Effect of Prior Therapy on the Efficacy and Safety of Oral Selinexor in Patients with Relapsed/Refractory (R/R) Diffuse Large B-Cell Lymphoma (DLBCL): A Post-Hoc Analysis of the Sadal Study
Authors: Cavallo Federica , Follows George A , Goy Andre , Vermaat Joost , Casasnovas Rene-Olivier , Lavee Orly , Maerevoet Marie , Zijlstra Josée M , Bakhshi Sameer , Bouabdallah Reda , Choquet Sylvain , Gurion Ronit , Hill Brian T. , Jaeger Ulrich , Sancho Juan-Manuel , Schuster Michael W. , Thieblemont Catherine , De la Cruz Fatima , Egyed Miklos , Mishra Sourav , Offner Fritz , Vassilakopoulos Theodoros P. , Warzocha Krzysztof , McCarthy Daniel , Ma Xiwen , Corona Kelly , Saint-Martin Jean-Richard , Joshi Anita , Shah Jatin , Van Den Neste Eric , Canales Miguel A , Kalakonda Nagesh 
Published: November 2019

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.