistant cell lines and produces high response rates in patients with PI refractory and non-refractory MM (Bahlis et al. Blood 2018). In the phase 3 BOSTON study, the combination of once weekly (QW) selinexor, QW bortezomib, and dexamethasone (SVd) in patients who had received 1-3 prior therapies led to a significantly longer (47%) median progression-free survival (PFS) of 13.93 vs 9.46 months, with a hazard ratio of 0.70 (P=0.0075) compared to standard twice weekly bortezomib and dexamethasone (Vd). In addition, SVd regimen produced higher response rates and deeper responses (ORR: 76.4% vs 62.3% and ≥CR 16.9% vs 10.2%) compared with Vd. The benefit with SVd was observed across all efficacy endpoints and was associated with lower incidence and severity of bortezomib-induced peripheral neuropathy. Here we analyzed the effect of prior PI therapy (bortezomib, carfilzomib, ixazomib) on the efficacy and safety of SVd compared with Vd. Methods BOSTON is an open-label, randomized phase 3 study in patients with MM comparing SVd (QW oral selinexor 100 mg, QW subcutaneous bortezomib 1.3 mg/m2, and BIW oral dexamethasone 20 mg), versus Vd (BIW bortezomib 1.3 mg/m2 and QIW dexamethasone 20 mg). Patients previously treated with a PI must have had at least a partial response (PR) to the PI and 6 months since the last PI regimen. The study primary end point was PFS. Here we report subgroup analysis of treatment outcomes based on prior PI treatment. Results Subgroups consisted of PI naïve patients (n=95; 24%) and patients with prior PI treatment (n=307; 76%). Both the subgroups and study arms were comparable for baseline patient demographic and disease characteristics. However, those with prior PI treatment more frequently had a previous stem cell transplant (38% vs 24%) or 3 lines of prior anti MM therapy (21% vs 13%). Median PFS was improved with SVd compared with Vd in both the PI naïve group (PFS not reached (NR) vs 9.7 months; HR 0.2585 [95% CI, 0.1116-0.5988]; P=0.0003) and in the PI treated group (11.7 vs 9.4 months; HR 0.7839 [95% CI, 0.5791-1.0612]; P=0.06). Other efficacy endpoints are shown in the table. Peripheral neuropathy ≥grade 2 (a secondary study endpoint) was less frequent in the SVd compared with the Vd arm (PI naïve: 25.5%, Vd 43.8%, P=0.0302; PI treated: SVd 19.6%, Vd 31.4%, P=0.0092). Adverse events of ≥grade 3 occurred in 71% of patients in the PI naïve group (SVd 77%, Vd 65%) and 74% of patients in the PI treated group (SVd 88%, Vd 60%). Thrombocytopenia was more frequent in patients in the SVd arms (PI naïve: SVd 32%, Vd 13%; PI treated: SVd 42%, Vd 19%) as was anemia (PI naïve: SVd 15%, Vd 6%; PI treated: SVd 16%, Vd 12%), and fatigue (PI naïve: SVd 15%, Vd 2%; PI treated: SVd 13%, Vd 1%). Conclusions The once-weekly SVd combination was associated with significant clinical benefit and reduced peripheral neuropathy as compared with standard twice-weekly Vd in patients with MM and 1-3 prior therapies, regardless of prior therapy with a PI. However, the benefits of SVd over Vd were more pronounced in patients who had never been treated with a PI (PFS HR 0.26), suggesting that selinexor could be an optimal partner for combining with weekly bortezomib as the first PI-containing MM regimen. Figure 1 Disclosures Mateos: Roche: Honoraria; Seattle Genetics: Honoraria; EDO Mundipharma: Honoraria; Adaptive Biotechnologies: Honoraria; GlaxoSmithKline: Honoraria; Abbvie: Honoraria; Takeda: Honoraria; Amgen: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Auner:Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Leleu:AbbVie: Honoraria; GSK: Honoraria; Amgen: Honoraria; Novartis: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; BMS-celgene: Honoraria; Janssen: Honoraria; Oncopeptide: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria. Hajek:Novartis: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharma MAR: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dimopoulos:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Kryachok:Janssen, Bayer, Karyopharm, MSD, Acerta, AvbbVie, Debiopharm: Research Funding; Takeda, Janssen: Consultancy; Takeda, MSD, AbbVie, Ro: Other: Travel, accommodations, expenses; Takeda, Janssen, Novartis, Roche, MSD, Bayer: Consultancy, Research Funding. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Research Funding; Glaxo Kline Smith: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria, Research Funding. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Moreau:Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Takeda: Honoraria; Janssen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Novartis: Honoraria. Levy:Karyopharm,Takeda, BMS: Consultancy, Honoraria, Speakers Bureau. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:Karyopharm: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding. Bahlis:Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; AbbVie: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; GSK: Consultancy, Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

Introduction Selinexor is a first-in-class, oral, potent selective inhibitor of nuclear export (SINE) which blocks XPO1, forcing the nuclear retention and activation of tumor suppressor proteins, leading to cancer cell apoptosis. Selinexor has demonstrated antimyeloma activity in triple class refractory multiple myeloma (MM) [Chari et al. NEJM 2019]. Selinexor synergizes with proteasome inhibitors (PIs) in PI-sensitive and -resistant cell lines and produces high response rates in patients with PI refractory and non-refractory MM. (Bahlis et al. Blood 2018). In the phase 3 BOSTON study, the combination of once weekly (QW) selinexor, QW bortezomib and dexamethasone (SVd) in patients who had received 1-3 prior therapies led to a significantly (47%) longer median progression-free survival (PFS) of 13.93 versus 9.46 months (HR 0.70; P=0.0075) compared to standard twice weekly bortezomib and dexamethasone (Vd). In addition, SVd regimen produced higher response rates and deeper responses (ORR: 76.4% vs 62.3% and ≥CR 16.9% vs 10.2%) compared with Vd. The benefit with SVd was observed across all efficacy endpoints and was associated with lower incidence and severity of bortezomib-induced peripheral neuropathy. Here we present subgroup analyses according to number of prior lines of therapy and prior treatment with lenalidomide (LEN). Methods BOSTON is an open-label, randomized phase 3 study in patients with MM comparing SVd (QW selinexor 100 mg, QW subcutaneous bortezomib 1.3 mg/m2, and 20 mg twice weekly [BIW] dexamethasone), versus Vd (1.3 mg/m2 bortezomib BIW and dexamethasone 20 mg 4 x weekly [QIW]). Patients previously treated with a PI must have had at least a partial response (PR) to the PI and 6 months since the last PI regimen. The study primary end point was PFS. Results Of the 402 patients in the BOSTON study, 198 (49%) had 1 prior line versus 204 (51%) with 2-3 prior lines. In addition, 154 (38%) comprised the LEN treated subgroup, versus 248 (62%) in the LEN naïve subgroup. Of note, 41% patients received prior thalidomide, which is consistent with most of the BOSTON study patients being treated in the EU. Baseline demographic and disease characteristics were well balanced between treatment arms across subgroups. A very good partial response (VGPR) or better to most recent prior line anti-MM therapy was more frequent in patients with 1 prior line of therapy (63% vs 41%) versus those with 2-3 prior lines of therapy. Patients with prior LEN therapy were more likely to have had 2-3 prior therapies (72.1%) compared with LEN naive patients (37.5%). As shown in the table, SVd was associated with longer PFS compared with Vd in all subgroups. Overall response rates (ORR) and times-to-next-treatment (TTNT) were statistically greater with SVd compared with Vd in all subgroups. Rates of very good partial response or better (VGPR) were statistically greater for SVd vs Vd in the LEN-naïve group and 1 prior treatment group. Grade ≥2 peripheral neuropathy (a key secondary endpoint prespecified in the study) occurred less frequently across all SVd subgroups compared with Vd: LEN treated (21% SVd, 37% Vd, P=0.0166); LEN-naïve (21% SVd, 33% Vd, P=0.0252), 1 prior line (21% SVd, 33% Vd, P=0.0501); 2-3 prior lines (21% SVd, 36% Vd, P=0.0107). Adverse events of ≥grade 3 were more commonly reported in the SVd treatment arm than in the Vd arm, LEN treated (83% SVd, 57% Vd), LEN-naïve (76% SVd, 55% Vd), 1 prior line (77% SVd, 56% Vd), 2-3 prior lines (81% SVd, 56% Vd), and were mostly managed with dose modification and/or supportive treatment. Pneumonia occurred at comparable rates between treatment arms. There were no differences between subgroups in grade 3 adverse events. Conclusions In the BOSTON study, once-weekly SVd significantly improved PFS, ORR, TTNT and reduced rates of ≥grade 2 peripheral neuropathy compared with Vd regardless of number of prior treatments or whether patients were previously treated with LEN. Adverse events were managed with dose modification and treatment-related discontinuation rates did not differ between the 2 regimens for any subgroup. The PFS of 16.6 months with SVd after 1 prior therapy, and the HR of 0.63 in patients with prior LEN treatment support the use of once-weekly SVd for the second line treatment of MM following a LEN-containing regimen. Table Disclosures Mateos: Takeda: Honoraria; Abbvie: Honoraria; GlaxoSmithKline: Honoraria; EDO Mundipharma: Honoraria; Seattle Genetics: Honoraria; Roche: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Adaptive Biotechnologies: Honoraria. Jagannath:Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Kryachok:Takeda, Janssen, Novartis, Roche, MSD, Bayer: Consultancy, Research Funding; Janssen, Bayer, Karyopharm, MSD, Acerta, AvbbVie, Debiopharm: Research Funding; Takeda, MSD, AbbVie, Ro: Other: Travel, accommodations, expenses; Takeda, Janssen: Consultancy. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Dimopoulos:Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Auner:Amgen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Leleu:BMS-celgene: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria; AbbVie: Honoraria; Oncopeptide: Honoraria; Janssen: Honoraria; Novartis: Honoraria; Amgen: Honoraria; GSK: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding. Moreau:Novartis: Honoraria; Amgen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria. Levy:Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; Baylor University Med Center: Current Employment; Takeda: Consultancy, Honoraria, Research Funding. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Bahlis:Genentech: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Sanofi: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

LBA4 Background: Optimal use of triplet/quadruplet induction, ASCT, and R-based maintenance in patients (pts) with NDMM who are eligible for transplant continues to evolve. The IFM 2009 trial, which used R maintenance for 1 year (y), showed progression-free survival (PFS; median, 35.0 vs. 47.3 months [mos]) but no overall survival benefit (OS; 60 vs. 62% at 8 y; median follow-up, 89.8 mos) with RVd + ASCT vs. RVd alone in the setting of multiple effective options at relapse, including ASCT at first relapse in 77% of pts (Attal M et al, N Engl J Med 2017; Perrot A et al, ASH 2020). We report primary data from our US DETERMINATION trial, which used R maintenance until progression. Methods: Pts with NDMM aged 18-65 y were randomly assigned to receive 3 RVd cycles, stem cell mobilization, and then 5 more RVd cycles (Arm A) or IV melphalan 200 mg/m2 + ASCT and 2 RVd cycles (Arm B). Each 21-d RVd cycle comprised PO R 25 mg (d 1-14), IV/SC bortezomib 1.3 mg/m2 (d 1, 4, 8, 11), and PO dexamethasone 20/10 mg (cycles 1-3/≥ 4; d 1, 2, 4, 5, 8, 9, 11, 12). Both arms received R 10-15 mg/d maintenance until progression or intolerance. The primary endpoint was PFS (90% power to detect PFS hazard ratio [HR] of 1.43 [Arm A vs. B] with α = 0.05 on stratified two-sided log-rank test; full information: 329 events in 720 pts). Data cut-off was Dec 10, 2021. Results: 357 and 365 pts were randomly assigned to Arms A and B, respectively; median age was 57 and 55 y, 14% and 13% had ISS stage III MM, and 18% each had high-risk cytogenetics [t(4;14), t(14;16), del17p]. In the respective arms, 291 and 290 pts received R maintenance for a median duration of 36 and 41 mos. After median follow-up of 76 mos and 328 events, median PFS was 46.2 vs. 67.6 mos in Arm A vs. B (HR 1.53; 95% CI, 1.23–1.91; p < .0001). Best responses in pts assessed to date were 52 vs. 62% ≥ CR (p = .006), 79 vs. 83% ≥ VGPR and 94 vs. 96% ≥ PR; in 251 evaluable pts, rate of MRD negativity (10-5) was 37.3 vs. 52.1% (p = .021) within 1 y of maintenance. 63 vs. 53% of pts have received subsequent treatment; of Arm A, 22% had ASCT as first non-protocol therapy. With 90 vs. 88 pts having died in Arm A vs. B, 4-y OS was 84% (95% CI, 80–88%) vs. 85% (95% CI, 81–88%); HR 1.10 (95% CI, 0.81–1.47; p = .274). Grade ≥ 3 related adverse events were less common in Arm A vs. B (78 vs. 94%; hematologic: 61 vs. 90%, p < .0001); 10 vs. 11% had secondary malignancies (ALL, 7 vs. 3 pts, p = .22; AML/MDS, 0 vs. 10 pts, p = .002). Difference in mean change from baseline in EORTC QLQ-C30 global health status score was < 10 points throughout treatment except at RVd cycle 5 vs. post-ASCT (compliance rate, 75% vs. 55%; mean change +3.0 vs. –11.1; p < .0001). Whole-genome sequencing, additional QOL, and correlative analyses are ongoing. Conclusions: RVd ± ASCT and R maintenance to progression resulted in the longest median PFS reported for each approach, and a highly significant 21.4-mo gain in median PFS benefit using RVd + ASCT. No OS advantage has been observed to date. Clinical trial information: NCT01208662.

8011 Background: In the primary analysis of the phase 2 randomized GRIFFIN study, DARA + RVd (D-RVd) improved the stringent complete response (sCR) rate by end of consolidation for transplant-eligible NDMM (42.4% vs 32.0%; 1-sided P = 0.068). With longer follow-up (median, 38.6 mo), D-RVd vs RVd improved MRD-negativity (10–5) rates in clinically relevant subgroups (ISS stage III, 71% vs 36%; high cytogenetic risk, 44% vs 29% [del17p, t(4;14), or t(14;16)]; revised high cytogenetic risk, 55% vs 32% [del17p, t(4;14), t(14;16), t(14;20), or gain 1q]). Here we present a post hoc analysis of sustained MRD negativity (median follow-up, 38.6 mo) in the same subgroups and in patients (pts) with ≥CR. Methods: Transplant-eligible NDMM pts were randomized 1:1 to 4 D-RVd/RVd induction cycles, ASCT, 2 D-RVd/RVd consolidation cycles, and 2 years of maintenance therapy with lenalidomide (R) ± DARA. For induction/consolidation (21-day cycles), pts received R (25 mg PO Days [D] 1-14), V (1.3 mg/m2 SC D1, 4, 8, 11), and d (40 mg PO weekly) ± DARA (16 mg/kg IV D1, 8, 15 of Cycles 1-4 and D1 of Cycles 5-6). In maintenance (28-day cycles), pts received R (10 mg PO D1-21; if tolerated, 15 mg in Cycles 10+) ± DARA (16 mg/kg IV Q8W/Q4W or 1800 mg SC per protocol amendments). The primary endpoint was sCR rate by end of consolidation. Results: The following features were balanced among randomized pts (D-RVd, n = 104; RVd, n = 103): high cytogenetic risk (16; 14), revised high cytogenetic risk (42; 37), gain 1q (34; 28), and ISS stage III (14; 14). Sustained MRD-negativity rates at 10–5 lasting ≥6 and ≥12 months were higher for D-RVd vs RVd among all high-risk subgroups (Table). D-RVd was superior to RVd for rates of sustained MRD negativity lasting ≥12 months for pts with ≥CR (53.7% vs 20.3%) and sCR (59.1% vs 17.4%; Table). Among all pts with sustained MRD negativity, only 1 D-RVd pt subsequently had disease progression, and 1 RVd pt died. Additional data on MRD at 10–6 and PFS will be presented. Conclusions: MRD data in GRIFFIN show that the addition of DARA to RVd induction/consolidation and R maintenance may lead to durable MRD-negativity (10–5) rates in pts with transplant-eligible NDMM with high cytogenetic risk, ISS stage III, and those who achieve ≥CR or sCR, however larger studies are needed. Clinical trial information: NCT02874742. [Table: see text]

Therapeutic regimens for previously treated multiple myeloma (MM) may not provide prolonged disease control and are often complicated by significant adverse events, including peripheral neuropathy. In patients with previously treated MM in the Phase 3 BOSTON study, once weekly selinexor, once weekly bortezomib, and 40 mg dexamethasone (XVd) demonstrated a significantly longer median progression-free survival (PFS), higher response rates, deeper responses, a trend to improved survival, and reduced incidence and severity of bortezomib-induced peripheral neuropathy when compared with standard twice weekly bortezomib and 80 mg dexamethasone (Vd). The pre-specified analyses described here evaluated the influence of the number of prior lines of therapy, prior treatment with lenalidomide, prior proteasome inhibitor (PI) therapy, prior immunomodulatory drug therapy, and prior autologous stem cell transplant (ASCT) on the efficacy and safety of XVd compared with Vd. In this 1:1 randomized study, enrolled patients were assigned to receive once weekly oral selinexor (100 mg) with once weekly subcutaneous bortezomib (1.3 mg/m2) and 40 mg per week dexamethasone (XVd) versus standard twice weekly bortezomib and 80 mg per week dexamethasone (Vd). XVd significantly improved PFS, overall response rate, time-to-next-treatment, and showed reduced all grade and grade ≥ 2 peripheral neuropathy compared with Vd regardless of prior treatments, but the benefits of XVd over Vd were more pronounced in patients treated earlier in their disease course who had either received only one prior therapy, had never been treated with a PI, or had prior ASCT. Treatment with XVd improved outcomes as compared to Vd regardless of prior therapies as well as manageable and generally reversible adverse events. XVd was associated with clinical benefit and reduced peripheral neuropathy compared to standard Vd in previously treated MM. These results suggest that the once weekly XVd regimen may be optimally administered to patients earlier in their course of disease, as their first bortezomib-containing regimen, and in those relapsing after ASCT.Trial registration: ClinicalTrials.gov (NCT03110562). Registered 12 April 2017. https://clinicaltrials.gov/ct2/show/NCT03110562.

Background Patients (pts) with RRMM who were exposed to immunomodulatory agents, proteasome inhibitors (PIs), and anti-CD38 monoclonal antibodies (mAbs) have poor outcomes with subsequent treatments. Ide-cel, a BCMA-directed CAR T-cell therapy, has shown frequent, deep, and durable responses in triple-class exposed pts with RRMM in the pivotal KarMMa study (NCT03361748; Munshi NC et al. N Engl J Med 2021). Here, we report updated results from this trial. Methods Eligible pts had received ≥3 prior regimens (including an immunomodulatory agent, a PI, and an anti-CD38 mAb) and had disease refractory to their last regimen per IMWG criteria. After 3 days of lymphodepletion (cyclophosphamide 300 mg/m2 + fludarabine 30 mg/m2), pts received 150–450×106 CAR+ T cells (target dose levels). Primary endpoint was overall response rate (ORR); key secondary endpoint was complete response (CR) rate (CR + stringent CR). Other secondary endpoints included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Results In total, 128/140 enrolled pts received ide-cel. Data are presented for the treated pts. Median age was 61 y. Pts had received a median of 6 (range, 3–16) prior regimens, with 84% being triple-class refractory and 26% penta-refractory (lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab). Most pts (88%) had received bridging therapy. At data cutoff (Dec 21, 2020), the median follow-up among surviving pts was 24.8 mo. In total, 94/128 pts (73%) achieved an overall response, with a CR rate of 33%; median DOR and PFS were 10.9 mo and 8.6 mo, respectively. In pts who achieved ≥CR, median DOR was 21.5 mo and median PFS was 22.4 mo. Outcomes improved at higher doses, with ORR of 81%, CR rate of 39%, median DOR of 11.3 mo, and median PFS of 12.2 mo at 450×106 CAR+ T cells; in pts who achieved ≥CR at this dose, median DOR was not reached. Responses were observed in all subgroups, including difficult-to-treat subsets (eg, high tumor burden [ORR, 71%], extramedullary disease [70%], and R-ISS stage III disease [48%]). Median OS was 24.8 mo; the estimated 24-mo OS rate was 51%. The most common any-grade toxicities were neutropenia (91%) and cytokine release syndrome (CRS; 84%). CRS was mostly grade 1/2; 5 pts (4%) had grade 3, 1 pt each had grade 4 and 5 events (both at 300×106). Investigator-identified neurotoxicity was reported in 23 pts (18%); 5 (4%) had grade 3 and 0 had grade ≥4 events. Tocilizumab was used in 67 and 3 pts, and steroids were used in 19 and 10 pts with CRS and neurotoxicity, respectively. Conclusion Updated results from the KarMMa trial continue to demonstrate durable and deep responses with ide-cel in heavily pretreated, triple-class–exposed pts with RRMM. Efficacy and safety data are consistent with prior reports and support a favorable clinical benefit–risk profile for ide-cel across the target dose levels.

Background DARA is approved across lines of therapy for multiple myeloma (MM). The phase 2 GRIFFIN study (NCT02874742) investigated DARA+RVd (D-RVd) in transplant-eligible NDMM; at the primary analysis, D-RVd improved efficacy, and safety was consistent with prior reports for DARA and RVd. We conducted a post-hoc analysis of GRIFFIN to evaluate anti-thrombosis prophylaxis use, in concordance with IMWG guidelines, and the incidence of VTEs, given a historical risk of VTEs with lenalidomide plus dexamethasone occurring in 10-25% of MM patients (pts). Methods Pts with NDMM eligible for autologous stem cell transplant (ASCT) were randomized 1:1 to receive 4 cycles of D-RVd/RVd induction, high-dose therapy, ASCT, 2 cycles of D-RVd/RVd consolidation, and maintenance with DARA-R/R for 24 months. During induction and consolidation (21-day cycles), pts received R (25 mg PO on Days 1-14); V (1.3 mg/m2 SC on Days 1, 4, 8, 11); and d (40 mg QW). DARA (16 mg/kg IV) was given on Days 1, 8, 15 of Cycles 1-4 and Day 1 of Cycles 5-6. During maintenance (Cycles 7-32; 28-day cycles), pts received R (10 mg PO on Days 1-21; if tolerated, 15 mg in Cycles 10+)±DARA (16 mg/kg IV Q8W or Q4W per protocol amendment 2). VTE prophylaxis was recommended for all pts (aspirin, ≥162 mg) with alternative prophylaxis for pts at increased VTE risk, based on medical history. VTEs were identified through standardized MedDRA queries, and treatment group comparisons were by descriptive analyses. Results VTEs occurred in 10% (10/99) of D-RVd pts and 15% (15/102) of RVd pts. Grade 3/4 VTEs occurred in 4% of D-RVd pts and 6% of RVd pts, with grade 3 pulmonary embolism in 1% of D-RVd pts and 4% of RVd pts. The median (range) time to VTE was 379 (6-810) and 232 (21-511) days in the D-RVd and RVd groups, respectively. Anti-thrombosis prophylaxis use was reported in 83% of D-RVd pts and 83% of RVd pts, including heparin derivates in 14% and 19% of pts, respectively (majority of pts on LMWH). Among pts who developed a VTE, 80% (8/10) of D-RVd pts and 93% (14/15) of RVd pts received anti-thrombosis medication, including LMWH in 30% and 27% of pts, respectively. However, only 60% (6/10) of D-RVd pts and 67% (10/15) of RVd pts were on anti-thrombosis prophylaxis at the time of the VTE, including aspirin in 40% and 60% of pts and LMWH in 10% and 7% of pts, respectively. One D-RVd pt received DOAC (rivaroxaban). Bone marrow involvement ≥60% plasma cells was seen in 50% of D-RVd pts and 60% of RVd pts developing VTEs, compared with 43% of all D-RVd pts and 41% of all RVd pts. Conclusion In this descriptive analysis, the use of daratumumab did not increase the VTE rate, and the median time to VTE was longer for D-RVd. Although no formal conclusion can be drawn, these observations indicate additional and larger investigations may be warranted to understand optimal VTE prophylaxis in NDMM pts, as current data show VTE prophylactic therapy adherence may be suboptimal.

Context The belamaf US EAP (NCT03763370) provided medicine access to patients unable to participate in a clinical trial prior to regulatory agency approval. Objective To obtain insight from the belamaf EAP on patient types potentially eligible for belamaf treatment in a real-world setting. Methods The EAP included patients with RRMM who received ≥3 prior lines of therapy and were refractory to proteasome inhibitors, immunomodulatory agents, and anti-CD38 monoclonal antibody. Patients received belamaf 2.5 mg/kg Q3W. Safety was closely monitored, and dose delays/reductions were permitted to manage adverse events. Treating physicians re-evaluated eligibility to continue belamaf at each treatment cycle; patients could withdraw at any time. The EAP closed following US FDA approval of belamaf. We report baseline characteristics from included patients. Results In this preliminary analysis (as of 3 Feb 2021), 263 patients were screened; 235 were treated with ≥1 dose of belamaf and were included in this analysis. The most common reasons for withdrawal were lack of continued clinical benefit (n=37) and death (n=21); 23 patients continued therapy beyond closure of the program. Of 235 treated patients, 137 (58.3%) were male. Median age was 66 years, with 106 patients (45.1%) aged 75 years. Two hundred eighteen patients had further medical history available; 61 (26.0%) had prior treatment-related toxicities, 10 (4.3%) had active renal disease, and 5 (2.1%) had undergone allogeneic stem cell transplant. Two hundred twenty-one patients had ocular baseline characteristics reported; these included prior glaucoma diagnosis (single-eye, n=16 [6.8%]), prior cataract diagnosis (single, n=124 [52.8%]), history of cataract surgery (single, n=66 [28.1%]), and prior dry eye diagnosis (n=46 [19.6%]). The most common prior anticancer therapies included bortezomib, lenalidomide, pomalidomide, and carfilzomib. Data cleaning is ongoing for this study. Conclusions This EAP provides insights from a real-world population of US belamaf-treated patients, which, in addition to data from the pivotal DREAMM-2 study, may help practitioners identify patients potentially eligible for belamaf treatment. Funding GlaxoSmithKline (213304). Drug linker technology licensed from Seagen Inc.; monoclonal antibody produced using POTELLIGENT Technology licensed from BioWa.

8036 Background: Ide-cel, a BCMA-directed CAR T cell therapy, showed promising efficacy in patients (pts) with RRMM in the KarMMa study with an ORR of 73% and a CRR of 33% across target doses of 150–450 × 106 CAR+ T cells (Munshi NC, et al. J Clin Oncol 2020;38[suppl 15]. Abstract 8503). Associations of neurotoxicity (NT) with pt and disease characteristics, pt management, and impact on outcomes in the KarMMa study are reported here. Methods: Enrolled pts were triple-class exposed and refractory to their last regimen, with ide-cel given at target doses of 150, 300, or 450 × 106 CAR+ T cells after lymphodepletion (NCT03361748). Investigator-identified NT events were captured under the single preferred term of neurotoxicity and graded according to NCI CTCAE v4.03. Events were managed with corticosteroids (CS), anakinra (ANR), and tocilizumab (Toci) as needed. Results: Of 128 pts treated with ide-cel, NT was reported in 23 (18%); 12 pts (9%) had maximum grade (gr) 1 NT, 7 (5%) had gr 2, and 4 (3%) had gr 3. No gr 4 or 5 NT occurred. Most baseline characteristics were similar in pts with and without NT, including stage III disease (22% and 15%), high-risk cytogenetics (39% and 34%), and extramedullary disease (35% and 40%); exceptions were high tumor burden (65% and 48%) and sex (48% and 62% men). NT (any gr/gr 3) occurred in 0%/0%, 17%/1%, and 20%/6% of pts at doses of 150, 300, and 450 × 106 CAR+ T cells. Median time to onset was similar regardless of gr, and there were no late-onset events (Table). NT was managed with CS in 10 pts (43%), Toci in 3 (13%), and ANR in 1 (4%). Median (range) time to first use of CS was 2 d (1–6). ORR and DOR were similar in pts with and without NT (Table). All NT occurred in the proximity of cytokine release syndrome (CRS) events with the start date of NT events either overlapping with or occurring within 1 wk of the start of a CRS event. Conclusions: NT occurred early in the KarMMa study, was generally of short duration, and was mostly gr 1/2 with no gr ≥4 events. All NT was proximal to CRS. Pts with NT had a favorable ORR after ide-cel treatment. These results continue to demonstrate the durable efficacy and tolerability of ide-cel in pts with RRMM. Clinical trial information: NCT03361748. [Table: see text]

NA

Elderly and frail patients with multiple myeloma (MM) are more vulnerable to the toxicity of combination therapies, often resulting in treatment modifications and suboptimal outcomes. The phase 3 BOSTON study showed that once-weekly selinexor and bortezomib with low-dose dexamethasone (XVd) improved PFS and ORR compared with standard twice-weekly bortezomib and moderate-dose dexamethasone (Vd) in patients with previously treated MM. This is a retrospective subgroup analysis of the multicenter, prospective, randomized BOSTON trial. Post hoc analyses were performed to compare XVd versus Vd safety and efficacy according to age and frailty status (

8016 Background: Patients (pts) with RRMM previously exposed to immunomodulatory agents, proteasome inhibitors (PIs), and CD38 antibodies (mAbs) have poor outcomes with subsequent treatments. Ide-cel, a BCMA-directed CAR T cell therapy, showed frequent, deep, and durable responses in heavily pretreated pts with RRMM in the pivotal KarMMa trial (Munshi NC, et al. J Clin Oncol 2020;38[suppl 15]. Abstract 8503). Here, we present updated data. Methods: Pts with ≥ 3 prior regimens (including immunomodulatory agent, PI, and CD38 mAb) and refractory to their last regimen per IMWG criteria were eligible (NCT03361748). Pts received 150─450 × 106 CAR+ T cells (target dose range) after 3 days of lymphodepletion (cyclophosphamide 300 mg/m2 + fludarabine 30 mg/m2). Endpoints included overall response rate (ORR; primary) and complete response (CR) rate (key secondary). Additional secondary endpoints included progression-free survival (PFS), overall survival (OS), and safety. Results: KarMMa enrolled 140 pts, and 128 received ide-cel. Pts had a median age of 61 years and a median of 6 (range, 3-16) prior regimens; 84% were triple-class refractory, and 26% were penta-class refractory (lenalidomide, pomalidomide, bortezomib, carfilzomib, and daratumumab). Most pts (88%) had bridging therapy. Median follow-up was 15.4 mo (data cutoff, 7 Apr 2020). ORR was 73% and median PFS was 8.8 mo in all treated pts; both increased with higher dose (Table). At the highest target dose (450 × 106 CAR+ T cells), the ORR was 81%, the CR rate was 39%, and the median PFS increased to 12.2 months with longer follow-up. Responses were observed in all subgroups including difficult-to-treat subsets (eg, extramedullary disease [ORR, 70%], high tumor burden [71%], and R-ISS stage III disease [48%]). OS continues to mature and the median has not been reached; the 15-month event-free rate for OS was 71%. Cytopenias (97%) and cytokine release syndrome (CRS; 84%) were the most common any-grade toxicities. CRS was mostly grade 1/2; 5 pts (4%) had grade 3, 1 had grade 4 (at 300 × 106), and 1 had grade 5 (at 300 × 106). Investigator-identified neurotoxicity was reported in 23 pts (18%); 4 pts (3%) had grade 3 and 0 had grade ≥ 4. Tocilizumab was used in 67 and 3 pts with CRS and neurotoxicity, respectively. Conclusions: Updated results from the KarMMa trial continue to demonstrate deep, durable responses with ide-cel in heavily pretreated pts with RRMM. Efficacy and safety reflect prior reports and support a favorable clinical benefit-risk profile for ide-cel across the target dose range. Clinical trial information: NCT03361748. [Table: see text]

BACKGROUND Idecabtagene vicleucel (ide-cel, also called bb2121), a B-cell maturation antigendirected chimeric antigen receptor (CAR) T-cell therapy, has shown clinical activity with expected CAR T-cell toxic effects in patients with relapsed and refractory multiple myeloma. METHODS In this phase 2 study, we sought to confirm the efficacy and safety of ide-cel in patients with relapsed and refractory myeloma. Patients with disease after at least three previous regimens including a proteasome inhibitor, an immunomodulating agent, and an anti-CD38 antibody were enrolled. Patients received ide-cel target doses of 150 x 10(6) to 450 x 10(6) CAR-positive (CAR+) T cells. The primary end point was an overall response (partial response or better); a key secondary end point was a complete response or better (comprising complete and stringent complete responses). RESULTS Of 140 patients enrolled, 128 received ide-cel. At a median follow-up of 13.3 months, 94 of 128 patients (73%) had a response, and 42 of 128 (33%) had a complete response or better. Minimal residual disease (MRD)-negative status (

In the phase 3 BOSTON study, patients with multiple myeloma (MM) after 1–3 prior regimens were randomized to once-weekly selinexor (an oral inhibitor of exportin 1 [XPO1]) plus bortezomib-dexamethasone (XVd) or twice-weekly bortezomib-dexamethasone (Vd). Compared with Vd, XVd was associated with significant improvements in median progression-free survival (PFS), overall response rate (ORR), and lower rates of peripheral neuropathy, with trends in overall survival (OS) favoring XVd. In BOSTON, 141 (35.1%) patients had MM with high-risk (presence of del[17p], t[4;14], t[14;16], or ≥4 copies of amp1q21) cytogenetics (XVd, n=70; Vd, n=71), and 261 (64.9%) exhibited standard-risk cytogenetics (XVd, n=125; Vd, n=136). Among patients with high-risk MM, median PFS was 12.91 months for XVd and 8.61 months for Vd (HR, 0.73 [95% CI, (0.4673, 1.1406)], p=0.082), and ORRs were 78.6% and 57.7%, respectively (OR 2.68; p= 0.004). In the standard-risk subgroup, median PFS was 16.62 months for XVd and 9.46 months for Vd (HR 0.61; p=0.004), and ORRs were 75.2% and 64.7%, respectively (OR 1.65; p=0.033). The safety profiles of XVd and Vd in both subgroups were consistent with the overall population. These data suggest that selinexor can confer benefits to patients with MM regardless of cytogenetic risk. ClinicalTrials.gov identifier: NCT03110562.

Multiple myeloma is a malignant neoplasm of plasma cells that accumulate in bone marrow, leading to bone destruction and marrow failure. This manuscript discusses the management of patients with solitary plasmacytoma, smoldering multiple myeloma, and newly diagnosed multiple myeloma.

Summary Background Selinexor combined with dexamethasone has shown activity in patients with heavily pre-treated multiple myeloma. In a phase 1b/2 study, the combination of oral selinexor with bortezomib (a proteasome inhibitor) and dexamethasone induced high response rates with low rates of peripheral neuropathy, the main dose-limiting toxicity of bortezomib. We aimed to evaluate the clinical benefit of weekly selinexor, bortezomib, and dexamethasone versus standard bortezomib and dexamethasone in patients with previously treated multiple myeloma. Methods This phase 3, randomised, open-label trial was done at 123 sites in 21 countries. Patients aged 18 years or older, who had multiple myeloma, and who had previously been treated with one to three lines of therapy, including proteasome inhibitors, were randomly allocated (1:1) to receive selinexor (100 mg once per week), bortezomib (1·3 mg/m2 once per week), and dexamethasone (20 mg twice per week), or bortezomib (1·3 mg/m2 twice per week for the first 24 weeks and once per week thereafter) and dexamethasone (20 mg four times per week for the first 24 weeks and twice per week thereafter). Randomisation was done using interactive response technology and stratified by previous proteasome inhibitor therapy, lines of treatment, and multiple myeloma stage. The primary endpoint was progression-free survival in the intention-to-treat population. Patients who received at least one dose of study treatment were included in the safety population. This trial is registered at ClinicalTrials.gov , NCT03110562 . The trial is ongoing, with 55 patients remaining on randomised therapy as of Feb 20, 2020. Findings Of 457 patients screened for eligibility, 402 were randomly allocated—195 (49%) to the selinexor, bortezomib, and dexamethasone group and 207 (51%) to the bortezomib and dexamethasone group—and the first dose of study medication was given between June 6, 2017, and Feb 5, 2019. Median follow-up durations were 13·2 months [IQR 6·2–19·8] for the selinexor, bortezomib, and dexamethasone group and 16·5 months [9·4–19·8] for the bortezomib and dexamethasone group. Median progression-free survival was 13·93 months (95% CI 11·73–not evaluable) with selinexor, bortezomib, and dexamethasone and 9·46 months (8·11–10·78) with bortezomib and dexamethasone (hazard ratio 0·70 [95% CI 0·53–0·93], p=0·0075). The most frequent grade 3–4 adverse events were thrombocytopenia (77 [39%] of 195 patients in the selinexor, bortezomib, and dexamethasone group vs 35 [17%] of 204 in the bortezomib and dexamethasone group), fatigue (26 [13%] vs two [1%]), anaemia (31 [16%] vs 20 [10%]), and pneumonia (22 [11%] vs 22 [11%]). Peripheral neuropathy of grade 2 or above was less frequent with selinexor, bortezomib, and dexamethasone (41 [21%] patients) than with bortezomib and dexamethasone (70 [34%] patients; odds ratio 0·50 [95% CI 0·32–0·79], p=0·0013). 47 (24%) patients in the selinexor, bortezomib, and dexamethasone group and 62 (30%) in the bortezomib and dexamethasone group died. Interpretation A once-per-week regimen of selinexor, bortezomib, and dexamethasone is a novel, effective, and convenient treatment option for patients with multiple myeloma who have received one to three previous lines of therapy. Funding Karyopharm Therapeutics.

Lenalidomide, bortezomib, and dexamethasone (RVd) followed by autologous stem cell transplantation (ASCT) is standard frontline therapy for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab (D) to RVd (D-RVd) in transplant-eligible NDMM patients was evaluated. Patients (N = 207) were randomized 1:1 to D-RVd or RVd induction (4 cycles), ASCT, D-RVd or RVd consolidation (2 cycles), and lenalidomide or lenalidomide plus D maintenance (26 cycles). The primary end point, stringent complete response (sCR) rate by the end of post-ASCT consolidation, favored D-RVd vs RVd (42.4% vs 32.0%; odds ratio, 1.57; 95% confidence interval, 0.87-2.82; 1-sided P = .068) and met the prespecified 1-sided α of 0.10. With longer follow-up (median, 22.1 months), responses deepened; sCR rates improved for D-RVd vs RVd (62.6% vs 45.4%; P = .0177), as did minimal residual disease (MRD) negativity (10−5 threshold) rates in the intent-to-treat population (51.0% vs 20.4%; P < .0001). Four patients (3.8%) in the D-RVd group and 7 patients (6.8%) in the RVd group progressed; respective 24-month progression-free survival rates were 95.8% and 89.8%. Grade 3/4 hematologic adverse events were more common with D-RVd. More infections occurred with D-RVd, but grade 3/4 infection rates were similar. Median CD34+ cell yield was 8.2 × 106/kg for D-RVd and 9.4 × 106/kg for RVd, although plerixafor use was more common with D-RVd. Median times to neutrophil and platelet engraftment were comparable. Daratumumab with RVd induction and consolidation improved depth of response in patients with transplant-eligible NDMM, with no new safety concerns. This trial was registered at www.clinicaltrials.gov as #NCT02874742.

This phase 1, dose-finding study investigated ibrutinib and carfilzomib ± dexamethasone in patients with relapsed or relapsed/refractory multiple myeloma (≥2 lines of therapy including bortezomib and an immunomodulatory agent). Of 43 patients enrolled, 74% were refractory to bortezomib and 23% had high-risk cytogenetics. No dose-limiting toxicities were observed. The recommended phase 2 dose was ibrutinib 840 mg and carfilzomib 36 mg/m2 with dexamethasone. The most common ≥ grade 3 (>10%) treatment-emergent adverse events were hypertension, anemia, pneumonia, fatigue, diarrhea, and thrombocytopenia. Overall response rate was 67% (very good partial response, 21%; stringent complete response, 2%), with an additional 9% minimal response. Median progression-free survival was 7.2 months and was not inferior in refractory nor high-risk patients. Median overall survival was not reached. Ibrutinib plus carfilzomib demonstrated encouraging responses with a manageable safety profile in this advanced population.

Introduction Outcomes for patients (pts) with relapsed/refractory multiple myeloma (RRMM) previously treated with immunomodulatory agents, proteasome inhibitors (PIs), and anti-CD38 antibodies are poor; novel treatments that prolong survival in pts with RMMM are essential. Idecabtagene vicleucel (ide-cel), a B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T cell therapy, showed frequent, deep, and durable responses in triple-class exposed pts with RRMM in the pivotal phase 2 KarMMa study (NCT03361748; Munshi et al. N Engl J Med 2021). Two updates of ide-cel in RRMM (phase 1 CRB-401 [NCT02658929] and the KarMMa study) demonstrated an overall survival (OS) of 34.2 and 24.8 months and median progression-free survival (PFS) of 8.8 and 8.6 months, respectively (Lin et al. ASH 2020 Abstract 131; Anderson et al. ASCO 2021 Poster 8016). The effect on median PFS and median OS was observed in all dose ranges, including in pts who received 450 x 10 6 CAR+ T cells (12.2 and 24.8 months, respectively). The difference between median PFS and OS in these studies prompted additional analyses examining outcomes for pts enrolled in KarMMa, including time to second disease progression (PFS2), duration of subsequent anti-myeloma therapy (sAMT), and OS in pts who received sAMT. Additionally, the subset of pts who received subsequent anti-BCMA therapy was analyzed. Methods Pts with MM, ≥ 3 prior lines of therapy (including an immunomodulatory agent, PI, and anti-CD38 antibody), and disease refractory to their last regimen per IMWG criteria received ide-cel infusion (target dose range 150-450 x 10 6 CAR+ T cells) after lymphodepletion (fludarabine 30 mg/m 2/day + cyclophosphamide 300 mg/m 2/day for 3 days). After ide-cel treatment, pts who relapsed could receive sAMT, ide-cel re-treatment (RT), or both. Baseline characteristics were collected prior to initial ide-cel transfusion. PFS2, type and duration of sAMT, and OS were assessed. Results Among 128 pts who received ide-cel, 104 (81%) had progressive disease or death after receiving ide-cel (median follow-up 24.8 months). Of the 128 ide-cel-treated pts, 68 received sAMT alone or with RT (of whom 11 received subsequent anti-BCMA therapy); 33 did not receive sAMT and relapsed after, or did not respond to, ide-cel; and 27 were not included in this analysis due to having received RT alone (n = 8) or continuing in remission after ide-cel at time of analysis. Baseline demographics and clinical characteristics of pts receiving sAMT, anti-BCMA, and no sAMT/RT were generally similar; median age (63, 55, 57 years), male (60%, 55%, 64%), and ECOG PS 0-1 (97%, 91%, 97%). However, a greater proportion of pts who did not receive sAMT/RT had revised International Staging System stage III disease compared with pts who had sAMT or anti-BCMA therapy (33%, 9%, 9%, respectively). The most frequent sAMT classes were corticosteroids (n = 58) and PIs (n = 47), while the most frequent sAMT agents were dexamethasone (n = 56) and carfilzomib (n = 32). Anti-BCMA agents included antibody-drug conjugate belantamab mafodotin (GSK2857916; n = 10) and inducible T-cell co-stimulator feladilimab (GSK3359609; n = 1). In pts who received sAMT, median PFS and OS to ide-cel was 6.1 and 24.8 months (Table). Median duration of first sAMT was 44 days and duration of all sAMT was 215 days, with a PFS2 of 13.6 months (inclusive of time on ide-cel). Among pts who received anti-BCMA therapy, median PFS and OS to ide-cel was 12.1 and 31.0 months. The median duration of first sAMT was 48 days and PFS2 was 15.5 months. Conclusions Pts who relapsed after ide-cel were able to successfully receive sAMT with a PFS2 longer than 13 months. No consistent drug class was used for sAMT. Although the number of pts who received anti-BCMA as sAMT was small, this subset of pts had overall favorable outcomes, including OS, after ide-cel and sAMT. BCMA loss has been noted as a potential mechanism of immune escape (Da Vià et al. Nat Med 2021); however, in KarMMa, it was suspected in just 3 of 71 pts who could be evaluated at progression (Munshi et al. N Engl J Med 2021). As such, pts who relapsed after initial ide-cel infusion may benefit from subsequent anti-BCMA therapy. Further exploration into the tumor microenvironment before and after ide-cel and how it relates to favorable PFS2 and OS in these subgroups is ongoing. Study support bluebird bio and Celgene, a Bristol-Myers Squibb Company. Figure 1 Figure 1. Disclosures Rodriguez-Otero: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Clínica Universidad de Navarra: Current Employment; Kite: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: 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; Pfizer: Consultancy; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria; Regeneron: Honoraria. San-Miguel: AbbVie, Amgen, Bristol-Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Karyopharm, Merck Sharpe & Dohme, Novartis, Regeneron, Roche, Sanofi, SecuraBio, Takeda: Consultancy, Other: Advisory board. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Lonial: Merck: Honoraria; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; AMGEN: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding. Truppel-Hartmann: bluebird bio: Current Employment. Sanford: Bristol Myers Squibb: Current Employment. Rowe: Bristol Myers Squibb: Current Employment. Campbell: Bristol Myers Squibb: Current Employment, Current holder of individual stocks in a privately-held company. Munshi: Abbvie: Consultancy; Pfizer: Consultancy; Amgen: Consultancy; Adaptive Biotechnology: Consultancy; Celgene: Consultancy; Karyopharm: Consultancy; Bristol-Myers Squibb: Consultancy; Janssen: Consultancy; Oncopep: Consultancy, Current equity holder in publicly-traded company, Other: scientific founder, Patents & Royalties; Takeda: Consultancy; Novartis: Consultancy; Legend: Consultancy.

Introduction: DARA is approved across lines of therapy for multiple myeloma, including in combination with standard-of-care regimens for NDMM. The CXCR4 receptor antagonist plerixafor is used in conjunction with granulocyte colony-stimulating factor (G-CSF) to increase stem cell mobilization for autologous stem cell transplant (ASCT) and can be given by upfront decision or as a rescue strategy. The phase 2 randomized GRIFFIN study (NCT02874742) evaluates frontline DARA in combination with lenalidomide, bortezomib, and dexamethasone (D-RVd) in transplant-eligible NDMM. In the primary analysis, more pts undergoing stem cell mobilization/collection in the D-RVd group received plerixafor compared with the RVd group (69.5% [66/95] vs 56.3% [45/80]) (Voorhees PM, et al. Blood. 2020). The phase 2 MASTER study (NCT03224507) evaluates DARA plus carfilzomib, lenalidomide, and dexamethasone (D-KRd) in transplant-eligible NDMM (Costa LJ, et al. EHA Library. 2020). Here, we present a summary of stem cell mobilization, collection yields, and ASCT data following frontline DARA-based induction therapy in GRIFFIN and MASTER. Methods: Eligible pts had NDMM and were candidates for ASCT. In GRIFFIN, pts were randomized 1:1 to receive D-RVd or RVd. Pts received 4 induction cycles (21 days) of lenalidomide (R; 25 mg PO on Days 1-14), bortezomib (1.3 mg/m 2 SC on Days 1, 4, 8, and 11), and dexamethasone (d; 40 mg PO QW) ± DARA (16 mg/kg IV QW in Cycles 1-4). After Cycle 4, pts underwent stem cell mobilization with G-CSF ± plerixafor, per institutional standards; if unsuccessful, chemo mobilization was permitted. Pts then received ASCT and subsequently 2 consolidation cycles (21 days) of D-RVd or RVd followed by maintenance therapy with R ± DARA. In the single-arm MASTER study, pts received 4 D-KRd induction cycles, ASCT, and 0, 4 or 8 D-KRd consolidation cycles followed by maintenance therapy with R, based upon achievement of minimal residual disease-negativity. In each 28-day cycle, all pts received carfilzomib (20/56 mg/m 2 IV QW), R (25 mg PO on Days 1-21), d (40 mg PO or IV QW), and DARA (16 mg/kg IV QW for Cycles 1-2, Q2W for Cycles 3-6, and Q4W for Cycles 7+). Mobilization was with G-CSF ± plerixafor as per institutional standards. Results: In GRIFFIN, among 207 (D-RVd, n=104; RVd, n=103) randomized pts, 91.3% (n=95) of D-RVd pts and 77.7% (n=80) of RVd pts underwent stem cell mobilization; of those mobilized, 98.9% (n=94) and 97.5% (n=78) underwent ASCT, respectively. In MASTER, 123 D-KRd pts enrolled and at last follow-up, 91.1% (n=112) underwent stem cell mobilization; of those mobilized, 98.2% (n=110) completed ASCT. In GRIFFIN, 46.3% (n=81) of mobilized pts received plerixafor upfront (D-RVd, 51.6%, n=49; RVd, 40.0%, n=32), and 18.3% (n=32 pts) received rescue plerixafor (D-RVd, 20.0%, n=19; RVd, 16.3%, n=13). In MASTER, 70.5% (n=79) D-KRd pts received upfront plerixafor and 25.9% (n=29) received rescue plerixafor. Median CD34 + cell yield was 8.3 × 10 6/kg for D-RVd and 9.4 ×10 6/kg for RVd in GRIFFIN, 6.0 ×10 6/kg for D-KRd in MASTER, and was numerically higher for pts who received upfront plerixafor. Median days for stem cell collection was 1 for pts receiving RVd and 2 for those receiving D-RVd or D-KRd. Median transplanted CD34 + cell count was 4.2 ×10 6/kg for D-RVd and 4.8 ×10 6/kg for RVd in GRIFFIN, and 3.2 ×10 6/kg for D-KRd in MASTER. In GRIFFIN, 93.7% of D-RVd pts and 98.8% of RVd pts reached the minimum institutional CD34 + threshold to perform a single ASCT, which was comparable to results in MASTER (95.5% of D-KRd pts) after first mobilization attempt; 85.3% of D-RVd pts, 92.5% of RVd pts, and 79.5% of D-KRd pts collected 2 times the minimum threshold of stem cells. Additional data by upfront and rescue plerixafor strategies are shown in the Table. Conclusion: The addition of DARA to proteasome inhibitor/immunomodulatory drug/dexamethasone-based induction therapy has a modest impact on stem cell mobilization, with a lower yield of stem cells and higher median number of days required for collection. Nonetheless, pts were able to undergo transplantation, and most pts collected sufficient stem cells for 2 transplants. Pts who received plerixafor by an upfront decision had numerically higher stem cell yields than pts who received plerixafor by a rescue strategy. An upfront plerixafor strategy for pts receiving DARA-based quadruplet induction therapy should be considered with allowance for additional days of apheresis as needed. Figure 1 Figure 1. Disclosures Chhabra: GSK: Honoraria. Costa: Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Kaufman: BMS: Consultancy, Research Funding; Fortis Therapeutics: Research Funding; Roche/Genetech, Tecnopharma: Consultancy, Honoraria; Sutro, Takeda: Research Funding; Genentech, AbbVie, Janssen: Consultancy, Research Funding; Novartis: Research Funding; Incyte, celgene: Consultancy; Tecnofarma SAS, AbbVie: Honoraria; Janssen: Honoraria; Incyte, TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; Heidelberg Pharma: Research Funding; Amgen: Research Funding. Sborov: Sanofi: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees; SkylineDx: Consultancy; GlaxoSmithKline: Consultancy. Reeves: Incyte Corporation: Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Speakers Bureau; Pharma Essentia: Consultancy, Honoraria. Rodriguez: Karyopharm: Consultancy, Speakers Bureau; Oncopeptides: Consultancy, Honoraria; Amgen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau. Chari: Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Shattuck Labs: Consultancy, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: 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; Novartis: Consultancy, Research Funding. Silbermann: Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Shah: Sutro Biopharma: Research Funding; Janssen: Research Funding; Indapta Therapeutics: Consultancy; CareDx: Consultancy; Sanofi: Consultancy; Kite: Consultancy; Poseida: Research Funding; Amgen: Consultancy; BMS/Celgene: Research Funding; Bluebird Bio: Research Funding; CSL Behring: Consultancy; GSK: Consultancy; Precision Biosciences: Research Funding; Teneobio: Research Funding; Oncopeptides: Consultancy; Nektar: Research Funding; Karyopharm: Consultancy. Bumma: Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen: Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees. Holstein: Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech, GSK, Janssen, Secura Bio, Sorrento: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Jakubowiak: BMS: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Gracell: 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; Janssen: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. Wildes: Carevive: Consultancy; Seattle Genetics: Consultancy; Sanofi: Consultancy; Janssen: Consultancy. Orlowski: CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Other: Clinical research funding; Asylia Therapeutics, Inc., BioTheryX, Inc., and Heidelberg Pharma, AG.: Other: Laboratory research funding; 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; 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. Shain: Novartis Pharmaceuticals Corporation: Consultancy; Karyopharm Therapeutics Inc.: Honoraria, Research Funding; Janssen oncology: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi Genzyme: Consultancy, Speakers Bureau; GlaxoSmithLine, LLC: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies Corporation: Consultancy, Speakers Bureau; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Cowan: Janssen: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Cellectar: Consultancy; Harpoon: Research Funding; GSK: Consultancy; Secura Bio: Consultancy; BMS: Research Funding; Nektar: Research Funding. Dholaria: Takeda: Research Funding; Jazz: Speakers Bureau; MEI: Research Funding; Angiocrine: Research Funding; Poseida: Research Funding; Celgene: Speakers Bureau; Pfizer: Research Funding; Janssen: Research Funding. Pei: Janssen: Current Employment, Current equity holder in publicly-traded company. Cortoos: Janssen: Current Employment, Current equity holder in publicly-traded company. Patel: Janssen: Current Employment. Bartlett: Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company. Lin: Janssen: Current Employment. Richardson: AstraZeneca: Consultancy; Regeneron: Consultancy; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; AbbVie: Consultancy; GlaxoSmithKline: Consultancy; Karyopharm: Consultancy, Research Funding; Protocol Intelligence: Consultancy; Janssen: Consultancy; Sanofi: Consultancy; Secura Bio: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding. Voorhees: Pfizer: 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; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The specific regimen combination is not yet approved, but individual components are.

Introduction: DARA is approved for NDMM and previously treated MM. In the primary analysis of the phase 2 GRIFFIN trial (NCT02874742) in autologous stem cell transplant (ASCT)-eligible NDMM pts (median follow-up, 13.5 mo), DARA plus RVd (D-RVd) improved the rate of stringent complete response (sCR) by the end of post-ASCT consolidation versus RVd (42.4% vs 32.0%, 1-sided P=0.068) (Voorhees PM, et al. Blood. 2020). With longer follow-up (median, 27.4 mo), responses deepened and were improved for D-RVd versus RVd (sCR rate: 63.6% vs 47.4%, 2-sided P=0.0253), as did the MRD-negativity (10 -5) rate (62.5% vs 27.2%, P Methods: Pts with NDMM eligible for high-dose therapy (HDT) and ASCT were randomized 1:1 to receive RVd or D-RVd, stratified by ISS disease stage (I, II, or III) and creatinine clearance (30-50 or >50 mL/min). Pts received 4 RVd or D-RVd induction cycles, HDT, ASCT, 2 RVd or D-RVd consolidation cycles, and maintenance with lenalidomide (R) alone or with DARA (D-R) for 24 months. During induction and consolidation (21-day cycles), pts received R (25 mg PO on Days 1-14), bortezomib (1.3 mg/m 2 SC on Days 1, 4, 8, and 11), and dexamethasone (40 mg PO QW) ± DARA (16 mg/kg IV on Days 1, 8, and 15 of Cycles 1-4 and Day 1 of Cycles 5-6). During maintenance (Cycles 7-32; 28-day cycles), pts received R (10 mg PO on Days 1-21; if tolerated, 15 mg in Cycle 10+) ± DARA (16 mg/kg IV) Q8W (or Q4W per pt decision after protocol amendment 2) until disease progression or up to 24 months. The primary endpoint was sCR rate by the end of post-ASCT consolidation (tested at 1-sided α of 0.10). Responses were assessed per IMWG criteria by a validated computer algorithm. Key secondary endpoints included progression-free survival (PFS) and MRD negativity assessed by NGS at the minimum sensitivity threshold of 10 -5, at suspected complete response or better (≥CR), at the end of induction and consolidation, and after 12 and 24 months of maintenance, regardless of response. Secondary analyses were evaluated using 2-sided α of 0.05, not adjusted for multiplicity. Results: In total, 207 pts were randomized (D-RVd, n=104; RVd, n=103); baseline characteristics were well balanced. After 24 months of D-R or R maintenance therapy, the rate of sCR favored D-RVd versus RVd in the response-evaluable population (66.0% [66/100] vs 47.4% [46/97], 2-sided P=0.0096; Figure). In the intent-to-treat (ITT) population, MRD-negativity (10 -5) rates also remained higher for D-RVd versus RVd (64.4% [67/104] vs 30.1% [31/103], P3-fold higher for D-RVd versus RVd (44.2% vs 12.6%, P Conclusion: After 24 months of maintenance therapy, the addition of DARA to RVd induction and consolidation in conjunction with ASCT, followed by DARA plus R maintenance, continued to demonstrate deep and durable responses in pts with transplant-eligible NDMM, including sCR and MRD-negativity (10 -5 and 10 -6) rates. While this study was not powered for PFS, there is a positive trend towards improved PFS in the D-RVd group. No new safety concerns were observed with longer follow-up. These results support the use of D-RVd induction/consolidation and D-R maintenance in transplant-eligible NDMM pts. Figure 1 Figure 1. Disclosures Kaufman: Sutro, Takeda: Research Funding; Incyte, TG Therapeutics: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Amgen: Research Funding; Tecnofarma SAS, AbbVie: Honoraria; Janssen: Honoraria; Fortis Therapeutics: Research Funding; Novartis: Research Funding; Incyte, celgene: Consultancy; Heidelberg Pharma: Research Funding; Roche/Genetech, Tecnopharma: Consultancy, Honoraria; Genentech, AbbVie, Janssen: Consultancy, Research Funding. Sborov: Sanofi: Consultancy; SkylineDx: Consultancy; GlaxoSmithKline: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees. Reeves: Bristol-Myers Squibb: Speakers Bureau; Incyte Corporation: Honoraria; Takeda: Honoraria; Pharma Essentia: Consultancy, Honoraria. Rodriguez: Janssen: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Karyopharm: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Oncopeptides: Consultancy, Honoraria. Chari: Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Research Funding; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Research Funding; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Consultancy, Research Funding; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Silbermann: Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Membership on an entity's Board of Directors or advisory committees, Research Funding. Costa: Pfizer: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Shah: GSK: Consultancy; Nektar: Research Funding; Kite: Consultancy; CareDx: Consultancy; CSL Behring: Consultancy; Indapta Therapeutics: Consultancy; Janssen: Research Funding; Poseida: Research Funding; Karyopharm: Consultancy; BMS/Celgene: Research Funding; Bluebird Bio: Research Funding; Oncopeptides: Consultancy; Teneobio: Research Funding; Sanofi: Consultancy; Precision Biosciences: Research Funding; Sutro Biopharma: Research Funding; Amgen: Consultancy. Bumma: Janssen: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau; Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Holstein: Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; Genentech, GSK, Janssen, Secura Bio, Sorrento: Honoraria; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding. Jakubowiak: Abbvie: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees. Wildes: Carevive: Consultancy; Seattle Genetics: Consultancy; Sanofi: Consultancy; Janssen: Consultancy. 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; 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; 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. Shain: AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Amgen Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi Genzyme: Consultancy, Speakers Bureau; GlaxoSmithLine, LLC: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies Corporation: Consultancy, Speakers Bureau; Janssen oncology: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm Therapeutics Inc.: Honoraria, Research Funding; Novartis Pharmaceuticals Corporation: Consultancy. Cowan: BMS: Research Funding; Secura Bio: Consultancy; GSK: Consultancy; Harpoon: Research Funding; Cellectar: Consultancy; Sanofi: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Nektar: Research Funding. Pei: Janssen: Current Employment, Current equity holder in publicly-traded company. Cortoos: Janssen: Current Employment, Current equity holder in publicly-traded company. Patel: Janssen: Current Employment. Bartlett: Janssen: Current Employment. Vermeulen: Janssen: Current Employment, Current equity holder in publicly-traded company. Lin: Janssen: Current Employment. Richardson: Sanofi: Consultancy; Secura Bio: Consultancy; Regeneron: Consultancy; Karyopharm: Consultancy, Research Funding; Janssen: Consultancy; Protocol Intelligence: Consultancy; Celgene/BMS: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; AstraZeneca: Consultancy; Oncopeptides: Consultancy, Research Funding; AbbVie: Consultancy; Jazz Pharmaceuticals: Consultancy, Research Funding. Voorhees: Amgen: Consultancy, Honoraria, 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; Oncopeptides: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Secura Bio: 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; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: The specific regimen combination is not yet approved, but individual components are.

Background: The risk of severe COVID-19 is increased in patients (pts) with hematologic malignancies, with a reported risk of death of 34% (Vijenthira et al, 2020). The ASH-ASTCT COVID-19 vaccine guidelines indicate that certain immunocompromised patient populations could have an attenuated response to the SARS-CoV-2 vaccine. However, most SARS-CoV-2 vaccine trials required pts to be off immune suppression to be eligible and therefore excluded most pts with hematologic malignancies. Little is known about the efficacy of SARS-CoV-2 vaccines in pts with hematologic malignancies. In this study, we aimed to evaluate the serological response of Pfizer and Moderna vaccination after two doses given in pts with hematologic malignancies with a focus on pts with myeloid malignancies. Methods: Patients with a history of hematologic malignancies treated at the University of Texas Southwestern Medical Center and received two doses of vaccination with quantitative measurement of SARS-CoV-2 IgG Spike antibody to assess vaccination response were included in this study. Baseline patient and disease characteristics including disease status and therapy given at the time of vaccination were collected. Time to vaccine response was defined as having a positive quantifiable spike IgG antibody titer per the lab reference range. The development of COVID-19 infection as well as antibody titer levels were collected. Categorical variables were compared using Chi-square and Fisher's exact tests and student t-test and ANOVA test were used to compare continuous variables. Results: A total of 61 pts with hematologic malignancies had spike IgG antibody testing after receiving 2 doses of the vaccine were included in this study. The median age at the time of vaccination was 72 (22-85) and 46% of pts were female. Eighty five percent of pts were Caucasian. The majority of pts (67.3%) had a myeloid malignancy (MDS/CMML 29.5%, AML 14.8%, myelofibrosis 16.4%, CML 6.6%), followed by chronic lymphocytic leukemia (16.4%), and others (6.6%). The median time from hematologic malignancy diagnosis to the first vaccine dose was 51 months (0.4-337 months). At the time of vaccine administration, 46 (75%) of pts were on active therapy and 39 (64%) of pts had active disease. Median time from the second vaccine dose to IgG spike antibody testing was 64 days (26-268 days). Most pts (75%) mounted a serological response with quantifiable COVID-IgG spike antibodies, 85% and 56% in myeloid and lymphoid malignancy, respectively. All pts with MDS/CMML/CCUS and CML mounted an immune response (100%), followed by acute myeloid leukemia (n: 7/9, 78%) and myelofibrosis (n: 6/10, 60%). Eight (13%) of pts were receiving hypomethylating agent therapy at the time of vaccination and all (100%) had a positive IgG response. Only one patient developed COVID-19 infection post vaccination with a documented IgG response and 2 pts had COVID-19 infection prior to the first dose of vaccination, both of these pts had IgG titers >10,000. Sixty percent of pts (9/15) with negative IgG response received treatment with either CD20 monoclonal antibodies or BTK inhibitors within 12 months of the first vaccine dose. Two out of three pts (67%) receiving Ruxolitinib had negative serology. Seven pts were on treatment with hydroxyurea, interestingly, all but the 2 pts with polycythemia vera had a negative antibody titer while on treatment with hydroxyurea. There was a strong positive correlation between vaccine titer and absolute lymphocyte count (r 2=0.27, p Conclusions: In this retrospective study, we demonstrate a higher rate of COVID-19 vaccine efficacy in pts with myeloid malignancy with varying responses per treatment and disease subtype compared to pts with B-cell malignancy with variable anti-CD20 or BTK inhibitor therapy. Pts with myelodysplastic syndromes, overlap syndromes of clonal cytopenia of undetermined significance all developed spike antibodies irrespective of hypomethylating therapy or Hydrea as did pts with chronic myeloid leukemia. However, pts with polycythemia vera and those on treatment with Ruxolitinib had an attenuated response to the vaccine. Albeit this single center study, pts with myelodysplastic syndromes should be offered COVID vaccines irrespective of their blood counts or ongoing treatment. Our findings should be validated in a larger group of patients. Figure 1 Figure 1. Disclosures Patel: Agios: Membership on an entity's Board of Directors or advisory committees; Celgene-BMS: Membership on an entity's Board of Directors or advisory committees; PVI: Honoraria. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Awan: Cardinal Health: Consultancy; BMS: Consultancy; Dava Oncology: Consultancy; Karyopharm: Consultancy; Merck: Consultancy; Johnson and Johnson: Consultancy; Incyte: Consultancy; Beigene: Consultancy; Verastem: Consultancy; MEI Pharma: Consultancy; Celgene: Consultancy; Kite pharma: Consultancy; Gilead sciences: Consultancy; Pharmacyclics: Consultancy; Janssen: Consultancy; Abbvie: Consultancy; ADCT therapeutics: Consultancy; Astrazeneca: Consultancy; Genentech: Consultancy. Madanat: Blue Print Pharmaceutical: Honoraria; Onc Live: Honoraria; Stem line pharmaceutical: Honoraria; Geron Pharmaceutical: Consultancy.

Introduction Multiple factors drive specific therapy selection for patients with hematologic malignancies including efficacy, toxicity, patient and physician preferences, comorbid conditions, cost, and logistics. However, the advent of many highly effective and generally well-tolerated targeted therapies for chronic lymphocytic leukemia (CLL) and lymphoid malignancies makes objective distinction between various therapeutic agents more difficult. As a result, the eventual therapy selection is often based on physician preference. Secure electronic communication portals (ECP) are federally mandated and frequently used in health care. Although important, ECPs impose a significant burden on the entire healthcare team. However, the extent of ECP use on healthcare burden is poorly ascertained particularly in hematology. While limited available data suggests that cancer patients are more likely than urology or family medicine patients to use ECP, healthcare utilization studies have historically not included this metric as a measure of therapy-related healthcare team burden (THTB). Our study not only uniquely evaluates the quantitative impact of ECP use on THTB, it also addresses qualitative domains that are used in ECPs to provide a holistic and granular assessment of THTB. Methods Patient and ECP data were retrospectively collected at a comprehensive cancer center after institutional IRB approval. The dataset included 412 patients with CLL and lymphoid malignancies treated with ibrutinib (n=237), acalabrutinib (n=70), and venetoclax (n=105). A subset of these patients with AML treated with venetoclax were also included to address disease and therapy specific issues. By leveraging common taxonomy from published literature, we created multiple domains specific to the evaluable metrics as detailed in the tables and utilized the Naranjo adverse drug reaction probability scale and provider documentation to code each message. Results Patients who had at least one patient-initiated or clinician-initiated ECP message thread were included in the final analysis (n=95, 23.06%). Table 1 shows patient, treatment, and disease characteristics. Ibrutinib was used mostly as initial or second-line therapy, while acalabrutinib and venetoclax were mostly used for later lines. We coded 3338 message threads, comprising 3272 patient-generated messages, and 2050 messages generated by 354 unique clinical staff. Our sampled population generated an average of 25.83 messages per patient and our healthcare clinical staff generated an average of 17.96 messages. Table 2 contains domain specific ECP interactions. Patient and healthcare team-generated messages were highest in the first six months of starting therapy and varied with treatment (p Conclusion Our study highlights an important but poorly described measure of THTB that can significantly impact therapy selection, especially when multiple therapeutic options with comparable outcomes are available. A non-reimbursed increase in ECP utilization poses significant THTB which is not easily offset by increased staffing efforts and might result in under-utilization of potentially effective therapies, especially in resource limited settings. In addition, our domain-specific appraisal of ECP allows for identification for improvements in healthcare delivery and intervention with structured enhancements that can maximize patient-centered care while decreasing THTB. THTB should therefore include ECP use and be evaluated as part of a comprehensive assessment tool. Figure 1 Figure 1. Disclosures Madanat: Geron Pharmaceutical: Consultancy; Blue Print Pharmaceutical: Honoraria; Stem line pharmaceutical: Honoraria; Onc Live: Honoraria. Patel: PVI: Honoraria; Celgene-BMS: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Awan: Beigene: Consultancy; Incyte: Consultancy; Celgene: Consultancy; Karyopharm: Consultancy; Kite pharma: Consultancy; Dava Oncology: Consultancy; Johnson and Johnson: Consultancy; Verastem: Consultancy; MEI Pharma: Consultancy; Gilead sciences: Consultancy; Pharmacyclics: Consultancy; Janssen: Consultancy; BMS: Consultancy; Cardinal Health: Consultancy; Merck: Consultancy; ADCT therapeutics: Consultancy; Abbvie: Consultancy; Astrazeneca: Consultancy; Genentech: Consultancy.

Introduction: Patients with multiple myeloma (MM) have a high rate of relapse resulting in a need for multiple lines of therapy. In contrast to MM with standard risk cytogenetics (SR-Cyto), high-risk cytogenetics (HR-Cyto) in MM such as del(17p), t(4;14), t(14;16), and gain(1q) (≥3 copies), can result in shorter progression-free survival (PFS) and overall survival (OS) with less durable responses. Treatment regimens that can overcome the negative effect of HR-Cyto abnormalities are required to address this area of unmet medical need. Exportin 1 (XPO1), is overexpressed in many hematologic and solid tumor malignancies including MM, and exports tumor suppressor proteins from the nucleus to the cytoplasm, leading to their inactivation. Elevated levels of XPO1 are correlated with more aggressive MM and resistance to therapy and confers a poor prognosis. The potent oral XPO1 inhibitor, selinexor, has been approved as a triplet combination with bortezomib and dexamethasone for previously-treated MM. In the Phase 3 BOSTON study, treatment with XVd in patients with previously treated MM significantly prolonged median PFS and improved the overall response rate (ORR), with a trend towards a prolonged OS amongst all patients as well as those with HR cytogenetics. Methods: We performed post hoc analyses on patients with previously-treated MM from the XVd arm of the Phase 1b/2 study STOMP (NCT02343042) and the Phase 3 BOSTON (NCT03110562) study to determine the effects of cytogenetic abnormalities on outcomes. The HR-Cyto group included patients with at least one of the following cytogenetic abnormalities at initial diagnosis or screening: del(17p), t(4;14), t(14;16), or gain(1q) (≥3 copies). Efficacy was based on independent review committee. Results: A total of 106 patients with HR-Cyto were identified, including del(17p) (n=25), t(4;14) (n=25), t(14;16) (n=10), and gain(1q) (n=80). There were 131 patients classified as SR-Cyto including those with unknown cytogenetics. Baseline demographics were similar between groups with median age of 66 years old (range 40-87). Patients with HR-Cyto had a median PFS of 12.9 months and patients with SR-Cyto had a median PFS of 16.6 months; PFS on the BOSTON Vd control arm were 8.6 and 9.5 months with HR- and SR-Cyto, respectively. Of the individual abnormalities, a PFS of 13.2 and 13.9 months was observed in the t(4;14) and gain1q subgroups, respectively. Of the HR-Cyto subgroups with more than 10 patients, a similar median OS was observed in comparison to SR-Cyto and ranged from 20.4 months to not reached. The response of XVd treatment was maintained across HR-Cyto risk subgroups, with an ORR of 76.4% overall and the following values for subgroups: del(17p) (72.0%), t(4;14) (88.0%), and gain1q (73.8%). The ORR of the SR group was 69.5%. Of all patients that received XVd, there were 6 CRs (5.7%) and 32 VGPRs (30.2%) in the HR group and 9 CRs (6.9%) and 29 VGPRs (22.1%) in the SR group. The ORRs on the BOSTON Vd control arm were 57.7% and 64.7% for HR- and SR-Cyto, respectively. The rates of the most common treatment emergent adverse events (TEAEs) of any grade were similar across risk groups (HR- vs SR-Cyto): thrombocytopenia (65.1% vs. 54.2%), nausea (53.8% vs. 53.4%), fatigue (47.2% vs. 45.0%) decreased appetite (37.7% vs. 42.0%) and anemia (34.6% vs 40.5%). Rates of AEs of any grade peripheral neuropathy (PN) were 35.8% overall, 40.0% in del(17p), t(4;14) (40.0%), t(14;16) (30.0%), gain(1q) (38.8%), and 23.7% in the SR group. The rates of PN in the HR and SR groups of the XVd arm of the BOSTON and STOMP studies were 37.1% and 29.6% and 11.1% and 15.2%, respectively. The corresponding rates for Vd alone in the BOSTON study were 48.6% and 47.0%. Conclusions: Patients with MM with HR-Cyto treated with XVd demonstrated a comparable ORR and PFS, with a manageable safety profile compared to patients with SR-Cyto, supporting the use of XVd in patients with any cytogenetic profile. These results are consistent with the distinct and broad mechanism of action associated with XPO1 inhibition and the use of the agent in earlier lines of therapy. Further assessment of selinexor in combination with other therapies in patients with MM across the entire cytogenetic spectrum is warranted. Figure 1 Figure 1. Disclosures Bahlis: Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Genentech: Consultancy; BMS/Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria. Richard: Karyopharm, Janssen: Honoraria. White: Amgen, Antengene, BMS/Celgene, Forus, GSK, Janssen, Karyopharm, Sanofi, Takeda: Consultancy, Honoraria. Chen: Gilead: Research Funding; BMS, Janssen, Abbvie, Novartis, Gilead, AstraZeneca: Consultancy. Delimpasi: Amgen: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau. Sutherland: Amgen: Consultancy; Janssen: Consultancy, Research Funding; GSK: Research Funding; Celgene: Consultancy; Karyopharm: Research Funding. Sebag: Janssen: Research Funding; Bristol Myers-Squibb: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria. Gavriatopoulou: GSK: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Genesis: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria; Amgen: Honoraria. Lentzsch: Oncopeptides: Consultancy; Sanofi: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding; Takeda: Consultancy; GSK: Consultancy; AbbVie: Consultancy; Celularity: Consultancy; Janssen: Consultancy; Caelum Biosciences: Consultancy, Current holder of individual stocks in a privately-held company; Ossium Health: Consultancy; Magenta Therapeutics: Current equity holder in publicly-traded company; Kadmon: Current equity holder in publicly-traded company. Chari: Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Research Funding; Oncopeptides: 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; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Shattuck Labs: 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; Novartis: Consultancy, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Millenium/Takeda: Consultancy, Research Funding; Pharmacyclics: Research Funding; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Consultancy, 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; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding. Kriachok: Takeda, Roche, Abbvie, Janssen, MSD, Pfizer: Honoraria, Speakers Bureau; Takeda, Roche, Abbivie, Janssen, MSD: Consultancy. Dimopoulos: BMS: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Beigene: Honoraria. Auner: Janssen: Speakers Bureau; Amgen: Research Funding; Takeda, Karyopharm: Other: Advisory role. Leleu: Bristol-Myers Squibb: Honoraria; Carsgen Therapeutics Ltd: Honoraria; Celgene: Honoraria; Gilead Sciences: Honoraria; Janssen-Cilag: Honoraria; Karyopharm Therapeutics: Honoraria; Merck: Honoraria; Mundipharma: Honoraria; Novartis: Honoraria; Oncopeptides: Honoraria; Pierre Fabre: Honoraria; Roche: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; AbbVie: Honoraria; Takeda: Honoraria, Other: Non-financial support. Usenko: Janssen: Consultancy, Honoraria, Other: Clinical Trials Investigator; AbbVie: Consultancy, Honoraria, Other: Clinical Trials Investigator; Pfizer: Consultancy, Honoraria; Acerta: Other: Clinical Trials Investigator; Ascentage: Other: Clinical Trials Investigator; Celgene: Other: Clinical Trials Investigator; Il-Yang: Other: Clinical Trials Investigator; Karyopharm: Other: Clinical Trials Investigator; Oncopeptides: Other: Clinical Trials Investigator; Rigel: Other: Clinical Trials Investigator; Takeda: Other: Clinical Trials Investigator; UCB: Other: Clinical Trials Investigator. Hajek: Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharma MAR: Consultancy, Honoraria; Novartis: Consultancy, Research Funding; AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding. Venner: Janssen: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Celgene: Research Funding; Amgen: Research Funding. Garg: Takeda Janssen Novartis Sanofi: Other: Travel Accommodations, Expenses; Amgen Janssen Novartis Sanofi Takeda: Honoraria; University Hospital Leicester: Current Employment. Quach: Antengene: 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; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen/Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: 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; Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; CSL: Consultancy, Membership on an entity's Board of Directors or advisory committees. Jagannath: Karyopharm Therapeutics: Consultancy; Bristol Myers Squibb: Consultancy; Legend Biotech: Consultancy; Janssen Pharmaceuticals: Consultancy; Sanofi: Consultancy; Takeda: Consultancy. Moreau: Celgene BMS: Honoraria; Sanofi: Honoraria; Janssen: Honoraria; Abbvie: Honoraria; Amgen: Honoraria; Oncopeptides: Honoraria. Levy: Takeda, Celgene, Seattle Genetics, AbbVie, Jazz Pharmaceuticals, Gilead Sciences, Bristol-Myers Squibb, Amgen, Spectrum Pharmaceuticals,Janssen.: Consultancy. Badros: J&J: Research Funding; Janssen: Research Funding; BMS: Research Funding; GlaxoSmithKline: Research Funding. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mateos: Oncopeptides: Honoraria; Janssen: 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; Takeda: 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; Roche: 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; 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; Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria; Bluebird bio: Honoraria; AbbVie: Honoraria; Amgen: 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. Cavo: AbbVie: Consultancy, Honoraria, 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, Speakers Bureau; GlaxoSmithKline: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Adaptive Biotechnologies: Consultancy, Honoraria; Takeda: Consultancy, 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 Accommodations, Speakers Bureau; Novartis: Honoraria; 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. DeCastro: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Chai: Karyopharm: Current Employment. Van Domelen: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Mishal: Karyopharm: Current Employment. Bentur: Karyopharm Therapeutics: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm: Current Employment. Shacham: Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Richardson: Secura Bio: Consultancy; Sanofi: Consultancy; AstraZeneca: Consultancy; Oncopeptides: Consultancy, Research Funding; Janssen: Consultancy; Protocol Intelligence: Consultancy; Takeda: Consultancy, Research Funding; Regeneron: Consultancy; Celgene/BMS: Consultancy, Research Funding; GlaxoSmithKline: Consultancy; AbbVie: Consultancy; Karyopharm: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding.

Introduction: CAR T-cells remain in a quiescent or dormant state when unstimulated, showing no proliferative activity. In contrast, upon specific antigen stimulation (i.e., CD19) CAR T-cells divide both in-vitro and in-vivo, initiate immune responses and can kill their target cells in the body. However, one of the major physiological immune changes with increased age is the progressive impairment of T-cell responses. This process termed immunosenescence (which may be similar T-cell exhaustion) is associated with the shortening of telomeres, specific DNA repeated sequences that protect the end of linear chromosomes from degradation and fusion with neighbor chromosomes. We aim to investigate change in T-cell telomere length with CAR-T cell therapy and its potential impact on outcome in patients receiving CART immunotherapy. Methods: We enrolled adult patients (age range: 30-80 years old) receiving CART immunotherapy for diffuse large B cell lymphoma (DLBCL), multiple myeloma (MM), mantle cell lymphoma (MCL), or follicular lymphoma (FL). We collected peripheral blood at two time points: i) pre-lymphodepletion therapy and ii) two weeks post CAR-T cell infusion. Peripheral blood mononuclear cells were isolated from blood via density gradient and T-cells isolated from PBMC with magnetic beads (negative selection). Telomere lengths are quantified from T-cells by using a highly sensitive technique called TeSLA (Telomere Shortest Length Assay) that allows absolute quantification of both the average telomere length and the lengths of critically short telomeres, which are believed to play a major role in promoting cell cycle arrest and T-cell exhaustion. Results: We identified 7 patients receiving CAR T cell therapy for hematological malignancies at University of Texas Southwestern Medical Center. The cohort included 7 patients, 2 patients with DLBCL and 1 patient with MCL receiving CD19 CAR-T Cell therapy and 4 patients with MM receiving BCMA CAR-T cell therapy. Median age of patient was 65 yrs. Median follow up was 273 days post CAR T-cell therapy with all patients being alive at last follow-up. Two patients experienced Grade I Cytokine release syndrome (CRS), two patients with Grade 2 CRS and one patient with Grade 2 ICANS. Our initial analysis shows that patients telomere lengths changes pre and post CAR T-cell infusion. Regarding change in critically short telomere ( Conclusions: CAR T-cell therapy is a game-changer for hematological malignancies; however, disease still relapse. Understanding the mechanics of poor response or relapse after CAR T-cell therapy is critical in advancing the field. Initial results suggest T-cell telomere length are significantly affected during CAR T-cell manufacturing process and post infusion. These results are potentially important as telomere length can be utilized as a biomarker to predict CAR T-cell therapy outcomes. Figure 1 Figure 1. Disclosures Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Awan: Verastem: Consultancy; Incyte: Consultancy; Cardinal Health: Consultancy; Dava Oncology: Consultancy; BMS: Consultancy; ADCT therapeutics: Consultancy; Beigene: Consultancy; Celgene: Consultancy; Karyopharm: Consultancy; Pharmacyclics: Consultancy; MEI Pharma: Consultancy; Merck: Consultancy; Kite pharma: Consultancy; Gilead sciences: Consultancy; Johnson and Johnson: Consultancy; Abbvie: Consultancy; Janssen: Consultancy; Astrazeneca: Consultancy; Genentech: Consultancy. Madanat: Onc Live: Honoraria; Blue Print Pharmaceutical: Honoraria; Geron Pharmaceutical: Consultancy; Stem line pharmaceutical: Honoraria. Patel: Celgene-BMS: Membership on an entity's Board of Directors or advisory committees; PVI: Honoraria; Agios: Membership on an entity's Board of Directors or advisory committees. Sweetenham: EMA Wellness: Membership on an entity's Board of Directors or advisory committees. Kansagra: Alynylam, Celgene/BMS, Cota Health, GSK, Janssen, Karyopharm, Oncopeptide, Pfizer, Takeda, Sanofi: Membership on an entity's Board of Directors or advisory committees.

The therapy of hematologic malignancies has been revolutionized by the development of therapies using chimeric antigen receptor modified T-cells (CAR-T). However, CAR-T cell therapy is often associated with cytokine release syndrome (CRS), characterized by fevers, hypotension, and hypoxia, as well as immune effector cell-associated neurotoxicity syndrome (ICANS). Severe cases of CRS can result in significant morbidity and mortality. Although disease features such as tumor burden may predict for more severe CRS and ICANS, other clinical features and biomarkers predictive of CRS and ICANS remain lacking, with the exception of measurements of serum cytokines following cell infusion (PMID: 27076371, PMID: 24553386). Experimental models have implicated elaboration of inflammatory cytokines such as IL-1 and IL-6 by monocytes in the pathogenesis of CRS and ICANS (PMID: 29808007, PMID: 29808005). Accordingly, the severity and duration of CRS and ICANS can be mitigated in part by IL-6 receptor blockade with tocilizumab and treatment with corticosteroids such as dexamethasone. Recent work has implicated ascorbate in the regulation of the activity of TET enzymes in hematopoietic cells (PMID: 28825709, PMID: 28823558). Given that TET2 deficiency has been associated with increased elaboration of inflammatory cytokines such as IL-6 and IL-1 by macrophages (PMID 3026882, PMID: 28104796, PMID: 28636844), we reasoned that ascorbate deficiency might predict for more pronounced cytokine release in patients leading to more severe CRS or ICANS. We identified 13 patients receiving CAR-T cell therapy for hematologic malignancies at the University of Texas Southwestern. Plasma specimens were collected from patients at baseline prior to receipt of lymphodepleting chemotherapy and/or at two weeks following CAR-T cell infusion. Given the poor reliability of clinical ascorbate measurements due to oxidation, we used an optimized protocol incorporating a C13-labeled ascorbate internal standard to obtain highly precise serum measurements using liquid-chromatography mass spectrometry. The incidence and severity of CRS and ICANS was classified using standardized grading criteria as per the American Society for Transplantation and Cellular Therapy. We measured serum ascorbate in 7 baseline and 12 post CAR-T cell infusion specimens obtained from 13 patients, with a median age of 65 (range 53 to 77). The cohort included eight patients with diffuse large B-cell lymphoma and two patients with mantle cell lymphoma receiving CD19-targeted CAR-T cells, as well as three patients with multiple myeloma receiving BCMA-targeted CAR-T cells. Eight patients developed grade one CRS, three patients developed grade two CRS, and two patients did not develop CRS. One patient developed grade one ICANS, one developed grade two ICANS, and one developed grade three ICANS. Eight patients received dexamethasone for CRS or ICANS, and eight patients received tocilizumab. Five patients only received one dose of tocilizumab, while two received two doses and one received three doses. Taking all pre- and post-CAR-T cell infusion ascorbate measurements into account, a significant correlation was found between having low serum ascorbate levels and a higher maximal grade of CRS or ICANS (Figure 1A, r 2=-0.64, p=0.0039). Post-infusion ascorbate measurements also demonstrated a significant correlation between low serum ascorbate levels and higher maximal CRS or ICANS (Figure 1B, r 2=-0.78, p=0.0035), while there was no correlation between pre-infusion ascorbate measurements and CRS or ICANS. Finally, we noted a significant decrease in serum ascorbate levels when comparing pre-infusion to post-infusion specimens (Figure 1C, p=0.048), including five paired specimens. There was no significant correlation between serum ascorbate levels and the number of doses of tocilizumab or dexamethasone administered. Low serum ascorbate levels may be associated with an increased risk for developing severe CRS and ICANS following CAR-T cell therapy. Although follow-up studies with a larger cohort of patient are necessary to substantiate this correlation, these data provide preliminary evidence that serum ascorbate levels may serve as a useful biomarker to predict severity of CRS and ICANS. Furthermore, they suggest ascorbate supplementation as a promising future strategy to mitigate these common complications of CAR-T cell therapy. Figure 1 Figure 1. Disclosures Kansagra: Alynylam, Celgene/BMS, Cota Health, GSK, Janssen, Karyopharm, Oncopeptide, Pfizer, Takeda, Sanofi: Membership on an entity's Board of Directors or advisory committees. Anderson: Celgene, BMS, Janssen, GSK, Karyopharm, Oncopeptides, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Awan: Abbvie: Consultancy; Dava Oncology: Consultancy; Johnson and Johnson: Consultancy; Incyte: Consultancy; BMS: Consultancy; Astrazeneca: Consultancy; ADCT therapeutics: Consultancy; Pharmacyclics: Consultancy; Janssen: Consultancy; Beigene: Consultancy; Merck: Consultancy; Gilead sciences: Consultancy; Cardinal Health: Consultancy; Verastem: Consultancy; MEI Pharma: Consultancy; Karyopharm: Consultancy; Celgene: Consultancy; Kite pharma: Consultancy; Genentech: Consultancy. Madanat: Stem line pharmaceutical: Honoraria; Blue Print Pharmaceutical: Honoraria; Onc Live: Honoraria; Geron Pharmaceutical: Consultancy. Patel: Agios: Membership on an entity's Board of Directors or advisory committees; PVI: Honoraria; Celgene-BMS: Membership on an entity's Board of Directors or advisory committees. Sweetenham: EMA Wellness: Membership on an entity's Board of Directors or advisory committees.

Background Patients (pts) with multiple myeloma (MM) refractory to lenalidomide (LEN) are a growing and clinically relevant patient population with a need for safe and effective therapies. In the OPTIMISMM trial (NCT01734928), pts with LEN RRMM who were treated with pomalidomide (POM), bortezomib (BORT), and dexamethasone (DEX; PVd) at first relapse had significantly improved median PFS (20.7 vs 11.6 mo; HR, 0.54; 95% CI, 0.36–0.82; P=0.0027) vs BORT and DEX (Vd; Richardson PG, et al. Lancet Oncol 2019;20:781–794). Treatment-emergent adverse events (TEAEs) reported with PVd were consistent with safety profiles of POM, BORT, or DEX alone. Here we report a safety analysis of TEAEs in the events of interest (EOI) category for PVd vs Vd administered at first relapse in OPTIMISMM. Methods Patients with RRMM and 1–3 prior lines of therapy were randomized 1:1 to receive PVd or Vd in 21-day cycles until disease progression, unacceptable toxicity, or withdrawal of consent. Key eligibility criteria included ≥2 cycles of prior LEN (LEN-refractory pts were included). AEs were graded according to the NCI CTCAE (v4.0) and summarized by system organ class and preferred term. Results The safety analysis included 221/559 pts (PVd, n=111; Vd, n=110) who had 1 prior line of therapy and received ≥1 dose of study drug. Baseline characteristics were balanced between Tx arms. All pts had prior LEN (57% were refractory); 59% had prior BORT. Median duration of treatment was longer with PVd (47.4 wk; range 4.7–147.0) vs Vd (27.1 wk; range 0.4–162.0). Grade (Gr) 3/4 TEAE EOI occurred in 57% of pts (PVd, 69%; Vd, 45%). The most common Gr 3/4 TEAE EOI were neutropenia (24%), infections and infestations (22%), and thrombocytopenia (20%). Gr 3/4 TEAE EOI more common with PVd vs Vd included neutropenia (37% vs 12%), infections and infestations (29% vs 15%), and peripheral neuropathy (12% vs 5%). Onset of neutropenia was mostly in the first 3 cycles and mainly Gr 3/4, with a median duration of 8 days with PVd and 5 days with Vd. Onset of infections and infestations commonly occurred during cycles 1–9, were mostly Gr 1/2, with a median duration of 12 days with both PVD and Vd. Among patients with ≥1 TEAE EOI, most were managed with dose reductions (PVd, 59%; Vd, 39%) or interruptions (PVd, 79%; Vd, 55%). POM discontinuations due to ≥1 any-grade TEAE EOI were low (9%), none due to neutropenia. In the PVd arm, 62% (31/50) of pts with any-grade neutropenia received G-CSF support. Infections and infestations were the main cause of PVd dose interruptions (54%). Peripheral neuropathy was the most common TEAE EOI leading to dose reduction (32%) and discontinuation (16%) with PVd. Conclusion The safety profile for PVd at first relapse in pts with RRMM is consistent with previous reports. Most TEAE EOI occurred in early cycles of treatment and were managed with dose modifications or appropriate treatment. Previous presentation Weisel K, et al. HemaSphere 2021;5:e464–465. EP988.

Introduction: Despite recent advances, there remains an unmet need for novel therapies to improve outcomes and abrogate the adverse effects of high-risk cytogenetics in patients with multiple myeloma (MM). In patients with triple class refractory MM in the Phase 2b STORM study, the clinical benefit of selinexor plus low dose dexamethasone (sel-dex) was preserved across high-risk cytogenetic subgroups, supporting further evaluation of selinexor combined with other anti-MM therapies (Nooka et al. ASH 2019). The phase 3 BOSTON study evaluated the combination of weekly sel-dex with the proteasome inhibitor (PI) bortezomib (SVd) against standard twice weekly bortezomib-dex (Vd) in patients with MM who had received 1-3 prior therapies. SVd significantly improved progression free survival (PFS), time to next therapy (TTNT), overall response rate (ORR) and depth of response (≥VGPR), while inducing less overall and grade ≥2 peripheral neuropathy (PN) compared with Vd. Here, we present the results of prespecified subgroup analyses from the BOSTON study according to cytogenetic risk status. Methods: In the BOSTON study, patients were randomly assigned (1:1) to once weekly oral sel (100 mg) plus once weekly subcutaneous (SC) bortezomib (1.3 mg/m2) and dex (20 mg BIW) in the SVd arm or twice weekly SC bortezomib (1.3 mg/m2) and dex (20 mg QIW) in the Vd arm. Treatment was administered in both arms until disease progression. The primary endpoint was PFS, as assessed by an Independent Review Committee (IRC). Central FISH analyses were performed on CD138+ sorted cells from bone marrow aspirates collected at screening. The high-risk group consisted of patients with at least 1 of the following abnormalities: del(17p), t(4;14), t(14;16), and amplification of 1q21 in ≥10% of screened plasma cells with amp (1q21) requiring ≥3 copies. The standard-risk group consisted of all other patients with available and known baseline cytogenetics. Results: Of the 402 enrolled patients, 192 (48%) had high-risk (SVd=97, Vd=95) and 210 (52%) had standard-risk (SVd=98, Vd=112) cytogenetics. Baseline patient and disease characteristics were well balanced across treatment arms. SVd significantly improved PFS relative to Vd in the high-risk (12.9 vs 8.1 months; HR, 0.67; 95% CI, 0.45-0.98; P=0.0192) and standard-risk (16.6 vs 9.7 months; HR, 0.63; 95% CI, 0.42-0.95; P=0.0131) groups. Time to next treatment was significantly increased with SVd in the high-risk (14.6 vs 8.7 months; P=0.0049) and standard risk groups (NR vs 13.1 months; P=0.0158). The ORR was significantly improved with SVd in the high-risk group (77.3% vs 55.8%; P=0.0008) and numerically improved in the standard-risk group (75.5% vs 67.9%; P=0.11) with comparable rates between the high-risk and standard-risk groups in the SVd arm. Very good partial response or better was achieved in 42.3% patients on SVd versus 24.2% on Vd (P=0.0041) and 46.9% on SVd versus 39.3% on Vd (P=0.13) in the high-risk and standard-risk groups, respectively. Overall survival was 23.5 months in the high-risk group in the Vd arm and was not reached in the other groups. Efficacy by specific cytogenetics abnormalities in the high-risk subgroup is shown in the table below. PFS and ORR were improved with SVd compared with Vd across all subgroups except t(14;16) which was the smallest subgroup (N=18, 4% of the study population). There were 61 deaths in the high-risk group (SVd=27 and Vd=34) versus 48 in the standard-risk group (SVd=20 and Vd=28). The safety profiles of SVd and Vd in the high-risk and standard-risk groups were consistent with the overall population. Rate of grade ≥2 peripheral neuropathy was lower with SVd compared with Vd in both the high-risk (26.8% vs 32.3%; P=0.18) and standard-risk groups (15.3% vs 36.0%; P=0.0003). Conclusions: These prespecified subgroup analyses from the BOSTON study demonstrate that despite utilizing 40% less bortezomib and 25% less dexamethasone during the first 24-weeks of treatment, SVd is superior to Vd in patients with MM including high-risk patients. The PFS benefit was particularly notable in patients with del(17p), t(4;14) and amp(1q21) abnormalities. The ORR was comparable between the high-risk and standard-risk groups in the SVd arm. These data support the use of selinexor, with its novel mechanism of action, in the treatment of patients with early relapsed MM, including those with high risk cytogenetic abnormalities. Figure 1 Disclosures Chari: Secura Bio: Consultancy; Novartis: Honoraria; Seattle Genetics: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Oncopeptides: Consultancy; Adaptive Biotechnology: Honoraria; The Binding Site: Honoraria; Bristol Myers Squibb: Consultancy; Pharmacyclics: Research Funding; Sanofi Genzyme: Consultancy; Karyopharm: Consultancy; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Antengene: Consultancy; Amgen: Consultancy, Research Funding; Array BioPharma: Honoraria; Glaxo Smith Kline: Consultancy. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Kryachok:Takeda, Janssen: Consultancy; Janssen, Bayer, Karyopharm, MSD, Acerta, AvbbVie, Debiopharm: Research Funding; Takeda, Janssen, Novartis, Roche, MSD, Bayer: Consultancy, Research Funding; Takeda, MSD, AbbVie, Ro: Other: Travel, accommodations, expenses. Dimopoulos:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Auner:Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Leleu:Oncopeptide: Honoraria; Incyte: Honoraria; Merck: Honoraria; Carsgen: Honoraria; Amgen: Honoraria; Karyopharm: Honoraria; Sanofi: Honoraria; GSK: Honoraria; AbbVie: Honoraria; Janssen: Honoraria; BMS-celgene: Honoraria; Novartis: Honoraria. Hajek:Novartis: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharma MAR: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria; Celgene, Amgen: Research Funding. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy; Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding. Jagannath:Takeda: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria. Moreau:Amgen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Novartis: Honoraria. Levy:Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; Baylor University Med Center: Current Employment; Amgen: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding. Badros:University of Maryland: Current Employment; Amgen: Consultancy. Anderson:Amgen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Bahlis:Sanofi: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; GSK: Consultancy, Honoraria; BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mateos:Janssen-Cilag: Consultancy, Honoraria; Abbvie/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; PharmaMar-Zeltia: Consultancy; Oncopeptides: 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; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees; Regeneron: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy; 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; Janssen: 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. Cavo:AbbVie: Consultancy, 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, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GlaxoSmithKline: Honoraria, Speakers Bureau; Karyopharm: Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel accomodations, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Chang:Karyopharm Therapeutics Inc: Current Employment. Landesman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

Introduction: DARA, a human IgGκ monoclonal antibody targeting CD38, is approved as monotherapy and in combination with standard-of-care regimens for relapsed/refractory multiple myeloma and NDMM. In the primary analysis of the phase 2 GRIFFIN study (NCT02874742) in patients with transplant-eligible NDMM, DARA plus RVd (D-RVd) significantly improved rates of stringent complete response (sCR) by the end of post-transplant consolidation therapy versus RVd (Voorhees P, Blood 2020). Here, we present updated efficacy and safety results following 12 months of maintenance therapy with lenalidomide (R) or DARA plus R (D-R). Methods: Patients with NDMM eligible for high-dose therapy (HDT) and autologous stem cell transplant (ASCT) were randomized 1:1 to RVd ± DARA, stratified by ISS stage and creatinine clearance rate. Patients received 4 induction cycles, HDT, ASCT, 2 consolidation cycles, and maintenance with R ± DARA for 24 months. During induction and consolidation, patients received R 25 mg PO on Days 1-14; V 1.3 mg/m2 SC on Days 1, 4, 8, and 11; and d 40 mg QW every 21 days. DARA 16 mg/kg IV was given on Days 1, 8, and 15 of Cycles 1-4 and Day 1 of Cycles 5-6. During maintenance (Cycles 7-32), patients received R 10 mg (15 mg in Cycles 10+ if tolerated) on Days 1-21 every 28 days ± DARA 16 mg/kg IV Q8W (or Q4W per patient decision after Amendment 2). The primary endpoint was rate of sCR at the end of post-ASCT consolidation per IMWG criteria, evaluated by a validated computer algorithm. Key secondary endpoints included progression-free survival (PFS) and rate of minimal residual disease (MRD) negativity (10-5 threshold per IMWG criteria) assessed by next-generation sequencing (clonoSEQ; Adaptive Biotechnologies). The primary hypothesis was tested at a 1-sided alpha of 0.10. All secondary analyses were evaluated using a 2-sided P value (alpha 0.05) and were not adjusted for multiplicity. Results: In total, 207 patients were randomized (D-RVd, n=104; RVd, n=103). Baseline demographics and disease characteristics were well balanced between arms. At the end of post-transplant consolidation (median follow-up, 13.5 months) in the response-evaluable population, the sCR rate favored D-RVd versus RVd (42.4% [42/99] vs 32.0% [31/97]; 1-sided P=0.0680). With additional D-R or R maintenance therapy, responses continued to deepen and remained higher for the D-RVd group versus the RVd group. At the 12-months-of-maintenance therapy data cut (median follow-up, 26.7 months), the sCR rate still favored D-RVd versus RVd (63.6% [63/99] vs 47.4% [46/97], 2-sided P=0.0253; Figure). MRD-negativity (10‒5) rates in the ITT population favored D-RVd versus RVd (62.5% [65/104] vs 27.2% [28/103], P Conclusions: After 26.7 months of median follow-up, the addition of DARA to RVd induction and consolidation, followed by D-R maintenance in patients with transplant-eligible NDMM continued to demonstrate deep and improved responses, including higher sCR and MRD negativity rates, compared with lenalidomide alone. Maintenance therapy increased sCR and MRD negativity rates, compared to post-consolidation rates. No new safety concerns were observed with longer follow-up. Support: Alliance Foundation Trials; https://acknowledgments.alliancefound.org; Janssen Oncology Disclosures Kaufman: Tecnopharma: Consultancy, Honoraria; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria; Sanofi/Genyzme: Consultancy, Honoraria; AbbVie: Consultancy; Amgen: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees. Sborov:University of Utah: Current Employment; Celgene, Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees. Reeves:Incyte: Honoraria; Takeda: Honoraria; Bristol Myers Squibb: Speakers Bureau. Rodriguez:BMS, Takeda, Amgen: Consultancy, Speakers Bureau. Chari:Janssen, Celgene, Novartis, Amgen, Bristol-Myers Squibb, Karyopharm, Sanofi, Genzyme, Seattle Genetics, Oncopeptides, Millennium/Takeda, Antengene, Glaxo Smith Kline, Secura Bio: Consultancy; Janssen, Celgene, Novartis, Amgen, Pharmacyclics, Seattle Genetics, Millennium/Takeda: Research Funding. Silbermann:Karyopharm: Consultancy; Janssen: Consultancy; Sanofi-Aventis: Consultancy, Research Funding. Costa:AbbVie: Consultancy; Sanofi: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Genentech: Consultancy; BMS: Consultancy, Honoraria. Anderson:Amgen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding. Shah:GSK, Amgen, Indapta Therapeutics, Sanofi, BMS, CareDx, Kite, Karyopharm: Consultancy; BMS, Janssen, Bluebird Bio, Sutro Biopharma, Teneobio, Poseida, Nektar: Research Funding. Efebera:Pharmacyclics: Research Funding; Ohio State University: Current Employment; Celgene: Research Funding; Takeda: Honoraria, Speakers Bureau. Holstein:Sorrento: Consultancy; Adaptive Biotechnologies: Consultancy; Takeda: Consultancy; GSK: Consultancy; Celgene: Consultancy; Genentech: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy, Research Funding. Costello:Takeda, Celgene: Consultancy, Honoraria. Jakubowiak:Adaptive, Juno: Consultancy, Honoraria; AbbVie, Amgen, BMS/Celgene, GSK, Janssen, Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Wildes:Seattle Genetics: Consultancy; Carevive Systems: Consultancy; Janssen: Research Funding. Orlowski:Founder of Asylia Therapeutics, Inc., with associated patents and an equity interest, though this technology does not bear on the current submission.: Current equity holder in private company, Patents & Royalties; STATinMED Research: Consultancy; Sanofi-Aventis, Servier, Takeda Pharmaceuticals North America, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen, Inc., AstraZeneca, BMS, Celgene, EcoR1 Capital LLC, Forma Therapeutics, Genzyme, GSK Biologicals, Ionis Pharmaceuticals, Inc., Janssen Biotech, Juno Therapeutics, Kite Pharma, Legend Biotech USA, Molecular Partners, Regeneron Pharmaceuticals, Inc.,: Honoraria, Membership on an entity's Board of Directors or advisory committees; Laboratory research funding from BioTheryX, and clinical research funding from CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Research Funding. Shain:BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; AbbVie: Research Funding; GlaxoSmithKline: Speakers Bureau; Adaptive: Consultancy, Honoraria; Sanofi/Genzyme: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Speakers Bureau; Karyopharm: Research Funding, Speakers Bureau; Amgen: Speakers Bureau. Cowan:Nektar: Research Funding; Janssen: Consultancy, Research Funding; Abbvie: Research Funding; Bristol-Myer Squibb: Research Funding; Celgene: Consultancy, Research Funding; Cellectar: Consultancy; Sanofi-Aventis: Consultancy. Lutska:Janssen: Current Employment. Bobba:Janssen: Current Employment. Pei:Janssen: Current Employment, Current equity holder in publicly-traded company. Ukropec:Janssen: Current Employment, Current equity holder in publicly-traded company. Vermeulen:Janssen: Current Employment, Current equity holder in publicly-traded company. Lin:Janssen Scientific Affairs: Current Employment, Current equity holder in publicly-traded company. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Voorhees:TeneoBio: Other: Advisory Board; Oncopeptides: Consultancy, Honoraria; Novartis: Consultancy; Janssen: Other: Advisory Board; GSK: Honoraria; BMS: Other: Advisory Board; Adaptive Biotechnologies: Other: Advisory Board. OffLabel Disclosure: The specific regimen combination is not yet approved, but individual components are.

Introduction: Treatment of older or frail patients (pts) with multiple myeloma (MM) remains challenging due to impaired organ function, underlying comorbidities, need for convenient regimens and burden of care, all of which impact the tolerability of anti-MM therapies. In the STORM study, selinexor plus dexamethasone (sel-dex) demonstrated anti-MM activity with an ORR of 26.2% and similar safety across all age groups in pts with triple-class refractory MM (Chari et al. NEJM 2019, Gavriatopoulou et al. IMW 2019). In the phase 3 BOSTON study, the combination of weekly sel-dex with once weekly bortezomib (SVd) was superior to standard twice weekly bortezomib and dex (Vd) across all efficacy endpoints in pts with MM who had received 1-3 prior therapies. Furthermore, while conferring a longer PFS and higher ORR than Vd, SVd was associated with significantly reduced rates of peripheral neuropathy (PN), the most clinically relevant toxicity associated with bortezomib that limits long term administration, especially in older and/or frail pts. Here we present results of subgroup analyses of the BOSTON study to evaluate the safety and efficacy of SVd versus Vd based on age and frailty index. Methods: Pts enrolled in BOSTON were assigned (1:1) to once weekly oral sel (100 mg) plus once weekly subcutaneous (SC) bortezomib (1.3 mg/m2) and dex (20 mg BIW) in the SVd arm or to standard twice weekly SC bortezomib (1.3 mg/m2) and dex (20 mg QIW) in the Vd arm. Treatment was administered in both arms until disease progression. The primary endpoint was PFS, as assessed by an Independent Review Committee. For these analyses, pts were assigned to 2 groups based on age ( Results: Of the 402 enrolled pts, 241 (60%) were ≥65 years (SVd=109, Vd=132). Of these, 81 (37%) were ≥75 and 106 (44%) were categorized as frail (SVd=51, Vd=55). Baseline pt and disease characteristics were well balanced between treatment arms in the subgroups. PFS was prolonged in both age groups with SVd compared with Vd. In ≥65, PFS was 21.0 vs 9.5 months (HR, 0.55; 95% CI, 0.37-0.83; P=0.0018) and in Conclusions: In pts with previously treated MM, the once weekly SVd regimen led to prolonged PFS, improved response rates and rates of PN regardless of age and frailty score compared to standard twice weekly Vd. Non-PN AEs were higher with triplet than doublet therapy, but most of the AEs were reversible and treatable. There were fewer deaths on SVd in pts ≥65 and in frail pts compared to Vd. Once weekly SVd is a potent and convenient treatment option for pts with previously treated MM, including those who are ≥65 years and/or frail. Figure Disclosures Auner: Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Dimopoulos:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Leleu:Incyte: Honoraria; Merck: Honoraria; AbbVie: Honoraria; Carsgen: Honoraria; Janssen: Honoraria; Novartis: Honoraria; BMS-celgene: Honoraria; Amgen: Honoraria; GSK: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria; Oncopeptide: Honoraria. Hajek:Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Pharma MAR: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria; Celgene, Amgen: Research Funding. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy. Jagannath:Sanofi: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Moreau:Sanofi: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Novartis: Honoraria. Levy:Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; Baylor University Med Center: Current Employment. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Bahlis:BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mateos:EDO Mundipharma: Honoraria; Seattle Genetics: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria; GlaxoSmithKline: Honoraria; Adaptive Biotechnologies: Honoraria; Takeda: Honoraria; Roche: Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

BACKGROUND Lenalidomide (LEN), an established treatment (Tx) for newly diagnosed multiple myeloma, is routinely administered until disease progression. Therefore, patients (pts) for whom LEN is no longer an option at first relapse, including LEN-refractory pts, are a clinically relevant and growing population. Tx of these pts remains challenging, as they have been poorly represented in phase 3 clinical trials. OPTIMISMM (NCT01734928), a phase 3 trial specifically designed to address this population, demonstrated significantly improved progression-free survival (PFS) with pomalidomide (POM), bortezomib (BORT), and low-dose dexamethasone (PVd) compared with BORT and low-dose dexamethasone (Vd) in pts who received 1-3 prior regimens and were 100% LEN pretreated (70% LEN refractory) (Richardson PG, et al. Lancet Oncol. 2019;20:781-794). Here, we report the efficacy and safety of PVd in pts treated after 1 prior line of therapy (LOT) according to age, prior stem cell transplant (SCT), and in pts with high-risk cytogenetic abnormalities (HR CAs). METHODS Pts were randomized 1:1 to receive PVd or Vd in 21-day cycles. POM 4 mg/day was given on days 1-14 (PVd arm only); bortezomib (BORT) 1.3 mg/m2 was given on days 1, 4, 8, and 11 of cycles 1-8 and on days 1 and 8 of cycles 9+; and dexamethasone 20 mg/day (10 mg/day for pts aged > 75 yrs) was given on the days of and after BORT. Key eligibility criteria included ≥ 2 cycles of prior LEN, including LEN-refractory pts. The primary endpoint was PFS. RESULTS As of October 26, 2017, 226 of 559 pts enrolled in OPTIMISMM had 1 prior LOT; 100 pts were aged ≤ 65 yrs (49 PVd, 51 Vd) and 126 were aged > 65 yrs (62 PVd, 64 Vd). In pts aged ≤ 65 yrs (PVd vs Vd), the median age was 58.0 vs 59.0 yrs, 63.3% vs 47.1% were male, 55.1% vs 51.0% were LEN refractory, and 83.7% vs 72.5% had prior BORT. In pts aged > 65 yrs, the median age was 73.0 vs 71.5 yrs, 58.1% vs 51.6% were male, 59.7% vs 60.9% were LEN refractory, and 41.9% vs 46.9% had prior BORT. After 1 prior LOT, PVd vs Vd significantly improved PFS in pts aged ≤ 65 yrs (median, 22.0 vs 13.1 mos; P = .0305) and those > 65 yrs (median, 17.6 vs 9.9 mos; P = .0348) (Figure). The overall response rate (ORR) was significantly higher with PVd vs Vd across the age groups (Table). The rate of ≥ very good partial response (VGPR) was 65.3% vs 17.6% in pts aged ≤ 65 yrs and 58.1% vs 26.6% in pts aged > 65 yrs. Comparable PFS and ORR outcomes were noted for an age cutoff of ≤ 70 yrs (median PFS, 17.8 vs 13.1 mos with PVd [n = 71] vs Vd [n = 78]; ORR, 88.7% [≥ VGPR, 62.0%] vs 55.1% [≥ VGPR, 21.8%], respectively) vs > 70 yrs (median PFS, 16.5 vs 9.5 mos with PVd [n = 40] vs Vd [n = 37]; ORR, 92.5% [≥ VGPR, 60.0%] vs 54.1% [≥ VGPR, 24.3%], respectively). These PFS and ORR findings were similar to those reported in pts with and pts without prior SCT (Table). Median PFS was 22.0 mos with PVd vs 13.8 mos with Vd in pts with prior SCT (P = .0241) and 16.5 vs 9.5 mos, respectively, in pts without prior SCT (P = .0454). Pts with HR CAs (n = 32 [18 PVd, 14 Vd]), defined as having a del(17p), t(4;14), or t(14;16), had a median PFS of 14.7 mos with PVd and 9.9 mos with Vd. The most common grade 3/4 treatment-emergent adverse events (TEAEs) with PVd vs Vd were neutropenia (49.0% vs 6.3%), infections (30.6% vs 14.6%), and thrombocytopenia (26.5% vs 18.8%) in pts aged ≤ 65 yrs and neutropenia (25.8% vs 12.9%), infections (27.4% vs 16.1%), and thrombocytopenia (14.5% vs 22.6%) in pts aged > 65 yrs. CONCLUSIONS In pts with LEN-pretreated relapsed or refractory multiple myeloma at first relapse, PVd reduced the risk of progression or death by 50% in pts aged ≤ 65 yrs and by 43% in pts aged > 65 yrs vs Vd. Additionally, across age subgroups, second-line Tx with PVd vs Vd significantly improved ORR and led to deeper responses. Similar findings were observed in pts with and pts without prior SCT. PVd also benefited pts with HR CAs vs Vd. Overall, TEAEs with PVd were generally consistent with the known profiles of the constituent agents. These data in pts at first relapse continue to demonstrate that PVd is effective and safe as a second-line Tx following LEN, regardless of age, prior SCT status, and presence of HR CAs. Disclosures Dimopoulos: Sanofi Oncology: Research Funding. Weisel:GSK: Honoraria; Juno: Consultancy; Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Adaptive Biotech: Consultancy, Honoraria; Celgene Corporation: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Moreau:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Anderson:Amgen, Janssen, Takeda, Celgene: Consultancy, Speakers Bureau. White:Sanofi: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. San-Miguel:Amgen, Bristol-Myers Squibb, Celgene, Janssen, MSD, Novartis, Roche, Sanofi, and Takeda: Consultancy, Honoraria. Sonneveld:SkylineDx: Research Funding; Takeda: Honoraria, Research Funding; Karyopharm: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; BMS: Honoraria; Amgen: Honoraria, Research Funding. Jenner:Abbvie, Amgen, Celgene, Novartis, Janssen, Sanofi Genzyme, Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Dürig:Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Celgene: Consultancy, Other: Travel or accommodations, Speakers Bureau. Pavic:Celgene, Janssen, Takeda, Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Casal:Celgene Corporation: Employment. Srinivasan:Celgene: Employment, Equity Ownership. Nguyen:Celgene Corporation: Employment, Equity Ownership. Biyukov:Celgene: Employment, Equity Ownership. Peluso:Celgene Corporation: Employment. Richardson:Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Yes. The triplet combination is not currently approved in the US for the treatment of multiple myeloma.

3088 Background: The nucleoside analog Aza-TdC inhibits DNA methyltransferase 1 (DNMT1), which regulates methylation-mediated silencing of tumor suppressor genes. Aza-TdC offers an improvement over traditional DNA methyltransferase inhibitors by virtue of a higher incorporation rate into DNA at lower levels of cytotoxicity. Aza-TdC has also shown improved preclinical antitumor activity compared to other hypomethylating agents in some solid tumor xenograft models. In an ongoing phase I trial, we evaluate the safety and activity of Aza-TdC in patients (pts) with advanced solid tumors. Methods: Adult pts with solid tumors whose disease has progressed on standard therapy or for which there is no standard therapy were treated with Aza-TdC administered orally once a day for 5 days of each week for 2 weeks in 21-day cycles. The study followed Simon accelerated titration design 3, with 1 pt per dose level at 100% dose increments. Accelerated titration continued until 1 pt experienced a dose-limiting toxicity (DLT) or 2 pts experience drug-related grade 2 toxicity at any dose level, after which, a 3 + 3 dose escalation design was used. Intrapatient dose escalation was allowed. Correlative studies included pharmacokinetic assays and pharmacodynamic assays in circulating tumor cells. Results: As of January 2021, a total of 18 pts have been enrolled on study. Median pt age is 61.5 years (range 35-84). Tumor types included colorectal adenocarcinoma (5 pts), sarcoma (3), breast carcinoma (2), and ovarian carcinoma (2). The DLTs at 48 mg were grade 3 rash and grade 3 acute kidney injury in one pt and < 75% of dosing completed in another pt due to grade 3 myelosuppression. Among the 10 pts treated at 32 mg, 1 pt experienced a DLT: grade 4 neutropenia. The maximum tolerated dose (MTD) is 32 mg. Grade 3 or 4 toxicities across all cycles possibly attributable to study drug were leukopenia (6), lymphopenia (6), neutropenia (4), rash (2), febrile neutropenia (1), anemia (1), thrombocytopenia (1), acute kidney injury (1), elevated AST (1), elevated ALT (1), diarrhea (1), and dehydration (1). Of the 14 pts evaluable for response, 11 had a best response of stable disease, and 3 had a best response of progressive disease. Median cycles on study is 4 (range 1-10+). A pt with clear cell ovarian carcinoma has been on study for > 10 cycles with stable disease. Conclusions: At the MTD of 32 mg, Aza-TdC is safe and well tolerated with a toxicity profile similar to currently approved hypomethylating agents. Global DNA methylation profiling, RNAseq, and DNMT immunohistochemical analyses of tumor biopsies are planned for the currently accruing dose expansion cohort. Funded by NCI Contract No. HHSN261200800001E. Clinical trial information: NCT03366116.

Central nervous system (CNS) involvement in patients with acute myeloid leukemia (AML) varies, ranging from 0.6%-46%. Leukocyte immunoglobulin-like receptor B4 (LILRB4) has been shown to be critical in orchestration of infiltration of AML cells into the CNS in animal models, however it is unknown if an association exists between LILRB4 and CNS involvement (CNS+) in human patients with AML. LILRB4 was measured by flow cytometry in a heterogeneous population of fifty-six AML patients. Patients were then followed clinically for the development of CNS + . LILRB4 was positive in 91 % of patients with CNS + compared to 38 % without CNS involvement (p < 0.002). In logistic analysis: age, BMI, serum albumin and positive LILRB4 were predictive for CNS+ [OR, 95 % CI, p-value]: 0.95, 0.92-0.99, p < 0.01; 0.85, 0.73-0.998, p < 0.05; 0.23, 0.066-0.78, p < 0.02; 16.46, 1.93-140.2, p < 0.02, respectively. This finding of the association of LILRB4 with CNS + in combination with earlier findings suggests that LILRB4 has a mechanistic role in infiltration of the CNS and may provide insight into the pathogenesis of AML seeding the CNS. Moreover, this proof of concept and the findings in the present study may lead to the development of innovative and novel therapies to improve the lives of patients with AML.

8525 Background: RRMM patients (pts) triple-class exposed (to immunomodulatory drugs [IMiDs], proteasome inhibitors [PIs] and anti-CD38 monoclonal antibodies [mAbs]) have limited treatment (tx) options. The ongoing phase II KarMMa study (NCT03361748) is examining idecabtagene vicleucel (ide-cel; bb2121), a BCMA targeted CAR T cell therapy, in RRMM pts with ≥3 prior regimens (IMiD, PI and CD38 mAb inclusive) who are refractory to their last tx per IMWG criteria. This study aimed to 1) assess tx patterns and outcomes in real world (RW) RRMM pts similar to the KarMMa population and; 2) compare outcomes with SoC in a synthetic cohort vs ide-cel in KarMMa. Methods: In this global, noninterventional, retrospective study (KarMMa-RW), pt-level data from clinical sites, registries and databases were collated into a single data model. RW pts meeting KarMMa eligibility criteria (eligible cohort; EC) were compared with KarMMa (N = 128) using trimmed stabilized inverse probability of tx weighted propensity scores (IPTW PS) for pts in both studies with Poisson regression for ORR and ≥VGPR, and Cox models with study as a term for PFS. All models were adjusted for unbalanced covariates. Results: Of 1949 RW pts, 1171 were refractory to last regimen (median age, 68 y; median no. of prior regimens, 5; triple-class refractory, 41%). Further selection for subsequent tx, organ function and no comorbidities yielded 190 EC pts who had > 90 distinct tx regimens. With a median follow-up of 11.3 mo (KarMMa) and 10.2 mo (EC) at data cutoff (Oct 30, 2019), ORR, ≥VGPR and PFS were significantly improved in KarMMa vs EC (Table). Conclusions: Results from the KarMMa-RW study confirm that there is no clear SoC for heavily pretreated RW RRMM pts and responses are suboptimal with currently available therapies. Ide-cel showed deep, durable responses and significantly improved PFS in RRMM pts, representing a potential new tx option in RRMM. Clinical trial information: tbd . [Table: see text]

e20562 Background: Upfront LEN until disease progression is a standard treatment (Tx) in multiple myeloma (MM). Data are limited on optimal Tx after first-line LEN, especially in LEN-refractory patients (pts), a growing population. In OPTIMISMM (phase 3, NCT01734928), PVd significantly improved median PFS at first relapse in relapsed refractory MM (RRMM) pts, of whom 100% were LEN pretreated and 57% were LEN refractory (median, 20.7 vs 11.6 mos; HR = 0.54 [95% CI, 0.36-0.82]; P = .0027) vs Vd (Richardson, 2019). Pd has shown efficacy and safety in RRMM pts with moderate or severe renal impairment (RI), including those on dialysis (Dimopoulos, 2018). However, outcomes with second-line PVd in RRMM pts with RI have not been assessed. Here we report efficacy and safety of PVd vs Vd at first relapse by renal status (CrCl < 60 vs ≥ 60 mL/min). Methods: Pts received PVd or Vd (1:1) in 21-day (D) cycles (C); POM 4 mg/D on D1-14 (PVd arm only); BORT 1.3 mg/m2 on D1, 4, 8, 11 of C1-8 and on D1, 8 of C9+; and DEX 20 mg/D (10 mg/D for pts aged > 75 yrs) on days of and after BORT. Pts on dialysis were excluded. Results: Of 559 pts enrolled, 226 (40%) had 1 prior line of therapy; of whom 28% had CrCl < 60 mL/min and 4% had severe RI (CrCl < 30 mL/min). In pts with CrCl < 60 mL/min (PVd vs Vd), median age was 74 vs 73 yrs. In pts with CrCl ≥ 60 mL/min (PVd vs Vd), median age was 62 vs 64 yrs. A higher proportion of pts with baseline CrCl < 60 (23% vs 43%) than ≥ 60 mL/min (7% vs 8%) had ISS stage III at study entry. Data cutoff was Oct 26, 2017. Median PFS was improved with PVd in both renal groups (Table). ORR significantly improved regardless of renal status. Depth of response also improved with PVd vs Vd; ≥ VGPR occurred in 54% vs 21% in the CrCl < 60 mL/min group and 64% vs 23% in the CrCl ≥ 60 mL/min group. Myelosuppression was the most common grade 3/4 TEAE (Table). Conclusions: Second-line PVd led to improved vs Vd in pts with RRMM and RI; however, the PFS difference was not statistically significant. Safety was consistent for PVd with no new signals in pts with RI. These findings further support the earlier use of POM-based Tx in RRMM pts, including those with mild to moderate RI. Clinical trial information: NCT01734928. [Table: see text]

8503 Background: Outcomes are poor in triple-class exposed RRMM patients (pts) who progress on immunomodulatory agents (IMiDs), proteasome inhibitors (PIs), and CD38 antibodies (mAbs). Ide-cel, a BCMA targeted CAR T cell therapy, showed promising tolerability and efficacy in RRMM pts in the phase I CRB-401 study ( NEJM2019;380:1726). We present primary efficacy and safety data from the pivotal phase II KarMMa trial of ide-cel in RRMM (NCT03361748). Methods: Enrolled pts had ≥3 prior regimens (including IMiD, PI, and CD38 mAb) and were refractory to their last regimen per IMWG criteria. After lymphodepletion (cyclophosphamide 300 mg/m2+ fludarabine 30 mg/m2 x 3), pts received 150─450 × 106 CAR+ T cells (target dose range). Endpoints included overall response rate (ORR; primary), complete response (CR) rate, duration of response (DoR), and PFS. Results: Of 140 pts enrolled, 128 received ide-cel. Median age was 61 y; median no. of prior regimens was 6; 84% were triple- and 26% were penta-refractory. Most pts (88%) had bridging therapy. At data cutoff (16 Oct 2019), median follow up was 11.3 mo. ORR was 73% and median PFS was 8.6 mo; both increased with higher dose (Table). All subgroups had an ORR ≥50%, including older and high-risk pts. Most common any-grade (Gr) toxicities were cytopenias (97%) and cytokine release syndrome (CRS; 84%). CRS was mainly Gr 1/2; 5 pts (5%) had Gr 3, 1 had Gr 4, and 1 had Gr 5 (at 300 × 106). Neurotoxicity developed in 23 pts (18%); 4 (3%) Gr 3 and 0 Gr ≥4. Median peak CAR+ T cell expansion occurred at 11 d. Expansion was higher in responders and parameters (AUC0−28d, Cmax) increased with higher dose, with exposure overlap across doses. Persistence was durable, with CAR+ T cells detected in 29/49 (59%) and 4/11 pts (36%) at 6 and 12 mo. Conclusions: Ide-cel demonstrated deep, durable responses in heavily pretreated RRMM pts. Efficacy and safety reflected prior reports and support a favorable ide-cel clinical benefit-risk profile across the target dose range. Clinical trial information: NCT03361748 . [Table: see text]

Background The prevalence of central nervous system (CNS) involvement in patients with acute myeloid leukemia (AML) is variable with a reported range of 0.6% to 46%. Unfortunately, the clinical consequences of untreated CNS involvement in AML which include complete paraplegia and bilateral total blindness, can be devastating. In addition, both the diagnostic evaluation and treatment of CNS involvement are associated with potential significant morbidity. Thus, there is a need to predict CNS involvement in a noninvasive manner in patients with AML. The leukocyte immunoglobulin-like receptors are a family of receptors that regulate the activity of cancer stem cells, cancer development and relapse. These receptors are expressed on many cell types and the leukocyte immunoglobulin-like receptor B4 (LILRB-4) is expressed on monocytic myeloid cells. Purpose To investigate whether measurement of LILRB-4 is predictive of CNS involvement in patients with AML. Methods Fifty-six patients with AML and followed at the University of Texas Southwestern medical system had measurement of the LILRB-4 by flow cytometry. Demographic, laboratory, risk stratification, cytogenetics and clinical variables were acquired from electronic medical chart review. Results The study cohort of 56 patients with AML had a median age of 60 years (range: 0.83 - 92); 52% male; and racial/ethnic composition of African American 20%, Asians 4%, White Hispanic 13% and White Non-Hispanic 64%. Eleven (20%) patients were diagnosed with CNS involvement (CNS+). LILRB-4 was positive in 91% of patients with CNS+ compared to 38% without CNS (CNS-) (p Conclusions A positive LILRB-4 by flow cytometry on leukemia cells is strongly associated with CNS involvement in patients with AML. These novel findings suggest that LILRB-4+ may be useful in risk stratification for CNS+. Moreover, combined with preclinical studies, LILRB-4 may provide insight into the pathogenesis of AML seeding the CNS. Further prospective studies are needed to confirm these intriguing results.

Progressive multifocal leukoencephalopathy (PML) is a fatal demyelinating disease associated with immunocompromised states. We describe a case of PML, which developed after prolonged ibrutinib use and a low burden of chronic lymphocytic leukemia disease. The delay in diagnosis of the patient despite multiple presentations to medical providers across different facilities suggests that there is a lack of awareness of PML as a potential complication of ibrutinib. Treatments with postulated anti-John Cunningham polyomavirus agents and IL-2 were ineffective, likely due to the advanced state of the patient’s disease. Although recent evidence indicates that ibrutinib may enhance cell-mediated immunity, consistent with elevated CD4+ and CD8+ T cells and appropriate T-cell response to mitogens in the patient, ibrutinib-mediated inhibition of the humoral function may contribute to PML pathogenesis. As the duration of ibrutinib use is often indefinite, and the number of indications for ibrutinib continues to grow, recognition and further evaluation of the link between PML and ibrutinib is warranted.

Summary Background B-cell maturation antigen (BCMA) is a cell-surface receptor of the tumour necrosis superfamily required for plasma cell survival. BMCA is universally detected on patient-derived myeloma cells and has emerged as a selective antigen to be targeted by novel treatments in multiple myeloma. We assessed the safety, tolerability, and preliminary clinical activity of GSK2857916, a novel anti-BCMA antibody conjugated to microtubule-disrupting agent monomethyl auristatin F, in patients with relapsed and refractory multiple myeloma. Methods We did an international, multicentre, open-label, first-in-human phase 1 study with dose escalation (part 1) and dose expansion (part 2) phases, at nine centres in the USA, Canada, and the UK. Adults with histologically or cytologically confirmed multiple myeloma, Eastern Cooperative Oncology Group performance status 0 or 1, and progressive disease after stem cell transplantation, alkylators, proteasome inhibitors, and immunomodulators were recruited for this study. In part 1, patients received GSK2857916 (0·03–4·60 mg/kg) through 1 h intravenous infusions once every 3 weeks. In part 2, patients received the selected recommended phase 2 dose of GSK2857916 (3·40 mg/kg) once every 3 weeks. Primary endpoints were maximum tolerated dose and recommended phase 2 dose. Secondary endpoints for part 2 included preliminary anti-cancer clinical activity. All patients who received one or more doses were included in this prespecified administrative interim analysis (data cutoff date June 26, 2017), which was done for internal purposes. This study is registered with ClinicalTrials.gov, number NCT02064387, and is ongoing, but closed for recruitment. Findings Between July 29, 2014, and Feb 21, 2017, we treated 73 patients: 38 patients in the dose-escalation part 1 and 35 patients in the dose-expansion part 2. There were no dose-limiting toxicities and no maximum tolerated dose was identified in part 1. On the basis of safety and clinical activity, we selected 3·40 mg/kg as the recommended phase 2 dose. Corneal events were common (20 [53%] of 38 patients in part 1 and 22 [63%] of 35 in part 2); most (18 [47%] in part 1 and 19 [54%] in part 2) were grade 1 or 2 and resulted in two treatment discontinuations in part 1 and no discontinuations in part 2. The most common grade 3 or 4 events were thrombocytopenia (13 [34%] of 38 patients in part 1 and 12 [34%] of 35 in part 2) and anaemia (6 [16%] in part 1 and 5 [14%] in part 2). There were 12 treatment-related serious adverse events and no treatment-related deaths. In part 2, 21 (60·0%; 95% CI 42·1–76·1) of 35 patients achieved an overall response. Interpretation At the identified recommended phase 2 dose, GSK2857916 was well tolerated and had good clinical activity in heavily pretreated patients, thereby indicating that this might be a promising candidate for the treatment of relapsed or refractory multiple myeloma. Funding GlaxoSmithKline.

BACKGROUND As lenalidomide (LEN) becomes increasingly established as a standard of care in the treatment (Tx) of newly diagnosed multiple myeloma (NDMM), patients (pts) for whom LEN is no longer a Tx option, including those who have become refractory to LEN, represent a clinical reality. These pts represent the largest population with MM at first relapse in the United States and a growing population globally. To date, they have been poorly studied and remain difficult to treat. Previous trials have demonstrated a clinical benefit with pomalidomide (POM) therapy in LEN-refractory pts with relapsed or refractory MM (RRMM), including those who were heavily pretreated (median of 5 prior regimens) (San Miguel et al. Lancet Oncol 2013; Richardson et al. Blood 2014; Dimopoulos et al. Blood 2016). These studies led to the approval of POM + low-dose dexamethasone (LoDEX) in RRMM. The pomalidomide, bortezomib, and low-dose dexamethasone (PVd) regimen has shown promising activity in early-phase clinical trials in LEN-refractory pts. In the phase 3 OPTIMISMM trial, PVd showed significantly improved progression-free survival (PFS) and a manageable safety profile compared with bortezomib and low-dose dexamethasone (Vd) in intent-to-treat population of pts who received 1-3 prior regimens and were 100% LEN pretreated; 70% of pts were LEN refractory (Richardson et al. ASCO 2018 abstract 8001). Here, we present efficacy and safety results in LEN-refractory and -nonrefractory pts treated at first relapse. METHODS Pts were randomized 1:1 to receive PVd or Vd in 21-day cycles: POM 4 mg/day on days 1-14 (PVd arm only); bortezomib (BORT) 1.3 mg/m2 on days 1, 4, 8, and 11 of cycles 1-8 and on days 1 and 8 of cycles 9+; and DEX 20 mg/day (10 mg/day if aged > 75 yrs) on the days of and after BORT. Key eligibility criteria included ≥ 2 cycles of prior LEN therapy, including LEN-refractory pts. BORT-exposed pts were eligible to enroll, provided they did not have progressive disease during therapy or within 60 days of the last dose of a BORT-containing regimen with BORT dosed at 1.3 mg/m2 twice weekly. The primary endpoint was PFS. RESULTS Out of 559 pts enrolled patients, 226 were treated in the second line (2L), data cut off October 26, 2017: 111 with PVd and 115 with Vd. Median follow-up for 2L pts was 16.4 mos. Among 2L pts, 129 (57.1%) were LEN refractory (64 PVd; 65 Vd) and 97 (42.9%) were LEN nonrefractory (47 PVd; 50 Vd). In LEN-refractory pts (PVd vs Vd) median age was 68.0 vs 69.0 yrs, 57.8% vs 58.5% were male, and 56.3% vs 47.7% had prior BORT. In LEN-nonrefractory pts, median age was 66.0 vs 65.5 yrs, 63.8% vs 38% were male, and 66.0% vs 72.0% had prior BORT. Other key baseline characteristics were similar between Tx arms and subgroups. Median PFS was 17.8 mos with PVd vs 9.5 mos with Vd in LEN-refractory (HR 0.55; 95% CI, 0.33-0.94; Figure 1A) and 22.0 vs 12.0 mos in LEN-nonrefractory pts (HR 0.54; 95% CI, 0.29-1.01; Figure 1B). Response outcomes are shown in Figure 2. ORR was 85.9% with PVd vs 50.8% with Vd in LEN-refractory pts (P < .001) and 95.7% vs 60.0% in LEN-nonrefractory pts (P < .001). In 2L LEN-refractory pts, the most common grade 3 or 4 treatment-emergent adverse events (TEAEs) with PVd vs Vd were neutropenia (35.9% vs 12.9%), thrombocytopenia (17.2% vs 22.6%), and anemia (17.2% vs 8.1%). Grade 3 or 4 infections occurred in 29.7% vs 21.0% of pts. In 2L LEN-nonrefractory pts, the most common grade 3 or 4 TEAEs were neutropenia (36.2% vs 6.3%) and thrombocytopenia (23.4% vs 18.8%). Grade 3 or 4 infections occurred in 27.7% vs 8.3% of pts. In 2L LEN-refractory pts, median Tx duration of PVd vs Vd was 9.7 vs 6.1 mos. In 2L LEN-nonrefractory pts, median Tx duration of Pvd vs Vd was 13.6 vs 6.6 mos. CONCLUSIONS To date, OPTIMISMM is the only phase 3 trial to address Tx of pts with RRMM following LEN exposure in early lines and the first to report data in LEN-refractory pts after first relapse. PVd reduced the risk of progression and death by 45% and 46% vs Vd in LEN-refractory and -nonrefractory pts, respectively. Further, in both subgroups, 2L Tx with PVd significantly improved ORR and led to deeper responses compared with Vd. AEs with PVd therapy were generally consistent with the known AEs of POM, BORT, and DEX. These data further demonstrate that PVd is effective and tolerable in pts for whom LEN is no longer a Tx option, including LEN-refractory pts, supporting its use as 2L therapy in RRMM. Disclosures Dimopoulos: Celgene: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Takeda: Honoraria; Bristol-Myers Squibb: Honoraria. Weisel:Amgen, Celgene, Janssen, and Sanofi: Research Funding; 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. Moreau: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; Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. Anderson:Celgene: Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau. White: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; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees. San-Miguel:Celgene: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; Roche: Honoraria; BMS: Honoraria; Novartis: Honoraria. Sonneveld:Amgen: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Karyopharm: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Jenner:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Chugai: 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, Other: travel support, Research Funding, 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, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding, Speakers Bureau. Dürig:Janssen: Consultancy, Honoraria; Celgene: Honoraria; Roche: Honoraria, Speakers Bureau. Pavic:AstraZeneca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: 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, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Salomo:Cilag: Consultancy; Janssen: Consultancy. Yu:Celgene: Employment, Equity Ownership. Nguyen:Celgene Corporation: Employment. Bensmaine:Celgene: Equity Ownership. Peluso:Celgene Corporation: Employment, Equity Ownership. Zaki:Celgene Corporation: Employment, Equity Ownership. Richardson:BMS: Research Funding; Karyopharm: 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, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees.