Abstract: 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, 〈 20 mg DEX and 20 mgs DEX. Results: In MM.1s cells Sel-Dex showed synergy for nuclear retention of the DEX activated GR (Ser211-phosphorylated) and concomitant GR transcriptional activation. Sel-Dex showed highly synergistic cytotoxicity in MM.1s cells in vitro and in vivo, with a corresponding increase in apoptosis. Selinexor alone was potently cytotoxic in the DEX resistant MM cell lines MM.1R and ANBL6, but addition of DEX provided no additional effect. Twenty-eight pts with heavily pretreated refractory MM (16 M, 12 F; median age 62; ECOG PS 0/1: 7/21; median prior regimens: 6) received selinexor at 30 – 60 mg/m2 with either 0, 〈 20, or 20 mgs DEX. All pts have received a proteasome inhibitor and an Imid and the majority of the pts have received pomalidomide (68%) and/or carfilzomib (36%). The most common Grade 1/2 AEs for these three groups were: nausea (82%/86%/70%), fatigue (55%/86%/40%), anorexia (36%/71%/60%), and vomiting (36%/57%/10%). Of the 28 pts treated; 10 heavily pretreated refractory MM pts treated with a combination of selinexor (45 mg/m2 twice weekly) and DEX (20 mg with each selinexor dose) were found to have dramatically improved disease response (n=10, ORR 60%), with one stringent complete response (sCR, 10%), 5 partial responses (PR, 50%) and clinical benefit rate (CBR) rate of 80% (Figure 1). Treatment with ³30mg/m2 selinexor and 〈 20 mg DEX (n=7), resulted in ORR of 14% and CBR of 86%, while treatment with selinexor (30-60 mg/m2) without DEX (n=12) showed best response of stable disease (50%). Sel-Dex was also associated with an increase in time on study relative to selinexor alone, with 7 of out 10 pts in the 20 mg DEX combo group still on study (11-25 weeks). Five additional pts were treated with selinexor at a dose of 60 mg/m2 in combination with 20 mg DEX. Response evaluation is pending. Conclusions: Sel-Dex combination is markedly synergistic in preclinical models, which is supported by the preliminary clinical data presented. One potential mechanism underlying this synergy is the amplification of GR activity due the combined effects of selinexor-induced nuclear retention of activated GR coupled with DEX-mediated GR agonism. These results provide a promising basis for the continuing study of Sel-Dex for treatment of pts with refractory MM. Phase 2 studies of Sel-Dex in pts with MM refractory to both pomalidomide and carfilzomib are planned for early 2015. 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.

Abstract: Purpose: The high fatality-to-case ratio of ovarian cancer is directly related to platinum resistance. Exportin-1 (XPO1) is a nuclear exporter that mediates nuclear export of multiple tumor suppressors. We investigated possible clinicopathologic correlations of XPO1 expression levels and evaluated the efficacy of XPO1 inhibition as a therapeutic strategy in platinum-sensitive and -resistant ovarian cancer. Experimental Design: XPO1 expression levels were analyzed to define clinicopathologic correlates using both TCGA/GEO datasets and tissue microarrays (TMA). The effect of XPO1 inhibition, using the small-molecule inhibitors KPT-185 and KPT-330 (selinexor) alone or in combination with a platinum agent on cell viability, apoptosis, and the transcriptome was tested in immortalized and patient-derived ovarian cancer cell lines (PDCL) and platinum-resistant mice (PDX). Seven patients with late-stage, recurrent, and heavily pretreated ovarian cancer were treated with an oral XPO1 inhibitor. Results: XPO1 RNA overexpression and protein nuclear localization were correlated with decreased survival and platinum resistance in ovarian cancer. Targeted XPO1 inhibition decreased cell viability and synergistically restored platinum sensitivity in both immortalized ovarian cancer cells and PDCL. The XPO1 inhibitor–mediated apoptosis occurred through both p53-dependent and p53-independent signaling pathways. Selinexor treatment, alone and in combination with platinum, markedly decreased tumor growth and prolonged survival in platinum-resistant PDX and mice. In selinexor-treated patients, tumor growth was halted in 3 of 5 patients, including one with a partial response, and was safely tolerated by all. Conclusions: Taken together, these results provide evidence that XPO1 inhibition represents a new therapeutic strategy for overcoming platinum resistance in women with ovarian cancer. Clin Cancer Res; 23(6); 1552–63. ©2016 AACR.

Abstract: 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/m 2 ) 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/m 2 using a twice-a-week (days 1 and 3) dosing schedule. The recommended phase II dose of 35 mg/m 2 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/m 2 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.

Abstract: The PENELOPE trial evaluated pertuzumab added to chemotherapy for biomarker-selected platinum-resistant ovarian cancer. As previously reported, pertuzumab did not statistically significantly improve progression-free survival (primary end point: HR 0.74, 95% CI 0.50 to 1.11), although results in the paclitaxel and gemcitabine cohorts suggested activity. Here, we report final overall survival and patient-reported outcomes. Patients and methods Eligible patients had ovarian carcinoma that progressed during/within 6 months of completing ≥4 platinum cycles, low tumor human epidermal growth factor receptor 3 (HER3) mRNA expression, and ≤2 prior chemotherapy lines. Investigators selected single-agent topotecan, gemcitabine or weekly paclitaxel before patients were randomized to either placebo or pertuzumab (840→420 mg every 3 weeks), stratified by selected chemotherapy, prior anti-angiogenic therapy, and platinum-free interval. Final overall survival analysis (key secondary end point) was pre-specified after 129 deaths. Patient-reported outcomes (secondary end point) were assessed at baseline and every 9 weeks until disease progression. Results At database lock (June 9, 2016), 130 (83%) of 156 randomized patients had died. Median follow-up was 27 months in the pertuzumab arm versus 26 months in the control arm. In the intent-to-treat population there was no overall survival difference between treatment arms (stratified HR 0.90, 95% CI 0.61 to 1.32; p=0.60). Results in subgroups defined by stratification factors indicated heterogeneity similar to previous progression-free survival results. Updated safety was similar to previously published results. Compliance with patient-reported outcomes questionnaire completion was 〉 75% for all validated patient-reported outcomes measures. Pertuzumab demonstrated neither beneficial nor detrimental effects on patient-reported outcomes compared with placebo, except for increased diarrhea symptoms. Discussion Consistent with the primary results, adding pertuzumab to chemotherapy for low tumor HER3 mRNA-expressing platinum-resistant ovarian cancer did not improve overall survival, but showed trends in some cohorts. Except for increased diarrhea symptoms, pertuzumab had no impact on patient-reported outcomes. ClinicalTrials.gov: ClinicalTrials.gov: NCT01684878 .

Abstract: 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. Abstract 396. Table 1 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 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.

Abstract: Tweetable abstract Cumulative efficacy, quality-of-life and safety data demonstrate that niraparib has a positive benefit:risk ratio for patients with BRCA mutations in a review of clinical evidence from registrational trials.

Abstract: (Abstracted from N Engl J Med 2019;381:2391–2402) The standard treatment for newly diagnosed advanced epithelial ovarian cancer involves cytoreductive surgery and platinum-taxane combination chemotherapy. Unfortunately, recurrence occurs in up to 85% of patients after completing this chemotherapy regimen.