Abstract: Renal impairment is a common complication of multiple myeloma (MM). The estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease formula is the recommended method for the assessment of renal function in patients with MM with stabilized serum creatinine. In acute renal injury, the RIFLE (risk, injury, failure, loss and end-stage kidney disease) and Acute Renal Injury Network criteria seem to be appropriate to define the severity of renal impairment. Novel criteria based on eGFR measurements are recommended for the definition of the reversibility of renal impairment. Rapid intervention to reverse renal dysfunction is critical for the management of these patients, especially for those with light chain cast nephropathy. Bortezomib with high-dose dexamethasone is considered as the treatment of choice for such patients. There is limited experience with thalidomide in patients with myeloma with renal impairment. Thus, thalidomide can be carefully administered, mainly in the context of well-designed clinical trials, to evaluate if it can improve the rapidity and probability of response that is produced by the combination with bortezomib and high-dose dexamethasone. Lenalidomide is effective in this setting and can reverse renal insufficiency in a significant subset of patients, when it is given at reduced doses, according to renal function. The role of plasma exchange in patients with suspected light chain cast nephropathy and renal impairment is controversial. High-dose melphalan (140 mg/m 2 ) and autologous stem-cell transplantation should be limited to younger patients with chemosensitive disease.

Abstract: Introduction: Treatment of older or frail patients (pts) with multiple myeloma (MM) remains challenging due to impaired organ function, underlying comorbidities, need for convenient regimens and burden of care, all of which impact the tolerability of anti-MM therapies. In the STORM study, selinexor plus dexamethasone (sel-dex) demonstrated anti-MM activity with an ORR of 26.2% and similar safety across all age groups in pts with triple-class refractory MM (Chari et al. NEJM 2019, Gavriatopoulou et al. IMW 2019). In the phase 3 BOSTON study, the combination of weekly sel-dex with once weekly bortezomib (SVd) was superior to standard twice weekly bortezomib and dex (Vd) across all efficacy endpoints in pts with MM who had received 1-3 prior therapies. Furthermore, while conferring a longer PFS and higher ORR than Vd, SVd was associated with significantly reduced rates of peripheral neuropathy (PN), the most clinically relevant toxicity associated with bortezomib that limits long term administration, especially in older and/or frail pts. Here we present results of subgroup analyses of the BOSTON study to evaluate the safety and efficacy of SVd versus Vd based on age and frailty index. Methods: Pts enrolled in BOSTON were assigned (1:1) to once weekly oral sel (100 mg) plus once weekly subcutaneous (SC) bortezomib (1.3 mg/m2) and dex (20 mg BIW) in the SVd arm or to standard twice weekly SC bortezomib (1.3 mg/m2) and dex (20 mg QIW) in the Vd arm. Treatment was administered in both arms until disease progression. The primary endpoint was PFS, as assessed by an Independent Review Committee. For these analyses, pts were assigned to 2 groups based on age ( & lt;65 and ≥65 years) and Frailty Score categories (frail and fit). Frailty Score was assessed using baseline characteristics including age, Charlson Comorbidity Index, and Eastern Cooperative Oncology Group performance status (Facon et al. Leukemia 2019). Results: Of the 402 enrolled pts, 241 (60%) were ≥65 years (SVd=109, Vd=132). Of these, 81 (37%) were ≥75 and 106 (44%) were categorized as frail (SVd=51, Vd=55). Baseline pt and disease characteristics were well balanced between treatment arms in the subgroups. PFS was prolonged in both age groups with SVd compared with Vd. In ≥65, PFS was 21.0 vs 9.5 months (HR, 0.55; 95% CI, 0.37-0.83; P=0.0018) and in & lt;65, PFS was 12.2 vs 9.4 months (HR, 0.74; 95% CI, 0.41-1.10; P=0.07). The PFS benefit of SVd was sustained and comparable in the frail pts: 13.9 vs 9.5 months (HR, 0.69; 95% CI, 0.40-1.17; P=0.08); and in the fit pts: 13.2 vs 9.4 months (HR, 0.66; 95% CI, 0.47-0.93; P=0.0076) (Figure). The ORR was significantly improved with SVd in those ≥65 (76.1% vs 64.4%; P=0.0243) and & lt;65 (76.7% vs 58.7%, P=0.0071). The ORR was improved with SVd in both the frail (69.7% vs 60.9%; P=0.14) and fit groups (79.8% vs 62.9%; P=0.0011). Overall survival was 24.8 months and 23.5 months in the Vd arm in the ≥65 and frail pts respectively and was not reached in any of the subgroups in the SVd arm. There were more deaths in the ≥65 (30% [SVd 23%, Vd 36%]) and frail groups (35% [SVd 26%, Vd 44%] ) compared with the & lt;65 (23% [SVd 26%, Vd 20%]) and fit groups (24% [SVd 23%, Vd 24%] ). Similar to the overall population, the most common grade ≥3 adverse events (AEs) were thrombocytopenia, anemia, pneumonia and fatigue. In the SVd arm, the incidence of AEs was comparable across subgroups except for a higher incidence of fatigue in ≥65 versus & lt;65 (17% vs 8%) and pneumonia in the frail versus fit (19% vs 7%). The incidence of serious AEs in the SVd versus Vd arms was (56% vs 45%) and (47% vs 25%) in ≥65 and & lt;65 and (59% vs 48%) and (48% and 33%) in the frail and fit groups, respectively. Treatment discontinuation due to AEs occurred in 21% pts on SVd versus 16% on Vd in ≥65 and in 18% on SVd versus 11% on Vd in the frail group. Grade ≥ 2 PN rates were lower in the SVd compared with Vd arms in all subgroups with significant differences in ≥65 (22% vs 37%; P=0.0060) and frail groups (15% vs 44%; P=0.0002). Conclusions: In pts with previously treated MM, the once weekly SVd regimen led to prolonged PFS, improved response rates and rates of PN regardless of age and frailty score compared to standard twice weekly Vd. Non-PN AEs were higher with triplet than doublet therapy, but most of the AEs were reversible and treatable. There were fewer deaths on SVd in pts ≥65 and in frail pts compared to Vd. Once weekly SVd is a potent and convenient treatment option for pts with previously treated MM, including those who are ≥65 years and/or frail. Figure Disclosures Auner: Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria, Research Funding. Gavriatopoulou:Amgen: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Genesis Pharma: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Delimpasi:GENESIS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Spicka:Celgene, Amgen, Janssen-Cilag, Takeda, Bristol-Myers Squibb, Novartis, Sanofi: Consultancy, Honoraria, Speakers Bureau. Dimopoulos:BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Personal fees, Research Funding, Speakers Bureau. Leleu:Incyte: Honoraria; Merck: Honoraria; AbbVie: Honoraria; Carsgen: Honoraria; Janssen: Honoraria; Novartis: Honoraria; BMS-celgene: Honoraria; Amgen: Honoraria; GSK: Honoraria; Sanofi: Honoraria; Karyopharm: Honoraria; Oncopeptide: Honoraria. Hajek:Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Pharma MAR: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Consultancy, Honoraria, Research Funding. Sinha:Dr Reddys Lab, Intas Pharmaceuticals, Karyopharm Therapeutics: Honoraria. Venner:Janssen, BMS/Celgene, Sanofi, Takeda, Amgen: Honoraria; Celgene, Amgen: Research Funding. Garg:Janssen, Takeda, Celgene, Novartis, Sanofi: Honoraria. Stevens:Amgen, MorphoSys: Consultancy. Quach:Amgen, Celgene, karyopharm, GSK, Janssen Cilag, Sanofi.: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Honoraria; Amgen, sanofi, celgene, Karyopharm, GSK: Research Funding; GlaxoSmithKline, Karyopharm, Amgen, Celgene, Janssen Cilag: Consultancy. Jagannath:Sanofi: Consultancy, Honoraria; Legend Biotech: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Moreau:Sanofi: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Abbvie: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Novartis: Honoraria. Levy:Takeda: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Bristol Meyers Squibb: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy, Research Funding, Speakers Bureau; Baylor University Med Center: Current Employment. Badros:Amgen: Consultancy; University of Maryland: Current Employment. Anderson:BMS: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; GSK: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Bahlis:BMS/Celgene and Janssen: Consultancy, Honoraria, Other: Travel, Accomodations, Research Funding; Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Genentech: Consultancy, Honoraria; GSK: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria. Facon:Celgene, Janssen, Takeda, Amgen, Roche, Karyopharm, Oncopeptides, BMS, Sanofi: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Mateos:EDO Mundipharma: Honoraria; Seattle Genetics: Honoraria; Abbvie: Honoraria; Janssen: Honoraria; Bristol-Myers Squibb: Honoraria; Amgen: Honoraria; GlaxoSmithKline: Honoraria; Adaptive Biotechnologies: Honoraria; Takeda: Honoraria; Roche: Honoraria. Cavo:Jannsen, BMS, Celgene, Sanofi, GlaxoSmithKline, Takeda, Amgen, Oncopeptides, AbbVie, Karyopharm, Adaptive: Consultancy, Honoraria. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chai:Karyopharm Therapeutics Inc: Current Employment. Arazy:Karyopharm Therapeutics Inc.: Current Employment. Shah:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding.

Abstract: The role of high-dose therapy followed by autologous stem cell transplantation (ASCT) in the treatment of multiple myeloma (MM) continues to evolve in the novel agent era. The choice of induction therapy has moved from conventional chemotherapy to newer regimens incorporating the immunomodulatory derivatives thalidomide or lenalidomide and the proteasome inhibitor bortezomib. These drugs combine well with traditional therapies and with one another to form various doublet, triplet, and quadruplet regimens. Up-front use of these induction treatments, in particular 3-drug combinations, has affected unprecedented rates of complete response that rival those previously seen with conventional chemotherapy and subsequent ASCT. Autotransplantation applied after novel-agent-based induction regimens provides further improvement in the depth of response, a gain that translates into extended progression-free survival and, potentially, overall survival. High activity shown by immunomodulatory derivatives and bortezomib before ASCT has recently led to their use as consolidation and maintenance therapies after autotransplantation. Novel agents and ASCT are complementary treatment strategies for MM. This article reviews the current literature and provides important perspectives and guidance on the major issues surrounding the optimal current management of younger, transplantation-eligible MM patients.

Abstract: Introduction: Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) compound that selectively binds and inactivates XPO1, therefore forcing the nuclear retention and re-activation of cell cycle regulators such as p53, FOXO, IkB, and Rb. Selinexor in combination with low dose dexamethasone (Sel-dex) was recently approved based on data from the STORM study, which induced an overall response rate (ORR) of 26.2% in patients with penta-exposed, triple-class refractory multiple myeloma (TCR-MM). Patients with TCR-MM often present with plasmacytomas along with serological markers of MM. Methods: Here we analyzed the effects of Sel-dex in patients from the STORM study who had baseline plasmacytomas. Results: 122 patients were in enrolled in the STORM study including 27 with a baseline plasmacytoma. The majority of plasmacytomas were soft tissue (22 patients) and 5 patients had soft tissue disease extension from a bone (rib (2), iliac (2), sacral vertebral). The median age of patients with plasmacytomas was 64 years, the median prior therapies were 7 (range 4 - 15), and 8/27 patients with a plasmacytoma had high risk cytogenetics. Of the 27 patients, 11 patients did not have a follow up plasmacytoma assessment: 6 were not evaluable for response as they came off therapy due to clinical progression and/or adverse events, 4 had stable disease (SD) with no evidence of plasmacytoma change, and 1 had progressive disease (PD) on serum M-protein with no evidence of plasmacytoma change. Sixteen of the 27 patients did have follow-up plasmacytoma assessments (methods of measurements included PET, CT, MRI or Clinical). The median days from baseline plasmacytoma evaluation to follow up was 41 days (range 22 - 119). Five patients had objective responses, based upon para-protein and plasmacytoma reductions according to IMWG criteria (1 very good partial response [VGPR], 4 partial responses [PR] ) for an ORR of 18.5%. In addition, 2 patients had a minimal response (MR), 4 had SD and 5 had objective PD. Among the 5 patients with ≥PR, 3 plasmacytomas completely resolved, 1 showed near complete resolution, and another showed size reduction with no metabolic activity on PET. Of the 2 patients with a MR, 1 plasmacytoma completely resolved and 1 showed reduced PET uptake. Among the 4 patients with SD, 1 plasmacytomas completely resolved, 1 increased in size and 2 had unknown outcomes as they were assessed clinically. Among the 5 patients with PD, 1 plasmacytomas decreased in size, 1 increased in size, and 3 had unknown outcomes as they were assessed clinically. Conclusions: Of the 16 patients with TCR-MM and a follow up plasmacytoma assessment enrolled on STORM, 9/16 of the plasmacytomas either completely resolved or decreased in size and/or metabolic activity. Effects on plasmacytomas occurred in patients with objective responses (≥PR), as well as in patients with MR, SD and PD. These observations support the finding that Sel-dex is active in patients with plasmacytomas and heavily pretreated TCR-MM. Disclosures Yee: Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Consultancy; Karyopharm: Consultancy; Adaptive: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding. Huff:Member of Safety Monitoring Board for Johnson and Johnson: Membership on an entity's Board of Directors or advisory committees; Karyopharm, Sanofi, MiDiagnostics: Consultancy. Chari:Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Oncoceutics: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium/Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Array Biopharma: Research Funding; GlaxoSmithKline: Research Funding; Novartis Pharmaceuticals: Research Funding. Vogl:Active Biotech: Consultancy; Janssen: Consultancy; Karyopharm Therapeutics: Consultancy; Takeda: Consultancy; Celgene: Consultancy; Amgen: Consultancy. Gavriatopoulou:Genesis: Honoraria, Other: Travel expenses; Amgen: Honoraria; Janssen: Honoraria, Other: Travel expenses; Takeda: Honoraria, Other: Travel expenses. Nooka:Adaptive technologies: Honoraria, Other: advisory board participation; Spectrum pharmaceuticals: Honoraria, Other: advisory board participation; GSK: Honoraria, Other: advisory board participation; Janssen: Honoraria, Other: advisory board participation; Amgen: Honoraria, Other: advisory board participation; Takeda: Honoraria, Other: advisory board participation; Celgene: Honoraria, Other: advisory board participation; BMS: Honoraria, Other: advisory board participation. Moreau:AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria. Dingli:Karyopharm: Research Funding; Rigel: Consultancy; Millenium: Consultancy; Janssen: Consultancy; alexion: Consultancy. Lonial:Janssen: Consultancy, Research Funding; GSK: Consultancy; Karyopharm: Consultancy; BMS: Consultancy; Celgene Corporation: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Amgen: Consultancy; Genentech: Consultancy. Dimopoulos:Sanofi Oncology: Research Funding. Vij:Takeda: Honoraria, Research Funding; Sanofi: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria; Genentech: Honoraria; Celgene: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding. Tuchman:Prothena: Research Funding; Amgen: Research Funding; Karyopharm: Honoraria; Alnylam: Honoraria, Research Funding; Sanofi: Research Funding; Merck: Research Funding; Roche: Research Funding; Celgene: Honoraria, Research Funding, Speakers Bureau. Hoffman:Celgene: Speakers Bureau. Costa:Abbvie: Consultancy; Celgene: Consultancy, Honoraria, Research Funding; Sanofi: Consultancy, Honoraria, Speakers Bureau; GSK: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Janssen: Research Funding, Speakers Bureau; Fujimoto Pharmaceutical Corporation Japan: Other: Advisor. Biran:Janssen: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria; Bristol Meyers Squibb: Research Funding; Takeda: Consultancy, Honoraria. Siegel:Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Bristol-Myers Squibb Company: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Shah:Karyopharm Therapeutics: Employment, Equity Ownership. Picklesimer:Karyopharm Therapeutics: Employment, Equity Ownership. Saint-Martin:Karyopharm Therapeutics: Employment, Equity Ownership. Li:Karyopharm Therapeutics: Employment, Equity Ownership. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Richardson:Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncopeptides: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Research Funding; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Jagannath:Multiple Myeloma Research Foundation: Speakers Bureau; Medicom: Speakers Bureau; Merck: Consultancy; Celgene: Consultancy; Novartis: Consultancy; BMS: Consultancy.

Abstract: Background Ricolinostat is the first selective oral HDAC6 inhibitor studied clinically in the treatment of MM. Preclinical and phase 1a clinical data support the hypothesis that the safety profile of a selective HDAC inhibitor will facilitate combination therapy with other active agents. No dose limiting toxicities (DLT) were noted in 15 patients (pts) in a phase 1a dose escalation study of ricolinostat at doses up to 360 mg/day where the best response was stable disease (SD). (Raje Blood 2012;120:4061). HDAC6 inhibition impairs the aggresome/autophagy pathway, an alternate pathway to proteasome clearance of misfolded proteins (Santo L Blood 2012;119(11):2578-89) providing the rationale for combining ricolinostat with bortezomib (Btz). Methods We report the first part of a phase 1b open label dose escalation study of ricolinostat in combination with Btz and dexamethasone (Dex) using a standard 3+3 design. Eligible pts had relapsed or relapsed and refractory MM, previously received at least two lines of therapy including a proteasome inhibitor and an IMiD® immunomodulatory agent, had either progressed after or were ineligible for autologous stem cell transplant, and had adequate bone marrow reserve, hepatic function and creatinine clearance of 〉 30 mg/mL/min. Ricolinostat was given orally days 1-5 and 8-12 of a 21 day cycle, with Btz on days 1,4,8,11 and Dex on days 1,2,4,5,8,9,11,12. Peripheral blood samples were obtained for pharmacokinetic (PK) and pharmacodynamic assessments of acetylated tubulin (HDAC6 inhibition) and acetylated histones (Class 1 HDAC inhibition). Definitions of response, relapsed and refractory were by IMWG criteria (Rajkumar SV Blood:2011;117(18):4691-5) and included response less than minimal response (MR) as refractory. Seventeen pts were treated in an expansion cohort at the potential recommended phase 2 dose and schedule. Results Forty-two pts were enrolled to 8 combination dose cohorts. The first cohort dosed ricolinostat 40 mg QD with Btz 1.0 mg/m2; subsequent cohorts used Btz 1.3 mg/m2 with ricolinostat doses of 40, 80 , 160, and 240 mg QD, and 160 mg BID. Median age was 65, and 79% were refractory to the most recent therapy. 34 pts had previously received 〉 4 prior regimens. The first combination cohort was expanded due to a DLT of asymptomatic increase in amylase. No other DLTs have been observed in the cohort escalations. Treatment emergent adverse events (AEs) were predominantly grade 1-2. The most common AEs were diarrhea, increased creatinine, fatigue, anemia, nausea and thrombocytopenia and only diarrhea increased with ricolinostat dose. Grade 3-4 AEs possibly related to ricolinostat included thrombocytopenia (24%), anemia, diarrhea, and asymptomatic laboratory abnormalities (1%). Fatigue, dehydration, orthostatic hypotension, nausea, vomiting, stomach cramps and pulmonary embolism were seen in ≤1% of pts. Of 25 pts evaluable for response, overall response rate (ORR) was 44%: 2 pts had a very good partial response (VGPR), 9 had a partial response (PR), and 2 had an MR, with 9 pts achieving SD and 3 with progressive disease (PD). Responding pts remained on study for a median of 4 cycles (range 2 to 18). Pts who were not evaluable were those who were too early in treatment (3), or who came off study before cycle 2 (14). Of these 10 had early PD and 3 died due to disease or unrelated AE. 15 pts refractory to Btz prior to study entry were evaluable for response. Of those, response rate (PR or better) was 27% with best outcome VGPR (1), PR (3), SD (8) and PD (3). Pts with SD were on study a median of 3 (2-10) mos. PK and pharmacodynamic data from the first 16 pts were similar to the same dose levels in phase 1a monotherapy suggesting coadministration of Btz does not impact the PK of ricolinostat. Maximal levels were ≥1µM at ≥80 mg correlating with measurable increases 〉 2x in acetylated tubulin with a minimal increase in acetylated histones. Updated PK and pharmacodynamic data will be provided. Conclusions Ricolinostat in combination with Btz and Dex was well tolerated at doses up to 240 mg QD and 160 mg BID in the dose escalation cohorts. Diarrhea was the only dose-related AE. Results of the expansion cohort as well as cytogenetic risk categories will be presented. Responses were observed even in Btz-refractory pts. Disclosures Vogl: Celgene Corporation: Consultancy; Amgen: Consultancy; Millennium/Takeda: Research Funding; GSK: Research Funding; Acetylon: Research Funding. Raje:Eli Lilly, Acetylon: Research Funding; novartis, Amgen, Celgene, Millenium, Onyx: Consultancy. Jones:Acetylon Pharmaceuticals Inc.: Employment. Supko:Acetylon Pharmaceuticals: Research Funding. Leone:Acetylon Pharmaceuticals: Employment. Wheeler:Acetylon Pharmaceuticals: Employment. Orlowski:Novartis: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Array BioPharma: Membership on an entity's Board of Directors or advisory committees, Research Funding; JW Pharmaceutical: Research Funding; Spectrum Pharmaceuticals: Research Funding; Millennium: The Takeda Oncology Company: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees. Lonial:Millennium: Consultancy; Celgene: Consultancy; Novartis: Consultancy; BMS: Consultancy; Onyx: Consultancy; Sanofi: Consultancy. Tamang:Acetylon Pharmaceuticals, Inc: Employment, Equity Ownership. Jagannath:Celgene Corporation: Consultancy; Millennium: Consultancy; Sanofi: Consultancy.

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

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: 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.