-Author name in bold denotes the presenting author
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126 A Once Daily, Oral, Triple Combination of BTK Inhibitor, mTOR Inhibitor and IMiD for Treatment of Relapsed/Refractory Richter’s Transformation and De Novo Diffuse Large B-Cell Lymphoma

Program: Oral and Poster Abstracts
Type: Oral
Session: 642. CLL: Therapy, excluding Transplantation I
Hematology Disease Topics & Pathways:
Adult, Lymphoma (any), Diseases, Combinations, Therapies, Non-Hodgkin Lymphoma, B-Cell Lymphoma, DLBCL, Lymphoid Malignancies, Study Population, Clinically relevant
Saturday, December 5, 2020: 10:15 AM

Anthony R. Mato, MD1, Stephen J. Schuster, MD2, Francine M. Foss, MD3, Iris Isufi, MD3, Shalin K. Kothari, MD3, Wei Ding, MD, PhD4, Danielle M. Brander, MD5, Andrea Sitlinger, MD5, Allison C. Rosenthal, D.O.6, Jose F. Leis, MD, PhD7, Han W. Tun, MD8, Kaitlin Kennard, RN, BSN2*, Allison R. Nelson, RN2*, Victoria Falco, BSN1*, Celina J. Komari, BS1*, Amber B. Koehler, PA-C, MS4*, Rachel Stowe, RN5*, Wei He, PhD9,10*, Albert Kearney, Ph.D.9*, Min Gui, Ph.D.9*, Tim McKinlay9*, Lindsey E Roeker, MD1, Meghan C. Thompson, MD1 and Scott F. Huntington, MD, MPH3

1Memorial Sloan Kettering Cancer Center, New York, NY
2Lymphoma Program, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA
3Yale Cancer Center, New Haven, CT
4Mayo Clinic, Rochester, MN
5Duke University Medical Center, Durham, NC
6Mayo Clinic, Phoenix, AZ
7Division of Hematology and Medical Oncology, Mayo Clinic Health System, Phoenix, AZ
8Division of Hematology-Oncology and Blood and Marrow Transplantation Program, Mayo Clinic, Jacksonville, FL
9Zhejiang DTRM Biopharma LLC, Plymouth Meeting, PA
10Zhejiang DTRM Biopharma Co. Ltd., Hangzhou Fuyang, China

Introduction: With a median overall survival (OS) measured in months, successful treatment of Richter’s transformation (RT) of chronic lymphocytic leukemia (CLL) to diffuse large B-cell lymphoma (DLBCL) remains a major unmet medical need. While targeted agents, such as Bruton tyrosine kinase inhibitor (BTKi) monotherapy, have greatly improved outcomes for patients (pts) with CLL and some B-cell lymphomas, available BTKi therapies have been ineffective for RT, as well as for large cell transformation of indolent B-cell lymphomas and relapsed/refractory (r/r) DLBCL, which rapidly develop mechanisms of resistance by activation of downstream targets of BTKi or upregulation of alternative/parallel pathways. Focusing on a synthetic lethality approach via in vitro and in vivo studies, we discovered that concurrent inhibition of BTK & mTOR targets plus an IMiD synergistically kill malignant B-cells. DTRM-555 is an optimized oral triple combination of a novel irreversible BTKi DTRMWXHS-12 (DTRM-12), everolimus (EV) and pomalidomide (POM). This once daily therapy was tested in a stepwise, phase I, multicenter study in pts with the greatest unmet medical needs. Here we present results for this novel combination therapy in pts with RT, and r/r DLBCL.

Methods: We conducted a phase I (3+3 design), first in human trial exploring DTRM-555 in adult pts with B-cell lymphomas with no available standard therapies (NCT02900716) at 6 US cancer centers. Our goal was to determine the optimal dose for DTRM-555. In phase Ia, an MTD was not reached for DTRM-12 monotherapy; In phase Ib and expansion cohorts, we evaluated double (DTRM-12/EV at 200mg/5mg or 300mg/5mg) and triple combinations (DTRM-12/EV/POM at 200mg/5mg/2mg or 300mg/5mg/2mg) administered once daily for 21 days of a 28-day cycle, until disease progression or unacceptable toxicity. The primary endpoint was safety and the dose limiting toxicity (DLT) period was cycle 1 (28 days). Secondary endpoints included overall response rate (ORR; Cheson 2014), duration of response (DOR), and DTRM-12 pharmacokinetics. The trial began on 9/27/2016 and completed enrollment with evaluable follow-up data cut-off date on 08/06/2020.

Results: 39 pts were enrolled and treated, including 24 with RT (n=12) or r/r DLBCL (n=12). The safety analyses included all 39 pts treated with combination therapies while efficacy analyses were focused on RT and r/r DLBCL. Baseline characteristics (n=39): 66% male, median age 71 years (range 43-94) and 94% white. For the entire study cohort, median number of prior therapies was 3 (range 1-10), 49% had been treated with prior BTKi monotherapy,13% prior CAR-T or stem cell transplant (SCT) and 59% ≥1 prior small molecule targeted agent. For pts with RT and r/r DLBCL (n=24), median prior therapies were 5 (range 1-10) and 2 (range 10), respectively. Table 1 summarizes prior therapies for the 24 RT and r/r DLBCL pts. Table 2 describes Grade 3 and 4 related AEs for 39 pts treated with the combination therapies. AEs were manageable and similar to known AEs for BTKi, EV or POM, with a total of 4 DLTs observed with combination therapies. The most common AEs were hematological events; specifically, thrombocytopenia, neutropenia, and anemia. The MTD of DTRM-555 was determined to be DTRM-12 200mg, EV 5mg, & POM 2mg. For 11 evaluable RT pts, ORR was 45% (1 CR, 4 PR); 1 RT pt has not undergone first response assessment. For 10 evaluable DLBCL pts, ORR was 60% (2 CR, 4 PR). Responders with RT or r/r DLBCL have durable responses (Figure 1). Kaplan Meier estimated median duration of response for RT and DLBCL pts was 15 months as of the cut-off. Dose dependent DTRM-12 drug plasma levels were observed in all arms with minimal inter-pt variability.

Conclusions: This clinical trial met its primary endpoint. The once-daily oral triple combination therapy DTRM-555 has an acceptable safety profile. Encouraging clinical activity was observed in several high-risk, multi-refractory pts with RT (median 5 prior therapies, ORR 45%) or r/r DLBCL (median 2 prior therapies, ORR 60%), including pts previously treated with targeted therapies, cellular therapies, checkpoint inhibitors and other experimental agents. A phase II US expansion study is underway targeting pts with RT, r/r DLBCL, r/r transformed follicular lymphoma and BTKi/BCL2 inhibitor exposed r/r CLL pts.

Disclosures: Mato: Genentech: Consultancy, Research Funding; AstraZeneca: Consultancy, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding; BeiGene: Consultancy; TG Therapeutics: Consultancy, Other: DSMB, Research Funding; Janssen: Consultancy, Research Funding; LOXO: Consultancy, Research Funding; Adaptive: Consultancy, Research Funding; AbbVie: Consultancy, Research Funding. Schuster: AlloGene, AstraZeneca, BeiGene, Genentech, Inc./ F. Hoffmann-La Roche, Juno/Celgene, Loxo Oncology, Nordic Nanovector, Novartis, Tessa Therapeutics: Consultancy, Honoraria; Novartis, Genentech, Inc./ F. Hoffmann-La Roche: Research Funding. Ding: DTRM: Research Funding; Astra Zeneca: Research Funding; Abbvie: Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Membership on an entity's Board of Directors or advisory committees; alexion: Membership on an entity's Board of Directors or advisory committees; Beigene: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding. Brander: Novartis: Consultancy, Other; Tolero: Research Funding; NCCN: Other; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Teva: Consultancy, Honoraria; Tolero: Research Funding; ArQule: Consultancy, Other, Research Funding; Ascentage: Other, Research Funding; AstraZeneca: Consultancy, Honoraria, Other, Research Funding; BeiGene: Other, Research Funding; DTRM: Other, Research Funding; Genentech: Consultancy, Honoraria, Other, Research Funding; Juno/Celgene/BMS: Other, Research Funding; MEI Pharma: Other, Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Honoraria, Other, Research Funding; Pfizer: Consultancy, Other; TG Therapeutics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other, Research Funding; Verastem: Consultancy, Honoraria, Other, Research Funding; NCCN: Other; Novartis: Consultancy, Other; Teva: Consultancy, Honoraria. Tun: Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Mundipharma: Research Funding; Curis: Research Funding; TG Therapeutics: Research Funding; Acrotech: Research Funding; DTRM Biopharma: Research Funding. He: DTRM Biopharma LLC: Current Employment. Kearney: DTRM Biopharma LLC: Current Employment. Gui: DTRM Biopharma LLC: Current Employment. McKinlay: DTRM Biopharma LLC: Current Employment. Roeker: American Society of Hematology: Research Funding; AbbVie: Other: spouse with minority ownership interest ; Abbott Laboratories: Other: spouse with minority ownership interest . Huntington: Celgene: Consultancy, Research Funding; AbbVie: Consultancy; DTRM: Research Funding; Bayer: Consultancy, Honoraria; Pharmacyclics: Honoraria; Novartis: Consultancy; Genentech: Consultancy; Astrazeneca: Honoraria; TG Therapeutics: Research Funding; Flatiron Health: Consultancy; BeiGene: Consultancy.

*signifies non-member of ASH