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Background Multiple myeloma (MM) is considered an incurable hematologic malignancy despite a plethora of standard and novel agents. There is no consensus on the optimal sequencing of available therapies in relapsed/refractory MM (RRMM), even in the second line setting. Novel agents such as selinexor (XPOVIO [X]), an oral, first-in-class selective inhibitor of nuclear export (SINE) compound that blocks XPO1, or those that target B-cell maturation antigen (BCMA), have shown significant activity in RRMM. X is approved with bortezomib (V) and dexamethasone (XVd) in patients (pts) with at least 1 prior therapy and is not associated with known long-term clinically significant toxicities such as visual loss, cardiac dysfunction, renal failure, neuropathy, irreversible bone marrow suppression, second malignancies, venous thromboembolism, or rash. Currently, BCMA-targeting agents include 1 form each of chimeric antigen receptor T cell (CAR-T cell) and antibody drug conjugate (ADC) therapy approved in RRMM: idecabtagene vicleucel and belantamab mafodotin, respectively. BCMA-refractory MM represents an area of unmet need in MM without known standards for best treatment. Various novel combinations with X have demonstrated strong benefit in RRMM after 1 or more lines of therapy and activity even in CAR-T cell BCMA-refractory MM (N=7): 1 pt stringent complete (sCR), 3 very good partial (VGPR), 2 partial (PR), and 1 minimal (MR) response (Chari BJH 2020). Here we report on the outcomes of heavily pretreated RRMM pts, a majority of whom had received ADC-BCMA, and who were treated with X-containing regimens on the STOMP trial. Methods STOMP (NCT02343042) is a phase 1b/2, multi-arm, open-label trial of various combinations of X with backbone agents for pts with RRMM or newly diagnosed MM. Here we report on all pts in STOMP with prior anti-BCMA treatment who were treated on STOMP with X+pomalidomide +dexamethasone (XPd); XVd; X+carfilzomib+d (XKd); XPVd; and XPd+elotuzumab (E) (XPEd). Results In total, 11 pts with prior anti-BCMA therapy (6 pts with belantamab mafodotin; 1 each with MEDI2228, SEA-BCMA, BCMA BITE; 2 with idecabtagene vicleucel) were treated with 5 X-containing regimens (Table 1): 9 pts were treated with triplets XPd (4), XVd (3), or XKd (2) and 2 pts with quadruplets XPVd (1) or XPEd (1). Median age was 71 years (range 46-85), 7 pts (63.6%) were women, 11 pts were white. Median duration from MM diagnosis to treatment with a STOMP regimen was 6.9 years (range 2.3-12.8). Five pts (45.5%) had high-risk cytogenetics; pts received median of 6 prior therapies (range 4-10). Eight pts (72.7%) received anti-BCMA in their immediate prior line of therapy. Ten pts (90.9%) were previously treated with all backbone drugs of the STOMP treatments (i.e., X was the only new drug). The overall response rate (ORR) and clinical benefit rate (CBR) for the prior anti-BCMA-containing regimens were 40.0% (2 pts VGPR, 2 PR, 5 stable disease [SD], 1 progressive disease, 1 unknown). Median progression free survival (PFS) was 1.8 months (95% CI: 1.5, NE), and the 6-month PFS probability was 12.5% (95% CI: 2.1, 76.2). ORR for the X-based treatments was 54.5% and CBR was 81.8%: 1 pt VGPR, 5 PR, 3 MR, 2 SD. Median PFS was not reached (95% CI: 5.9, NE) and the 6-month PFS probability was 68.6% (95% CI: 40.3, 100.0). Median overall survival was 10.5 months (95% CI: 9.6, NE) and median time to discontinuation was 8.1 months (95% CI: 6.1, NE). The most common treatment-emergent adverse events were nausea and thrombocytopenia. Nausea was Grade (G) 1/2 (n=8, 72.7%); thrombocytopenia G1-4 in 8 pts (72.7%), 4 with ≥G3; there were no concurrent bleeding events. One pt on XPEd died of pulmonary nocardiosis considered to be associated with the 4-drug regimen. No new safety signals or long-term toxicities due to X were reported. Conclusions In this follow-up cohort of heavily pretreated pts, a majority of whom with MM refractory to ADC-BCMA, we demonstrate impressive potency and durability of the X-based treatments, particularly as compared to that of their prior anti-BCMA therapies. These data support the rationale for the development of novel regimens containing X plus immunomodulatory drugs or proteasome inhibitors in earlier lines of therapy, including first relapse, and further suggest their strong value in the emerging BCMA RRMM space. Figure 1 Figure 1. Disclosures Baljevic: Exelixis: Research Funding; Amgen: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Janssen Research: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees. Gasparetto: Karyopharm: Consultancy, Honoraria, Speakers Bureau; Gsk: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy; Sanofi: Consultancy, Honoraria, Speakers Bureau; Oncopeptide: Consultancy, Honoraria, Speakers Bureau. Schiller: Sangamo: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Celator: Research Funding; Geron: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; PrECOG: Research Funding; Onconova: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Genentech-Roche: Research Funding; Karyopharm: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Takeda: Research Funding; Abbvie: Research Funding; Forma: Research Funding; Deciphera: Research Funding; Daiichi-Sankyo: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Regimmune: Research Funding; FujiFilm: Research Funding; Gamida Cell Ltd.: Research Funding; Constellation Pharmaceuticals: Research Funding; Mateon: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Arog: Research Funding; Delta-Fly: Research Funding; Tolero: Research Funding; Samus: Research Funding; Actuate: Research Funding; Actinium Pharmaceuticals, Inc: Research Funding; Trovagene: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Elevate: Research Funding; Bio: Research Funding; Ono-UK: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Cyclacel: Research Funding; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Tuchman: Caelum: Consultancy, Research Funding; Sanofi / Genzyme: Consultancy, Research Funding; Shattuck Labs: Consultancy; Karyopharm: Research Funding; Oncopeptides: Consultancy. Lentzsch: Sanofi: Consultancy, Research Funding; Celularity: Consultancy; AbbVie: Consultancy; GSK: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy, Research Funding; Janssen: Consultancy; Oncopeptides: 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. Monge: Karyopharm: Research Funding; BMS: Consultancy. Kotb: Celgene: Honoraria; Karyopharm: Current holder of individual stocks in a privately-held company; Pfizer: Honoraria; Amgen: Honoraria; Janssen: Honoraria; Takeda: Honoraria; BMS: Honoraria; Sanofi: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Akcea: Honoraria. Bahlis: GlaxoSmithKline: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Genentech: Consultancy. White: Forus: Consultancy, Honoraria; Antengene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Chen: BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Sutherland: GSK: Research Funding; Celgene: Consultancy; Janssen: Consultancy, Research Funding; Karyopharm: Research Funding; Amgen: Consultancy. Madan: Janssen: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; Sanofi: Consultancy, Research Funding; GSK: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Karyopharm: Research Funding, Speakers Bureau; Takeda: Speakers Bureau. Leblanc: Celgene/BMS: Research Funding; BMS/Celgene Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Canada: Membership on an entity's Board of Directors or advisory committees; Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Sanofi Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees. Sebag: Janssen: Research Funding; Amgen: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Bristol Myers-Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria. Venner: Janssen: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Celgene: Research Funding; Amgen: Research Funding. Bensinger: BMS, Janssen, Poseida, Regeneron, Trillium: Research Funding; Amgen, BMS, Janssen, Sanofi: Speakers Bureau. DeCastro: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Van Domelen: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Bentur: Karyopharm Therapeutics: Current Employment, Current equity holder in publicly-traded company. Zhang: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. 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. Lipe: Seagen Inc.: Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; sanofi: Consultancy; GlaxoSmithKline: Consultancy; amgen: Research Funding; Cellectar: Research Funding; Karyopharm: Research Funding; Harpoon: Research Funding.

Purpose: Lenalidomide, thalidomide, and pomalidomide (LTP) are immunomodulatory agents approved for use in multiple myeloma, but in some settings, especially with alkylating agents, an increase in Hodgkin lymphoma and other secondary primary malignancies (SPM) has been noted. Some of these malignancies have been linked to Epstein–Barr virus (EBV), raising the possibility that immunomodulatory drugs disrupt latent EBV infection.Experimental Design: We studied the ability of LTP to reactivate latently infected EBV-positive cell lines in vitro and in vivo, and evaluated the EBV viral load in archived serum samples from patients who received a lenalidomide, thalidomide, and dexamethasone (LTD) combination.Results: Treatment of EBV-infected B-cell lines with LTP at physiologically relevant concentrations induced the immediate early gene BZLF1, the early gene BMRF1, and the late proteins VCA and BCFR1. This occurred in the potency order pomalidomide > lenalidomide > thalidomide, and the nucleoside analogue ganciclovir enhanced the cytotoxic effects of lenalidomide and pomalidomide in Burkitt lymphoma cells in vitro and in vivo. EBV reactivation was related to PI3K stimulation and Ikaros suppression, and blocked by the PI3Kδ inhibitor idelalisib. Combinations of lenalidomide with dexamethasone or rituximab increased EBV reactivation compared with lenalidomide alone and, importantly, lenalidomide with melphalan produced even greater reactivation.Conclusions: We conclude LTP may reactivate EBV-positive resting memory B cells thereby enhancing EBV lytic cycle and host immune suppression. Clin Cancer Res; 22(19); 4901–12. ©2016 AACR.

EBV viral loads in patient serum samples on a LEN, THAL, DEX combination.

Supplementary Table from Safety and Efficacy of Combination Maintenance Therapy with Ixazomib and Lenalidomide in Patients with Posttransplant Myeloma

Table A1. Prior therapies received (agents received by >5 patients); Table A2. Summary of pevonedistat plasma pharmacokinetic parameters on days 1 and 9 of cycle 1 on schedule A (administration on days 1, 2, 8, 9 of 21-day cycles); Table A3. Summary of pevonedistat plasma pharmacokinetic parameters on days 1 and 4 (or, alternatively, day 11) of cycle 1 on schedule B (administration on days 1, 4, 8, 11 of 21-day cycles); Table A4. Changes from baseline in gene expression levels for NAEregulated transcriptional targets on cycle 1, day 1 following pevonedistat administration at the MTDs on schedules A and B; Table A5. Patients achieving partial responses; Table A6. Patients achieving stable disease and receiving at least 5 cycles of pevonedistat.

Purpose: Waldenström macroglobulinemia (WMG) is a lymphoproliferative disorder characterized by good initial responses to standard therapeutics, but only a minority of patients achieve complete remissions, and most inevitably relapse, indicating a need for novel agents. B-cell receptor signaling has been linked to clonal evolution in WMG, and Spleen tyrosine kinase (Syk) is overexpressed in primary cells, suggesting that it could be a novel and rational target.Experimental Design: We studied the impact of the Syk inhibitor fostamatinib on BCWM.1 and MWCL-1 WMG-derived cell lines both in vitro and in vivo, as well as on primary patient cells.Results: In WMG-derived cell lines, fostamatinib induced a time- and dose-dependent reduction in viability, associated with activation of apoptosis. At the molecular level, fostamatinib reduced activation of Syk and Bruton's tyrosine kinase, and also downstream signaling through MAPK kinase (MEK), p44/42 MAPK, and protein kinase B/Akt. As a single agent, fostamatinib induced tumor growth delay in an in vivo model of WMG, and reduced viability of primary WMG cells, along with inhibition of p44/42 MAPK signaling. Finally, fostamatinib in combination with other agents, including dexamethasone, bortezomib, and rituximab, showed enhanced activity.Conclusions: Taken together, these data support the translation of approaches targeting Syk with fostamatinib to the clinic for patients with relapsed and possibly even newly diagnosed WMG. Clin Cancer Res; 21(11); 2538–45. ©2015 AACR.

Representative images (20 x magnification) of formalin-fixed paraffin-embedded clots prepared from bone marrow aspirates.

P values of mouse tumor volumes over time

Supplementary Figures 1-3. Supplementary Figure 1. Fostamatinib induces apoptosis in a dose-dependent manner. Supplementary Figure 2. Fostamatinib shows enhanced activity in combination with bendamustine. Supplementary Figure 3. Fostamatinib shows enhanced activity in combination with bendamustine.

Purpose: Evaluate the safety, pharmacokinetic profile, pharmacodynamic effects, and antitumor activity of the first-in-class investigational NEDD8-activating enzyme (NAE) inhibitor pevonedistat (TAK-924/MLN4924) in patients with relapsed/refractory lymphoma or multiple myeloma.Experimental Design: Patients with relapsed/refractory myeloma (n = 17) or lymphoma (n = 27) received intravenous pevonedistat 25 to 147 mg/m2 on days 1, 2, 8, 9 (schedule A; n = 27) or 100 to 261 mg/m2 on days 1, 4, 8, 11 (schedule B; n = 17) of 21-day cycles.Results: Maximum tolerated doses were 110 mg/m2 (schedule A) and 196 mg/m2 (schedule B). Dose-limiting toxicities included febrile neutropenia, transaminase elevations, muscle cramps (schedule A), and thrombocytopenia (schedule B). Common adverse events included fatigue and nausea. Common grade ≥3 events were anemia (19%; schedule A), and neutropenia and pneumonia (12%; schedule B). Clinically significant myelosuppression was uncommon. There were no treatment-related deaths. Pevonedistat pharmacokinetics exhibited a biphasic disposition phase and approximate dose-proportional increases in systemic exposure. Consistent with the short mean elimination half-life of approximately 8.5 hours, little-to-no drug accumulation in plasma was seen after multiple dosing. Pharmacodynamic evidence of NAE inhibition included increased skin levels of CDT-1 and NRF-2 (substrates of NAE-dependent ubiquitin ligases), and increased NRF-2-regulated gene transcript levels in whole blood. Pevonedistat–NEDD8 adduct was detected in bone marrow aspirates, indicating pevonedistat target engagement in the bone marrow compartment. Three lymphoma patients had partial responses; 30 patients achieved stable disease.Conclusions: Pevonedistat demonstrated anticipated pharmacodynamic effects in the clinical setting, a tolerable safety profile, and some preliminary evidence that may be suggestive of the potential for activity in relapsed/refractory lymphoma. Clin Cancer Res; 22(1); 34–43. ©2015 AACR.

Combination indices of LEN, THAL or POM in combination with GCV.

Supplementary Figure from Safety and Efficacy of Combination Maintenance Therapy with Ixazomib and Lenalidomide in Patients with Posttransplant Myeloma

Supplementary Figure Legends

Purpose:In this study, the addition of ixazomib to lenalidomide maintenance post-autologous stem cell transplant (ASCT) in 64 patients with newly diagnosed multiple myeloma was evaluated on the basis of the observed benefit of lenalidomide-only maintenance in prior studies.Patients and Methods:Patients were started on maintenance therapy with lenalidomide and ixazomib within 60–180 days of stem cell infusion.Results:Response rates deepened over time from baseline post-ASCT for 39 patients. The complete response (CR)/stringent CR rate was 43% and median overall survival was not reached with a median follow-up of 62 months (range, 25–82 months). Median PFS (mPFS) for all patients was 73 months and has not been reached for those with International Staging System (ISS) stage 1 disease. mPFS in 9 patients who had ISS stage 3 disease and 14 patients who had high-risk cytogenetics was 34 and 25 months, respectively. Twenty-two patients had progressive disease, while 19 patients continue to receive dual maintenance. The most common grade 3/4 adverse events included neutropenia, leukopenia, thrombocytopenia, lung infections, diarrhea, and maculopapular rash. Second primary malignancies occurred in 9 patients. Toxicity led to dose reductions in ixazomib and lenalidomide in 20 and 31 patients, respectively. Discontinuation of ixazomib due to toxicity occurred in 4 patients. Grade 1/2 neuropathy occurred in 22 patients and led to reduction or discontinuation of ixazomib in 2 patients.Conclusions:The addition of ixazomib to lenalidomide maintenance demonstrated a better than expected PFS compared with historical data using lenalidomide alone and was safe and tolerable.

1.Contains schematic of a LEN, THAL DEX dosing schedule. 2. EBV viral load in patients who received LEN, THAL, DEX with VTX or no VTX.

PURPOSE Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in patients with previously treated DD-LPS whose sarcoma progressed on approved agents. METHODS SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: NCT02606461 ). RESULTS Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided P = .011; medians 2.8 v 2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided P < .0001; medians 5.8 v 3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 [80.7%] v 11 [5.9]), decreased appetite (113 [60.4%] v 14 [7.5%]), and fatigue (96 [51.3%] v 12 [6.4%]). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of CALB1 expression was associated with longer PFS with selinexor compared with placebo (median 6.9 v 2.2 months; HR, 0.19; P = .001). CONCLUSION Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of CALB1 expression as a predictive biomarker for selinexor in DD-LPS is warranted.

Purpose: In this study, the addition of ixazomib to lenalidomide maintenance post-autologous stem cell transplant (ASCT) in 64 patients with newly diagnosed multiple myeloma was evaluated on the basis of the observed benefit of lenalidomide-only maintenance in prior studies. Patients and Methods: Patients were started on maintenance therapy with lenalidomide and ixazomib within 60–180 days of stem cell infusion. Results: Response rates deepened over time from baseline post-ASCT for 39 patients. The complete response (CR)/stringent CR rate was 43% and median overall survival was not reached with a median follow-up of 62 months (range, 25–82 months). Median PFS (mPFS) for all patients was 73 months and has not been reached for those with International Staging System (ISS) stage 1 disease. mPFS in 9 patients who had ISS stage 3 disease and 14 patients who had high-risk cytogenetics was 34 and 25 months, respectively. Twenty-two patients had progressive disease, while 19 patients continue to receive dual maintenance. The most common grade 3/4 adverse events included neutropenia, leukopenia, thrombocytopenia, lung infections, diarrhea, and maculopapular rash. Second primary malignancies occurred in 9 patients. Toxicity led to dose reductions in ixazomib and lenalidomide in 20 and 31 patients, respectively. Discontinuation of ixazomib due to toxicity occurred in 4 patients. Grade 1/2 neuropathy occurred in 22 patients and led to reduction or discontinuation of ixazomib in 2 patients. Conclusions: The addition of ixazomib to lenalidomide maintenance demonstrated a better than expected PFS compared with historical data using lenalidomide alone and was safe and tolerable.

Introduction: The BOSTON study is a Phase 3 trial comparing the novel triplet regimen of once weekly oral selinexor with once weekly bortezomib and dexamethasone (SVd) versus standard twice weekly Vd in patients with multiple myeloma (MM) after 1-3 prior therapies. The SVd regimen conferred a 47% increase in median progression-free survival (PFS) and time to next therapy (TTNT), higher overall response rates (ORR) and deeper responses compared to Vd. Furthermore, this is the first trial of a bortezomib-based triplet therapy (i.e., SVd) that showed lower rates of overall and Grade ≥2 peripheral neuropathy (PN) compared with doublet Vd while conferring a longer PFS, and the regimen requires ~35% fewer clinic visits than standard twice weekly Vd. This abstract reports analyses of the patient reported outcomes (PROs) in BOSTON to evaluate patterns in therapy-induced PN symptoms, pain and function. Methods: PROs were assessed at baseline and day 1 of each cycle using the European Organization for Research and Treatment of Cancer (EORTC) QLQ-C30 and EORTC QLQ-CIPN20 questionnaires. The QLQ-CIPN20 assesses patients' experience of symptoms and functional limitations related to chemotherapy induced PN (CIPN) and has 3 subscales: sensory, motor, and autonomic. The QLQ-C30 includes several functional and symptom scales and focuses on physical functioning, role functioning, and pain subscales as pre-specified domains of interest. Mixed effects repeated measures models were fit to the longitudinal data to estimate differences over time. Meaningful change thresholds derived using anchor- and distribution-based methods or estimated from the literature were used to identify patients who had experienced a meaningful worsening of symptoms or deterioration in functioning. Time to definitive deterioration was defined as the time from randomization to the first occurrence of meaningful deterioration that was not followed by subsequent improvement. Cox proportional hazard models compared the hazard rates between arms adjusted for baseline questionnaire score, randomization stratification factors (prior PI therapy, number of prior anti-MM regimens, R-ISS stage at MM) and prior bortezomib exposure. Results: A total of 402 patients were enrolled in the trial; 388 completed a baseline QLQ-CIPN20 assessment and are included in these analyses. Based on the mixed model repeated measures analysis (Table 1), a benefit was demonstrated for SVd in change from baseline to Day 106 for sensory (-5.3 points difference, p=0.0006) and pain (-6.6, p=0.007) scores. Patients in the SVd arm had a greater increase in autonomic symptom scores (+5.0, p=0.022). The number of patients with definitive deterioration in QLQ-CIPN20 sensory symptoms was greater in the Vd arm (86 patients, 45.7%) compared to 52 (27.7%) patients in the SVd arm (Table 2). The median time to deterioration was 20.7 months (95% confidence interval [CI]: 15.4, not estimable [NE]) in the SVd arm compared to 12.5 months (95% CI: 7.8, 19.9) in the Vd arm. The adjusted hazard ratio (HR) comparing time to deterioration in sensory scores between SVd and Vd arms was 0.53 (95% CI: 0.38, 0.75; p = 0.0004). Worsening of motor symptoms also trended in favor of SVd with a HR = 0.72 (p=0.052). Roughly half of the patients in each treatment arm experienced worsening autonomic symptoms (54.6% and 48.4%, SVd and Vd respectively) with no significant difference between arms (HR=1.14, p=0.37). While not statistically significant, fewer SVd patients had definitive deteriorations in pain and physical function compared to Vd patients, with similar or extended time to deterioration (Table 2). Conclusions: In the setting of a significant increase in PFS and TTNT, patients with MM after at least one prior therapy who received weekly SVd reported lower sensory symptom and pain scores but higher autonomic symptom scores. Further, patients treated with twice weekly Vd experienced a more rapid rate of sensory symptom worsening and a trend to more rapid worsening of motor symptoms, compared to patients treated with SVd. The improved pain scores in patients treated with SVd may be related to superior disease control. The reduction in PN-related pain and sensory symptoms observed with SVd in the setting of increased PFS and TTNT supports a potentially improved patient experience and decreased health care burden and long term morbidity. Disclosures Leleu: Janssen: Honoraria; BMS-celgene: Honoraria; Novartis: Honoraria; Amgen: Honoraria; GSK: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria; Oncopeptide: Honoraria; AbbVie: Honoraria; Carsgen: Honoraria; Incyte: Honoraria; Merck: Honoraria. Beaumont:Clinical Outcomes Solutions: Current Employment; Karyopharm Therapeutics: Consultancy. Yu:Clinical Outcomes Solutions: Current Employment; Karyopharm Therapeutics: Consultancy. Hudgens:Clinical Outcomes Solutions: Current Employment; Sierra Oncology: Consultancy; Karyopharm Therapeutics: Consultancy. Auner:Karyopharm: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria. Quach:Sanofi: Consultancy, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Glaxo Kline Smith: Consultancy, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen Cilag: Consultancy, Honoraria. Delimpasi:Amgen: Honoraria; Takeda: Honoraria; Janssen: Honoraria; GENESIS: Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Dimopoulos: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; 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. Hajek:Celgene: 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; BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Honoraria; PharmaMar: Consultancy, Honoraria; Oncopeptides: Consultancy. Venner:Celgene, Amgen: Research Funding; Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Jagannath:BMS, Janssen, Karyopharm, Legend Biotech, Sanofi, Takeda: Consultancy. Moreau:Janssen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Novartis: Honoraria; Takeda: Honoraria. Levy:Karyopharm,Takeda, BMS: Consultancy, Honoraria, Speakers Bureau. Bahlis:BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; AbbVie: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; 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. Chai:Karyopharm Therapeutics Inc: Current Employment. Ma:Karyopharm: Current Employment, Current equity holder in private company. Tang:Karyopharm Therapeutics: Current Employment. Leong:AbbVie: Ended employment in the past 24 months; Karyopharm Therapeutics: Current Employment. Shah:Karyopharm: 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.

2045 Background: Glioblastoma (GBM) is an aggressive primary tumor with poor prognosis and survival. Patients (pts) experience debilitating symptoms that have a negative effect on quality of life (QoL). A multidisciplinary approach is necessary to facilitate the reduction of morbidity, preserve QoL, and maximize benefits of treatment. Selinexor (SEL) is a first-in class, oral, selective inhibitor of nuclear export that blocks exportin 1 approved for use in multiple myeloma and diffuse large B-cell lymphoma and has shown activity in GBM. Digital measurements in the KING study through wearable sensors and other devices capture actionable daily data at home for improved care, symptom management, and QoL, are reported here. Methods: XPORT-GBM-029 (NCT04421378) is an ongoing phase 1 dose finding study followed by an open-label randomized phase 2, 5-arm trial to evaluate SEL in combination with standard therapies for newly diagnosed and recurrent GBM (n = 350): radiation+SEL /radiation and temozolomide; radiation and temozolomide±SEL; lomustine±SEL; bevacizumab±SEL; tumor treating field±SEL. The study is conducted at 18 sites in the US and Canada. GBM progression is assessed by standard clinical and imaging as well as QoL measurements by novel digital tools. Four parameters to determine the impact on QoL (cognitive function, lateralization, fatigue, sleep) are measured remotely by smartwatch and smartphone to continuously measure activity and sleep, and to complete a cognitive battery at baseline and before each MRI. Results: To date, pts wearing the smartwatch had higher compliance during the day for activity and gait measures compared to night for sleep measures. Younger pts had better compliance. Over the course of SEL treatment, changes were observed in balance (characterized by double support % and walking asymmetry) and activity level (characterized by step count and walking distance). Of the pts who participated in the cognitive battery (CANTAB) tests, 2 pts had a minor change in cognition measures including psychomotor and processing speed, episodic and spatial working memory, and executive function after 2 SEL treatment cycles. Overall, the CANTAB measures are stable, which align with the mRANO (MRI) results. The correlation between the CANTAB cognition measures and MRI data will be evaluated once more clinical data become available. Ongoing analyses will apply machine learning and statistical tools to determine potential correlations between digital and clinical data, such as physical examinations, AEs, Karnofsky scores, mRANO, NANO, KPS, and PRO QoL questionnaires. Conclusions: This is the first demonstration of digital measurement feasibility in a longitudinal study of pts with GBM. Digital measurements for pts with GBM could provide information on the impact of SEL-based treatment and functional outcomes in clinical trials and increase communication between clinicians and pts, thereby improving QoL and care management. Clinical trial information: NCT04421378.

Summary Background Bortezomib with lenalidomide and dexamethasone (VRd) is a standard regimen for the front-line treatment of multiple myeloma. Panobinostat is approved in combination with bortezomib and dexamethasone in patients with myeloma who 'have been given at least two previous regimens including bortezomib and an immunomodulatory agent. We aimed to determine the maximum tolerated dose of a new regimen combining VRd with panobinostat in patients with newly diagnosed multiple myeloma. Methods In this phase 1 study, we enrolled patients from the University of Texas MD Anderson Cancer Center (Houston, TX, USA) with newly diagnosed multiple myeloma who were aged 18 years or older and eligible for autologous stem-cell transplant (ASCT) according to International Myeloma Working Group 2014 diagnostic criteria. Participants were allocated either to the dose-escalation cohort or the dose-expansion cohort. In the dose-escalation cohort, in a 3 + 3 design, patients were treated in cycles of 21 days with bortezomib (1·3 mg/m2, subcutaneously) on days 1, 4, 8, 11; lenalidomide (25 mg, orally) on days 1–14; dexamethasone (20 mg, orally) on days 1, 2, 4, 5, 8, 9, 11, and 12; and escalating doses of panobinostat (10–20 mg, orally) on days 1, 3, 5, 8, 10, and 12. The dose level exceeded the maximum tolerated dose if at any given dose more than one of three patients, or two of six patients, had a dose-limiting toxic event. In the dose-expansion cohort, patients were given the maximum tolerated dose of the drug combination as determined from the dose-escalation cohort. Patients could proceed with upfront ASCT after two to four cycles of initial therapy or store their stem cells and proceed with a delayed ASCT approach. Patients with delayed ASCT could continue therapy for up to eight cycles, followed by maintenance with lenalidomide, dexamethasone, and panobinostat at their last tolerated dose for up to 2 years. The primary objective was to determine the maximum tolerated dose of VRd with panobinostat. Safety was assessed in all patients who completed at least one cycle of therapy. This trial is registered with ClinicalTrials.gov , number NCT01440582 , and is no longer recruiting participants. Findings Between Feb 18, 2013, and June 8, 2016, 55 patients were identified as eligible for enrolment. The dose-escalation cohort comprised 12 participants. The first three (25%) patients at dose level 1 (panobinostat 10 mg) did not encounter dose-limiting toxicity. Of six (50%) patients at dose level 2 (panobinostat 15 mg), two (33%) had dose-limiting toxic events during cycle 1; one (17%) had grade 4 thrombocytopenia with bleeding and the other had grade 3 diarrhoea, thus exceeding the maximum tolerated dose. Because the maximum tolerated dose had been exceeded, three more patients were accrued to dose level 1 and these patients did not experience dose-limiting toxic events. Dose level 1 (21 day cycles of bortezomib 1·3 mg/m2 subcutaneously on days 1, 4, 8, 11; lenalidomide 25 mg orally on days 1–14; dexamethasone 20 mg orally on days 1, 2, 4, 5, 8, 9, 11, 12; and panobinostat 10 mg orally on days 1, 3, 5, 8, 10 and 12) was established as the maximum tolerated dose. Interpretation The combination of VRd with panobinostat 10 mg is safe and effective in patients who are newly diagnosed with multiple myeloma and who are transplant eligible. Further studies in large randomised controlled settings are needed to confirm these results. Funding: Novartis and MD Anderson Cancer Center Support Grant.

Triple-class-refractory multiple myeloma (MM) describes MM refractory to proteasome inhibitors, immunomodulatory agents, and anti-CD38 monoclonal antibodies. In the Phase IIb STORM study (NCT02336815), oral selinexor plus low-dose dexamethasone (Sel-dex) demonstrated a 26.2% overall response rate in triple-class-refractory MM. Here, we compare overall survival (OS) of 122 patients with triple-class-refractory MM who received Sel-dex in STORM Part 2 with that of 64 similar patients treated with other available therapies in a Flatiron Health Analytic Database (FHAD) cohort. OS from the date that the patients' MM became triple-class-refractory was longer in STORM versus FHAD, with an unadjusted hazard ratio (HR) of 0.43 (

Introduction Bortezomib plus lenalidomide and dexamethasone (VRD) is a standard induction therapy for newly diagnosed multiple myeloma (NDMM) patients. Given preclinical and clinical data suggesting the synergistic activity of the histone deacetylase inhibitor vorinostat with both bortezomib and lenalidomide for the treatment of multiple myeloma, we hypothesized that adding vorinostat to VRD (R2V2) would increase the rate and the quality of responses to induction treatment. Here we report the results of a phase 1 trial (NCT01038388) evaluating R2V2 as up-front treatment for NDMM patients. Patients and Methods R2V2 was tested as induction therapy in a dose-escalation phase 1 study in 30 NDMM patients deemed eligible for autologous stem-cell transplantation. Treatment consisted of 4 induction cycles with R2V2, followed by either autologous stem-cell transplantation or 4 additional R2V2 cycles and lenalidomide maintenance therapy. Results The maximum tolerated dose of vorinostat was 200 mg daily. The most common adverse events were gastrointestinal (87%), fatigue and peripheral neuropathy (60%), and thrombocytopenia (33%). R2V2 induced an objective response in 96% of patients, with 48% obtaining at least a complete remission. Median progression-free survival was 52 months, with 77% of patients alive at 5 years. Conclusion R2V2 as induction treatment for NDMM patients resulted in remarkable response rates at the cost of increased toxicity.

110 Background: Single agent selinexor, an oral selective inhibitor of nuclear export (SINE), showed activity against heavily pretreated CRC with RAS mutations (mut) or wildtype (wt) in 2 clinical studies. In preclinical studies, selinexor showed superior potency in KRAS mut over wt with improved activity in combination with PD-1/PD-L1 blockade. A phase 1b study (NCT02419495) showed the safety and antitumor activity of combined selinexor and a PD-1/PD-L1 inhibitor. This phase 1/2 open-label study is evaluating selinexor with pembrolizumab in patients with microsatellite instability (MSI)-stable CRC. Methods: The study enrolled patients with advanced/metastatic CRC who progressed after prior chemotherapy (1-3 lines for RAS wt, 1-2 for RAS mut) and are ineligible for anti-PD-1/PD-L1 therapy. Patients received weekly oral selinexor 80 mg and pembrolizumab 200 mg IV every 3 weeks. Antitumor activity, safety and tolerability were assessed. Results: Thirty-four patients, median age 57.5 years, male 59%, RAS mut 53%, median prior lines 2, are enrolled. At data cutoff (1-SEP-21) median treatment duration was 57 days (range: 1-246) and 25 patients were evaluable for response. Best response was stable disease in 8/13 patients with RAS mut CRC (62%) and in 3/12 patients with RAS wt CRC (25%). Median overall survival (months) has not been reached for the overall population (95% CI: 6.3, NE), for RAS mut (95% CI: 7.6, NE), and for the RAS wt (95% CI: 6.1, NE). Median progression-free survival is 3.0 and 1.4 months for patients with CRC with RAS mut and wt, respectively (p=0.04; HR: 0.43 [959% CI: 0.18, 1.01]). Thirty patients (88%) discontinued therapy, mostly due to progressive disease (44%). The most common treatment-emergent adverse events (TEAEs) (total; Grade ≥3) were nausea (77%; 3%), vomiting (41%; 0%), fatigue (41%; 12%), decreased appetite (35%; 0%), diarrhea (32%; 0%). Nine patients (26%) had serious treatment-emergent adverse events. Conclusions: Combined selinexor with pembrolizumab demonstrated higher disease control rates and prolonged overall survival in patients with chemotherapy-refractory advanced/metastatic CRC with RAS mut vs RAS wt tumors. These patients would not have been eligible for anti-PD-1 mAb therapy because their tumors were not MSI-high, suggesting that the combination may be active in RAS mut CRC. Therapy was well tolerated with no unanticipated adverse events. Further investigation of this combined treatment is warranted, particularly in patients with CRC with RAS mut. Clinical trial information: NCT04256707.

Background: Once multiple myeloma (MM) becomes refractory to αCD38 mAb, pts have limited effective treatment options and poor prognoses. With standard therapies, overall response rate (ORR) to the first regimen after refractoriness to an αCD38 mAb is 31%, median progression-free survival (PFS) - 3.4 months and median overall survival (OS) - 9.3 months (Gandhi et al, Leukemia, 2019). Exportin 1 (XPO1) mediates the nuclear export and functional inactivation of tumor suppressor proteins. XPO1 is required for MM cell growth, is associated with poor prognosis and mediates resistance to standard MM and other anticancer therapies. Selinexor (SEL) is a first-in-class, oral selective inhibitor of nuclear export (SINE) compound approved for patients (pts) with previously treated MM as well as DLBCL. The doublet SEL-dexamethasone (Xd) achieved ORR ~26% in triple-class (Immunomodulatory drug [IMiD], proteosome inhibitor [PI], αCD38 mAb) refractory MM and improved OS over matched cohorts in community (Richardson et al, eJHaem, 2021) and academic (Cornell et al, AJH, 2020) settings. Hence, SEL-based triplets could be more effective in this triple class-treated population. We analyzed the efficacy and safety of SEL-containing triplets in pts in the STOMP study who were previously treated with regimens containing αCD38 mAb. Methods: STOMP is a multi-arm, open-label, Phase 1b/2 study evaluating SEL in various combinations (NCT02343042). Here, we analyzed ORR, clinical benefit rate (CBR), duration of response (DOR), PFS, OS, and treatment-emergent adverse events (TEAEs) of pts who received Xd plus pomalidomide (XPd, n=23) or carfilzomib (XKd, n=23) after prior therapy with αCD38 mAb. Results: Among 46 pts treated, median age was 64 yrs (XPd), 70 yrs (XKd), females 57% (XPd) and 39% (XKd), median time from diagnosis was 5 yrs, and median number of prior regimens 4 (range, 2-10). All pts were previously treated with a PI and IMiD and αCD38 mAb; 78% (XPd) and 52% (XKd) had triple refractory MM. Prior treatment with αCD38 mAb included daratumumab (XPd: 91%, XKd: 100%) and isatuximab (XPd: 9%); 52% (XPd) and 74% (XKd) had αCD38 mAb in their most recent prior regimen. Refractoriness to daratumumab was documented in 87% (XPd) and 96% (XKd); isatuximab in 9% (XPd). Median durations from end of most recent αCD38 mAb therapy to first dose of study treatment were 8 weeks (XPd), 4 weeks (XKd). Among evaluable pts, ORR and CBR were 52% and 76%, respectively in the XPd arm (n=21; 2 pts were not efficacy evaluable) and 65% and 74%, respectively in the XKd arm. In the XPd arm median PFS was 8.7 months (95% CI: 7.6, NE), median DOR was 7.9 months (95% CI: 3.9, NE), and median OS was 21.8 months (95% CI: 8, NE). In the XKd arm median PFS was 15 months (95% CI: 12.0, NE), median DOR was 13.1 months (95% CI: 10.2, NE), and median OS was 33.0 months (95% CI: 20.4, NE). Among the evaluable pts, response to SEL-containing triplets compared favorably to the prior αCD38 mAb-containing regimen used at least 1 line earlier: XPd arm (n=21), ORR 52% vs 58% for prior regimen, CBR 76% vs 58%, median PFS 8.7 months (95% CI: 7.6, NE) vs 10.2 months (95% CI: 5.2, 20.5); XKd arm (n=23), ORR 65% vs 52%, CBR 74% vs 57%, median PFS 15.0 months (95% CI: 12.0, NE) vs 8.5 months (95% CI: 5.9, 17.3). The most common hematological TEAEs (total; grade≥3) were thrombocytopenia (XPd: 35%; 30%; XKd: 78%; 39%), anemia (XPd: 57%; 39%; XKd: 57%; 22%), and neutropenia (XPd: 57%; 48%; XKd: 35%; 4%). Other common TEAEs (total; grade≥3) were nausea (XPd: 74%; 0; XKd: 74%; 4%), fatigue (XPd: 61%; 4%; XKd: 52%; 4%) and decreased appetite (XPd: 48%; 4%; XKd: 48%; 4%). No cases of severe bleeding with thrombocytopenia occurred. Three pts (13%, all XPd) had febrile neutropenia (the outcome of which was fatal in 1 pt, deemed related to SEL and pomalidomide). TEAEs were managed with standard supportive care and dose modifications. Summary/Conclusion: XPd and XKd administered to pts with heavily pretreated MM, including prior αCD38 mAb therapy, exhibit tolerability and comparable effectiveness to that of the prior αCD38 mAb-containing regimen. These results suggest that the use of SEL-containing triplets, implementing the novel XPO1 inhibition mechanism, can provide prolonged disease control with good tolerability rather than recycling previously utilized drugs/mechanisms. The all oral XPd regimen will be evaluated in Study EMN29 against elotuzumab-Pd in patients who have received lenalidomide, a PI and an αCD38 mAb. Disclosures Lentzsch: Janssen: Consultancy; AbbVie: Consultancy; Celularity: Consultancy; GSK: Consultancy; Takeda: Consultancy; Karyopharm: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Oncopeptides: 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. Lipe: Seagen Inc.: Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; sanofi: Consultancy; GlaxoSmithKline: Consultancy; amgen: Research Funding; Cellectar: Research Funding; Karyopharm: Research Funding; Harpoon: Research Funding. Tuchman: Karyopharm: Research Funding; Shattuck Labs: Consultancy; Sanofi / Genzyme: Consultancy, Research Funding; Caelum: Consultancy, Research Funding; Oncopeptides: Consultancy. Bahlis: Takeda: Consultancy, Honoraria; Genentech: Consultancy; Amgen: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria. Bensinger: BMS, Janssen, Poseida, Regeneron, Trillium: Research Funding; Amgen, BMS, Janssen, Sanofi: Speakers Bureau. Sebag: Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Bristol Myers-Squibb: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Janssen: Research Funding. Sutherland: Janssen: Consultancy, Research Funding; GSK: Research Funding; Karyopharm: Research Funding; Celgene: Consultancy; Amgen: Consultancy. Monge: Bristol Myers Squibb: Consultancy; Karyopharm Therapeutics: Research Funding. Gasparetto: Karyopharm Therapeutics Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; Oncopeptite: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Connect Registry: Membership on an entity's Board of Directors or advisory committees. Baljevic: Exelixis: Research Funding; Karyopharm: Other: Advisory Board; BMS/Celgene: Other: Advisory Board; Janssen Research: Other: Advisory Board; Oncopeptides: Other: Advisory Board; BMS/Celgene: Consultancy; Amgen: Research Funding. Venner: Janssen: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; BMS: Honoraria; GSK: Honoraria; Takeda: Honoraria. White: Amgen, Antengene, BMS/Celgene, Forus, GSK, Janssen, Karyopharm, Sanofi, Takeda: Consultancy, Honoraria. Kotb: Takeda: Honoraria; Karyopharm: Current holder of individual stocks in a privately-held company; Amgen: Honoraria; BMS: Honoraria; Celgene: Honoraria; Janssen: Honoraria; Sanofi: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Akcea: Honoraria; Pfizer: Honoraria. Chen: BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Astrazeneca: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Schiller: Celator: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Mateon: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Tolero: Research Funding; Constellation Pharmaceuticals: Research Funding; Takeda: Research Funding; Abbvie: Research Funding; Sangamo: Research Funding; Trovagene: Research Funding; Johnson & Johnson: Current equity holder in publicly-traded company; Cyclacel: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Forma: Research Funding; Daiichi-Sankyo: Research Funding; Bio: Research Funding; Ono-UK: Consultancy, Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Delta-Fly: Research Funding; FujiFilm: Research Funding; Deciphera: Research Funding; Arog: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; PrECOG: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Onconova: Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; Karyopharm: Research Funding; Agios: Consultancy, Research Funding, Speakers Bureau; Regimmune: Research Funding; Ono: Consultancy; Samus: Research Funding; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Actuate: Research Funding; Actinium Pharmaceuticals, Inc: Research Funding; Geron: Research Funding; Genentech-Roche: Research Funding; Gamida Cell Ltd.: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Elevate: Research Funding; Novartis: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding, Speakers Bureau; Pharma: Consultancy; Biomed Valley Discoveries: Research Funding; Eli Lilly: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Incyte: Consultancy; Ariad: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; MedImmune: Research Funding; Ambit: Research Funding; Leukemia & Lymphoma Society: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Madan: Karyopharm: Research Funding, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; GSK: Consultancy, Speakers Bureau; Sanofi: Consultancy, Research Funding; BMS: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Speakers Bureau. Leblanc: Sanofi Canada: Membership on an entity's Board of Directors or advisory committees; Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Canada: Membership on an entity's Board of Directors or advisory committees; BMS/Celgene Canada: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Research Funding; Takeda Canada: Membership on an entity's Board of Directors or advisory committees. DeCastro: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Bentur: Karyopharm Therapeutics: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Van Domelen: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Kauffman: 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) .

Aggressive non-Hodgkin's lymphomas (NHLs) [diffuse large b-cell lymphoma (DLBCL), grade 3b follicular lymphoma, and mantle cell lymphoma (MCL)] have dismal cure rates, especially in the relapsed/refractory setting, substantiating the need for novel treatment strategies to improve outcomes. Here we show that p21-activated kinase 4 (PAK4) and nicotinamide phosphoribosyltransferase (NAMPT) are essential for lymphoma subsistence and dual-targeting PAK4-NAMPT by the small molecule inhibitor KPT-9274 (orally bioavailable phase 1 compound), previously shown to be cancer cell-selective, acts by energy depletion, inhibiting cell proliferation and eventual apoptosis as a reasonable treatment strategy for aggressive NHLs. To demonstrate PAK4-NAMPT is essential for lymphoma survival, we showed increased PAK4 expression in primary NHL tissue (n=94) than in normal lymph nodes (n=8) (Fig1A). Lymphoma cell lines were sensitive to the PAK4/NAMPT dual inhibitor KPT-9274 (induced apoptosis with an EC 50 of 95.17 nM in WSU-DLCL2 and 13.9 nM in WSU-FSCCL cells). Similar results were obtained with positive controls PAK4 [PF-3578309] and NAMPT specific inhibitors [FK-866]. RT-PCR confirmed PAK4 and NAMPT down-expression in KPT-9274 treated WSU-FSCCL cells. Western blot of WSU-DLCL2 and WSU-FSCCL cells treated with KPT-9274 showed significant reductions in BCL-2 and enhanced cleaved-Caspase-3 and cleaved-PARP expression. We then assessed the impact of KPT-9274 on the cellular ATP and NAD pool since NAMPT inhibition can suppress both and induce cell death. NAD/NADH and ATP levels decreased in both cell lines [WSU-DLCL2 & WSU-FSCCL], with increasing KPT-9274 concentrations (Fig.1B&1C). We then showed KPT-9274 to synergize with the standard of care chemotherapy cyclophosphamide, vincristine, and adriamycin used for NHL management (decreased IC25 and IC50 in several combination treatments). In lymphoma xenografts, mice with transplanted WSU-DLCL2 fragments showed ~50% reduction in tumor volume (p 150-day increase in host life span compared to control and 3/6 mice were cured) (Fig.1F). After day 150, the remaining mice were dissected to confirm cures. Blood smears drawn from mice post three weeks of KPT-9274 treatment showed a significant reduction of circulating WSU-FSCCL cells validating its efficacy systemically (Fig.1G). Since exogenous niacin can regenerate NAD regulated by NAMPT in a rate-limiting step, the impact of niacin co-dosing with KPT-9274 was evaluated on tumor growth using the Z-138 MCL tumor xenograft model in nude mice. Tumor-bearing mice were treated with vehicle, KPT-9274 (200 mg/kg BID), niacin (30 mg/kg), or a combination of KPT-9274/niacin. All groups that received KPT-9274 treatment showed reductions in tumor size, while the vehicle control and niacin alone groups showed a rapid increase in tumor volume. Both KPT-9274 and combo groups showed a significant decrease in tumor growth compared to control (p=0.0002); however, there were no statistically significant differences between the KPT-9274 and the KPT-9274/niacin combo (Fig.1H). Similarly, in another MCL xenograft model, KPT-9274 resulted in a statistically significant reduction in JeKo-1 tumors compared to control (p = 0.0059). Niacin did not affect the tumor growth suppression induced by KPT-9274 treatment. No animals died in this study. Thus, supplementing niacin with KPT-9274 may alleviate the adverse effect without compromising the efficacy of the treatment. Also, KPT-9274 treated Z-138 residual tumors showed a reduction in PAK4, GEF-H1, paxillin, vinculin, cyclin D1, Dvl2, and Ki67 and enhancement in apoptosis by IHC staining (Fig.1I). The anti-tumor potential of KPT-9274 ± niacin in several aggressive lymphoma models strongly supports its efficacy in this setting. It strengthens our phase I study design to evaluate safety and tolerability and anti-tumor activity in patients with advanced solid malignancies or NHL (NCT02702492). Figure 1 Figure 1. Disclosures Balasubramanian: Servier Pharmaceuticals: Research Funding. Zonder: Caelum Biosciences: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Amgen: Consultancy; Alnylam: Consultancy; Regeneron: Consultancy; Janssen: Consultancy; Intellia: Consultancy. Senapedis: Karyopharm Therapeutics: Ended employment in the past 24 months, Patents & Royalties; Omega Therapeutics: Current Employment; Restorbio: Other: Personal fees. Baloglu: Karyopharm Therapeutics: Current Employment, Other: Personal fees. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Landesman: Karyopharm Therapeutics: 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. Azmi: Karyopharm Therapeutics: Research Funding.

Background: Overexpression of the nuclear export protein exportin 1 (XPO1) mediates the functional inactivation of tumor suppressor proteins (TSPs), facilitates the export of oncogene mRNA thus facilitating oncoprotein expression, is associated with poor prognosis in multiple myeloma (MM), and contributes to immunomodulatory drug (IMiD) resistance. Selinexor is an oral, first-in-class, selective inhibitor of nuclear export (SINE) compound that by blocking XPO1 forces the nuclear retention and activation of TSPs and nuclear retention and inactivation of oncoproteins. 1 Selinexor is approved with low-dose dexamethasone ± bortezomib for patients with previously treated MM. Pomalidomide plus dexamethasone (Pd) has an overall response rate (ORR) of ~30% and median PFS (mPFS) of ~4 months in patients with MM refractory to bortezomib and lenalidomide. We hypothesized that selinexor could be safely combined with Pd (XPd) and would improve the combination's efficacy. Methods: In the XPd arm of the multi-arm Phase 1b/2 STOMP study, selinexor was evaluated at 60, 80, or 100 mg in combination with Pd. Study objectives were to determine the maximum tolerated dose and recommended Phase 2 dose (RP2D) and to assess the safety and activity of the XPd regimen. The dose of selinexor 60 mg once weekly (QW), pomalidomide 4 mg once daily (days 1-21), dexamethasone 40 mg QW (XPd-60) was the lowest evaluated dose of selinexor in combination with the approved dose of Pd, and in light of the marked efficacy of that dose (ORR 65%), Phase 2 cohorts at a lower (40 mg weekly) dose of selinexor (XPd-40), were evaluated. Of the 19 patients enrolled at XPd-40 and evaluable for efficacy, 12 patients were enrolled into STOMP and 7 patients were enrolled at the same dose level and similar inclusion criteria into a parallel study XPORT-MM-028. Results: As of 14 July 2021, 39 patients were enrolled into the 60 (N=20) and 40 (N=19) mg selinexor dose levels in combination with Pd: 19 males, median age 66.0 years (range 37-85 years), median number of prior lines of therapy 2 (range 1-9). 85% of patients had MM refractory to a proteasome inhibitor (PI; bortezomib or carfilzomib or ixazomib), 79% to an IMiD (thalidomide or lenalidomide or pomalidomide), 33% to an anti-CD38 mAb (daratumumab or isatuximab); 26% had triple class refractory disease. Common hematologic, treatment-emergent adverse events (TEAEs) consisted of (all grades, grade ≥3) neutropenia (72%, 59%; and two cases of grade 3 [G3] febrile neutropenia one in each of the dose levels), and anemia (51%, 15% all G3). Non-hematologic TEAEs were reversible and included fatigue (56%, 10% all G3) and nausea (49%, 0%). On XPd-60, the RP2D (N=20), ORR was 65% (1 stringent complete response [sCR], 5 very good partial responses [VGPR], 7 PR); mPFS was 8.9 months (95% CI, 7.6 - NE, median follow-up 8.3 months). In patients treated at XPd-40 (N=19), ORR was 42% (3 VGPR, 5 PR); mPFS was not reached (95% CI, 5.7 - NE, median follow-up 2.8 months). Among patients who had received anti-CD38 mAb, the ORR was 64% overall and 100% at the RP2D (1 sCR, 2 VGPR, 3 PR). All patients who had MM refractory to pomalidomide (N=3; all at the 60 mg dose level) responded with 1 VGPR and 2 PR. For the 21 responders across both dose levels, median time to response was 1.0 months (95% CI 1.0 - 2.0) and median duration of response was not reached (95% CI: 8.0, NE). Conclusions: Selinexor, once weekly, can be safely combined with Pd in patients with relapsed MM. The all-oral combination of XPd is highly active with an ORR of 65% at XPd-60, the RP2D, and an ORR of 42% at XPd-40 dose level (compared to expected ORR ~30% for Pd). The high ORR that was achieved at the RP2D, including in patients previously treated with anti-CD38 mAb, supports XPd-60 as a promising therapy with no significant cross-resistance to anti-CD38, PIs or lenalidomide. No new safety signals were identified. The most common TEAE, neutropenia, is a common AE of Pd and was managed effectively with standard G-CSF. The regimen leverages the concept of mechanism switching from an anti-CD38 mAb-based regimen to a selinexor-based regimen. These data support the new Phase 3 study (XPORT-MM-031) with an all-oral combination of XPd vs elotuzumab-Pd in patients who have been previously treated with lenalidomide, a PI, and an anti-CD38 mAb. Figure 1 Figure 1. Disclosures White: Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Antengene: Consultancy, Honoraria; Forus: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Karyopharm Therapeutics Inc.: Consultancy, Honoraria. Chen: Astrazeneca: Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy. Baljevic: BMS/Celgene: Consultancy; Exelixis: Research Funding; Karyopharm: Other: Advisory Board; BMS/Celgene: Other: Advisory Board; Amgen: Research Funding; Janssen Research: Other: Advisory Board; Oncopeptides: Other: Advisory Board. Tuchman: Caelum: Consultancy, Research Funding; Sanofi / Genzyme: Consultancy, Research Funding; Shattuck Labs: Consultancy; Karyopharm: Research Funding; Oncopeptides: Consultancy. Bahlis: Janssen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genentech: Consultancy; Amgen: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; GlaxoSmithKline: Consultancy, Honoraria. Schiller: Eli Lilly: Research Funding; Jazz: Consultancy, Honoraria, Research Funding, Speakers Bureau; Ambit: Research Funding; MedImmune: Research Funding; Cyclacel: Research Funding; Geron: Research Funding; Genentech-Roche: Research Funding; Amgen: Consultancy, Current equity holder in publicly-traded company, Honoraria, Research Funding, Speakers Bureau; Agios: Consultancy, Research Funding, Speakers Bureau; Trovagene: Research Funding; Gamida Cell Ltd.: Research Funding; Bio: Research Funding; Pfizer: Current equity holder in publicly-traded company, Research Funding; Forma: Research Funding; Deciphera: Research Funding; Regimmune: Research Funding; Delta-Fly: Research Funding; FujiFilm: Research Funding; Tolero: Research Funding; Takeda: Research Funding; AstraZeneca: Consultancy; Kaiser Permanente: Consultancy; Daiichi-Sankyo: Research Funding; Celator: Research Funding; Arog: Research Funding; Actuate: Research Funding; Actinium Pharmaceuticals, Inc: Research Funding; Karyopharm: Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Elevate: Research Funding; Samus: Research Funding; PrECOG: Research Funding; Constellation Pharmaceuticals: Research Funding; Onconova: Research Funding; Novartis: Consultancy, Research Funding; Ono-UK: Consultancy, Research Funding; Astellas: Honoraria, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Current equity holder in publicly-traded company, Research Funding, Speakers Bureau; Sangamo: Research Funding; Stemline Therapeutics, Inc.: Honoraria, Research Funding, Speakers Bureau; Abbvie: Research Funding; Kite/Gilead: Honoraria, Research Funding, Speakers Bureau; Mateon: Research Funding; Pharma: Consultancy; Sanofi: Honoraria, Research Funding, Speakers Bureau; Johnson & Johnson: Current equity holder in publicly-traded company; Biomed Valley Discoveries: Research Funding; ASH foundation: Other: Chair-unpaid; Sellas: Research Funding; Ono: Consultancy; Incyte: Consultancy; Ariad: Research Funding; Leukemia & Lymphoma Society: Research Funding; Bluebird Bio: Research Funding; Boehringer-Ingleheim: Research Funding; Cellerant: Research Funding; CTI Biopharma: Research Funding; Janssen: Research Funding; Kura Oncology: Research Funding; Pharmacyclics: Honoraria, Speakers Bureau; Millennium: Research Funding; National Marrow Donor Program: Research Funding; NIH: Research Funding; Onyx: Research Funding; Pharmamar: Research Funding; UC Davis: Research Funding; UCSD: Research Funding; Evidera: Consultancy; NCI: Consultancy; Novartis: Speakers Bureau. Lipe: Seagen Inc.: Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; sanofi: Consultancy; GlaxoSmithKline: Consultancy; amgen: Research Funding; Cellectar: Research Funding; Karyopharm: Research Funding; Harpoon: Research Funding. Kotb: Akcea: Honoraria; Karyopharm: Current holder of individual stocks in a privately-held company; Amgen: Honoraria; Pfizer: Honoraria; Merck: Honoraria, Research Funding; Janssen: Honoraria; Celgene: Honoraria; Sanofi: Honoraria, Research Funding; Takeda: Honoraria; BMS: Honoraria. Sutherland: Celgene: Consultancy; Karyopharm: Research Funding; GSK: Research Funding; Janssen: Consultancy, Research Funding; Amgen: Consultancy. Bensinger: Amgen, BMS, Janssen, Sanofi: Speakers Bureau; BMS, Janssen, Poseida, Regeneron, Trillium: Research Funding. Madan: Amgen: Consultancy, Speakers Bureau; Karyopharm: Consultancy, Research Funding; GSK: Consultancy, Speakers Bureau; Sanofi: Consultancy, Research Funding; BMS: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Speakers Bureau. Sebag: Janssen: Research Funding; Takeda: Consultancy, Honoraria; Bristol Myers-Squibb: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Venner: GSK: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Janssen: Honoraria; BMS: Honoraria; Amgen: Honoraria. Leblanc: BMS/Celgene Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Canada: Membership on an entity's Board of Directors or advisory committees; Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Sanofi Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Research Funding. Monge: Karyopharm Therapeutics: Research Funding; Bristol Myers Squibb: Consultancy. Tadmor: Janssen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. DeCastro: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Van Domelen: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Zhang: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Mishal: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Bentur: Karyopharm Therapeutics: Current Employment, Current equity holder in publicly-traded company. 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. Gasparetto: Karyopharm Therapeutics Inc.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Speakers Bureau; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy; Oncopeptite: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Connect Registry: 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.

Backrground: Several randomized controlled clinical trials have demonstrated improved outcomes for newly diagnosed multiple myeloma (NDMM) patients who were treated with lenalidomide as maintenance therapy after autologous stem cell transplant (ASCT). Proteasome inhibitors have demonstrated clinical benefit in myeloma patients when used as part of induction and maintenance regimens, and the combination of proteasome inhibitors and lenalidomide in induction regimens has produced strong clinical responses. In this study, the addition of ixazomib to lenalidomide maintenance post-ASCT in NDMM patients was evaluated. Methods: Patients (n=64) were started on maintenance therapy with lenalidomide and ixazomib within 60-180 days of stem cell infusion. Each cycle was defined as 28 days with lenalidomide starting at 10 mg/day orally for 28 days with the option to increase the dose to 15 mg after 3 cycles. Ixazomib was provided at 3 mg (n=48 patients) or 4 mg (n=16 patients) orally on days 1, 8, and 15 of each 28-day cycle. However, ixazomib dose was reduced to 3 mg in all patients based on toxicity observed in other clinical trials of ixazomib at that time. The primary endpoint measured was progression-free survival (PFS), which was defined as the time between ASCT and disease progression or death, whichever occurred first. Results: A total of 64 patients were enrolled on this study between December 4, 2012, and May 13, 2015. Of these patients, 41 (64.06%) were 60 years of age or older and 42 (65.63%) were male. Fourteen patients had high-risk cytogenetic features (+1q21, Del17p, t(14:16), t(4:14)), 50 patients had standard cytogenetic risk features (t(11:14), t(6:14), hyperdiploidy, normal) and 9 patients had International Staging System stage 3 disease. Median PFS (mPFS) for all patients was 73.3 months and has not been reached for those with ISS stage 1 disease. mPFS for ISS Stage 3 disease and high-risk cytogenetic subgroups was 33.8 and 25.4 months, respectively. Twenty-two patients had progressive disease, while 21 patients continue to receive dual maintenance. Response rates deepened over time from baseline post-ASCT for 39 patients. The complete response (CR)/stringent CR rate was 42.9% and median overall survival was not reached with a median follow-up of 62 months (range 25.4 - 82.1 months). Thirty-one patients (48%) had improvement from their baseline response after maintenance therapy: 6 patients improved from PR to VGPR; 7 from PR to stringent CR (sCR)/CR; 16 from VGPR to sCR/CR; 1 from SD to CR; and 1 patient improved from SD to VGPR. The median time to response in the 31 patients with improved response to maintenance therapy was 10.9 months (range, 0.9 to 51.3 months). Minimal residual disease (MRD) was evaluated by multicolor flow cytometry (10^-5) in 21 patients by bone marrow biopsy; 8 patients were MRD-positive. The most common grade 3/4 adverse events (AEs) included neutropenia (46.9%), leukopenia (20.3%), thrombocytopenia (15.6%), lung infections (26.6%), diarrhea and maculopapular rash (12.5% each). Secondary primary malignancies occurred in 9 patients; these included squamous cell carcinoma of the skin (n=4), basal cell carcinoma of the skin (n=1), squamous cell carcinoma and basal cell carcinoma of the skin (n=1), hepatocellular carcinoma (n=1), melanoma (n=1) and leukemia (n=1). AEs led to dose reductions in ixazomib and lenalidomide in 20 and 31 patients, respectively. Discontinuation of ixazomib due to AEs occurred in 4 patients. Grade 1/2 neuropathy occurred in 22 patients and led to reduction or discontinuation of ixazomib in 2 patients. Conclusion: Addition of ixazomib to lenalidomide maintenance in myeloma patients demonstrated a better than expected PFS compared with what has been reported in studies of lenalidomide alone, and was both safe and tolerable. These results indicate a significant clinical benefit, especially for standard risk patients. Figure 1 Figure 1. Disclosures Patel: Oncopeptides: Consultancy; Pfizer: Consultancy; Janssen: Consultancy, Research Funding; BMS Celgene: Consultancy, Research Funding. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Lee: GlaxoSmithKline: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Regeneron: Research Funding; Takeda Pharmaceuticals: Consultancy, Research Funding; Oncopetides: Consultancy; Amgen: Consultancy, Research Funding; Karyopharm: Consultancy; Legend Biotech: Consultancy; Sanofi: Consultancy; Janssen: Consultancy, Research Funding; Genentech: Consultancy. Thomas: BeiGene: Membership on an entity's Board of Directors or advisory committees; BMS: Research Funding; Ascentage Pharma: Research Funding; X4 Pharma: Research Funding; Genentech: Research Funding; Acerta Pharma: Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees. Qazilbash: NexImmune: Research Funding; Angiocrine: Research Funding; Amgen: Research Funding; Bristol-Myers Squibb: Other: Advisory Board; Oncopeptides: Other: Advisory Board; Janssen: Research Funding; Biolline: Research Funding. Orlowski: Amgen, Inc., BioTheryX, Inc., Bristol-Myers Squibb, Celgene, EcoR1 Capital LLC, Genzyme, GSK Biologicals, Janssen Biotech, Karyopharm Therapeutics, Inc., Neoleukin Corporation, Oncopeptides AB, Regeneron Pharmaceuticals, Inc., Sanofi-Aventis, and Takeda P: Consultancy, Honoraria; Asylia Therapeutics, Inc., 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.

Background: Patients with higher-risk myelodysplastic syndrome (MDS) refractory to hypomethylating agents (HMAs) have limited therapeutic options and poor prognosis with a median overall survival (mOS) of 4-6 months. Lack of response to HMA therapy, advanced age at relapse, male sex, bone marrow blasts >5% and high risk disease classification by International Prognostic Scoring System (IPSS) confer worse outcomes. Eltanexor is a second-generation, oral, selective inhibitor of nuclear export (SINE) compound with markedly reduced brain penetration relative to selinexor in preclinical models. This is believed to result in attenuation of centrally mediated anorexia, weight loss, and nausea, allowing for more frequent dosing. Early results from a phase 1/2 study of eltanexor in patients with higher-risk HMA-refractory MDS demonstrated marrow complete responses (mCRs), hematologic improvement (HI) and stable disease (SD); side effects were primarily low-grade, dose-dependent, and reversible (Lee EHA 2021). Here we provide an update on baseline characteristics, blast reduction in mCR patients, extent of transfusion independence and additional subgroup analyses. Methods: This phase 1/2 study (NCT02649790) evaluated oral eltanexor monotherapy in patients with high-risk or intermediate-2 by IPSS and 5%-19% myeloblasts. Of 20 patients enrolled, 15 patients were evaluable for efficacy and constitute the population studied in this analysis; 5 patients were non evaluable for efficacy due to trial discontinuation prior to response assessment. Two doses of eltanexor were evaluated: 10 mg (n=5) or 20 mg (n=10) each given qd 5 days per week. Results: Amongst the 15 efficacy evaluable patients, there were 8 males, median age 76 years (range 62-89), 10.0% (range 7-18%) median bone marrow blasts at enrollment, and with a median of two prior regimens (range 1-4). All patients primary HMA-refractory MDS; 9 patients (60%) with high risk and 5 (33%) with intermediate-2 per IPSS, 1 with intermediate-1 per IPSS. Similarly, using the global MD Anderson Cancer Center risk prognosis model, 14 patients (93%) had intermediate-2 or high-risk MDS. The overall response rate (mCR+HI) was 53% including 47% mCRs. Additionally, 5 patients (33%) had SD. Median blast reduction in the 7 patients with mCR was 78.6% (range 55.6%, 85.7%). Four patients had hematologic improvement (HI) including 2 patients with tri-lineage HI. Of the 7 patients who achieved mCR, 4 had significant reduction in transfusion requirements with 3 of these patients achieving complete transfusion independence for 5-10 cycles. In the 10-mg cohort (n=5), all patients derived clinical benefit with 3 patients reaching mCR and 2 patients with SD. In the 20-mg cohort (n=10), 4 patients had mCR and 3 had SD. Median overall survival for all efficacy evaluable patients was 9.86 months. OS for patients who reached mCR (n=7) was significantly longer than for patients who did not reach mCR (n=8): median 11.86 vs 8.67 months (hazard ratio [HR]=0.27, p=0.05), and significantly longer than OS for patients with PD (n=3, mOS=3.15 months, HR=0.23, p=0.04). Notably, mCR was seen in the 3 patients treated with >2 prior therapies and/or with secondary MDS: 1 patient with secondary MDS and 4 prior therapies; 1 with secondary MDS and one prior therapy; and 1 with de novo MDS and 3 prior therapies). Conclusions: Single-agent oral eltanexor was active in patients with higher-risk, primary HMA-refractory MDS including those with secondary MDS or with >2 lines of prior therapy. Patients with mCR had significantly longer mOS than patients without mCR and had median blast reduction of 78.6%. Further evaluation of eltanexor in MDS as a single agent and in combination with other agents is ongoing. Disclosures Lee: Innate: Consultancy, Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pin Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Mohan: Astex: Research Funding; Incyte: Research Funding. Knupp: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Chamoun: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Karasik: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Bai: Abbvie: Current equity holder in publicly-traded company; Takeda: Current Employment, Current equity holder in publicly-traded company; Karyopharm Therapeutics Inc.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Ingalls: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Yang: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Kauffman: 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) . Bhatnagar: Astellas: Honoraria; Cell Therapeutics: Honoraria, Research Funding; Celgene: Honoraria; Pfizer: Honoraria; Kite: Honoraria; Karyopharm Therapeutics Inc.: Honoraria, Research Funding; Novartis: Honoraria; Sumitomo Dainippon Pharma: Research Funding.

Introduction: Patients with relapsed or refractory diffuse large B-cell lymphoma (RR DLBCL) who cannot tolerate or who are not eligible for autologous or chimeric antigen receptor T cell (CAR-T) therapy have limited therapeutic options and suboptimal long-term outcomes. In patients who were not eligible for HSCT, the rituximab plus gemcitabine, dexamethasone and cisplatin (R-GDP) regimen (and variations using methylprednisolone or carboplatin/oxaliplatin) have shown an overall response rates (ORR) of ~50%, a complete response (CR) rate of ~25% (Gopal, Leuk Lymphoma, 2010), and a median progression-free survival (PFS) and an overall survival (OS) of 3 and 9 months, respectively (Crump, Hematol Oncol Clin N Am. 2016; Gopal Leuk Lymphoma, 2010; Ng, Br J Cancer, 2005; Sirohi, Hematology, 2007; Barton, Eur J Haematol. 2015; Moccia Leuk Lymphoma, 2017). Selinexor is an oral small molecule selective inhibitor of exportin-1 (XPO1) mediated nuclear export (SINE) compound leading to activation of tumor suppressor proteins and reduction in oncoprotein levels. It also reduces the expression of deoxyribonucleic acid (DNA) damage repair proteins and therefore potentiates DNA damage-based therapies leading to an increased death of cancer cells. Selinexor has synergistic effects with gemcitabine and cisplatin, and enhanced anti-lymphoma effects with dexamethasone. In the SADAL study (n=134), single-agent oral selinexor 60 mg twice weekly induced an ORR of 29% and a CR rate of 13% in patients with RR DLBCL. The response rates were consistent across various subgroups including patients Selinexor in combination with R-GDP was evaluated in a Phase 1 clinical trial (SELINDA), in which patients with DLBCL received either 40 or 60 mg selinexor once or twice weekly in combination with standard dose R-GDP. The recommended phase 2 dose for further exploration was 40 or 60 mg once weekly with an ORR of 60-80%. Therefore, combining selinexor with R-GDP is expected to improve response rates, and continuation of treatment with single-agent selinexor is expected to prolong the duration of responses, improve PFS (and potentially OS) in patients with RR DLBCL. Materials and methods: XPORT-DLBCL-030 is a Phase 2/3, multicenter study. The Phase 2 portion of the study is an open-label randomized study to identify the optimal dose of selinexor (40 or 60 mg) in combination with R-GDP in patients (n=120) with RR DLBCL. Patients ≥18 years with 1-3 prior lines of therapy and ECOG performance status ≤2 who are not intended for HSCT or CAR-T therapy are randomized 1:1:1 to one of 3 treatment arms: Arm 1: selinexor 40 mg+R-GDP (S40+R-GDP); Arm 2: selinexor 60 mg+R-GDP (S60 + R-GDP); Arm 3: R-GDP. Combination treatment will be given for up to 6 cycles (21 days/cycle). After completing the SR-GDP combination therapy (EoC), patients in Arms 1 and 2 who reach at least partial response (PR), will receive weekly single-agent selinexor 60 mg (28 days/cycle) as "continuous therapy" until disease progression (PD) or unacceptable toxicity. After PD, patients will be followed up for survival. Patients in the R-GDP arm will be followed up for PD and survival. Patients who are ineligible for HSCT due to an active disease, or those who have primary refractory DLBCL, defined as no response or relapse within 6 months after ending first-line treatment, will be allowed to enroll in the study (up to 15% and 25%, respectively of all patients enrolled). The primary endpoint of the study is ORR according to the Lugano 2014 criteria. Secondary endpoints include PFS, OS, ORR-EoC, DOR and incidence and severity of adverse events. Figure 1 Figure 1. Disclosures Pinto: Takeda: Consultancy; MSD: Honoraria; Incyte: Honoraria; Roche: Honoraria, Speakers Bureau; Bristol Myers Squibb-CELGENE: Honoraria. Yimer: Texas Oncology: Current Employment; Pharmacyclics: Speakers Bureau; Amgen: Speakers Bureau; Sanofi: Speakers Bureau; GSK: Speakers Bureau; Beigene: Speakers Bureau; Janssen: Speakers Bureau; Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau. Manda: Morphosys: Honoraria; Genmab: Current equity holder in publicly-traded company. Canales: Sanofi: Consultancy; Incyte: Consultancy; Novartis: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; iQone: Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Jurczak: European Medicines Agency, Sandoz-Novartis, Janssen China R&D, BeiGene, Epizyme, Acerta, AstraZeneca: Consultancy; AbbVie, AstraZeneca, Bayer, BeiGene, Celtrion, Celgene, Debbiopharm, Epizyme, Incyte, Janssen, Loxo Oncology, Merck, Mei Pharma, Morphosys, Novo Nordisk, Roche, Sandoz, Takeda, TG Therapeutics, Pharmacyclics, Affirmed, Gilead Sciences, Nordic Nanovecto: Research Funding; Jagiellonian University: Ended employment in the past 24 months; Maria Sklodowska-Curie National Research Institute of Oncology: Current Employment; AstraZeneca, BeiGene, Janssen, Loxo Oncology, Sandoz, Roche: Membership on an entity's Board of Directors or advisory committees. Sureda: Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau; BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau. Ma: Karyopharm Therapeutics Inc.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Li: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Ingalls: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arriola: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arazy: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. 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. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees.

BACKGROUND Filanesib (ARRY-520) is a highly selective inhibitor of kinesin spindle protein, which has demonstrated preclinical antimyeloma activity. METHODS This open-label Phase 1/2 study determined the maximum tolerated dose of Filanesib administered on Days 1 and 2 of 14-Day Cycles in patients with multiple myeloma (MM) and included expansion cohorts with and without dexamethasone (40 mg/week). Patients in the dose-escalation (N = 31) and Phase 2 single-agent (N = 32) cohorts had received prior bortezomib as well as prior thalidomide and/or lenalidomide. Patients in the Phase 2 Filanesib plus dexamethasone cohort (N = 55) had received prior alkylator therapy and had disease refractory to lenalidomide, bortezomib, and dexamethasone. Prophylactic filgrastim was incorporated during dose escalation and was used throughout Phase 2. RESULTS Patients in each cohort had received a median of ≥6 prior therapies. The most common dose-limiting toxicities were febrile neutropenia and mucosal inflammation. In Phase 2, Grade 3 and 4 cytopenias were reported in approximately 50% of patients. Nonhematologic toxicities were infrequent. Phase 2 response rates (partial responses or better) were 16% (single agent) and 15% (Filanesib plus dexamethasone). All responding patients had low baseline levels of α1-acid glycoprotein, a potential selective biomarker. CONCLUSIONS Filanesib 1.50 mg/m2/day administered with prophylactic filgrastim has a manageable safety profile and encouraging activity in heavily pretreated patients This study is registered at www.clinicaltrials.gov as NCT00821249. Cancer 2017. © 2017 American Cancer Society.

Early mortality (EM; death ≤ 6 months from diagnosis) has been reported in several newly diagnosed multiple myeloma (NDMM) trials. Before the era of novel agents, the incidence was 10%-14%. Causes of death included infections/pneumonia, renal failure, refractory disease, and cardiac events. Staging systems, such as the revised International Staging System (r-ISS), and prognostic factors including cytogenetics, lactate dehydrogenase levels, and myeloma-specific factors, are useful to assess overall prognosis; however, they cannot predict EM. We evaluated patients treated with novel agents in the Connect MM® Registry and identified risk factors of the EM cohort. Eligible patients were enrolled in the registry within 60 days of diagnosis. Univariate and multivariate analyses were conducted to evaluate associations between baseline characteristics and EM. Prediction matrices for EM were constructed from a logistic model. Between September 2009 and December 2011, 1493 patients were enrolled in the registry and had adequate follow-up. Of these patients, 102 (6.8%) had EM and 1391 (93.2%) survived for > 180 days. Baseline factors significantly associated with increased EM risk included age > 75 years, higher Eastern Cooperative Oncology Group performance status, lower EQ-5D mobility score, higher ISS stage, lower platelet count, and prior hypertension. Renal insufficiency trended toward increased EM risk. These risk factors were incorporated into a prediction matrix for EM. The EM prediction matrix uses differential weighting of risk factors to calculate EM risk in patients with NDMM. Identifying patients at risk for EM may provide new opportunities to implement patient-specific treatment strategies to improve outcomes.

High dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT) are the standard of care for eligible patients with newly diagnosed myeloma [1]. Unfortunately, relapse rate...

Introduction: Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) that blocks XPO1, forcing the nuclear retention and re-activation of tumor suppressor proteins including p53, p73, FOXO, I□B and Rb. The phase 2b SADAL study included 134 patients with relapsed or refractory DLBCL with single agent oral selinexor twice weekly. The overall response rate (ORR) was 29.1%, median duration of response (DOR) was 9.3 months and the median overall survival (OS) was 9 months. Based on these data, selinexor was recently approved by the US FDA for the treatment of relapsed or refractory DLBCL, de novo or transformed from follicular lymphoma. Patients with DLBCL tend to be older (over the age of 65) and have a number of comorbidities, which limits the use of aggressive and multi-agent combination therapies. We performed post-hoc analyses of the SADAL study to determine the effects of age on the efficacy and safety of selinexor in this population. Methods: The SADAL study is multi-center, open-label Phase 2b study that enrolled patients with DLBCL previously treated with 2-5 lines of therapy. Patients may have progressed post-stem cell therapy (SCT) or were not candidates for SCT. In this study, 60 mg of selinexor was administered twice weekly until disease progression. The primary endpoint was ORR, and other endpoints included DOR, OS, and safety assessments. For the current analysis, outcomes were assessed in patients Results: Of the 134 patients enrolled in the study, 52 (39%) were 65 (3.8% vs. 11.0%). Conclusions: Patients with relapsed/refractory DLBCL who were ≥65 years had a similar clinical benefit to those Disclosures Schuster: Amgen, Abbvie, Gilead, Takeda, Celgene, Pharmacyclics, Astellas, Verastem, Merck, Novartis, Takeda, Genentech,, Seattle Genetics: Other: Personal Fees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Canales:Janssen: Honoraria; Roche: Speakers Bureau; Gilead: Honoraria; Sandoz: Honoraria; Janssen: Speakers Bureau; Sandoz: Speakers Bureau; Roche: Speakers Bureau; Novartis: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Sandoz: Honoraria; Roche: Honoraria; Takeda: Speakers Bureau; Novartis: Honoraria; Sandoz: Speakers Bureau; iQone: Honoraria; Karyopharm: Honoraria; Takeda: Speakers Bureau; Roche: Honoraria; Janssen: Speakers Bureau. Westin:Genentech: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Curis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; 47: Research Funding; Amgen: Consultancy; Janssen: Consultancy, Research Funding. Zijlstra:Roche: Research Funding. Follows:Karyopharm, Roche, Abbvie, Astrazeneca, Janssen, BMS: Membership on an entity's Board of Directors or advisory committees. Karmali:Takeda: Research Funding; Karyopharm: Honoraria; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Kalakonda:Verastem, Gilead, Celgene, Roche: Research Funding; Gilead, Janssen, Karyopharm: Honoraria. Goy:Constellation: Research Funding; Regional Cancer Care Associates/OMI: Current Employment; COTA: Consultancy, Current equity holder in publicly-traded company, Other: leadership role; Infinity: Research Funding; Karyopharm: Research Funding; PracticeUpdate Oncology: Consultancy; MD Anderson: Research Funding; AbbVie: Research Funding; Acerta: Consultancy, Honoraria, Other: leadership role, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: leadership role, Research Funding; Xcenda: Consultancy; Infinity Verastem: Research Funding; RCCA/OMI: Current Employment; Morphosys: Research Funding; Genentech/Roche: Research Funding; Hackensack UMC and University of Nebraska: Research Funding; Bayer: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: leadership role, Research Funding; Kite, a Gilead Company: Consultancy, Current equity holder in publicly-traded company, Honoraria, Other: leadership role, Research Funding; CALBG: Research Funding. Casasnovas:Roche: Consultancy, Honoraria, Other: travel, accomodations, expenses, Research Funding; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Takeda: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Abbvie: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Thieblemont:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Speakers Bureau; Bristol-Myers Squibb: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Hospira: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Incyte: Honoraria; Bayer: Honoraria; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support. Cavallo:Gilead: Other: Speaker Fee; Takeda, Janssen: Membership on an entity's Board of Directors or advisory committees. Hill:Pharmacyclics: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding. Tilly:BMS: Honoraria. Jaeger:Novartis: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Karyopharm: Honoraria; CDR Life AG: Consultancy, Research Funding; Miltenyi: Consultancy, Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria. Gurion:JC Health CARE: Consultancy, Honoraria; Medison: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Takeda Pharmaceuticals: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Caimi:Celgene Corp: Other: Incyte Corporation - Ownership - Pharmacyclics, Inc. - Ownership - Celgene Corp. - Other, Speakers Bureau; ADC Therapeutics: Research Funding; Genentech: Research Funding. Martin:Janssen: Consultancy; Regeneron: Consultancy; Teneobio: Consultancy; Celgene: Consultancy; Sandoz: Consultancy; I-MAB: Consultancy; Bayer: Consultancy; Beigene: Consultancy; Cellectar: Consultancy; Incyte: Consultancy; Kite: Consultancy; Morphosys: Consultancy; Karyopharm: Consultancy, Research Funding. Davies:Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding; Celegene, Roche, Kite Pharma, Celegene: Honoraria. Smith:TG Therapeutics: Consultancy, Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding; FortySeven: Research Funding; Karyopharm: Consultancy, Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; Celgene: Consultancy, Research Funding; BMS: Consultancy; Janssen: Consultancy. Collins:Amgen: Research Funding; Pfizer: Honoraria; Celgene: Research Funding; Celleron: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodations, expenses , Speakers Bureau; Taekda: Consultancy, Honoraria, Other: travel, accommodations, expenses, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau. Salles:Abbvie: Consultancy, Honoraria, Other: Participation in educational events; Novartis: Consultancy, Honoraria, Other; MorphoSys: Consultancy, Honoraria, Other; Debiopharm: Consultancy; Genmab: Consultancy; Karyopharm: Consultancy; Amgen: Honoraria, Other: Participation in educational events; Kite: Consultancy, Honoraria, Other; Epizyme: Consultancy; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Other; Takeda: Consultancy, Honoraria, Other; Bristol Myers Squibb: Consultancy, Other; Autolus: Consultancy; Gilead: Consultancy, Honoraria, Other: Participation in educational events; Janssen: Consultancy, Honoraria, Other: Participation in educational events; Celgene: Consultancy, Honoraria, Other: Participation in educational events. Ma:Karyopharm: Current Employment, Current equity holder in private company. Corona:Karyopharm: Current Employment. Saint-Martin:Karyopharm: Current Employment. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chamoun:Karyopharm: Current Employment. Wang:Curis: Ended employment in the past 24 months; Karyopharm: Current Employment. Shah:Karyopharm: 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.

Background: Lenalidomide (LEN) monotherapy has been effective in extending progression free survival (PFS) after AuSCT in pts with MM. Elotuzumab (ELO), a humanized IgG1 immunostimulatory monoclonal antibody against signaling lymphocytic activation molecule F7 (SLAM F7), is FDA approved in combination with LEN and dexamethasone (DEX) for treatment of MM pts who have received 1-3 prior therapies. We report updated results of this phase 2 trial evaluating the efficacy and safety of adding ELO to LEN as maintenance therapy post- AuSCT. Patients and Methods: Between 4/15/2015-1/27/2016, 27 evaluable pts were treated on 28 day cycles with ELO, 10 mg/kg iv weekly for cycles 1-2, q2weeks for cycles 3-6, then 20 mg/kg once monthly for cycles 7+. Pts enrolled after 1/28/2016 (n=73 pts) have received ELO, 10 mg/kg IV weekly for cycles 1-2, and 20 mg/kg on day 1 from cycle 3 until disease progression (PD). LEN has been dosed at 10 mg/day for cycles 1-3, with a dose increase to 15 mg/day at physician discretion starting with cycle 4, in the absence of non-hematologic toxicity > grade 1 and significant cytopenias (ANC < 1000/mL, platelet count < 100,000/ml). For the 1st 8 weeks, pts The study's primary endpoint is PFS, defined as time from AuSCT to PD or death (whichever occurs first), or censored at date of last contact. Secondary objectives are best response, OS, incidence of second primary malignancies (SPMs) and adverse event (AE) profile. Total enrollment of 100 evaluable pts was completed on 6/5/2019. Patients are followed until death, withdrawal of consent or removal from study. Eligible pts received ≤2 lines of induction therapy, and were 60-210 days post-AuSCT. Results: Pts (n=100) have been treated for a median of 27.5 cycles (4-67). At study entry, 37 (37%) had complete response (CR), 40 (40%) very good partial response (VGPR), 22 (22%) partial response (PR) and 1 (1%) minor response (MR). Best response achieved to date on study is CR in 61 pts (61%), VGPR in 29 pts (29%) and PR in 10 pts (10%). Median time for conversion to CR on study is 1 month. Of pts in CR and tested for minimal residual disease (MRD) to date, 42/48 are negative (flow cytometry on ≥ 2 x106 cells). Eleven of 42 have converted from VGPR to MRD negative CR while on study. With a median follow up of 41 months, 90% of pts (n=90) remain alive. Eighteen pts have had PD; of these, 10 had high-risk cytogenetics. Three died of PD while receiving salvage therapy, 1 of pneumonia, 4 of second malignancies and 1 of unknown cause at another facility. One additional pt died on study in VGPR, after developing acute cerebral encephalopathy with refractory status epilepticus of unclear etiology. Estimated 4 year PFS is 75%. High-risk cytogenetics (n =31) adversely affected PFS (p=0.01); 14/31 pts remain on study. Of 23 pts transitioned to another therapy, median 2nd PFS has not been reached. Grade 3-4 Hematologic AEs (no. of pts/102 pts) were: neutropenia 32% (33), febrile neutropenia 15% (15), thrombocytopenia 7% (7), and anemia 10% (10). Grade 3-4 non-Hematologic AEs (no. of pts): hypophosphatemia 29% (30), respiratory infections 21% (21), diarrhea 15% (15), fatigue 12% (12), peripheral neuropathy 8% (8), other infections 7% (7), myalgias 5% (5), dyspnea 5% (5). SPMs include cutaneous basal and squamous cell carcinomas (8), AML (1), B-cell ALL (1), t-MDS (4), osteosarcoma (1), intra-epidermal adenocarcinoma of the neck (1), mucinous appendiceal neoplasm (1), mucinous epidermoid carcinoma of parotid (1), prostate cancer (1). Renal cell carcinoma was diagnosed in 1 pt, 15 months after removal from study for PD. Conclusions: Lenalidomide-elotuzumab is a well-tolerated maintenance therapy on which 38% of pts have had improvement in quality of response while on therapy, including 27% who converted to CR. SPM rates seem consistent with those observed in CALGB 100104 and IFM 2005-02 trials of lenalidomide alone. Longer follow up is required to determine how median PFS and OS will compare with those from lenalidomide monotherapy trials, and how SPM rates will continue to evolve. Table 1 Disclosures Thomas: X4 Pharma: Research Funding; Ascentage: Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Research Funding; Xencor: Research Funding; Pharmacyclics: Other: Advisory Boards; Genentech: Research Funding. Shah:Karyopharm: Current Employment, Current equity holder in publicly-traded company. Lee:Regeneron: Research Funding; Daiichi Sankyo: Research Funding; Sanofi: Consultancy; GlaxoSmithKline: Consultancy, Research Funding; Genentech: Consultancy; Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Genentech: Consultancy. Manasanch:JW Pharma: Research Funding; Merck: Research Funding; Quest Diagnostics: Research Funding; Takeda: Honoraria; BMS: Honoraria; Glaxo Smith Kline: Honoraria; Adaptive Biotechnologies: Honoraria; Novartis: Research Funding; Sanofi: Honoraria, Research Funding. Patel:Oncopeptides: Consultancy; Takeda: Consultancy, Research Funding; Cellectis: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Nektar: Consultancy, Research Funding; Precision Biosciences: Research Funding; Poseida: Research Funding. Kaufman:Bristol Myers Squibb: Research Funding; Karyopharm: Honoraria; Janssen: Research Funding. Iyer:Trillium: Research Funding; Daiichi Sankyo: Consultancy; Legend Biotech: Consultancy; Merck: Research Funding; Rhizen: Research Funding; Seattle Genetics, Inc.: Research Funding; Target Oncology: Honoraria; Afffimed: Research Funding; CRISPR: Research Funding; Spectrum: Research Funding; Curio Biosciences: Honoraria. Qazilbash:Angiocrine: Research Funding; Bioclinica: Consultancy; Janssen: Research Funding; Bioline: Research Funding; Amgen: Research Funding. Bashir:Amgen: Other: Advisory Board; Purdue: Other: Advisory Board; Takeda: Other: Advisory Board, Research Funding; Acrotech: Research Funding; StemLine: Research Funding; Celgene: Research Funding; KITE: Other: Advisory Board. Orlowski: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; 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; Sanofi-Aventis, Servier, Takeda Pharmaceuticals North America, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; 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. OffLabel Disclosure: Elotuzumab (ELO), a humanized IgG1 immunostimulatory monoclonal antibody against SLAM F7. It is FDA approved in combination with Lenalidomide and dexamethasone (DEX) for treatment of MM pts who have received 1-3 prior therapies. This is a phase 2 trial evaluating the efficacy and safety of adding ELO to LEN as maintenance therapy post-autologous stem cell transplant.

Introduction: Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) that blocks XPO1, forcing the nuclear retention and re-activation of tumor suppressor proteins including p53, p73, FOXO, IkB and Rb. The phase 2b SADAL study included 134 patients with relapsed or refractory DLBCL with single agent oral selinexor twice weekly. The overall response rate (ORR) was 29.1%, median duration of response (DOR) was 9.3 months and the median overall survival (OS) was 9 months. Based on these data, selinexor was recently approved by the US FDA for the treatment of relapsed or refractory DLBCL, de novo or transformed from follicular lymphoma. Patients with DLBCL tend to have a number of comorbidities, including poor renal function, which can require a reduction in the dose of intensive chemotherapy as well as lenalidomide, leading to inferior outcomes. Selinexor is not metabolized nor cleared by the kidneys and has been demonstrated to be safe and active in patients with myeloma and renal dysfunction. We performed post-hoc analyses of the SADAL study to determine the efficacy and safety among patients stratified by renal function at baseline. Methods: The SADAL study is multi-center, open-label Phase 2b study that enrolled patients with DLBCL previously treated with 2-5 lines of therapy. Patients may have progressed post-stem cell therapy (SCT) or were not candidates for SCT. In this study, 60 mg of selinexor was administered twice weekly until disease progression. The primary endpoint was ORR, and other endpoints included DOR, OS, and safety assessments. For the current analysis, outcomes were assessed according to baseline renal function as estimated by the Cockroft-Gault formula for creatinine clearance (CrCl). Groups included those with reduced (CrCl ≤60 mL/min) and normal (CrCl >60 mL/min) renal function. Results: Of 134 patients, 37 (28%) had a reduced baseline CrCl (≤60 mL/min) while 97 (72%) had CrCl >60 mL/min. The median age of patients with reduced CrCl was 74 years with 70% ≥70 years, while the median for those with normal CrCl was 65 years, with 35% ≥70 years. De novo and transformed DLBCL showed similar renal function levels: 78% and 22% with reduced CrCl and 76% and 24% with normal CrCl. Of patients with reduced CrCl, the DLBCL subtype was 41% GCB and 57% non-GCB compared to 50% and 46% in patients with normal CrCl. The group of patients with reduced CrCl had baseline ECOG performance status of 2 in 16% vs 11% in those with normal CrCl. Treatment with selinexor demonstrated a similar ORR in patients with a baseline reduced CrCl (29.7%) versus normal CrCl (28.9%). A complete response (CR) was observed in 8 (21.6%) patients with reduced and 10 (10.3%) patients with normal CrCl. The median duration of response (DOR) in patients who had reduced CrCl was 23.0 months compared to 9.2 months in patients with normal CrCl. The median progression-free survival (PFS) was 3.5 months (95% CI 1.7, 24.8) and 2.3 months (95% CI 1.9, 3.7) and overall survival was 7.8 months and 9.1 months in patients with reduced CrCl and those with normal CrCl. The most common grade ≥3 treatment-related AEs for patients with reduced versus normal CrCl were thrombocytopenia (45.9% vs. 38.1%), nausea (5.4% vs. 6.2%), and fatigue (8.1% vs. 11.3%). There was no clinically significant increase in treatment-related serious adverse events (21.6% vs. 20.6%) and adverse events leading to discontinuation (10.8% vs. 7.2%) in patients with reduced or normal CrCl, respectively. Conclusions: Selinexor showed similar anti-DLBCL activity and tolerability in patients with relapsed/refractory DLBCL with a reduced renal function (CrCl Disclosures Schuster: Amgen, Abbvie, Gilead, Takeda, Celgene, Pharmacyclics, Astellas, Verastem, Merck, Novartis, Takeda, Genentech,, Seattle Genetics: Other: Personal Fees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Canales:Novartis: Honoraria; Janssen: Honoraria; Novartis: Honoraria; iQone: Honoraria; Sandoz: Speakers Bureau; Karyopharm: Honoraria; Janssen: Speakers Bureau; Janssen: Honoraria; Roche: Speakers Bureau; Takeda: Speakers Bureau; Janssen: Speakers Bureau; Roche: Speakers Bureau; Sandoz: Speakers Bureau; Takeda: Speakers Bureau; Celgene: Honoraria; Roche: Honoraria; Sandoz: Honoraria; Sandoz: Honoraria; Gilead: Honoraria; Roche: Honoraria; Karyopharm: Honoraria. Westin:Novartis: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Curis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; Amgen: Consultancy; 47: Research Funding. Zijlstra:Roche: Research Funding. Follows:Karyopharm, Roche, Abbvie, Astrazeneca, Janssen, BMS: Membership on an entity's Board of Directors or advisory committees. Karmali:Takeda: Research Funding; AstraZeneca: Speakers Bureau; Karyopharm: Honoraria; BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Kalakonda:Gilead, Janssen, Karyopharm: Honoraria; Verastem, Gilead, Celgene, Roche: Research Funding. Goy:AbbVie: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: leadership role, Research Funding; Acerta: Consultancy, Honoraria, Other: leadership role, Research Funding; MD Anderson: Research Funding; Xcenda: Consultancy; Kite, a Gilead Company: Consultancy, Current equity holder in publicly-traded company, Honoraria, Other: leadership role, Research Funding; Regional Cancer Care Associates/OMI: Current Employment; Bayer: Research Funding; PracticeUpdate Oncology: Consultancy; RCCA/OMI: Current Employment; Morphosys: Research Funding; Karyopharm: Research Funding; Genentech/Roche: Research Funding; Constellation: Research Funding; CALBG: Research Funding; Infinity Verastem: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: leadership role, Research Funding; COTA: Consultancy, Current equity holder in publicly-traded company, Other: leadership role; Hackensack UMC and University of Nebraska: Research Funding; Infinity: Research Funding. Casasnovas:Takeda: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Roche: Consultancy, Honoraria, Other: travel, accomodations, expenses, Research Funding; Abbvie: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Thieblemont:Cellectis: Speakers Bureau; Roche, Amgen, Kyte Gilead, Celgene, Abbvie, Novartis, Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche, Hospita: Research Funding. Cavallo:Takeda, Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Other: Speaker Fee. Hill:Celgene: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Takeda: Research Funding. Tilly:BMS: Honoraria. Jaeger:Novartis: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Karyopharm: Honoraria; AbbVie: Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding; Miltenyi: Consultancy, Honoraria; CDR Life AG: Consultancy, Research Funding. Gurion:JC Health CARE: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda Pharmaceuticals: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Medison: Consultancy, Honoraria. Caimi:Celgene Corp: Other: Incyte Corporation - Ownership - Pharmacyclics, Inc. - Ownership - Celgene Corp. - Other, Speakers Bureau; ADC Therapeutics: Research Funding; Genentech: Research Funding. Martin:Kite: Consultancy; Morphosys: Consultancy; I-MAB: Consultancy; Janssen: Consultancy; Sandoz: Consultancy; Regeneron: Consultancy; Incyte: Consultancy; Karyopharm: Consultancy, Research Funding; Teneobio: Consultancy; Celgene: Consultancy; Bayer: Consultancy; Cellectar: Consultancy; Beigene: Consultancy. Davies:Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celegene, Roche, Kite Pharma, Celegene: Honoraria. Smith:TG Therapeutics: Consultancy, Research Funding; Janssen: Consultancy; Celgene: Consultancy, Research Funding; BMS: Consultancy; Karyopharm: Consultancy, Research Funding; FortySeven: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding. Collins:BeiGene: Consultancy; MSD: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau; Taekda: Consultancy, Honoraria, Other: travel, accommodations, expenses, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria; ADC Therapeutics: Consultancy, Honoraria; Celleron: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Speakers Bureau; Celgene: Research Funding; Roche: Consultancy, Honoraria, Other: travel, accommodations, expenses , Speakers Bureau; Amgen: Research Funding. Salles:Epizyme: Consultancy; Gilead: Consultancy, Honoraria, Other: Participation in educational events; Abbvie: Consultancy, Honoraria, Other: Participation in educational events; Janssen: Consultancy, Honoraria, Other: Participation in educational events; Kite: Consultancy, Honoraria, Other; Debiopharm: Consultancy; Celgene: Consultancy, Honoraria, Other: Participation in educational events; Karyopharm: Consultancy; Genmab: Consultancy; Amgen: Honoraria, Other: Participation in educational events; Autolus: Consultancy; MorphoSys: Consultancy, Honoraria, Other; Novartis: Consultancy, Honoraria, Other; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Other; Bristol Myers Squibb: Consultancy, Other; Takeda: Consultancy, Honoraria, Other. Ma:Karyopharm: Current Employment, Current equity holder in private company. Corona:Karyopharm: Current Employment. Saint-Martin:Karyopharm: Current Employment. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chamoun:Karyopharm: Current Employment. Wang:Curis: Ended employment in the past 24 months; Karyopharm: Current Employment. Shah:Karyopharm: 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.

The gain/amplification of the CKS1B gene on chromosome 1q21 region is associated with a poor outcome in patients with multiple myeloma (MM). However, there are limited data on the outcome of patients with CKS1B amplification after a single high-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT). We retrospectively evaluated the outcome of patients with CKS1B amplification who received an auto-HCT between June 2012 and July 2014 at our institution. We identified 58 patients with MM and CKS1B gene amplification detected by fluorescent in situ hybridization (FISH). We compared their outcomes with a propensity score–matched control group of 58 patients without CKS1B amplification who were treated at approximately the same time. The primary objective was to compare the progression-free (PFS) and overall survival (OS) between the CKS1B and the control groups. Stratified log-rank test with the matched pairs as strata and double robust estimation under the Cox model were used to assess the effect of CKS1B gene amplification on PFS or OS in the matched cohort. Patients in the CKS1B and control groups were well matched for age, gender, disease status, year of auto-HCT, response to pretransplantation therapy, and baseline hemoglobin level. In both groups, 57% patients were in first remission and 43% had relapsed disease at auto-HCT. Twenty-seven (47%) patients with CKS1B amplification had concurrent monosomy 13 or 13q deletion; 6 (10%) by conventional cytogenetics only, 16 (28%) by FISH only, and 5 (9%) by both. Median follow-up after auto-HCT was 25.4 months. The median PFS of the CKS1B and the control groups were 15.0 months and 33.0 months (P = .002), respectively. The median OS have not been reached yet. The 2-year OS rates in the CKS1B and the control groups were 62% and 91% (P = .02), respectively. In conclusion, Patients with CKS1B amplification are more likely to have additional high-risk cytogenetic abnormalities and a shorter PFS and OS after an auto-HCT.

5565 Background: Selinexor is a first-in-class novel, oral potent selective inhibitor of nuclear export (SINE) which blocks Exportin-1 (XPO1) leading to nuclear accumulation and activation of tumor suppressor proteins and prevention of translation of proto-oncogenes. Weekly paclitaxel is a standard chemotherapy regimen used in various tumor types. Preclinical models show that selinexor with paclitaxel exerts antitumor activity against multiple solid tumors. Our objective was to determine the maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of selinexor and weekly paclitaxel. Methods: This was an open label, single-center, multi-arm phase 1b study utilizing a “3 + 3” design and a “basket type” expansion. Selinexor (twice weekly orally) and weekly paclitaxel (80mg IV 2 week on, 1 week off) was employed as one of 13 parallel arms. Two dose levels (DL) of selinexor were explored: DL1 selinexor 60mg; DL2 selinexor 80mg. Patients (pts) with advanced or metastatic solid tumors were eligible if they had adequate bone marrow and organ function. There was no limit on prior lines of therapy. Efficacy was evaluated using RECIST 1.1. Progression free survival (PFS) was defined as time from treatment until disease progression or death. Results: Of 35 pts treated, all were evaluable for toxicity, and 31 (88%) were evaluable for response. Pt diagnoses included ovarian (n = 28), breast (n = 4), prostate (n = 2), and cervical (n = 1) cancer. Pts had a median of four prior therapies (range 1-10), and 47% had a prior taxane. All pts with ovarian cancer had platinum resistant/refractory disease; high grade serous histology was most common. There were no DLTs and DL1 was chosen as the RP2D given its long term tolerability. 97% of pts had at least one treatment-emergent adverse event (TEAE) and the most common TEAEs were anemia (74%), nausea (57%), fatigue (51%), leukopenia (51%), neutropenia (49%), thrombocytopenia (46%), and vomiting (31%). The most prevalent grade ≥ 3 TEAE were neutropenia (46%), anemia (31%), leukopenia (17%), and fatigue (9 %). Partial responses (PR) were noted in 4 pts (13%); 10 pts (32%) achieved stable disease for > 4 months for a clinical benefit rate (CBR) of 45%. 16 pts (47%) had prior exposure to a taxane, including 1 pt who achieved PR. Among 24 evaluable pts with ovarian cancer, response rate was 17%, CBR was 58%, and PFS was 6.83 months (95% CI 3.73, not reached (NR)). Median duration of clinical benefit in ovarian cancer was 7.57 months (95% CI: 4.43, NR). Conclusions: Oral selinexor in combination with weekly paclitaxel demonstrated promising clinical activity with manageable toxicity, and further evaluation with once weekly selinexor is warranted. This combination should be considered for further exploration in a randomized study, especially in ovarian malignancies. Clinical trial information: NCT02419495.

11509 Background: Patients (pts) with recurrent inoperative DDLS have a poor prognosis and limited treatment options. Selinexor is an oral, selective inhibitor of nuclear export (SINE) compound approved for previously treated pts with myeloma and diffuse large B-cell lymphoma. SEAL was a Phase 2-3 randomized, double-blind, study of selinexor versus placebo in pts with progressive DDLS and 2-5 prior systemic therapies. SEAL showed significantly prolonged progression-free survival (PFS, HR = 0.70, p = 0.0228) with well managed toxicity. A biomarker predictive of clinical activity could be used to optimize selection of pts with DDLS for selinexor. Methods: Pts were randomized 2:1 for Phase 3: 188 received twice weekly selinexor (60mg) and 97 received placebo. Three exploratory biomarker analyses (RNA sequencing of biopsies) from selinexor-treated pts were performed: discovery set of sensitive (n = 8) or resistant (n = 9) tumors; a validation set of pts with favorable (n = 19) or poor (n = 14) tumor control based on PFS, and paired lesions from a pt who harbored both a responsive and resistant lesion. Tumor biopsies from 24 pts on placebo with short ( < 5 months, n = 18) and long ( > 6 months, n = 6) PFS were RNA sequenced. Gene expressions were compared using a negative binomial distribution with DeSeq2. Pathway analyses were performed using Gene Set Enrichment Analysis (GSEA) with MSigDB Cancer Gene Neighborhoods. Results: RNA sequencing analysis comparing 17 sensitive and resistant tumors identified 114 differentially expressed genes (adjusted p-values < 0.05). Expression of CALB1, which encodes the calcium-binding protein calbindin, was significantly lower in sensitive tumors (adjusted P [Padj] = 7.5x10-20), and expression of GRM1, which encodes a metabotropic glutamate receptor that activates phospholipase C, was higher in selinexor sensitive tumors (Padj= 0.003). These findings were confirmed in an independent validation set (Padj = 0.01 – 0.02). In the pt with paired sensitive and resistant lesions, CALB1 expression was 52-fold lower in the sensitive tumor. In a comparison of placebo-treated pts, neither CALB1 or GRM1 was differentially expressed between pts with short or long PFS, indicating they are markers of response to selinexor treatment, rather than general markers of disease aggressiveness. Gene set enrichment analyses revealed that selinexor sensitive tumors in the discovery and validation sets showed upregulation of cancer genes related to SNRK and the netrin 1 receptor tumor suppressor DCC. The resistant tumors showed upregulated EIF3S2 translation initiator-related genes. Conclusions: Selinexor sensitive DDLS tumors showed low expression of CALB1 and high GRM1. If validated, pts with DDLS whose tumors match this expression profile are especially likely to benefit from selinexor. Clinical trial information: NCT02606461.

TPS5610 Background: Endometrial cancer (EC) is the most common gynecologic malignancy. Options for advanced or recurrent EC following platinum-based therapy and/or radiotherapy are limited and prognosis remains poor. Selinexor is a novel, oral selective inhibitor of nuclear export (SINE) which forces nuclear retention and activation of tumor suppressor proteins. Selinexor in combination with low dose dexamethasone is approved for relapsed/refractory multiple myeloma. In addition, selinexor monotherapy has demonstrated broad activity in other hematologic malignancies and solid tumors. In a phase 2 study, 50 mg/m2 (̃80 mg) selinexor administered twice weekly demonstrated a disease control rate ( SD ≥ 12 weeks or a PR) of 35% with 2 confirmed partial responses among 23 heavily pretreated EC patients); similar results were observed in 60 pts with platinum resistant or refractory ovarian cancer (median 5 prior regimens, ORR 8%, DCR 30%) (Vergote I et al. Gynecol Oncol 2020). In the absence of approved maintenance therapies, we conducted this study to evaluate the efficacy of selinexor compared with placebo as maintenance therapy in patients with advanced or recurrent EC following platinum-based chemotherapy. Methods: This is a multicenter, double-blind, placebo-controlled, randomized phase 3 study in patients in partial (PR) or complete remission (CR) after completing at least 12 weeks of taxane-platinum combination therapy for primary Stage IV disease and recurrent disease (i.e., relapse after primary therapy for early stage disease including surgery and/or adjuvant therapy). A total of 248 patients will be enrolled at 80 sites in Europe, North America, and Israel. Patients will be randomized in a 2:1 ratio to either maintenance therapy with 80 mg oral selinexor once weekly or placebo. Stratification factors include primary Stage IV versus first recurrence at the time of taxane-platinum therapy and disease status after chemotherapy (PR vs CR). Treatment will continue until disease progression. The primary endpoint is progression free survival (PFS) per RECIST v1.1. Secondary endpoints include disease-specific survival, overall survival, time to first subsequent therapy, time to second subsequent therapy, PFS on subsequent therapy and safety and tolerability. The study is currently open and enrolling patients. Clinical trial information: NCT03555422.

e19037 Background: Patients (pts) with myelodysplastic syndrome (MDS) refractory to hypomethylating agents (HMAs) have limited therapeutic options and a dismal prognosis with a median overall survival (mOS) of 4-6 months. Eltanexor (ELTA) is a second-generation, oral, selective inhibitor of nuclear export (SINE) compound that showed anti-tumor activity and lower brain penetration compared to selinexor (SEL) in nonclinical models. It was hypothesized that ELTA could be dosed more frequently than SEL with a lower incidence of centrally mediated nausea. Early results from a phase 1/2 study of ELTA in pts with HMA refractory MDS showed anti-tumor activity with marrow complete response (mCR) and stable disease (SD); side effects were primarily low-grade, dose-dependent, and reversible (Lee et al. ASH 2019). In this abstract, we provide a subgroup analysis of the efficacy evaluable population with an update on mOS in the same population. Methods: This phase 1/2 study (NCT02649790) evaluated single-agent ELTA in pts with higher-risk MDS, ie, high-risk or intermediate-2 MDS by International Prognostic Scoring System (IPSS) and 5%-19% myeloblasts. Out of 20 pts enrolled, 15 pts were evaluable for efficacy and constitute the population studied in this analysis. Two doses of ELTA were evaluated: 10 mg (n=5) or 20 mg (n=15) every day for 5 days per week of a 28-day cycle. Results: As of 1 Feb 2021, the 15 pts evaluable for efficacy (median age 76 years; range 62-89) had a median of 2 prior treatment regimens (range 1-4); 93% had high/int-2 risk per IPSS. Of the 20 enrolled patients, 7 (35%) had mCR, and 5 (25%) had SD for a total disease control (mCR+SD) rate of 60%. Of the 15 pts evaluable for efficacy, 7 (47%) had mCR and 5 (33%) had SD. In the 10-mg cohort (n=5), all pts derived clinical benefit with 3 pts (60%) reaching mCR and 2 pts (40%) SD. In the 20-mg cohort (n=10), 4 pts (40%) had mCR and 3 (30%) had SD. Four pts had hematologic improvement (HI) and became transfusion independent for at least 8 weeks including 2 pts with tri-lineage HI. OS for pts who reached mCR (n=7) was significantly longer than for pts who did not reach mCR (n=8): median 11.86 vs 8.67 months (mo) (hazard ratio [HR]=0.27, p=0.05), and significantly longer than OS for pts with PD (n=3, mOS=3.15 mo, HR=0.23, p=0.04). Pts with disease control (n=12) had numerically longer mOS than pts with PD (9.86 vs 3.15 mo, HR=0.38, p=0.09). Pts with HI had a mOS of 10.58 months. Conclusions: Single-agent oral ELTA was active in pts with high-risk, HMA refractory MDS. Pts with mCR had significantly longer mOS than pts without mCR or with PD. Further evaluation of ELTA in MDS as a single agent and in combination with other agents is ongoing. Clinical trial information: NCT02649790.

2016 Background: Among the primary aims of new therapies for glioblastoma (GBM) are the reduction of morbidity and restoration or preservation of quality of life (QoL). Selinexor (SEL) is a first-in class, oral, selective inhibitor of nuclear export which blocks exportin 1 (XPO1), forcing the nuclear retention and reactivation of tumor suppressor proteins, ultimately causing cell death in cancer cells. SEL is approved for the treatment of previously treated multiple myeloma and DLBCL. XPORT-GBM-029 (NCT04421378) is a phase 1 dose finding study followed by an open-label randomized phase 2, 3-arm trial to evaluate SEL in combination with standard therapies for newly diagnosed and recurrent GBM: Arm A (ndGBM, uMGMT) – radiation +/- SEL; Arm B (ndGBM, mMGMT) – radiation and temozolomide +/- SEL; Arm C (rGBM) – lomustine +/- SEL at first relapse. We look to identify sensitive, reliable, and clinically meaningful digital assessments of the functional status of ndGBM and rGBM patients via a patient-centric approach. Methods: XPORT-GBM-029 incorporates standard clinical and imaging evaluations of GBM progression with novel digital tools that objectively measure motor and cognitive function. The study is conducted at 50 sites globally with the aim of enrolling 350 patients with newly diagnosed and recurrent GBM. Following discussions with KOLs and patient advocacy partners at EndbrainCancer, we surveyed GBM patients and their caregivers to identify disease manifestations critical to patients’ QoL. The survey revealed four key areas impacting patients’ QoL that can be affected by GBM therapies and can be objectively monitored: cognitive function, lateralization, fatigue, and sleep. In this trial we use objective measurements to evaluate SEL’s effects on GBM patients’ QoL. Patients wear inertial sensors to measure their activity and sleep and complete a cognitive battery at baseline and before each MRI. Results: Associations between objective digital measures of activity, gait, fatigue, sleep, and cognition will be examined with respect to clinical assessments including physical examinations, modified Response Assessment in Neuro-Oncology (mRANO), Neurologic Assessment in Neuro-Oncology (NANO), Karnofsky Performance Score (KPS) and Patient Reported Outcome (PRO) QoL questionnaires. Descriptive summary statistics and plots are employed in exploratory data analysis, and other advanced data mining methods may also be considered. Conclusions: XPORT-GBM-029 trial is probably the first large, prospective, longitudinal study in GBM patients employing digital markers and may provide useful information regarding the utility of wearable and mobile devices for measuring functional outcomes in clinical trials. Clinical trial information: NCT04421378.

8024 Background: Lenalidomide (LEN) is typically a frontline therapy for newly diagnosed MM. Patients (pts) with MM refractory to LEN are less likely to repond to other IMiDs and represent a signification area of unmet medical need. In the BOSTON study in the ITT population, XVd was associated with significant improvements in median progression-free survival (PFS), overall response rate (ORR), and rates of peripheral neuropathy, with trends in overall survival (OS) favoring XVd. Methods: The BOSTON trial (NCT03110562) is a Phase 3 randomized, controlled, open-label study of once weekly XVd vs twice weekly Vd in pts with MM and 1-3 prior therapies. We performed post-hoc analyses on two different subgroups to compare outcomes based on refractory status to LEN and immunomodulatory drug (IMiD) therapy. These post hoc analyses evaluated if PFS, overall response rate (ORR), time to next treatment (TTNT) and safety was influenced by prior treatment with LEN when comparing XVd with Vd. Results: Amongst the 402 pts in BOSTON, 160 had MM refractory to any IMiD (XVd = 74, Vd = 86). Of those, 106 were documented to be refractory to LEN (XVd = 53, Vd = 53) and 296 were not refractory to LEN (XVd = 142, Vd = 154). Baseline characteristics were generally well balanced between subgroups. In these subgroups based on refractory status to IMiD or LEN, median PFS was significantly longer in the XVd arm as compared to Vd (IMiD refractory, 13.9 vs. 8.4 months (mo), p = 0.005; LEN refractory, 10.2 vs. 7.1 mo, p = 0.012; not LEN refractory, 15.4 vs 9.6 mo, p = 0.014). Significant increases in TTNT were observed with XVd treatment in pts that were IMiD refractory (14.8 vs. 10.2 mo, p = 0.003), LEN refractory (13.0 vs. 7.6 mo, p = 0.015), and not refractory to LEN (19.1 vs 12.9 mo, p = 0.005). ORR was improved with XVd compared to Vd regardless of refractory status (IMiD refractory, 68.9% vs 55.8%, p = 0.045; LEN refractory, 67.9% vs. 47.2%, p = 0.016; and not refractory to LEN, 79.6% vs 67.5%, p = 0.010). The most common treatment-emergent AEs for the XVd/Vd arms for all subgroups were thrombocytopenia (66.2/30.6%; 71.7/40.4%; 55.6/22.4%), nausea (48.6/11.8%; 50.9/11.5%; 50.0/9.2%), and fatigue (40.5/20.0%; 45.3/21.2%; 40.8/17.1%) for IMiD, LEN, and not LEN refractory, respectively. Incidence of PN AEs of any grade were reduced compared to pts treated with Vd (IMiD refractory, 27% vs. 42.4%; LEN refractory, 30.2% vs 36.5%; not refractory, LEN 33.1% vs 50.7%). Conclusions: In pts with previously treated MM, PFS, ORR, and TTNT were significantly improved regardless of documented refractory status to any IMiD or to LEN-specifically. These analyses support the use of the XVd combination for pts with disease refractory to LEN and likely to any IMiD. Clinical trial information: NCT03110562.

8027 Background: Activating mutations of the RAS genes NRAS, KRAS, and HRAS ( RASmut) occur in up to 50% of MM and portend poor survival and high recurrence rates. MM cells with RASmut are susceptible to inhibition of germinal center kinase (GCK), resulting in IKAROS degradation independent of cereblon (CRBN). Selinexor is a selective inhibitor of nuclear export (SINE) compound that can induce IKAROS degradation through CRBN-independent pathways to overcome immunomodulatory drug resistance. We explored the benefit of selinexor treatment for pts with RASmut MM. Methods: In the randomized BOSTON study, pts with MM after 1-3 therapies received weekly XVd or twice weekly Vd. In the single-arm STORM study pts with penta-treated, triple class refractory MM were treated with twice weekly Xd. Both treatment regimens are now FDA approved. Mutations were assessed post-hoc by exome sequencing of 119 and 52 pts from BOSTON and STORM, respectively. Pts were considered RASmut if their MM had NRAS, KRAS or HRAS mutations in codons 12, 13 or 61. Results: There were 54 pts (45%) with RASmut in BOSTON (XVd = 26, Vd = 28), and 17 (33%) in STORM. In BOSTON, pts with RASmut MM treated with XVd had significantly longer progression-free survival (PFS) than those treated with Vd (median [med] = 12.9 vs 6.7 months [mo], hazard ratio [HR] = 0.48 [95% CI 0.24-0.97], p = 0.039). For pts treated with Vd, those with RASmut had significantly shorter overall survival (OS) compared to RASwild-type (WT) (med = 16.8 mo vs not reached [NR], HR = 2.87 [95% CI 1.03-7.99], p = 0.035). PFS was not significantly different (med = 6.74 vs 9.82 mo, HR = 1.64 [95% CI 0.88-3.07], p = 0.122). Amongst pts on XVd, there was no difference in survival between RASmut and RASWT pts (PFS: med = 12.8 vs 12.9 mo, HR = 1.08 [95% CI 0.52-2.26], p = 0.83; OS: med = NR vs NR, HR = 0.94 [95% CI 0.36-2.45], p = 0.91). In STORM, pts with RASmut had shorter OS compared to RASwt pts (med = 6.1 vs NR, HR = 2.05 [95% CI 1.22-5.19], p = 0.010). Preliminary studies to explore the mechanisms of action related to RASmut MM sensitivity to XVd demonstrated that selinexor treatment in vitro leads to downregulation of GCK. Conclusions: Despite typically having the worst outcomes, pts with RASmut MM had a similar benefit from XVd as RASWT MM, showing that the XVd combination can overcome RASmut. Mechanistically, selinexor induced down regulation of GCK and enhanced killing of RASmut MM cells. With a manageable safety profile, the XVd regimen could provide a viable treatment option to improve survival of pts with MM with RAS mutations. Clinical trial information: NCT03110562. [Table: see text]