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We assessed the safety, efficacy, maximum tolerated dose (MTD), and the recommended phase 2 dose (RP2D) of selinexor, a first in class oral selective inhibitor of nuclear export (100 mg once weekly [QW] or 60 mg twice weekly), in combination with daratumumab (16 mg/kg per label) and dexamethasone (40 mg QW) (SDd) in patients with relapsed refractory multiple myeloma (RRMM). Thirty-four patients (median prior therapies, 3 [range, 2-10]) were enrolled; MM was refractory to proteasome inhibitor (PI) in 85%, immunomodulatory agent (IMiD) in 76%, both in 74%, and daratumumab in 6% of patients. Two dose-limiting toxicities (DLTs) were reported in the selinexor 60 mg twice-weekly cohort with no DLTs in the 100 mg QW cohort, making 100 mg QW the MTD and RP2D. Common treatment-related adverse events included thrombocytopenia (70.6%), nausea (70.6%), fatigue (61.8%), anemia (61.8%), and neutropenia (50.0%). Overall response rate was 73% and median progression-free survival 12.5 months in daratumumab-naïve patients. SDd was well tolerated and its promising efficacy suggests that further study of this PI- and IMiD-free regimen in RRMM patients who had at least one prior line of therapy including a PI and an IMiD but whose disease is naïve to daratumumab is warranted.

BACKGROUND: Relapsed or refractory diffuse large B-cell lymphoma (DLBCL) is an aggressive cancer with a median overall survival of less than 6 months. We aimed to assess the response to single-agent selinexor, an oral selective inhibitor of nuclear export, in patients with relapsed or refractory DLBCL who had no therapeutic options of potential clinical benefit. METHODS: SADAL was a multicentre, multinational, open-label, phase 2b study done in 59 sites in 19 countries. Patients aged 18 years or older with pathologically confirmed diffuse large B-cell lymphoma, an Eastern Cooperative Oncology Group performance status of 2 or less, who had received two to five lines of previous therapies, and progressed after or were not candidates for autologous stem-cell transplantation were enrolled. Germinal centre B-cell or non-germinal centre B-cell tumour subtype and double or triple expressor status were determined by immunohistochemistry and double or triple hit status was determined by cytogenetics. Patients received 60 mg selinexor orally on days 1 and 3 weekly until disease progression or unacceptable toxicity. The study was initially designed to evaluate both 60 mg and 100 mg twice-weekly doses of selinexor; however, the 100 mg dose was discontinued in the protocol (version 7.0) on March 29, 2017, when an improved therapeutic window was observed at 60 mg. Primary outcome was overall response rate. The primary outcome and safety were assessed in all patients who received 60 mg selinexor under protocol version 6.0, or enrolled under protocol versions 7.0 or higher and received at least one dose of selinexor. This trial is registered at ClinicalTrials.gov, NCT02227251 (active but not enrolling). FINDINGS: Between Oct 21, 2015, and Nov 2, 2019, 267 patients were randomly assigned, with 175 allocated to the 60 mg group and 92 to the discontinued 100 mg group. 48 patients assigned to the 60 mg group were excluded due to enrolment before version 6.0 of the protocol; the remaining 127 patients received selinexor 60 mg and were included in analyses of primary outcome and safety. The overall response rate was 28% (36/127; 95% CI 20·7-37·0); 15 (12%) achieved a complete response and 21 (17%) a partial response. The most common grade 3-4 adverse events were thrombocytopenia (n=58), neutropenia (n=31), anaemia (n=28), fatigue (n=14), hyponatraemia (n=10), and nausea (n=8). The most common serious adverse events were pyrexia (n=9), pneumonia (n=6), and sepsis (n=6). There were no deaths judged as related to treatment with selinexor. INTERPRETATION: Single-drug oral selinexor induced durable responses and had a manageable adverse events profile in patients with relapsed or refractory DLBCL who received at least two lines of previous chemoimmunotherapy. Selinexor could be considered a new oral, non-cytotoxic treatment option in this setting. FUNDING: Karyopharm Therapeutics Inc.

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

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

Purpose Selinexor, a first-in-class, oral, selective exportin 1 (XPO1) inhibitor, induces apoptosis in cancer cells through nuclear retention of tumor suppressor proteins and the glucocorticoid receptor, along with inhibition of translation of oncoprotein mRNAs. We studied selinexor in combination with low-dose dexamethasone in patients with multiple myeloma refractory to the most active available agents. Patients and Methods This phase II trial evaluated selinexor 80 mg and dexamethasone 20 mg, both orally and twice weekly, in patients with myeloma refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide (quad-refractory disease), with a subset also refractory to an anti-CD38 antibody (penta-refractory disease). The primary end point was overall response rate (ORR). Results Of 79 patients, 48 had quad-refractory and 31 had penta-refractory myeloma. Patients had received a median of seven prior regimens. The ORR was 21% and was similar for patients with quad-refractory (21%) and penta-refractory (20%) disease. Among patients with high-risk cytogenetics, including t(4;14), t(14;16), and del(17p), the ORR was 35% (six of 17 patients). The median duration of response was 5 months, and 65% of responding patients were alive at 12 months. The most common grade ≥ 3 adverse events were thrombocytopenia (59%), anemia (28%), neutropenia (23%), hyponatremia (22%), leukopenia (15%), and fatigue (15%). Dose interruptions for adverse events occurred in 41 patients (52%), dose reductions occurred in 29 patients (37%), and treatment discontinuation occurred in 14 patients (18%). Conclusion The combination of selinexor and dexamethasone has an ORR of 21% in patients with heavily pretreated, refractory myeloma with limited therapeutic options.

Introduction: Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) that blocks XPO1, forcing the nuclear retention and re-activation of tumor suppressor proteins including p53, p73, FOXO, I□B and Rb. The phase 2b SADAL study included 134 patients with relapsed or refractory DLBCL with single agent oral selinexor twice weekly. The overall response rate (ORR) was 29.1%, median duration of response (DOR) was 9.3 months and the median overall survival (OS) was 9 months. Based on these data, selinexor was recently approved by the US FDA for the treatment of relapsed or refractory DLBCL, de novo or transformed from follicular lymphoma. Patients with DLBCL tend to be older (over the age of 65) and have a number of comorbidities, which limits the use of aggressive and multi-agent combination therapies. We performed post-hoc analyses of the SADAL study to determine the effects of age on the efficacy and safety of selinexor in this population. Methods: The SADAL study is multi-center, open-label Phase 2b study that enrolled patients with DLBCL previously treated with 2-5 lines of therapy. Patients may have progressed post-stem cell therapy (SCT) or were not candidates for SCT. In this study, 60 mg of selinexor was administered twice weekly until disease progression. The primary endpoint was ORR, and other endpoints included DOR, OS, and safety assessments. For the current analysis, outcomes were assessed in patients Results: Of the 134 patients enrolled in the study, 52 (39%) were 65 (3.8% vs. 11.0%). Conclusions: Patients with relapsed/refractory DLBCL who were ≥65 years had a similar clinical benefit to those Disclosures Schuster: Amgen, Abbvie, Gilead, Takeda, Celgene, Pharmacyclics, Astellas, Verastem, Merck, Novartis, Takeda, Genentech,, Seattle Genetics: Other: Personal Fees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Canales:Janssen: Honoraria; Roche: Speakers Bureau; Gilead: Honoraria; Sandoz: Honoraria; Janssen: Speakers Bureau; Sandoz: Speakers Bureau; Roche: Speakers Bureau; Novartis: Honoraria; Karyopharm: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Sandoz: Honoraria; Roche: Honoraria; Takeda: Speakers Bureau; Novartis: Honoraria; Sandoz: Speakers Bureau; iQone: Honoraria; Karyopharm: Honoraria; Takeda: Speakers Bureau; Roche: Honoraria; Janssen: Speakers Bureau. Westin:Genentech: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Curis: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; 47: Research Funding; Amgen: Consultancy; Janssen: Consultancy, Research Funding. Zijlstra:Roche: Research Funding. Follows:Karyopharm, Roche, Abbvie, Astrazeneca, Janssen, BMS: Membership on an entity's Board of Directors or advisory committees. Karmali:Takeda: Research Funding; Karyopharm: Honoraria; AstraZeneca: Speakers Bureau; BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Kalakonda:Verastem, Gilead, Celgene, Roche: Research Funding; Gilead, Janssen, Karyopharm: Honoraria. Goy:Constellation: Research Funding; Regional Cancer Care Associates/OMI: Current Employment; COTA: Consultancy, Current equity holder in publicly-traded company, Other: leadership role; Infinity: Research Funding; Karyopharm: Research Funding; PracticeUpdate Oncology: Consultancy; MD Anderson: Research Funding; AbbVie: Research Funding; Acerta: Consultancy, Honoraria, Other: leadership role, Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: leadership role, Research Funding; Xcenda: Consultancy; Infinity Verastem: Research Funding; RCCA/OMI: Current Employment; Morphosys: Research Funding; Genentech/Roche: Research Funding; Hackensack UMC and University of Nebraska: Research Funding; Bayer: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: leadership role, Research Funding; Kite, a Gilead Company: Consultancy, Current equity holder in publicly-traded company, Honoraria, Other: leadership role, Research Funding; CALBG: Research Funding. Casasnovas:Roche: Consultancy, Honoraria, Other: travel, accomodations, expenses, Research Funding; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Takeda: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Abbvie: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Thieblemont:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Cellectis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Speakers Bureau; Bristol-Myers Squibb: Consultancy, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Hospira: Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company); Incyte: Honoraria; Bayer: Honoraria; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support. Cavallo:Gilead: Other: Speaker Fee; Takeda, Janssen: Membership on an entity's Board of Directors or advisory committees. Hill:Pharmacyclics: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Takeda: Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding. Tilly:BMS: Honoraria. Jaeger:Novartis: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Karyopharm: Honoraria; CDR Life AG: Consultancy, Research Funding; Miltenyi: Consultancy, Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Honoraria. Gurion:JC Health CARE: Consultancy, Honoraria; Medison: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Takeda Pharmaceuticals: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Caimi:Celgene Corp: Other: Incyte Corporation - Ownership - Pharmacyclics, Inc. - Ownership - Celgene Corp. - Other, Speakers Bureau; ADC Therapeutics: Research Funding; Genentech: Research Funding. Martin:Janssen: Consultancy; Regeneron: Consultancy; Teneobio: Consultancy; Celgene: Consultancy; Sandoz: Consultancy; I-MAB: Consultancy; Bayer: Consultancy; Beigene: Consultancy; Cellectar: Consultancy; Incyte: Consultancy; Kite: Consultancy; Morphosys: Consultancy; Karyopharm: Consultancy, Research Funding. Davies:Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding; Celegene, Roche, Kite Pharma, Celegene: Honoraria. Smith:TG Therapeutics: Consultancy, Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding; FortySeven: Research Funding; Karyopharm: Consultancy, Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; Celgene: Consultancy, Research Funding; BMS: Consultancy; Janssen: Consultancy. Collins:Amgen: Research Funding; Pfizer: Honoraria; Celgene: Research Funding; Celleron: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau; ADC Therapeutics: Consultancy, Honoraria; Roche: Consultancy, Honoraria, Other: travel, accommodations, expenses , Speakers Bureau; Taekda: Consultancy, Honoraria, Other: travel, accommodations, expenses, Speakers Bureau; Gilead: Consultancy, Honoraria, Speakers Bureau; MSD: Consultancy, Honoraria, Research Funding; BeiGene: Consultancy; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau. Salles:Abbvie: Consultancy, Honoraria, Other: Participation in educational events; Novartis: Consultancy, Honoraria, Other; MorphoSys: Consultancy, Honoraria, Other; Debiopharm: Consultancy; Genmab: Consultancy; Karyopharm: Consultancy; Amgen: Honoraria, Other: Participation in educational events; Kite: Consultancy, Honoraria, Other; Epizyme: Consultancy; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Other; Takeda: Consultancy, Honoraria, Other; Bristol Myers Squibb: Consultancy, Other; Autolus: Consultancy; Gilead: Consultancy, Honoraria, Other: Participation in educational events; Janssen: Consultancy, Honoraria, Other: Participation in educational events; Celgene: Consultancy, Honoraria, Other: Participation in educational events. Ma:Karyopharm: Current Employment, Current equity holder in private company. Corona:Karyopharm: Current Employment. Saint-Martin:Karyopharm: Current Employment. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chamoun:Karyopharm: Current Employment. Wang:Curis: Ended employment in the past 24 months; Karyopharm: Current Employment. Shah:Karyopharm: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees.

Introduction: Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) that blocks XPO1, forcing the nuclear retention and re-activation of tumor suppressor proteins including p53, p73, FOXO, IkB and Rb. The phase 2b SADAL study included 134 patients with relapsed or refractory DLBCL with single agent oral selinexor twice weekly. The overall response rate (ORR) was 29.1%, median duration of response (DOR) was 9.3 months and the median overall survival (OS) was 9 months. Based on these data, selinexor was recently approved by the US FDA for the treatment of relapsed or refractory DLBCL, de novo or transformed from follicular lymphoma. Patients with DLBCL tend to have a number of comorbidities, including poor renal function, which can require a reduction in the dose of intensive chemotherapy as well as lenalidomide, leading to inferior outcomes. Selinexor is not metabolized nor cleared by the kidneys and has been demonstrated to be safe and active in patients with myeloma and renal dysfunction. We performed post-hoc analyses of the SADAL study to determine the efficacy and safety among patients stratified by renal function at baseline. Methods: The SADAL study is multi-center, open-label Phase 2b study that enrolled patients with DLBCL previously treated with 2-5 lines of therapy. Patients may have progressed post-stem cell therapy (SCT) or were not candidates for SCT. In this study, 60 mg of selinexor was administered twice weekly until disease progression. The primary endpoint was ORR, and other endpoints included DOR, OS, and safety assessments. For the current analysis, outcomes were assessed according to baseline renal function as estimated by the Cockroft-Gault formula for creatinine clearance (CrCl). Groups included those with reduced (CrCl ≤60 mL/min) and normal (CrCl >60 mL/min) renal function. Results: Of 134 patients, 37 (28%) had a reduced baseline CrCl (≤60 mL/min) while 97 (72%) had CrCl >60 mL/min. The median age of patients with reduced CrCl was 74 years with 70% ≥70 years, while the median for those with normal CrCl was 65 years, with 35% ≥70 years. De novo and transformed DLBCL showed similar renal function levels: 78% and 22% with reduced CrCl and 76% and 24% with normal CrCl. Of patients with reduced CrCl, the DLBCL subtype was 41% GCB and 57% non-GCB compared to 50% and 46% in patients with normal CrCl. The group of patients with reduced CrCl had baseline ECOG performance status of 2 in 16% vs 11% in those with normal CrCl. Treatment with selinexor demonstrated a similar ORR in patients with a baseline reduced CrCl (29.7%) versus normal CrCl (28.9%). A complete response (CR) was observed in 8 (21.6%) patients with reduced and 10 (10.3%) patients with normal CrCl. The median duration of response (DOR) in patients who had reduced CrCl was 23.0 months compared to 9.2 months in patients with normal CrCl. The median progression-free survival (PFS) was 3.5 months (95% CI 1.7, 24.8) and 2.3 months (95% CI 1.9, 3.7) and overall survival was 7.8 months and 9.1 months in patients with reduced CrCl and those with normal CrCl. The most common grade ≥3 treatment-related AEs for patients with reduced versus normal CrCl were thrombocytopenia (45.9% vs. 38.1%), nausea (5.4% vs. 6.2%), and fatigue (8.1% vs. 11.3%). There was no clinically significant increase in treatment-related serious adverse events (21.6% vs. 20.6%) and adverse events leading to discontinuation (10.8% vs. 7.2%) in patients with reduced or normal CrCl, respectively. Conclusions: Selinexor showed similar anti-DLBCL activity and tolerability in patients with relapsed/refractory DLBCL with a reduced renal function (CrCl Disclosures Schuster: Amgen, Abbvie, Gilead, Takeda, Celgene, Pharmacyclics, Astellas, Verastem, Merck, Novartis, Takeda, Genentech,, Seattle Genetics: Other: Personal Fees; Karyopharm: Membership on an entity's Board of Directors or advisory committees. Canales:Novartis: Honoraria; Janssen: Honoraria; Novartis: Honoraria; iQone: Honoraria; Sandoz: Speakers Bureau; Karyopharm: Honoraria; Janssen: Speakers Bureau; Janssen: Honoraria; Roche: Speakers Bureau; Takeda: Speakers Bureau; Janssen: Speakers Bureau; Roche: Speakers Bureau; Sandoz: Speakers Bureau; Takeda: Speakers Bureau; Celgene: Honoraria; Roche: Honoraria; Sandoz: Honoraria; Sandoz: Honoraria; Gilead: Honoraria; Roche: Honoraria; Karyopharm: Honoraria. Westin:Novartis: Consultancy, Research Funding; Kite: Consultancy, Research Funding; Curis: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Morphosys: Consultancy, Research Funding; Amgen: Consultancy; 47: Research Funding. Zijlstra:Roche: Research Funding. Follows:Karyopharm, Roche, Abbvie, Astrazeneca, Janssen, BMS: Membership on an entity's Board of Directors or advisory committees. Karmali:Takeda: Research Funding; AstraZeneca: Speakers Bureau; Karyopharm: Honoraria; BeiGene: Speakers Bureau; BMS/Celgene/Juno: Honoraria, Other, Research Funding, Speakers Bureau; Gilead/Kite: Honoraria, Other, Research Funding, Speakers Bureau. Kalakonda:Gilead, Janssen, Karyopharm: Honoraria; Verastem, Gilead, Celgene, Roche: Research Funding. Goy:AbbVie: Research Funding; Celgene: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Other: leadership role, Research Funding; Acerta: Consultancy, Honoraria, Other: leadership role, Research Funding; MD Anderson: Research Funding; Xcenda: Consultancy; Kite, a Gilead Company: Consultancy, Current equity holder in publicly-traded company, Honoraria, Other: leadership role, Research Funding; Regional Cancer Care Associates/OMI: Current Employment; Bayer: Research Funding; PracticeUpdate Oncology: Consultancy; RCCA/OMI: Current Employment; Morphosys: Research Funding; Karyopharm: Research Funding; Genentech/Roche: Research Funding; Constellation: Research Funding; CALBG: Research Funding; Infinity Verastem: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: leadership role, Research Funding; COTA: Consultancy, Current equity holder in publicly-traded company, Other: leadership role; Hackensack UMC and University of Nebraska: Research Funding; Infinity: Research Funding. Casasnovas:Takeda: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Gilead: Consultancy, Honoraria, Other: TRAVEL, ACCOMMODATIONS, EXPENSES (paid by any for-profit health care company), Research Funding; Roche: Consultancy, Honoraria, Other: travel, accomodations, expenses, Research Funding; Abbvie: Consultancy, Honoraria; MSD: Consultancy, Honoraria; Amgen: Consultancy, Honoraria. Thieblemont:Cellectis: Speakers Bureau; Roche, Amgen, Kyte Gilead, Celgene, Abbvie, Novartis, Cellectis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Roche, Hospita: Research Funding. Cavallo:Takeda, Janssen: Membership on an entity's Board of Directors or advisory committees; Gilead: Other: Speaker Fee. Hill:Celgene: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria; Kite, a Gilead Company: Consultancy, Honoraria, Research Funding; AstraZenica: Consultancy, Honoraria, Research Funding; Beigene: Consultancy, Honoraria, Research Funding; Pharmacyclics: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria, Research Funding; Takeda: Research Funding. Tilly:BMS: Honoraria. Jaeger:Novartis: Consultancy, Honoraria, Research Funding; Gilead: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; Karyopharm: Honoraria; AbbVie: Honoraria; F. Hoffmann-La Roche: Honoraria, Research Funding; Miltenyi: Consultancy, Honoraria; CDR Life AG: Consultancy, Research Funding. Gurion:JC Health CARE: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda Pharmaceuticals: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Medison: Consultancy, Honoraria. Caimi:Celgene Corp: Other: Incyte Corporation - Ownership - Pharmacyclics, Inc. - Ownership - Celgene Corp. - Other, Speakers Bureau; ADC Therapeutics: Research Funding; Genentech: Research Funding. Martin:Kite: Consultancy; Morphosys: Consultancy; I-MAB: Consultancy; Janssen: Consultancy; Sandoz: Consultancy; Regeneron: Consultancy; Incyte: Consultancy; Karyopharm: Consultancy, Research Funding; Teneobio: Consultancy; Celgene: Consultancy; Bayer: Consultancy; Cellectar: Consultancy; Beigene: Consultancy. Davies:Roche, Acerta Pharma, AstraZeneca, Celgene, Gilead, ADC Therapeutics, Gilead: Research Funding; Roche, Celgene, Kite Pharma, Acerta, Karyopharma, Regeneron, Incyte: Consultancy; Roche: Other: TRAVEL, ACCOMMODATIONS, EXPENSES; Celegene, Roche, Kite Pharma, Celegene: Honoraria. Smith:TG Therapeutics: Consultancy, Research Funding; Janssen: Consultancy; Celgene: Consultancy, Research Funding; BMS: Consultancy; Karyopharm: Consultancy, Research Funding; FortySeven: Research Funding; Pharmacyclics: Research Funding; Acerta: Research Funding; Genentech/Roche: Consultancy, Other: Support of parent study and funding of editorial support, Research Funding. Collins:BeiGene: Consultancy; MSD: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Speakers Bureau; Taekda: Consultancy, Honoraria, Other: travel, accommodations, expenses, Speakers Bureau; BMS: Consultancy, Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria; ADC Therapeutics: Consultancy, Honoraria; Celleron: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Speakers Bureau; Celgene: Research Funding; Roche: Consultancy, Honoraria, Other: travel, accommodations, expenses , Speakers Bureau; Amgen: Research Funding. Salles:Epizyme: Consultancy; Gilead: Consultancy, Honoraria, Other: Participation in educational events; Abbvie: Consultancy, Honoraria, Other: Participation in educational events; Janssen: Consultancy, Honoraria, Other: Participation in educational events; Kite: Consultancy, Honoraria, Other; Debiopharm: Consultancy; Celgene: Consultancy, Honoraria, Other: Participation in educational events; Karyopharm: Consultancy; Genmab: Consultancy; Amgen: Honoraria, Other: Participation in educational events; Autolus: Consultancy; MorphoSys: Consultancy, Honoraria, Other; Novartis: Consultancy, Honoraria, Other; F. Hoffman-La Roche Ltd: Consultancy, Honoraria, Other; Bristol Myers Squibb: Consultancy, Other; Takeda: Consultancy, Honoraria, Other. Ma:Karyopharm: Current Employment, Current equity holder in private company. Corona:Karyopharm: Current Employment. Saint-Martin:Karyopharm: Current Employment. Joshi:Karyopharm Therapeutics Inc: Consultancy. Chamoun:Karyopharm: Current Employment. Wang:Curis: Ended employment in the past 24 months; Karyopharm: Current Employment. Shah:Karyopharm: Current Employment, Current equity holder in publicly-traded company. Shacham:Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman:Karyopharm Therapeutics Inc: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees.

Selinexor is an oral inhibitor of the nuclear export protein exportin 1. Preclinical studies demonstrated synergistic antimyeloma activity between selinexor and proteasome inhibitors (PI) through suppression of NF-κB signaling and nuclear retention of tumor suppressor proteins. We tested selinexor in combination with low-dose bortezomib and dexamethasone (SVd) for the treatment of relapsed or refractory multiple myeloma (MM). The primary objectives of this study were to determine the safety profile, overall response rate (ORR), and a recommended phase 2 dose (RP2D) of SVd. We enrolled 42 patients to receive selinexor (60, 80, or 100 mg orally) plus bortezomib (1.3 mg/m2 subcutaneously) and dexamethasone (20 mg orally) once or twice weekly in 21- or 35-day cycles. Patients had a median of 3 (range 1-11) prior lines of therapy, and 50% were refractory to a PI. Treatment-related grade 3 or 4 adverse events reported in ≥10% of patients were thrombocytopenia (45%), neutropenia (24%), fatigue (14%), and anemia (12%). Incidence (4 patients, 10%) and grade (≤2) of peripheral neuropathy were low. The ORR for the entire population was 63%: 84% ORR for PI nonrefractory and 43% for PI-refractory patients. The median progression-free survival for all patients was 9.0 months; 17.8 months for PI nonrefractory, and 6.1 months for PI refractory. SVd treatment produced high response rates in patients with relapsed or refractory MM, including borezomib-refractory MM, with no unexpected side effects. The RP2D is selinexor (100 mg once weekly), bortezomib (1.3 mg/m2 once weekly for 4 weeks), and dexamethasone (40 mg once weekly) per 35-day cycle. This trial was registered at www.clinicaltrials.gov as #NCT02343042.

Purpose We evaluated the pharmacokinetics (PKs), pharmacodynamics, safety, and efficacy of selinexor, an oral selective inhibitor of nuclear export compound, in patients with advanced soft tissue or bone sarcoma with progressive disease. Patients and Methods Fifty-four patients were treated with oral selinexor twice per week (on days 1 and 3) at one of three doses (30 mg/m2, 50 mg/m2, or flat dose of 60 mg) either continuously or on a schedule of 3 weeks on, 1 week off. PK analysis was performed under fasting and fed states (low v high fat content) and using various formulations of selinexor (tablet, capsule, or suspension). Tumor biopsies before and during treatment were evaluated for pharmacodynamic changes. Results The most commonly reported drug-related adverse events (grade 1 or 2) were nausea, vomiting, anorexia, and fatigue, which were well managed with supportive care. Commonly reported grade 3 or 4 toxicities were fatigue, thrombocytopenia, anemia, lymphopenia, and leukopenia. Selinexor was significantly better tolerated when administered as a flat dose on an intermittent schedule. PK analysis of selinexor revealed a clinically insignificant increase (approximately 15% to 20%) in drug exposure when taken with food. Immunohistochemical analysis of paired tumor biopsies revealed increased nuclear accumulation of tumor suppressor proteins, decreased cell proliferation, increased apoptosis, and stromal deposition. Of the 52 patients evaluable for response, none experienced an objective response by RECIST (version 1.1); however, 17 (33%) showed durable (≥ 4 months) stable disease, including seven (47%) of 15 evaluable patients with dedifferentiated liposarcoma. Conclusion Selinexor was well tolerated at a 60-mg flat dose on a 3-weeks-on, 1-week-off schedule. There was no clinically meaningful impact of food on PKs. Preliminary evidence of anticancer activity in sarcoma was demonstrated.

Introduction: R/R DLBCL patients who have received ≥2 lines of therapy, including those progressed post stem cell transplantation (SCT) or who are not candidates for SCT, have limited treatment options. Selinexor, a selective oral XPO1 inhibitor leads to nuclear accumulation and activation of tumor suppressor proteins and reductions in c-Myc and Bcl-2 oncogenes. Selinexor plus low dose dexamethasone (Sel-dex) was recently approved in relapsed/refractory myeloma in the United States based on data from the STORM study, wherein Sel-dex induced an overall response rate (ORR) of 26.2% in patients with penta-exposed, triple-class refractory multiple myeloma. We conducted the SADAL study to evaluate the efficacy and safety of single agent selinexor in patients with R/R DLBCL. In this patient population, selinexor demonstrated deep and durable responses with an overall response rate (ORR) of 28.3% including a 11.0% complete response (CR) rate. The median duration of response (DOR) was 9.2 months. In patients with CR, the DOR was 13.4 months. Here we evaluate the effect of prior therapy on the efficacy and safety of selinexor. Methods: SADAL is a multicenter, open-label study in R/R DLBCL patients with 2-5 prior lines of therapy, who may have progressed post SCT or are not candidates for SCT. Patients were stratified by subtype (germinal center B-cell or non-GCB) and treated with 60 mg selinexor BIW per 28-day cycle. The primary endpoint was ORR. Secondary endpoints included duration of response (DOR) and safety. We performed post-hoc analyses to compare outcomes based on the number (2 vs. >2) and type (SCT vs. no SCT) of prior lines of therapy received. Results: Of 127 patients, 83 (65%) received 2 prior lines of therapy and 43 (34%) received >2 prior lines of therapy. Thirty-six patients (28%) received prior SCT and 91 (72%) had no prior SCT. In general, patient demographic and baseline characteristics were well balanced in both subgroups. ORR was 30.1% vs. 25.6% (P=0.74) in patients with 2 vs >2 prior lines of therapy respectively. The CR rate was 10.8% in patients with 2 prior lines of therapy compared with 11.6% in patients with >2 prior lines of therapy (P=1.00). The median DOR was 9.2 months in patients with 2 prior lines of therapy compared with 8.4 months in those with >2 prior lines of therapy (P=0.64). Median progression free survival was 3.7 months and 1.9 months (P=0.37) and median overall survival was 11.0 months and 9.8 months (P=0.69) in patients with 2 and >2 prior lines of therapy respectively. In patients with prior SCT, the ORR was 44.4% compared with 22.0 % (P=0.02) in patients with no prior SCT. The CR rate was 16.7% in patients with prior SCT compared with 8.8% in patients with no prior SCT (P=0.34). The DOR was 8.4 months in patients with prior SCT and 9.2 months with no prior SCT (P=0.80). Median progression free survival was 5.9 months and 2.3 months (P=0.07) and median overall survival was 9.1 and 9.8 months (P=0.36) in patients with prior SCT and no prior SCT respectively. The most common related adverse events (AEs) [grade ≥3] included thrombocytopenia (2 prior lines: 36%, >2 prior lines: 42%; prior SCT: 58%, no prior SCT: 31%), neutropenia (2 prior lines: 19%, >2 lines: 23%; prior SCT: 25%, no prior SCT: 20%), and anemia (2 prior lines: 15%, >2 prior lines: 14%, prior SCT: 17%, no prior SCT: 14%). Treatment-related serious AEs were reported in 23%, 14%, 25%, and 19% of patients with 2 prior lines, >2 prior lines, prior SCT, and no prior SCT respectively. Conclusions: Single agent oral selinexor with its novel mechanism of action demonstrated deep and durable responses with no new safety signals regardless of prior therapy. Patients with 2 prior lines of therapy had a higher response rate (30.1% vs. 25.6%) compared with those with >2 prior lines of therapy. The greatest benefit, with an ORR of 44.4% was observed in patients with prior SCT. Collectively, these data support the clinical benefit of single agent selinexor and importantly in earlier lines of therapy. Further evaluation of selinexor in combination with other agents to improve outcomes in R/R DLBCL is ongoing. Disclosures Cavallo: Takeda: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees. Follows:Roche: Consultancy, Honoraria, Speakers Bureau; Abbvie: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Goy:Astrazenca: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Hackensack University Medical Center, RCCA: Employment; Pharmacyclics/Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work; Takeda: Other: Grants outside of the submitted work; Acerta: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Grants outside of the submitted work, Research Funding; Genentech: Other: Grants outside of the submitted work, Research Funding; University of Nebraska: Research Funding; Hakensackumc: Research Funding; COTA: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Other: leadership role for profit healthcare company. Casasnovas:Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Merck Sharp and Dohme: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Abbvie: 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, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Zijlstra:Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria. Choquet:Keocyt: Honoraria. Gurion:Roche: Consultancy. Hill:TG therapeutics: Research Funding; Abbvie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Research Funding; Kite: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria; Celegene: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria; Takeda: Research Funding; Amgen: Research Funding. Jaeger:Novartis, Roche, Sandoz: Consultancy; AbbVie, Celgene, Gilead, Novartis, Roche, Takeda Millennium: Research Funding; Celgene, Roche, Janssen, Gilead, Novartis, MSD, AbbVie, Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen, AbbVie, Celgene, Eisai, Gilead, Janssen, Novartis, Roche, Takeda Millennium, MSD, BMS, Sanofi: Honoraria. Sancho:Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Sandoz: Consultancy; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Honoraria, Other: Advisory board; Novartis: Honoraria; Kern Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria; Celltrion: Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squib: Membership on an entity's Board of Directors or advisory committees. Schuster:Celgene: Speakers Bureau; Genentech: Speakers Bureau; Janssen: Speakers Bureau; Novartis: Speakers Bureau; Seattle Genetics: Speakers Bureau; Takeda: Speakers Bureau; Verastem: Speakers Bureau; Astellas: Speakers Bureau; Actinium: Research Funding; Incyte: Research Funding; Karyopharm Therapeutics: Research Funding; Morphosys: Research Funding; Nordic Nanovector: Research Funding; Pharmacyclics: Research Funding, Speakers Bureau; Rafael: Research Funding; F2G Ltd.: Research Funding; AbbVie: Speakers Bureau; Amgen: Speakers Bureau. Thieblemont:Roche: Honoraria, Research Funding; Gilead: Honoraria; Novartis: Honoraria; Kyte: Honoraria; Janssen: Honoraria; Celgene: Honoraria; Cellectis: Membership on an entity's Board of Directors or advisory committees. Vassilakopoulos:Abbvie: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene / GenesisPharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; WinMedica: 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. McCarthy:Karyopharm Therapeutics: Employment, Equity Ownership. Ma:Karyopharm: Employment, Equity Ownership. Corona:Karyopharm Therapeutics: Employment, Equity Ownership. Saint-Martin:Karyopharm Therapeutics: Employment, Equity Ownership. Joshi:Karyopharm Therapeutics: Employment, Equity Ownership. Shah:Karyopharm Therapeutics: Employment, Equity Ownership. Van Den Neste:Gilead: Other: travel support. Canales:Sandoz: Honoraria; F. Hoffmann-La Roche Ltd: Honoraria, Speakers Bureau; Celgene: Honoraria; Novartis: Honoraria; Takeda: Speakers Bureau; SOBI: Research Funding; iQone: Honoraria; Karyopharm: Honoraria; Gilead: Honoraria; Janssen: Honoraria, Speakers Bureau.

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.

Selinexor is a novel, first-in-class, selective inhibitor of nuclear export compound, which blocks exportin 1 (XPO1) function, leads to nuclear accumulation of tumor suppressor proteins, and induces cancer cell death. A phase 1 dose-escalation study was initiated to examine the safety and efficacy of selinexor in patients with advanced hematological malignancies. Ninety-five patients with relapsed or refractory acute myeloid leukemia (AML) were enrolled between January 2013 and June 2014 to receive 4, 8, or 10 doses of selinexor in a 21- or 28-day cycle. The most frequently reported adverse events (AEs) in patients with AML were grade 1 or 2 constitutional and gastrointestinal toxicities, which were generally manageable with supportive care. The only nonhematological grade 3/4 AE, occurring in >5% of the patient population, was fatigue (14%). There were no reported dose-limiting toxicities or evidence of cumulative toxicity. The recommended phase 2 dose was established at 60 mg (∼35 mg/m2) given twice weekly in a 4-week cycle based on the totality of safety and efficacy data. Overall, 14% of the 81 evaluable patients achieved an objective response (OR) and 31% percent showed ≥50% decrease in bone marrow blasts from baseline. Patients achieving an OR had a significant improvement in median progression-free survival (PFS) (5.1 vs 1.3 months; P = .008; hazard ratio [HR], 3.1) and overall survival (9.7 vs 2.7 months; P = .01; HR, 3.1) compared with nonresponders. These findings suggest that selinexor is safe as a monotherapy in patients with relapsed or refractory AML and have informed subsequent phase 2 clinical development. This trial was registered at www.clinicaltrials.gov as #NCT01607892.

Patients with relapsed or refractory (R/R) non-Hodgkin lymphoma (NHL) have a poor prognosis and limited treatment options. We evaluated selinexor, an orally bioavailable, first-in-class inhibitor of the nuclear export protein XPO1, in this phase 1 trial to assess safety and determine a recommended phase 2 dose (RP2D). Seventy-nine patients with various NHL histologies, including diffuse large B-cell lymphoma, Richter’s transformation, mantle cell lymphoma, follicular lymphoma, and chronic lymphocytic leukemia, were enrolled. In the dose-escalation phase, patients received 3 to 80 mg/m2 of selinexor in 3- or 4-week cycles and were assessed for toxicities, pharmacokinetics, and antitumor activity. In the dose-expansion phase, patients were treated with selinexor at 35 or 60 mg/m2. The most common grade 3 to 4 drug-related adverse events were thrombocytopenia (47%), neutropenia (32%), anemia (27%), leukopenia (16%), fatigue (11%), and hyponatremia (10%). Tumor biopsies showed decreases in cell-signaling pathways (Bcl-2, Bcl-6, c-Myc), reduced proliferation (Ki67), nuclear localization of XPO1 cargos (p53, PTEN), and increased apoptosis after treatment. Twenty-two (31%) of the 70 evaluable patients had an objective responses, including 4 complete responses and 18 partial responses, which were observed across a spectrum of NHL subtypes. A dose of 35 mg/m2 (60 mg) was identified as the RP2D. These findings suggest that inhibition of XPO1 with oral selinexor at 35 mg/m2 is a safe therapy with encouraging and durable anticancer activity in patients with R/R NHL. The trial was registered at www.clinicaltrials.gov as #NCT01607892.

Purpose This trial evaluated the safety, pharmacokinetics, pharmacodynamics, and efficacy of selinexor (KPT-330), a novel, oral small-molecule inhibitor of exportin 1 (XPO1/CRM1), and determined the recommended phase II dose. Patients and Methods In total, 189 patients with advanced solid tumors received selinexor (3 to 85 mg/m2) in 21- or 28-day cycles. Pre- and post-treatment levels of XPO1 mRNA in patient-derived leukocytes were determined by reverse transcriptase quantitative polymerase chain reaction, and tumor biopsies were examined by immunohistochemistry for changes in markers consistent with XPO1 inhibition. Antitumor response was assessed according Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 guidelines. Results The most common treatment-related adverse events included fatigue (70%), nausea (70%), anorexia (66%), and vomiting (49%), which were generally grade 1 or 2. Most commonly reported grade 3 or 4 toxicities were thrombocytopenia (16%), fatigue (15%), and hyponatremia (13%). Clinically significant major organ or cumulative toxicities were rare. The maximum-tolerated dose was defined at 65 mg/m2 using a twice-a-week (days 1 and 3) dosing schedule. The recommended phase II dose of 35 mg/m2 given twice a week was chosen based on better patient tolerability and no demonstrable improvement in radiologic response or disease stabilization compared with higher doses. Pharmacokinetics were dose proportional, with no evidence of drug accumulation. Dose-dependent elevations in XPO1 mRNA in leukocytes were demonstrated up to a dose level of 28 mg/m2 before plateauing, and paired tumor biopsies showed nuclear accumulation of key tumor-suppressor proteins, reduction of cell proliferation, and induction of apoptosis. Among 157 patients evaluable for response, one complete and six partial responses were observed (n = 7, 4%), with 27 patients (17%) achieving stable disease for ≥ 4 months. Conclusion Selinexor is a novel and safe therapeutic with broad antitumor activity. Further interrogation into this class of therapy is warranted.

Introduction - The nuclear export protein exportin 1 (XPO1) is overexpressed in a wide variety of cancers including multiple myeloma (MM). Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) compound that binds and inactivates XPO1. Selinexor forces nuclear retention and reactivation of cell cycle regulators such as p53, IkB, and Rb. Pomalidomide/dexamethasone (Pd) is approved in relapsed/refractory MM (RRMM)with an overall response rate (ORR) of 30% and progression-free survival (PFS) rate of Methods- Pts with RRMM who received ≥ 2 prior therapies including lenalidomide (len) and a PI were enrolled. Selinexor was evaluated in 2 different dosing schedules of once-weekly (QW, 60 or 80 mg) or twice-weekly (BIW, 60 or 80 mg), with pomalidomide (pom)3 or 4 mg PO daily, and dexamethasone (dex) 20 mg BIW or 40 mg QW. The primary objectives were to determine the maximum tolerated dose (MTD), recommended phase 2 dose (RP2D), safety, and preliminary efficacy of the combination of selinexor, pomalidomide, and low dose dex (SPd) in pts with RRMM. Results- As of July 20th2018, 34 pts (16 male / 18 female) have been enrolled. The median age is 61 years and patients received a median of 4 (range, 2 - 9) prior treatment regimens. Thirty-two patients were IMiD refractory (21 len, 11 pom/len). Six dose limiting toxicities (DLTs) were observed: G3 fatigue (60 mg BIW, pom 4 mg), G3 febrile neutropenia (FN) (60 mg BIW, pom 3 mg), G3 FN and G4 neutropenia (80 mg QW, pom 4), G3 thrombocytopenia (80 mg QW, pom 3 mg) and 4 missed doses in Cycle 1 due to symptomatic hyponatremia (80 mg BIW, pom 4 mg). Enrollment on selinexor 80 mg QW, pom 3 mg is ongoing. Common SPd treatment related adverse events included (all grades, grades 3/4): neutropenia (62%, 56%), thrombocytopenia (59%, 32%), anemia (53%, 29%), anorexia (56%, 0%), fatigue (50%, 9%), nausea (47%, 0% ). Thirty pts were evaluable for response, which is outlined in Table 1. Median PFS is 10.3 months with a median follow up of 9.4 months. Conclusions- Enrollment is ongoing to evaluate once weekly selinexor in combination with Pd , (SPd). This all-oral SPd combination has clinical activity with an ORR 55% in pom-naive pts with heavily pretreated MM compared to previously published data of 30% ORR for Pd alone. Similarly, the PFS on SPd is 10.3 months vs. Disclosures Chen: Amgen: Honoraria. Sebag:Janssen Inc.: Membership on an entity's Board of Directors or advisory committees; Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees; Celgene Canada: Membership on an entity's Board of Directors or advisory committees. White:Amgen, Celgene, Janssen, Takeda: Honoraria. Bensinger:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Speakers Bureau; celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Speakers Bureau. Gasparetto:Bristol-Myers Squibb: Consultancy, Honoraria, Other: Travel; Janssen: Consultancy, Honoraria, Other: Travel; Takeda: Honoraria; Celgene: Consultancy, Honoraria, Other: Travel, Research Funding. Leblanc:Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees. Venner:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria. Schiller:Pharmacyclics: Research Funding; Celator/Jazz Pharmaceuticals: Research Funding. Lipe:Celgene: Consultancy. Shah:Karyopharm Therapeutics: Employment. Jeha:Karyopharm Therapeutics: Employment. Saint-Martin:Karyopharm Therapeutics: Employment. Kauffman:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Bahlis:Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding.

Introduction - Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) compound that binds and inactivates Exportin 1 (XPO1). Selinexor with low dose dexamethasone (Sd) or in with protesome inhibitors (PIs) or immunomodulatory drugs (IMiDs), has shown anti-MM activity in patients (pts) with relapsed or refractory MM. Daratumumab (Dara), an anti-CD38 mAb, is approved for the treatment of heavily pretreated MM is limited by short PFS and an ORR of ~21% in quad-refractory MM. Selinexor in combiniation with dara have shown preclinical synergistic killing of MM cells. Methods - Pts were eligible if they had received ≥ 3 prior lines of anti-myeloma therapy, including a PI and an IMiD. Selinexor was dose-escalated in 2 concurrent cohorts: once-weekly (QW, at 100 mg) or twice-weekly (BIW, at 60 mg). Dara was 16 mg/kg IV (recommended schedule) and dexamethasone (dex) was 40 mg QW or 20 mg BIW. The objectives were to determine the maximum tolerated dose (MTD), recommended phase 2 dose (RP2D), safety, tolerability and preliminary efficacy of the combination of this SDd combination in pts with PI/IMiD refractory MM Results - As of Jul 20th2018, 25 pts (11 males / 14 females) have been enrolled. Three pts have been enrolled into the 60 mg BIW and 22 pts in the 100 mg QW cohorts. Pts have a median age of 68 years and a median of 3 (range, 2 - 10) prior treatment regimens. Common SDd treatment related adverse events included (all grades, grades 3/4): thrombocytopenia (58%, 42%), leukopenia (54%, 38%), anemia (46%, 29%), nausea (50%, 0%) and fatigue (46%, 8%). Two dose limiting toxicities (DLTs) were reported in the 60 mg BIW cohort: G3 thrombocytopenia and G2 fatigue requiring dose reduction in selinexor to 100 mg QW. In the 100 mg QW escalation cohort, 6 pts enrolled, 5 evaluable, with no DLTs. This cohort was expanded and enrollment is ongoing. A total of 21 pts were evaluable for response. In 19 dara-naïve pts, the ORR was 74% (5 VGPR, 9 PR, 2 MR, 2 SD, 1 PD), including 3 unconfirmed PRs, 1 unconfirmed MR. In the 2 pts with dara refractory MM, there was one PD and one SD. The longest duration of therapy is 13 months. Based on tolerability and efficacy, the RP2D of SDd is selinexor 100 mg, daratumumab 16 mg/kg and dex 40 mg, administered QW. Conclusions - Selinexor 100 mg QW can be combined safely with dara (per approved dosing) and dex. The preliminary ORR of 74% with SDd in patients with PI/IMiD refractory MM who are dara naïve is promising and compares favorably to 21% ORR of Dara and Sd in quad refractory myeloma. This once weekly regimen is well tolerated with no major organ toxicities to date. Data from the full phase 1 dose expansion will be presented. Disclosures Gasparetto: Takeda: Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria, Other: Travel; Janssen: Consultancy, Honoraria, Other: Travel; Celgene: Consultancy, Honoraria, Other: Travel, Research Funding. Schiller:Celator/Jazz Pharmaceuticals: Research Funding; Pharmacyclics: Research Funding. Bensinger:Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; amgen: Speakers Bureau; Takeda: Speakers Bureau. Bahlis:Celgene: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria. White:Amgen, Celgene, Janssen, Takeda: Honoraria. Sebag:Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees; Janssen Inc.: Membership on an entity's Board of Directors or advisory committees; Celgene Canada: Membership on an entity's Board of Directors or advisory committees. Venner:Janssen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Amgen: Honoraria; Takeda: Honoraria. Leblanc:Janssen Inc.: Membership on an entity's Board of Directors or advisory committees; Amgen Canada: Membership on an entity's Board of Directors or advisory committees; Celgene Canada: Membership on an entity's Board of Directors or advisory committees; Takeda Canada: Membership on an entity's Board of Directors or advisory committees. Chen:Amgen: Honoraria. Shah:Karyopharm Therapeutics: Employment. Jeha:Karyopharm Therapeutics: Employment. Saint-Martin:Karyopharm Therapeutics: Employment. Kauffman:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Lipe:Celgene: Consultancy.

Introduction - With over 12,000 deaths from MM anticipated in 2016, nearly all patients (pts) with multiple myeloma (MM) will become "quad refractory" to IMIDs (lenalidomide and pomalidomide) and proteasome inhibitors (bortezomib and carfilzomib), and eventually "penta refractory" to anti-CD38 Abs (daratumumab and isatuximab), defining high unmet need populations. Selinexor, an oral selective XPO1 inhibitor, induces nuclear accumulation and activation of tumor suppressor proteins, inhibition of NF-kB, and inhibition of translation of several oncoprotein mRNAs such as c-myc and cyclin D. Selinexor showed potent induction of apoptosis of MM cells independent of p53 signaling. In phase 1 clinical studies, selinexor with low dose dexamethasone (Sd) demonstrated potent anti MM activity in pts with MM. Methods - This phase II clinical trial evaluated Sd in pts with MM refractory to bortezomib, carfilzomib, lenalidomide, and pomalidomide ("quad"), with a subset also refractory to an anti-CD38 Ab ("penta"). Inclusion required CrCL≥20 mL/min, ANC≥1000/µL, platelets ≥50K/µL (≥30K if plasma cells were ≥50% of marrow cellularity). Pts were treated twice weekly (BIW) with oral selinexor 80 mg for 6 or 8 doses per 28 day cycle and dexamethasone (dex) 20 mg BIW. All pts received 5-HT3 antagonists. The primary objective was to determine the overall response rate (ORR) per IMWG criteria and duration of response (DOR), both adjudicated by an independent review committee (IRC). Secondary endpoints include progression free survival (PFS) and overall survival (OS). FISH analyses and gene expression profiling were performed on bone marrow aspirates. Results - 79 pts were enrolled: 48 quad (24 M/24 F, median age 62 yrs) and 31 penta (13 M / 18 F, median age 68 yrs). Both groups had a median of 7 prior treatment regimens including multiple dex-containing regimens. Baseline laboratory abnormalities included grade (Gr)≥3 anemia in 13% and Gr≥3 thrombocytopenia in 8%. Most penta pts received 8 doses / cycle (65%); most quad pts received 6 doses / cycle (83%). Common treatment-related adverse events (TRAEs) hematological: thrombocytopenia (72%, Gr 3/4 58%), anemia (48%, Gr 3 25%) and neutropenia (29%, Gr≥3 21%). TRAEs non-hematological: nausea (72%, Gr 3 6%), fatigue (62%, Gr 3 14%) anorexia (49%, Gr 3 3%), vomiting (43%, Gr3 4%), asymptomatic hyponatremia (42%. Gr 3 20%), diarrhea (42%, Gr 3 5%) and weight loss (33%, Gr 3 1%). There was one case of febrile neutropenia (1%) and one case of clinically significant bleeding related to thrombocytopenia (1%). Seventy pts have discontinued therapy: PD (73%), AEs (17%), physician/pt preference (1%) and 6 deaths (one case related to selinexor, intracranial bleed in pt with Gr4 thrombocytopenia). Nine pts remain on study. Efficacy was evaluated in 78 pts (1 pt did not have measurable disease). The IRC-determined ORR (≥PR) for all pts was 21%, including 5% VGPR. ORR was 21% for quad pts and 20% for penta pts. Clinical benefit rates (≥MR) were 32% (all), 29% (quad), and 37% (penta). Median OS was 9.3 months (mo) for all pts, >11 mo (median not reached) for responders (≥PR), and 5.7 mo for non-responders. Median DOR in responding pts was 5 mo, and median PFS in all pts was 2.1 mo. Baseline cytogenetics were assessed in 41 pts. The ORR in 18 pts with high-risk FISH abnormalities was 33% (Table 1). Notably, 3 of the 13 pts with a 17p abnormality responded (ORR 23%). Transcriptomic profiling revealed differentially expressed genes (DEGs) between responders and non-responders in both whole blood RNA and CD138+ bone marrow cells. Pathways enriched in responders included IL-6, IL-8 and IGF-1 pathways. Conclusions - Oral Sd is active in heavily pretreated pts with refractory MM, including those with MM refractory to anti-CD38 Ab and those with high-risk cytogenetic abnormalities. Response was associated with longer survival. The main toxicities of Sd are thrombocytopenia, nausea, anorexia, and fatigue. AEs were manageable with supportive care and dose interruptions/reductions. To our knowledge, this is the first report of anti-tumor activity in the penta-refractory MM population. This population of MM pts has exhausted all currently available treatment options and has an extremely poor prognosis and therefore requires new therapies. Expansion of this trial in this high unmet medical need, penta refractory population is planned. Table 1 Activity of Sd in Patients with High Risk MM Cytogenetics Table 1. Activity of Sd in Patients with High Risk MM Cytogenetics Disclosures Vogl: Constellation: Research Funding; Karyopharm: Consultancy; Acetylon: Research Funding; GSK: Research Funding; Calithera: Research Funding; Teva: Consultancy; Celgene: Consultancy; Takeda: Consultancy, Research Funding. Jagannath:Bristol-Myers Squibb: Consultancy; Janssen: Consultancy; Novartis: Consultancy; Merck: Consultancy; Celgene: Consultancy. Baz:Bristol-Myers Squibb: Research Funding; Takeda/Millennium: Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Signal Genetics: Research Funding; Novartis: Research Funding; Karyopharm: Research Funding; Merck: Research Funding. Nooka:Spectrum, Novartis, Onyx pharmaceuticals: Consultancy. Richter:Takeda: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau; Janssen: Speakers Bureau; Bristol-Myers Squibb: Speakers Bureau; Novartis: Speakers Bureau. Vij:Karyopharm: Honoraria; Amgen: Honoraria, Research Funding; Celgene: Consultancy; Takeda: Honoraria, Research Funding; Novartis: Honoraria; Bristol-Myers Squibb: Honoraria; Janssen: Honoraria. Schiller:Incyte Corporation: Research Funding. Costa:Sanofi: Honoraria, Research Funding. Chari:Array Biopharma: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Pharmacyclics: Research Funding; Janssen: Consultancy, Research Funding; Amgen Inc.: Honoraria, Research Funding; Novartis: Consultancy, Research Funding. Siegel:Takeda: Honoraria, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Amgen: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; BMS: Honoraria, Speakers Bureau; Merck: Honoraria. Fonseca:Janssen: Consultancy; AMGEN: Consultancy; Millennium, a Takeda Company: Consultancy; Bayer: Consultancy; Sanofi: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; AMGEN: Consultancy; Novartis: Consultancy; Millennium, a Takeda Company: Consultancy; Sanofi: Consultancy; AMGEN: Consultancy; Janssen: Consultancy; BMS: Consultancy; Celgene: Consultancy; BMS: Consultancy; Millennium, a Takeda Company: Consultancy; Millennium, a Takeda Company: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Bayer: Consultancy; Novartis: Consultancy; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; AMGEN: Consultancy; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent: Patents & Royalties: Prognostication of MM based on genetic categorization of FISH of the disease; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Patent Pending: Patents & Royalties: The use of calcium isotopes as biomarkers for bone metabolisms; Celgene: Consultancy. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Saint-Martin:Karyopharm: Employment. Picklesimer:Karyopharm: Employment. Friedlander:Karyopharm Therapeutics: Employment. Choe-Juliak:Karyopharm Therapeutics: Employment.

Introduction - Selinexor is a first-in-class Selective Inhibitor of Nuclear Export (SINE) compound that binds and inactivates Exportin 1 (XPO1). Selinexor with low dose dexamethasone (dex) has demonstrated potent anti-cancer activity in patients with heavily pretreated MM. While the development of proteasome inhibitors (PIs) has transformed the treatment of MM, acquired resistance to PIs limit their efficacy. Preclinical studies have shown that selinexor, when combined with bortezomib, can restore sensitivity of bortezomib-resistant MM to this drug, inducing tumor growth inhibition and increasing survival in MM models in mice. In this clinical trial (NCT02343042), we investigated the safety, tolerability and efficacy of the combination of selinexor, bortezomib and low dose dex (SdB) in patients (pts) with refractory MM. Methods - This phase 1b/2 dose escalation study using a standard 3+3 design, was designed to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) for SdB. The study included pts with refractory MM, after ≥ 1 prior therapy. Pts with prior PI relapsed and/or refractory disease were included, provided the patient's MM was not refractory to bortezomib as last therapy. Selinexor was independently dosed escalated in once-weekly (QW, starting at 80 mg; N=7, 100 mg N=6 pts) or twice-weekly (BIW, starting at 60 mg; N=3, 80 mg N=6 pts) regimens. Bortezomib (1.3 mg/m2 sc) was administered either once-weekly or twice-weekly and dex was given orally 40 mg QW or 20 mg BIW. Results - As of July 25th, 2016, enrollment in the dose escalation cohorts has been completed with 22 pts (12 male /10 female). The median age is 65 years (range, 46 - 74), with a median of 4 (range, 1 - 12) prior treatment regimens. One dose limiting toxicity (Grade 4 thrombocytopenia without bleeding) in the 80 mg BIW cohort was observed but the MTD has not been reached. Common related grade 1/2 adverse events (AEs) include: fatigue 41%, nausea 41%, anorexia 36%, and weight loss 18%. Grade 3/4 AEs include: thrombocytopenia 41%, anemia 18%, and neutropenia 18%. One case of grade 1 peripheral neuropathy in the 80 mg BIW cohort was reported. All pts were evaluable for response. The ORR (≥partial response, PR) was 77% with ≥VGPR 27% (1 pt in CR and 5 pts in VGPR) and 11 PRs. There were 3 minor responses (14%), 1 stable disease, 1 progressive disease (5% each). Seven of the 12 pts with PI-refractory MM responded (ORR 58%). A summary of response by PI treatment history is shown in Table 1. Ten patients have remained on study >4 months, including 7 patients still on trial (longest >9 months). Based on tolerability and anti-MM activity, RP2D of SdB is selinexor 100 mg, bortezomib 1.3 mg/m2 and dex 40 mg, all given once weekly. At the RP2D, all six pts achieved ≥PR (ORR 100%). Conclusions - Selinexor in combination with bortezomib and dex is well tolerated and highly active in refractory MM. Toxicities are manageable and similar to selinexor or bortezomib monotherapy. Peripheral neuropathy is uncommon, consistent with the use of weekly bortezomib sc and the lack of neuropathy with selinexor. Overall, the SdB regimens induced an ORR of 77% with ≥VGPR of 27%. In patients with PI-refractory MM, the ORR was 58%, indicating that the addition of selinexor restores sensitivity to bortezomib. These results confirm the preclinical data supporting synergistic effects of selinexor when combined with PIs. This promising, once-weekly treatment regimen may provide deeper and more durable responses in pts with relapsed / refractory MM, including those with PI-refractory disease. Table 1. Best Response by Prior Proteasome Inhibitor (PI) Treatment Status Table 1. Best Response by Prior Proteasome Inhibitor (PI) Treatment Status Disclosures Bahlis: Onyx: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; BMS: Honoraria. Sebag:Janssen: Honoraria; Novartis: Honoraria; Celgene: Honoraria. Sutherland:Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. White:Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Venner:Amgen: Honoraria; J+J: Research Funding; Takeda: Honoraria; Janssen: Honoraria; Celgene: Honoraria, Research Funding. Kouroukis:Amgen: Research Funding; Janssen: Research Funding; Karyopharm: Research Funding. McCurdy:Celgene: Honoraria. Lalancette:BMS: Honoraria; Celgene: Honoraria. Bensinger:Sanofi: Consultancy, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Acetylon: Research Funding; Takeda: Honoraria, Research Funding; Bayer: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding. Lentzsch:BMS: Consultancy; Celgene: Consultancy, Honoraria. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Shacham:Karyopharm Therapeutics: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Jeha:Karyopharm: Employment. Picklesimer:Karyopharm: Employment. Saint-Martin:Karyopharm: Employment. Choe-Juliak:Karyopharm Therapeutics: Employment. Chen:Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Takeda: Research Funding.

2044 Background: Patients (pts) with recurrent GBM have few treatment options and a poor prognosis. Selinexor is an oral inhibitor of XPO1 mediated nuclear export resulting in nuclear retention of ...

Background: The nuclear export protein XPO1 is overexpressed in all types of hematological malignancies. The SINE selinexor (KPT-330) is a novel, first-in-class, slowly reversible XPO1 antagonist that forces the nuclear retention and activation of over tumor suppressor proteins (TSPs) such as p53, IkB, FOXO and p21. Forced nuclear retention of TSPs leads to their reactivation, which can counteract a multitude of oncogenic pathways that perpetuate the neoplastic phenotype. In addition, XPO1 inhibition prevents the eIF4e-mediated export of messenger mRNA for a variety of oncoproteins (FLT3, c-KIT, cyclin D1, c-MYC, Bcl2), leading to decreased expressed to further provide anti-cancer activity. An ongoing Phase 1 (NCT01607892) open label, dose escalation, multi-center study in hematological malignancies was designed to evaluate the safety and tolerability of selinexor as well as response rate as the secondary objective. A maximum tolerated dose (MTD) was not identified yet in this study, but based on the ongoing Phase1 study of selinexor in pts with solid tumors, a MTD of 65 mg/m2 twice weekly was determined. The goal of the analyses reported here was to identify the recommended Phase 2 dose (RP2D) based on both tolerability and efficacy in patients with heavily pretreated hematological malignancies. Methods: A subset (N=157) of the Phase 1 patient population received oral selinexor twice weekly (8 doses/28-d cycle). General clinical observations suggested that doses of selinexor >35 mg/m2 (> ~60 mg flat dose) are associated with suboptimal tolerability. Therefore, based on the actual dose administered, patients were divided into groups receiving 45-65 mg (median 60 mg; N=59) and >65 mg (70-160 mg; median 90 mg, N=98) for comparison of safety and efficacy endpoints. The majority of the patients have heavily pretreated myeloma, NHL, and AML. Results: 157 pts received 45-160 mg selinexor twice weekly (89 M/68 F, median age 66 yr; median 4 prior regimens). The most common adverse events (AEs) were fatigue (66%), nausea (64%), anorexia (55%), vomiting (38%), which were mostly gr 1/2, and thrombocytopenia (44%), which was mostly grade 3/4. Incidence of certain selinexor-related high grade (3/4) adverse events was greater in pts receiving >65 mg selinexor vs those receiving 45-65 mg (Table 1). Grade 3 nausea (4%), anorexia (3%), vomiting (3%) and hypokalemia (3%) were observed in the >65 mg group but were not seen in the 45-65 mg group. Grade 3 and 4 anemia were 19% vs 14% and 4% vs 2% for the >65 mg vs 45-65 mg groups, respectively. Grade 3 and 4 thrombocytopenia was similar in both groups, but slightly higher in the >65 mg group, with 8% and 24 % in the 45-65 mg group vs 12% and 27% in the >65 mg group. Neutropenia was also very similar in Grade 3 and 4 toxicity for both groups with 10% and 12% in the 45-65 mg group vs 11% and 10% in the >65 mg group. In contrast, high grade cataract was only seen in the 45-65 mg group (8%; 3 gr 3, 1 gr 4). Selinexor-induced weight loss, as compared to baseline, was maximal by the end of cycle 2 in both dose groups, without further loss through at least cycle 4, but the >65 mg group lost on average >5-fold more weight (average of 3.8 ± 1.1 kg vs 0.7 ± 0.1 kg in the 65 mg group from 56 d- 126 d; p65 mg group; p=0. 05). In contrast, overall efficacy in the two dose groups was comparable, with 5 complete responses (CRs, 10%) and an overall response rate (ORR) of 23% in the 45-65 mg group and 4 CRs (5%) and ORR of 24% in the >65 mg group. A listing of all responses for both groups can be seen in Table 2. Conclusions: While efficacy is comparable, doses of selinexor from 45-65 mg (median 60 mg) are better tolerated than doses >65 mg, based upon decreased weight loss, incidence of high grade AEs, and greater numbers of days on study. Based on this superior risk-benefit, a flat dose of 60 mg selinexor, twice weekly, is the RP2D for patients with hematological cancers. Similar results have been observed for solid tumors. Disclosures Chen: Celgene: Consultancy, Honoraria, Research Funding. Jacoby:Novo Nordisk: Consultancy; Sunesis: Research Funding. Stone:AROG: Consultancy; Celator: Consultancy; Novartis: Research Funding; Pfizer: Consultancy; Juno: Consultancy; Celgene: Consultancy; Karyopharm: Consultancy; Amgen: Consultancy; Agios: Consultancy; Roche/Genetech: Consultancy; Abbvie: Consultancy; Sunesis: Consultancy, Other: DSMB for clinical trial; Merck: Consultancy. Baz:Sanofi: Research Funding; Celgene Corporation: Research Funding; Karyopharm: Research Funding; Millennium: Research Funding. Gabrail:Sanofi: Honoraria, Speakers Bureau; Janssen: Speakers Bureau; BI: Honoraria, Speakers Bureau; Onyx: Honoraria, Speakers Bureau. Wang:Celgene: Research Funding. Martin:Janssen: Consultancy, Honoraria; Acerta: Consultancy; Gilead: Consultancy; Celgene: Consultancy; Novartis: Consultancy; Bayer: Consultancy. Siegel:Celgene Corporation: Consultancy, Speakers Bureau; Amgen: Speakers Bureau; Takeda: Speakers Bureau; Novartis: Speakers Bureau; Merck: Speakers Bureau. Marshall:Karyopharm: Employment. Saint-Martin:Karyopharm: Employment. Carlson:Karyopharm: Employment. Shacham:Karyopharm: Employment, Equity Ownership. Kauffman:Karyopharm: Employment, Equity Ownership. Kuruvilla:Gilead: Consultancy; Hoffmann LaRoche: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; Merck: Honoraria; Bristol-Myers Squibb: Honoraria; Lundbeck: Honoraria; Karyopharm: Honoraria.

10569 Background: Sarcomas are a heterogeneous group of malignancies with diverse genetic abnormalities. Selinexor is a first-in-class, oral, inhibitor of XPO1, (nuclear exportin protein 1) with potent anti-tumor activity in multiple sarcoma cell lines and in murine liposarcoma xenografts. Here we report results from a Phase 1b dose expansion trial of selinexor in sarcoma patients (NCT01896505). Methods: Patients (pts) with advanced, refractory sarcomas with radiographic progression received oral selinexor at 50 mg/m2 twice weekly per 28 day cycle. Pharmacokinetics (PK, n = 12) was assessed in the fasted and fed state. Pharmacodynamic studies were performed on fresh tumor biopsies. Response was evaluated every 2 cycles (RECIST 1.1). Results: 36 pts (14 M / 22 F, ECOG 0/1: 19/17, median age 57.5 years [range 18–86], median lines of previous treatments: 3 [range 1–9]). Disease subtypes include liposarcoma (LPS; N = 12), leiomyosarcoma (LMS; N = 8) and other sarcomas (N = 16). Grade 3 drug related adverse ev...

Background: The nuclear export protein, XPO1 is overexpressed in all types of malignant lymphoma. The SINE selinexor (KPT-330) is a slowly reversible XPO1 antagonist that forces the nuclear retention and activation of over 10 tumor suppressor proteins (TSP) such as p53, IkB, FOXO and p21. In addition, selinexor inhibits the nuclear export and the translation of oncogenic mRNAs such as c-myc and Bcl-XL levels. Together these effects result in apoptosis of cancer cells in preclinical models of both T- and B- cell NHL. In DLBCL cell lines (n=10), selinexor induced potent cytotoxicity against both germinal center (GCB) and nonGCB including those with high MYC and/or BCL2/6 protein levels. Methods: Selinexor was administered orally for 4-10 doses in a 28-day cycle in this phase 1 study. Serial tumor biopsies were performed. Response evaluation was performed in cycle 1 and 2 and then every 2 cycles. All pts had heavily pretreated NHL with documented progressive disease (PD) on study entry. Results: 58 pts (34 males 24 females; median age 62 yrs; ECOG PS 0/1/2: 19/35/4; median prior regimens: 3) received selinexor across 13 dose levels (3 to 80 mg/m2). The recommended Phase 2 dose is 60 mg/m2 based on results across all Phase 1 studies. Grade 3/4 events (>5%) include thrombocytopenia (31%), neutropenia (22%), fatigue (10%), and anemia (7%). The most common Grade 1/2 AEs were: nausea (66%), anorexia (47%), fatigue (40%), and vomiting (40%) that were manageable with supportive care and were seen less frequently following cycle 1. Increases in XPO1 mRNA levels were observed at all doses and sustained for 4-48 hours, supporting twice weekly dosing. Tumor biopsies confirmed TSP nuclear localization, c-myc reductions, and apoptosis induction of cancer cells. Objective responses were observed in all classes of NHL studied (Table 1). An objective response rate (ORR) of 31% was observed across all NHL types. An ORR of 40% was observed in pts with rel/ref aggressive B-NHL (DLBCL, Follicular NHL grade 3b (FLgrd3b) and transformed NHL) at doses ³60 mg/m2 vs an ORR of 33% at 23-50 mg/m2 and 25% at ²20 mg/m2. Across all NHL types, time to best response was delayed, including 5 complete responses (CR) (4 in DLBCL and 1 T-NHL). Nine pts out of 34 have remained on therapy for >6-23 months without clinically significant cumulative toxicities or major organ dysfunction. Conclusions: Selinexor treatment is generally well tolerated with supportive care and can be given over a prolonged period. Durable single agent activity in pts with heavily pretreated NHL has been observed. Phase 2 studies in DLBCL, Richter's transformation and T-NHL of single agent selinexor as well as in combination with other agents including CD20 antibodies are expected to begin in the near future. | Cancer Type | Selinexor Dose (mg/m2) | N* | ORR (%) | CR (%) | PR (%) | SD (%) | PD (%) | WC/NE (%) | | ---------------------------------------------- | ---------------------- | -------- | -------- | -------- | -------- | -------- | -------- | --------- | | Aggressive B-NHL (DLBCL, FLgrd3b, Transformed) | ≤20 | 4 | 1 (25%) | -- | 1 (25%) | 1 (25%) | 2 (50%) | -- | | 20 – 50 | 21 | 7 (33%) | 4 (19%) | 3 (14%) | 5 (24%) | 6 (29%) | 3 (14%) | | ≥60* | 10 | 4 (40%) | -- | 4 (40%) | 4 (40%) | -- | 2 (20%) | | Follicular & Other Indolent NHL | ≤30 | 4 | -- | -- | -- | 4 (100%) | -- | -- | | ≥35 | 4 | 2 (50%) | -- | 2 (50%) | 1 (25%) | -- | 1 (25%) | | Mantle Cell Lymphoma | ≤30 | 2 | 1 (50%) | -- | 1 (50%) | 1 (50%) | -- | -- | | ≥35 | 2 | -- | -- | -- | -- | 1 (50%) | 1 (50%) | | T-Cell Lymphoma | ≤30 | 4 | -- | -- | -- | 2 (50%) | -- | 2 (50%) | | ≥35 | 1 | 1 (100%) | 1 (100%) | -- | -- | -- | -- | | Richter's Transformation | ≤30 | 3 | 1 (33%) | -- | 1 (33%) | 2 (67%) | -- | -- | | ≥35 | 3 | 1 (33%) | -- | 1 (33%) | -- | -- | 2 (67%) | | TOTAL | 58 | 18 (31%) | 5 (9%) | 13 (22%) | 20 (34%) | 9 (16%) | 11 (19%) | * * First pt in this population was dosed on 23-July-2012 * ORR=Objective Response Rate; CR=Complete Response; PR=Partial Response; SD=Stable Disease; PD=Progressive Disease; WC=Withdrew Consent; NE=Non-Evaluable Abstract 396. Table 1 Disclosures Byrd: Pharmacyclics, Genentech: Research Funding. Porcu: Infinity: Research Funding; Seattle genetics: Research Funding; Actelion: Honoraria; Celgene: Honoraria; United States Cutaneous Lymphoma Consortium: Membership on an entity's Board of Directors or advisory committees; Cutaneous Lymphoma Foundation: Membership on an entity's Board of Directors or advisory committees. Stone: AbbVie, Inc: Consultancy; Agios: Consultancy; Amgen: Consultancy; Celator: Consultancy; Celgene: Consultancy; Roche: Consultancy. Baz: Celgene: Research Funding; Millennium: Research Funding; Bristol Myers Squibb: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding. Flinn: AstraZeneca: Research Funding. Kukreti: Celgene: Honoraria. Landesman: Karyopharm Therapeutics: Employment. Klebanov: Karyopharm Therpeutics: Employment. Shacham: Karyopharm Therapeutics: Employment. Saint-Martin: Karyopharm Therpeutics: Employment. Marshall: Karyopharm Therpeutics: Employment. McCartney: Karyopharm Therpeutics: Employment. McCauley: Karyopharm Therapeutics: Employment, Equity Ownership. Carlson: Karyopharm Therapeutics: Employment. Norori: Karyopharm Therpeutics: Consultancy. Savona: Karyopharm Therpeutics: Membership on an entity's Board of Directors or advisory committees. Rashal: Karyopharm Therapeutics: Employment. Mirza: Karyopharm Therpeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Kauffman: Karyopharm Therapeutics: Employment, Equity Ownership. Shacham: Karyopharm Therpeutics: Employment, Equity Ownership.

Introduction: The nuclear export protein exportin 1, (XPO1) is overexpressed in a wide variety of cancers including MM and often correlate with poor prognosis. Selinexor (KPT-330) is an oral Selective Inhibitor of Nuclear Export (SINE) XPO1 antagonist in Phase 1 and 2 clinical studies. Selinexor forces nuclear retention and reactivation of tumor suppressor proteins (TSPs) and reduction of many proto-oncogenes, including MDM2, MYC and Cyclin D. In addition, selinexor potently deactivates NF-κB, through forced nuclear retention of IκBα. Together these effects induce selective apoptosis in MM cells and inhibition of NF-κB dependent osteoclast activation. XPO1 is also responsible for nuclear export of the glucocorticoid receptor (GR). We hypothesized that selinexor will enhance the activity of dexamethasone (DEX)-bound GR, resulting in synergistic tumor cell killing. Methods: In vitro tumor cell viability measurements were based on MTT (CellTiter 96¨/Promega) and combination indices were calculated using CalcuSyn software. For xenograft studies, utilized NOD-SCID mice with subcutaneous inoculation of MM.1s cells. GR nuclear localization was measured with immunofluorescent anti-GR (phosphor-S211) antibody and quantitative imaging. To assess GR transcriptional activation, GR binding to a GCR consensus sequence was measured in nuclear extracts using an ELISA method (GR ELISA kit/Affymetrix). Patients (pts) with heavily pretreated refractory MM were dosed with oral selinexor at doses of up to 60 mg/m2 (8-10 doses/4 wk cycle) as part of a Phase 1 program in advanced hematological malignancies. Response we defined based on the IMWG criteria. The effect of combining DEX with selinexor was analyzed in all pts who received selinexor at moderate to high doses (30-60 mg/m2). Safety and efficacy were analyzed separately in three groups: no DEX, Disclosures Chen: Celgene: Honoraria; Janssen: Honoraria. Off Label Use: Lenalidomide maintenance therapy after ASCT. Gutierrez:Senesco: PI Other. Siegel:Celgene, Millennium, Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Baz:Celgene: Research Funding; Millennium: Research Funding; Bristol Myers Squibb: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding. Kukreti:Celgene: Honoraria. Azmi:Karyopharm Therpeutics: Research Funding. Kashyap:Karyopharm Therapeutics: Employment. Landesman:Karyopharm Therapeutics: Employment. Marshall:Karyopharm Therpeutics: Employment. McCartney:Karyopharm Therpeutics: Employment. Saint-Martin:Karyopharm Therpeutics: Employment. Norori:Karyopharm Therpeutics: Consultancy. Savona:Karyopharm Therpeutics: Membership on an entity's Board of Directors or advisory committees. Rashal:Karyopharm Therapeutics: Employment. Carlson:Karyopharm Therapeutics: Employment. Mirza:Karyopharm Therpeutics: Consultancy, 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. Kauffman:Karyopharm Therapeutics: Employment, Equity Ownership. Reece:Millennium: Honoraria, Research Funding; Millennium: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Otsuka: Honoraria, Research Funding; Merck: Research Funding; Merck: Research Funding; BMS: Research Funding; BMS: Research Funding; Novartis: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Amgen : Honoraria; Amgen : Honoraria.

SINE (Selective Inhibitors of Nuclear Export) block the activity of XPO1/CRM1, 1 of 7 nuclear export proteins in cells, forcing the nuclear retention of key tumor suppressor proteins, leading to selective apoptosis of tumor cells. The purpose of these studies was to evaluate the in vitro activity of SINE against canine tumor cell lines and investigate the biological activity of verdinexor (KPT-335) in dogs with spontaneous cancers as proof of principle for human clinical studies. Several different canine tumor cell lines including those derived from non-Hodgkin Lymphoma (NHL) exhibited growth inhibition and apoptosis in response to nanomolar concentrations of SINE; NHL cells were particularly sensitive with IC50 2-42 nM. A Phase I clinical trial of verdinexor was performed in dogs with cancer with an emphasis on NHL given in vitro activity demonstrated against the tumor cell lines. The MTD was 1.75 mg/kg twice per week although biological activity was observed at 1 mg/kg. Clinical benefit including Partial Response (PR) and Stable Disease (SD) for at least 4 weeks was observed in 9/14 dogs with NHL with a median time to progression of 66 days (range 35-256). A dose expansion study was performed in 6 dogs with NHL given 1.5 mg/kg verdinexor on a Monday/Wednesday/Friday (MWF) regimen; clinical benefit (PR+SD) was observed in 4/6 dogs with a median time to progression of 83 days (range 35-354). Toxicities were primarily gastrointestinal consisting of anorexia, weight loss, vomiting and diarrhea and were manageable with supportive care and dose modulation. A validated health related Quality of Life (QOL) form used to assess dogs during treatment demonstrated that the overall quality of life did not decrease in dogs in this study supporting the notion that clinical toxicities associated with verdinexor are generally well tolerated. Based on these findings, a Phase IIb study was performed in 58 dogs with either newly diagnosed or relapsed NHL. Drug was administered initially at 1.5 mg/kg MWF, but this dosing regimen was changed to 1.25 mg/kg M/Th due to the high rate of anorexia and weight loss on the MWF regimen; dose escalation was permitted to 1.5 mg/kg on the M/Th regimen.. The objective response rate was 29% (1 CR, 16 PR) with an additional 25 dogs experiencing SD for a minimum of 4 weeks, resulting in a of 72% disease control rate. While the median time to progression was approximately 6 weeks, 19 dogs (32%) remained on study drug for more than 8 weeks. Laboratory abnormalities were minimal. Together, these data provide robust evidence that the novel orally bioavailable XPO1 inhibitor vrdinexor exhibits single agent biological activity in a spontaneous large animal model of human NHL. Furthermore, verdinexor was well tolerated even in the absence of supportive care, suggesting that SINE compounds could exhibit good long-term tolerability in people. Citation Format: Cheryl A. London, Luis Feo Bernabe, Sandra Barnard, William Kisseberth, Antonella Borgatti, Michael Henson, Heather Wilson-Robles, Kiersten Jensen, Daisuke Ito, Jaime Modiano, Misty Bear, Michael Pennell, Jean-Richard Saint-Martin, Dilara McCauley, Michael Kauffman, Sharon Shacham. Evaluation of the novel, orally bioavailable selective inhibitor of nuclear export (SINE) KPT-335 (verdinexor) in spontaneous canine cancer: Results of phase I and phase II clinical trials. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3809. doi:10.1158/1538-7445.AM2014-3809

SINE (Selective Inhibitors of Nuclear Export) block the activity of XPO1/CRM1, 1 of 7 nuclear export proteins in cells, forcing the nuclear retention of key tumor suppressor proteins (TSP), leading to selective apoptosis of tumor cells. The purpose of these studies was to evaluate the in vitro activity of SINE against canine tumor cell lines and investigate the biological activity of Verdinexor (KPT-335) in dogs with spontaneous cancers as proof of principle for human clinical studies with SINE. Several different canine tumor cell lines including those derived from Non-Hodgkin Lymphoma (NHL) exhibited growth inhibition and apoptosis in response to nanomolar concentrations of SINE; NHL cells were particularly sensitive with IC50 concentrations ranging from 2-42 nM. A Phase I clinical trial of Verdinexor was performed in dogs with cancer with an emphasis on NHL given in vitro activity demonstrated against the tumor cell lines. The maximum tolerated dose (MTD) was 1.75 mg/kg twice per week although biological activity was observed at 1 mg/kg. Clinical benefit including Partial Response (PR) and Stable Disease (SD) for at least 4 weeks was observed in 9/14 dogs with NHL with a median time to progression of 66 days (range 35-256). A dose expansion study was performed in 6 dogs with NHL given 1.5 mg/kg Verdinexor on a Monday/Wednesday/Friday (MWF) regimen; clinical benefit (PR + SD) was observed in 4/6 dogs with a median time to progression of 83 days (range 35-250+). Toxicities were primarily gastrointestinal in nature consisting of anorexia, weight loss, vomiting and diarrhea and were manageable with supportive care and dose modulation. A validated health related Quality of Life (QOL) form used to assess dogs during treatment demonstrated that the overall quality of life did not decrease in dogs in this study supporting the notion that clinical toxicities associated with Verdinexor are generally well tolerated. Based on these findings, a Phase IIb study was performed in 58 dogs with either newly diagnosed or relapsed NHL. Drug was administered initially at 1.5 mg/kg MWF, but this dosing regimen was changed to 1.25 mg/kg M/Th due to the high rate of anorexia and weight loss on the MWF regimen; dose escalation was permitted to 1.5 mg/kg on the M/Th regimen. The objective response rate was 34% (1 CR, 19 PR) with an additional 33 dogs experiencing SD for a minimum of 4 weeks, resulting in a of 91% disease control rate. While the median time to progression was approximately 5 weeks, 19 dogs (32%) remained on study drug for >8 weeks; several dogs continue to receive Verdinexor. Laboratory abnormalities were minimal and clinical toxicities were mild on the M/Th regimen. Together, these data provide robust evidence that the novel orally bioavailable XPO1 inhibitor Verdinexor exhibits single agent biological activity in a spontaneous large animal model of human NHL. Furthermore, Verdinexor was well tolerated even in the absence of supportive care, suggesting that SINE compounds could exhibit good long-term tolerability in people. Disclosures: London: Zoetis: Honoraria, Research Funding; Karyopharm: Consultancy, Research Funding; Abbott: Honoraria. Modiano:Karyopharm: Research Funding. Saint-Martin:Karyopharm: Employment. McCauley:Karyopharm : Employment, Equity Ownership, Patents & Royalties. Shacham:Karyopharm : Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties. Kauffman:Karyopharm Therapeutics Inc.: Employment.

Background Exportin 1 (CRM1/XPO1) is the exclusive transporter of the majority of Tumor Suppressor Proteins (TSP) out of the nucleus, rendering these TSPs non-functional. Selinexor (KPT-330) is a potent, oral SINE XPO1 antagonist, forcing the nuclear retention and activation of >10 TSPs resulting in NHL and CLL cell death in vitro, while sparing normal lymphocytes and other hematopoietic cells. Oral Selinexor has marked activity in murine models of NHL and CLL including R-CHOP resistant tumors. Dogs with spontaneous B- and T-cell lymphomas exposed to the related SINE Verdinexor demonstrate potent anti tumor effect and good tolerability. Methods Patients (pts) with advanced NHL or CLL relapsed/refractory to all available drug classes were dosed with oral Selinexor (8-10 doses / 4-week cycle) as part of a Phase 1 trial in hematological malignancies (NCT01607892). Detailed pharmacokinetic (PK) and pharmacodynamic (PDn) analyses and serial tumor biopsies were obtained. Response evaluation was performed every cycle. Results 18NHL/CLL pts with median age 66.5yrs; ECOG PS 0/1: 8/10; median number of prior regimens: 4.5 [range 2-11], received KPT-330 across 6 dose levels (3 to 30 mg/m2). Ten pts experienced drug-related grade 3/4 Adverse Events (AEs) including thrombocytopenia without bleeding (n=6), neutropenia (n=5), dehydration (n=1), syncope (n=1), hypotension (n=1), fatigue (n=1). The most common grade 1/2 toxicities were: anorexia (10/18pts; 56%), fatigue (9/18; 50%), diarrhea (6/18; 33%), vomiting (6/18; 33%), neutropenia (5/18; 28%), malaise (3/18; 17%), anemia (3/18; 17%) and weight loss (3/18; 17%). These adverse events were manageable with supportive care. 23mg/m2, one case of Grade 4 thrombocytopenia for >5 days without bleeding was reported as a DLT for the cohort; this patient with refractory follicular NHL was continued on therapy at the same dose and schedule with intermittent platelet support with SD for 83 days on study.Dose escalation continues.There were no clinically significant cumulative toxicities or major organ dysfunction and pts have remained on therapy for ≥6 cycles. Maximum tolerated dose has not been reached; dosing at 35 mg/m2 twice weekly is ongoing.PK analysis at doses of 3-35 mg/m2demonstrated a dose proportional increase in Cmax and AUC with increasing dose. Elimination half-life was independent of dose and ranged from 4.7-7.0 hours. Significant increases (2-20x) in total leukocyte XPO1 mRNA levels (PDn marker) were observed at all doses, with higher doses demonstrating higher levels of XPO1 mRNA induction.Evaluation of lymph node biopsies from 2 pts confirms Selinexor-induced nuclear localization of multiple TSPs as well as apoptosis of tumor cells. Response was evaluable in 15pts; Selinexor treatment induced tumor shrinkage or disease stabilization in 80%(n=12) of pts with relapsed/refractory NHL/CLL who had progressive disease on study entry (Figure 1). 20% (n=3) of pts had clinical progression. One patient with ibrutinib-refractory CLL with Richter's transformation who progressed on chemotherapy achieved a rapid 60% reduction in lymph nodes in Cycle 1 and was referred for transplantation. A patient with DLBCL refractory to R-CHOP and bone marrow transplantation achieved a near CR (93% tumor shrinkage) and remains on study >11 months. Conclusions Oral Selinexor is generally well tolerated, with favorable PK andPDn parameters. In this cohort of heavily pretreated, refractory/refractoryNHLand CLL with progressive disease on study entry, single agent oral Selinexor induced tumor shrinkage in the majority of pts. Disclosures: Kuruvilla: Seattle Genetics: Consultancy, Honoraria, Research Funding; Hoffman LaRoche: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; Celgene: Consultancy, Honoraria; Lundbeck: Consultancy, Honoraria; Karyopharm: Research Funding. Shah:Seattle Genetics, Inc.: Research Funding; NCCN: Membership on an entity’s Board of Directors or advisory committees; SWOG: Membership on an entity’s Board of Directors or advisory committees; Celgene: Speakers Bureau; Janssen/Pharmacyclics: Speakers Bureau. Garzon:Karyopharm: Research Funding. Siegel:Celgene, Millennium, Onyx: Honoraria, Speakers Bureau. Baz:Sanofi: Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Bristol Myers Squibb: Research Funding; Millenium: Research Funding; Celgene: Research Funding. Shacham:Karyopharm Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees, Patents & Royalties. Rashal:Karyopharm Therapeutics: Employment, Equity Ownership. Yau:NPM Pharma Inc: NPM Pharma hired Ozmosis Research as CRO for this trial Other. McCauley:Karyopharm Therapeutics: Employment, Equity Ownership, Patents & Royalties. Saint-Martin:Karyopharm Therapeutics: Employment, Equity Ownership. McCartney:Karyopharm Therapeutics: Employment, Equity Ownership. Landesman:Karyopharm Therapeutics: Employment. Klebanov:Karyopharm Therapeutics: Employment. Pond:Ozmosis Research: Consultancy. Kauffman:Karyopharm Therapeutics Inc.: Employment, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees. Mirza:Karyopharm Therapeutics: Consultancy, Equity Ownership, Membership on an entity’s Board of Directors or advisory committees.