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1420 A Phase 2/3, Multicenter Randomized Study of Rituximab-Gemcitabine-Dexamethasone-Platinum (R-GDP) with or without Selinexor in Patients with Relapsed/Refractory Diffuse Large B-Cell Lymphoma (RR DLBCL)

Program: Oral and Poster Abstracts
Session: 626. Aggressive Lymphomas: Prospective Therapeutic Trials: Poster I
Hematology Disease Topics & Pathways:
Clinical Trials, Adults, Lymphomas, Non-Biological, Clinical Research, B Cell Lymphoma, Diseases, Therapies, Lymphoid Malignancies, Study Population
Saturday, December 11, 2021, 5:30 PM-7:30 PM

Seung Tae Lee, MD, PhD1*, Antonio Pinto, MD2*, Habte Yimer, MD3, Don Stevens, MD4, Wanda Knopinska Posluszny, MD5*, Merrill Kingman Shum, MD6*, Sudhir Manda, MD7, Merav Leiba, MD8*, Miguel Canales, MD9, Maciej Kaźmierczak, MD, PhD10*, Wojciech Jurczak, PhD, MD11, Anna Sureda12, Xiwen Ma13*, Kai Li13*, Kimberly Ingalls, MD, MPH13*, Tara Arriola, PharmD13*, Melina Arazy, MD13*, Jatin J. Shah, MD13*, Sharon Shacham, PhD, MBA13*, Michael G. Kauffman, MD, PhD13 and Grzegorz S. Nowakowski, MD14

1University of Maryland, School of Medicine, Marlene & Stewart Greenebaum Comprehensive Cancer Center, Baltimore, MD
2IRCCS Istituto Nazionale Tumori “Fondazione G. Pascale", Napoli, Italy
3Texas Oncology-Tyler/US Oncology Research, Tyler, TX
4Norton Healthcare, Norton Cancer Institute, Louisville, KY
5Szpitale Pomorskie, Gdynia, Poland
6The Oncology Institute, Whittier, Whittier, CA
7Arizona Oncology Associates, Tucson, AZ
8Assuta Ashdod Medical Center, Ashdod, Israel
9Hospital Universitario La Paz, Madrid, Spain
10Department of Hematology, Poznań University of Medical Sciences, Poznań, Poland
11UJ CM, Krakow, Malopolskie, Poland
12Institut Català d'Oncologia – Hospitalet, IDIBELL, University of Barcelona, Barcelona, Spain
13Karyopharm Therapeutics Inc., Newton, MA
14Division of Hematology, Mayo Clinic, Rochester, MN

Introduction: Patients with relapsed or refractory diffuse large B-cell lymphoma (RR DLBCL) who cannot tolerate or who are not eligible for autologous or chimeric antigen receptor T cell (CAR-T) therapy have limited therapeutic options and suboptimal long-term outcomes.

In patients who were not eligible for HSCT, the rituximab plus gemcitabine, dexamethasone and cisplatin (R-GDP) regimen (and variations using methylprednisolone or carboplatin/oxaliplatin) have shown an overall response rates (ORR) of ~50%, a complete response (CR) rate of ~25% (Gopal, Leuk Lymphoma, 2010), and a median progression-free survival (PFS) and an overall survival (OS) of 3 and 9 months, respectively (Crump, Hematol Oncol Clin N Am. 2016; Gopal Leuk Lymphoma, 2010; Ng, Br J Cancer, 2005; Sirohi, Hematology, 2007; Barton, Eur J Haematol. 2015; Moccia Leuk Lymphoma, 2017).

Selinexor is an oral small molecule selective inhibitor of exportin-1 (XPO1) mediated nuclear export (SINE) compound leading to activation of tumor suppressor proteins and reduction in oncoprotein levels. It also reduces the expression of deoxyribonucleic acid (DNA) damage repair proteins and therefore potentiates DNA damage-based therapies leading to an increased death of cancer cells. Selinexor has synergistic effects with gemcitabine and cisplatin, and enhanced anti-lymphoma effects with dexamethasone.

In the SADAL study (n=134), single-agent oral selinexor 60 mg twice weekly induced an ORR of 29% and a CR rate of 13% in patients with RR DLBCL. The response rates were consistent across various subgroups including patients <70 vs ≥70 years old, those with de novo and transformed DLBCL, and GCB and non-GCB subtypes of DLBCL. The median duration of response (DOR) was 9.3 months, and 23 months for patients who achieved CR. OS was 9.0 months. In June 2020, selinexor monotherapy was approved in the US for the treatment of adult patients with RR DLBCL, not otherwise specified, including DLBCL arising from follicular lymphoma, after at least 2 lines of systemic therapy.

Selinexor in combination with R-GDP was evaluated in a Phase 1 clinical trial (SELINDA), in which patients with DLBCL received either 40 or 60 mg selinexor once or twice weekly in combination with standard dose R-GDP. The recommended phase 2 dose for further exploration was 40 or 60 mg once weekly with an ORR of 60-80%. Therefore, combining selinexor with R-GDP is expected to improve response rates, and continuation of treatment with single-agent selinexor is expected to prolong the duration of responses, improve PFS (and potentially OS) in patients with RR DLBCL.

Materials and methods: XPORT-DLBCL-030 is a Phase 2/3, multicenter study. The Phase 2 portion of the study is an open-label randomized study to identify the optimal dose of selinexor (40 or 60 mg) in combination with R-GDP in patients (n=120) with RR DLBCL. Patients ≥18 years with 1-3 prior lines of therapy and ECOG performance status ≤2 who are not intended for HSCT or CAR-T therapy are randomized 1:1:1 to one of 3 treatment arms: Arm 1: selinexor 40 mg+R-GDP (S40+R-GDP); Arm 2: selinexor 60 mg+R-GDP (S60 + R-GDP); Arm 3: R-GDP. Combination treatment will be given for up to 6 cycles (21 days/cycle). After completing the SR-GDP combination therapy (EoC), patients in Arms 1 and 2 who reach at least partial response (PR), will receive weekly single-agent selinexor 60 mg (28 days/cycle) as “continuous therapy” until disease progression (PD) or unacceptable toxicity. After PD, patients will be followed up for survival. Patients in the R-GDP arm will be followed up for PD and survival. Patients who are ineligible for HSCT due to an active disease, or those who have primary refractory DLBCL, defined as no response or relapse within 6 months after ending first-line treatment, will be allowed to enroll in the study (up to 15% and 25%, respectively of all patients enrolled). The primary endpoint of the study is ORR according to the Lugano 2014 criteria. Secondary endpoints include PFS, OS, ORR-EoC, DOR and incidence and severity of adverse events.

Disclosures: Pinto: Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Gilead Sciences: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel; MSD: Honoraria; Servier: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Other: Support for attending meetings and/or travel; F. Hoffmann-La Roche Ltd: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel. Yimer: Texas Oncology: Current Employment; Pharmacyclics: Speakers Bureau; Amgen: Speakers Bureau; Sanofi: Speakers Bureau; GSK: Speakers Bureau; Beigene: Speakers Bureau; Janssen: Speakers Bureau; Astrazeneca: Speakers Bureau; Karyopharm: Current equity holder in publicly-traded company, Speakers Bureau. Manda: Morphosys: Honoraria; Genmab: Current equity holder in publicly-traded company. Canales: Sanofi: Consultancy; Incyte: Consultancy; Novartis: Consultancy, Honoraria; Sandoz: Honoraria, Speakers Bureau; iQone: Honoraria; Karyopharm: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; F. Hoffmann-La Roche Ltd: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Gilead/Kite: Consultancy, Honoraria; Eusa Pharma: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria. Jurczak: Jagiellonian University: Ended employment in the past 24 months; Janssen-Cilag: Consultancy, Research Funding; Maria Sklodowska-Curie National Research Institute of Oncology: Current Employment; Roche: Consultancy, Research Funding; Astra Zeneca: Consultancy, Research Funding; Beigene: Consultancy, Research Funding; TG therapeutics: Consultancy, Research Funding; Merck: Research Funding. Sureda: BMS/Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Speakers Bureau; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kite, a Gilead Company: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; GSK: Consultancy, Honoraria, Speakers Bureau; Roche: Other: Support for attending meetings and/or travel; Bluebird: Membership on an entity's Board of Directors or advisory committees; Mundipharma: Consultancy; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Support for attending meetings and/or travel, Research Funding, Speakers Bureau. Ma: Karyopharm Therapeutics Inc.: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Li: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Ingalls: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arriola: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Arazy: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shah: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Shacham: Karyopharm: Current Employment, Current equity holder in publicly-traded company, Patents & Royalties: (8999996, 9079865, 9714226, PCT/US12/048319, and I574957) on hydrazide containing nuclear transport modulators and uses, and pending patents PCT/US12/048319, 499/2012, PI20102724, and 2012000928) . Kauffman: Karyopharm Therapeutics Inc.: Current Employment, Current equity holder in publicly-traded company. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees.

*signifies non-member of ASH