Abstract: Background: Immune cytopenia (IC) is one of the major complications in chronic lymphocytic leukemia (CLL). The paper describes the peculiarities of different immune cytopenia in CLL patients and the importance of individual prognostic markers in the course of the disease. Methods: We observed 62 patients with CLL complicated by immune cytopenia. Among these patients 30 had autoimmune hemolytic anemia (AIHA), 18 experienced immune thrombocytopenia (ITP), 10 had Fisher-Evans syndrome (FES), 3 were diagnosed with partial red cell aplasia (PRCA), and immune neutropenia (IN) was revealed in 1 patient. In addition to general examination and laboratory studies, the following examinations were performed: immunophenotyping of peripheral blood lymphocytes, flow cytometry (CD5; CD19; CD20; CD23; CD38; ZAP70), Coombs test, a molecular cytogenetic study of peripheral blood lymphocytes using the FISH method with TP53 and ATM probes, the level of ß2-microglobulin. Results: It was established that the overall survival of CLL patients with IC depends on the form of the latter. The median overall survival in patients with Fisher-Evans syndrome was the shortest (75 months), slightly better survival was observed in patients with AIHA (median 80 months), the best survival was found in patients with ITP (median not reached). Among unfavorable markers of CLL with IC, there is the presence of del 11q22.3. Unfavorable prognostic markers were also the following: a positive Coombs test, high levels of ZAP 70 expression, and high levels of ß2-microglobulin

Abstract: Elderly and frail patients with multiple myeloma (MM) are more vulnerable to the toxicity of combination therapies, often resulting in treatment modifications and suboptimal outcomes. The phase 3 BOSTON study showed that once‐weekly selinexor and bortezomib with low‐dose dexamethasone (XVd) improved PFS and ORR compared with standard twice‐weekly bortezomib and moderate‐dose dexamethasone (Vd) in patients with previously treated MM. This is a retrospective subgroup analysis of the multicenter, prospective, randomized BOSTON trial. Post hoc analyses were performed to compare XVd versus Vd safety and efficacy according to age and frailty status ( 〈 65 and ≥65 years, nonfrail and frail). Patients ≥65 years with XVd had higher ORR (OR 1.77, p  = .024), ≥VGPR (OR, 1.68, p  = .027), PFS (HR 0.55, p  = .002), and improved OS (HR 0.63, p  = .030), compared with Vd. In frail patients, XVd was associated with a trend towards better PFS (HR 0.69, p  = .08) and OS (HR 0.62, p  = .062). Significant improvements were also observed in patients 〈 65 (ORR and TTNT) and nonfrail patients (PFS, ORR, ≥VGPR, and TTNT). Patients treated with XVd had a lower incidence of grade ≥ 2 peripheral neuropathy in ≥65 year‐old (22% vs. 37%; p  = .0060) and frail patients (15% vs. 44%; p  = .0002). Grade ≥3 TEAEs were not observed more often in older compared to younger patients, nor in frail compared to nonfrail patients. XVd is safe and effective in patients 〈 65 and ≥65 and in nonfrail and frail patients with previously treated MM.

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

Abstract: Introduction: Treatment of multiple myeloma (MM) has greatly improved over the last two decades. However, most pts will relapse and develop refractory disease. Most anti-cancer regimens require dose modifications (interruption, reduction, or discontinuation) during the treatment course in order to optimize the therapeutic window; appropriate modifications improve tolerability while maintaining anti-cancer activity. Selinexor, an oral selective inhibitor of XPO1-mediated nuclear export (SINE) compound, enforces the nuclear retention and functional activation of tumor suppressor proteins within the nucleus and prevents the translation of oncoproteins. The combination of once weekly (QW) selinexor, QW bortezomib, and dexamethasone (XVd) is FDA approved for previously treated MM. Compared to standard twice weekly (BIW) bortezomib plus dexamethasone (Vd) and using 40% less bortezomib and 25% less dexamethasone, XVd demonstrated significantly prolonged median progression-free survival (PFS) and time-to-next-treatment (TTNT), increased the overall response rate (ORR), reduced rates of peripheral neuropathy, and showed a trend towards improved overall survival (OS) in the Phase 3 randomized BOSTON study (NCT03110562). The recommended starting dose of selinexor in XVd is 100mg QW, but the median dose administered in BOSTON was 80 mg QW. Here, we analyzed the efficacy outcomes and adverse events (AEs) in pts whose dose was reduced compared to those where it was not. Methods: The BOSTON study consisted of two arms: pts treated with selinexor QW (100mg), bortezomib QW (1.3mg/m 2) and dexamethasone BIW (20 mg) (XVd; n=195 in the intention-to-treat [ITT] population) compared to standard BIW Vd. Results: Of the XVd pts in the BOSTON study, 126 had a dose reduction of selinexor and 69 did not. The median age was 66.0 in both groups (range: with reduction, 47-87; without, 40-84) and the median number of prior therapies was 1.0 (range, 1-3) for both groups (Table 1). The median time to dose reduction in these pts was 68 days (range, 8-561 days). The median duration of study treatment for these pts was 34.5 weeks (range, 3-120 weeks) compared to 20.0 weeks (range, 1-118) in pts with no dose reduction. In the group with dose reduction, the median dose of selinexor received per week was 71.3 mg (range, 29.7, 101.4) compared to 100 mg (range, 33.3, 136.7) in pts with no reduction. Pts who dose reduced had a median PFS of 16.6 months compared to 9.2 months in pts who did not (one-sided p value, & lt;0.01), with a median follow up of 14.1 months with reduction and 10.6 months without. The ORR in the dose reduced group compared to pts who did not dose reduce was 81.7% vs 66.7% (one-sided p value, & lt;0.01), and the rate of VGPR or better was 51.6% vs 31.8% (Table 2). Duration of response (DOR) was NR in the dose reduced group and was 12.0 months in the group without reduction. TTNT was 22.6 months in the dose reduced group and 10.5 months in pts with no dose reductions (one-sided p value, & lt;0.001). The most common adverse events (AEs; dose reduction and without dose reduction) of any grade were thrombocytopenia (69.8% and 42.0%), nausea (55.6% and 40.6%), and fatigue (49.2% and 29.0%). The rate of treatment discontinuation in the dose reduced group was 24.6% and 14.5% without dose reductions. In the dose reduced group, there were 6 (4.8%) deaths and 6 (8.7%) in the group with no dose reduction. As pts with a dose reduction stayed on therapy for a prolonged period of time, to best understand the impact of dose reduction on the AE, we present the duration-adjusted incidence rates of AEs of clinical interest. The duration-adjusted incidence rates of AE were considerably lower after dose reduction of selinexor compared to the rates on or before dose reduction: thrombocytopenia (62.5% vs 47.6%), nausea (31.6% vs 7.3%), fatigue (28.1% vs 9.9%), decreased appetite (21.5% vs 6.4%), anemia (17.9% vs 10.3%), and diarrhea (12.9% vs 5.2) (Table 3). Conclusions: While all pts on XVd initiated therapy at 100mg selinexor QW, and it was associated with very low rates of progressive disease (1 in 195 pts), appropriate dose reductions of selinexor were associated with a longer PFS, DOR, and TTNT, and significantly reduced AE with improved tolerability, highlighting dose reductions as an important tool to personalize and optimize the therapeutic window for pts with RRMM. Figure 1 Figure 1. Disclosures Jagannath: Bristol Myers Squibb: Consultancy; Janssen Pharmaceuticals: Consultancy; Karyopharm Therapeutics: Consultancy; Legend Biotech: Consultancy; Sanofi: Consultancy; Takeda: Consultancy. Badros: Janssen: Research Funding; GlaxoSmithKline: Research Funding; J & J: Research Funding; BMS: Research Funding. Levy: Takeda, Celgene, Seattle Genetics, AbbVie, Jazz Pharmaceuticals, Gilead Sciences, Bristol-Myers Squibb, Amgen, Spectrum Pharmaceuticals,Janssen.: Consultancy. Moreau: Celgene BMS: Honoraria; Oncopeptides: Honoraria; Amgen: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria; Janssen: Honoraria. Delimpasi: Takeda: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau. Kriachok: Takeda, Roche, Abbivie, Janssen, MSD: Consultancy; Takeda, Roche, Abbvie, Janssen, MSD, Pfizer: Honoraria, Speakers Bureau. Gavriatopoulou: Takeda: Honoraria; Sanofi: Honoraria; GSK: Honoraria; Janssen: Honoraria; Karyopharm: Honoraria; Genesis: Honoraria; Amgen: Honoraria. Auner: Janssen: Speakers Bureau; Amgen: Research Funding; Takeda, Karyopharm: Other: Advisory role. Leleu: Bristol-Myers Squibb: Honoraria; Carsgen Therapeutics Ltd: Honoraria; Celgene: Honoraria; Gilead Sciences: Honoraria; Janssen-Cilag: Honoraria; Karyopharm Therapeutics: Honoraria; Merck: Honoraria; Mundipharma: Honoraria; Novartis: Honoraria; Oncopeptides: Honoraria; Pierre Fabre: Honoraria; Roche: Honoraria; Sanofi: Honoraria; Amgen: Honoraria; AbbVie: Honoraria; Takeda: Honoraria, Other: Non-financial support. Usenko: Janssen: Consultancy, Honoraria, Other: Clinical Trials Investigator; AbbVie: Consultancy, Honoraria, Other: Clinical Trials Investigator; Pfizer: Consultancy, Honoraria; Acerta: Other: Clinical Trials Investigator; Ascentage: Other: Clinical Trials Investigator; Celgene: Other: Clinical Trials Investigator; Il-Yang: Other: Clinical Trials Investigator; Karyopharm: Other: Clinical Trials Investigator; Oncopeptides: Other: Clinical Trials Investigator; Rigel: Other: Clinical Trials Investigator; Takeda: Other: Clinical Trials Investigator; UCB: Other: Clinical Trials Investigator. Hajek: Janssen: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria; Pharma MAR: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Venner: BMS: Honoraria; Amgen: Research Funding; Celgene: Research Funding; Amgen: Honoraria; Takeda: Honoraria; Janssen: Honoraria; Sanofi: Honoraria; Pfizer: Honoraria. Garg: University Hospital Leicester: Current Employment; Amgen Janssen Novartis Sanofi Takeda: Honoraria; Takeda Janssen Novartis Sanofi: Other: Travel Accommodations, Expenses. Gironella Mesa: BMS, Janssen: Honoraria. Jurczyszyn: Janssen-Cilag, Amgen: Honoraria, Speakers Bureau. Robak: Biogen, Abbvie, Octapharma, Janssen: Honoraria, Other: Advisory board; AstraZeneca, Abbvie, Janssen, Octapharma, Gilead,Oncopeptides AB, Pharmacyclics, Pfizer, GlaxoSmithKline, Biogen: Research Funding; Medical University of Lodz: Current Employment. Galli: BMS, Celgene, Janssen, Sanofi, Takeda: Honoraria. Radinoff: Janssen, Pfizer, Novartis, Servier etc.: Consultancy, Honoraria; Amgen, Bayer, Takeda, etc.: Research Funding; the Bulgarian Minister of Health: Membership on an entity's Board of Directors or advisory committees. Liberati: abbvie, amgen, archigen, beigene, BMS, celgene, DR REDDY'S LABORATORIES SPA, fibrogen, glaxo, Janssen, Karyopharm, Morphosys, Novartis, Onconova, Oncopeptides ab, Roche, Sanophi, Secura Bio, Takeda, Verastem,: Research Funding. Quach: Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Janssen/Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CSL: Consultancy, Membership on an entity's Board of Directors or advisory committees. Bila: Takeda, AMGEN, Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Katodritou: GSK, Amgen, Karyopharm, Abbvie, Janssen-Cilag, Genesis Pharma, Sanofi: Honoraria, Research Funding. DeCastro: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Chai: Karyopharm: Current Employment. Van Domelen: Karyopharm: Current Employment, Current equity holder in publicly-traded company. Mishal: Karyopharm: Current Employment. Bentur: Karyopharm Therapeutics: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm: Current Employment. Shacham: Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Richardson: GlaxoSmithKline: Consultancy; Sanofi: Consultancy; AstraZeneca: Consultancy; Regeneron: Consultancy; Karyopharm: Consultancy, Research Funding; Janssen: Consultancy; AbbVie: Consultancy; Protocol Intelligence: Consultancy; Secura Bio: Consultancy; Takeda: Consultancy, Research Funding; Celgene/BMS: Consultancy, Research Funding; Oncopeptides: Consultancy, Research Funding; Jazz Pharmaceuticals: Consultancy, Research Funding.

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

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

Abstract: 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.

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

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