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1873 Results of a Phase 1/2 Study of Lower Dose CPX-351 for Patients with Int-2 or High Risk IPSS Myelodysplastic Syndromes and Chronic Myelomonocytic Leukemia after Failure to Hypomethylating Agents

Program: Oral and Poster Abstracts
Session: 637. Myelodysplastic Syndromes – Clinical and Epidemiological: Poster I
Saturday, December 9, 2023, 5:30 PM-7:30 PM

Guillermo Montalban-Bravo, MD1, Elias Jabbour2, Kelly S. Chien, MD1, Gautam Borthakur, MD1, Zeev Estrov, MD1, Tapan M. Kadia, MD1, Farhad Ravandi, MD, MBBS1, Naveen Pemmaraju, MD1, Graciela Nogueras-Gonzalez3*, Heather Schneider, BSN, RN4*, Rosmy John4*, Meghan Anne Meyer, BSN, RN4*, Hagop M. Kantarjian, MD4, Guillermo Garcia-Manero, MD5 and Xiao Qin DONG6*

1Department of Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX
2University of Texas M.D. Anderson Cancer Ctr., Houston, TX
3Biostatistics, The University of Texas MD Anderson Cancer Center, Houston, TX
4Leukemia, The University of Texas MD Anderson Cancer Center, Houston, TX
5The University of Texas MD Anderson Cancer Center, Houston, TX
6HOUSTON, TX

INTRODUCTION: Hypomethylating agents (HMAs) are the standard of care for patients (pts) with higher-risk myelodysplastic syndromes (HR-MDS) and chronic myelomonocytic leukemia (CMML). HMA failure (HMA-F) is associated with poor outcomes and median survival of 4 to 6 months. CPX-351 is a drug liposomal encapsulation of cytarabine (araC) and daunorubicin (dauno) at a synergistic 5:1 molar ratio approved for the treatment of pts with therapy-related acute myeloid leukemia (AML) or AML with MDS-related changes. Here we present the results of a phase I-II study of lower dose CPX-351 for HR-MDS and CMML after HMA-F.

METHODS: We conducted a phase I/II clinical trial of CPX-351 for pts with MDS or CMML after HMA-F with Int-2 or High risk by IPSS, or Int-1 with >10% bone marrow (BM) blasts. The study included an initial phase I dose-escalation portion, following a 3+3 design, followed by a phase II dose expansion portion. Dose escalation included 4 dose levels of CPX-351: 10 units/m2 (dauno 4.4mg/m2 and araC 10mg/m2), 25 units/m2 (dauno 11mg/m2 and araC 25mg/m2), 50 units/m2 (dauno 22mg/m2 and araC 50mg/m2) and 75 units/m2 (dauni 33mg/m2 and araC 75mg/m2). Therapy was administered intravenously on days 1, 3 and 5 of 28-day cycles during induction and on days 1 and 3 of re-induction or consolidation. Re-induction was allowed in pts not achieving response after induction. The primary end point was to evaluate safety and determine the maximum tolerated dose of CPX-351. Responses were evaluated following 2006 IWG criteria. The Kaplan-Meir product-limit method was used to estimate median survival.

RESULTS: Between June 2019 and September 2022, 23 pts have been treated: 15 in the phase I portion, and 8 in the phase II. A total of 17 pts had MDS, and 6 had CMML. Four (17%) pts had intermediate-1 risk IPSS and >10% blasts, 15 (65%) had intermediate-2 and 4 (17%) had high-risk IPSS. Median number of prior therapies was 1 (range 1-4) including 4 (17%) pts with failure to prior venetoclax therapy and 2 (9%) with prior HSCT.

In the phase I portion, 3 pts received CPX-351 at dose level 1, 3 at dose level 2, 3 at dose level 3 and six at dose level 4. One pt treated at dose level 4 developed grade 2 congestive heart failure with grade 2 reduction in left-ventricular ejection fraction (LVEF). No additional DLTs were detected during the 28-day DLT evaluation window. The initial two pts treated at the P2RD of 75units/m2 during phase II experienced cardiac complications: grade 3 congestive heart failure without reduction in LVEF and grade 3 right-sided heart failure, respectively. Study was amended to continue further treatment in phase II at dose level 3 (50units/m2).

Most common adverse events (AEs) were lower extremity edema (n=12, 52%), febrile neutropenia (n=11, 48%), dyspnea (n=10, 44%), mucositis (n=10, 44%), constipation (n=9, 39%), diarrhea (n=9, 39%), and generalized muscle weakness (n=9, 39%). Most common grade 3-4 AEs were febrile neutropenia (n=11, 48%), neutropenia (n=5, 22%), lung infection (n=4, 17%), diarrhea (n=4, 17%) and thrombocytopenia (n=3, 13%). The 4-week and 8-week cumulative incidences of mortality were 0% and 4%, respectively. Median number of days to cycle 2 was 47 days (range 30-83). Dose reductions of CPX-351 occurred in 4 (17%) pts. Median number of cycles was 3 (range 1-9). Median cycles to best response was 1 (range 1-3). Among pts with HR-MDS, the ORR was 71% (n=12): CR in 1 (6%), mCR with HI in 1 (6%) and mCR in 11 (59%) pts (Fig 1A). Among pts with BM blast reduction to <5% by the end of cycle 1, 11 (65%) and 9 (53%) had ANC recovery to >0.5x109/L and >1x109/L, respectively, and 8 (47%) and 6 (35%) had platelet recovery to >50x109/L and >100x109/L, respectively. Based on 2023 IWG response criteria, the ORR was 59% (n=10) including CR in 1 (6%), CR bilineage (CRbi) in 4 (24%) and CR unilineage in 5 (29%). Of 11 (65%) pts with baseline cytogenetic abnormalities, 2 (18%) and 2 (18%) achieved complete and partial cytogenetic responses, respectively. Three (13%) pts underwent HSCT at time of best response. Among pts with CMML (n=6), only one (17%) achieved response. Median response duration was 4.5 months (95% CI 0.7-8.2 months) and the median OS was 12.6 months (95% CI 3.6-21.7 months) (Fig 1B).

CONCLUSIONS: Lower doses of CPX-351 in HR-MDS after HMA-F can induce clinically meaningful responses and be used as a bridge to allogeneic stem-cell transplant. Therapy is associated with median OS of 12.6 months in this population with expected survival of 4-6 months.


Disclosures: Montalban-Bravo: Rigel: Research Funding; Takeda: Research Funding. Jabbour: Ascentage Pharma Group: Consultancy, Honoraria, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria, Research Funding; Adaptive Biotech: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Hikma Pharmaceuticals: Consultancy, Honoraria, Research Funding; Genentech: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Research Funding; Astex: Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding. Chien: AbbVie: Consultancy; Rigel Pharmaceuticals: Consultancy. Borthakur: Catamaran Bio, Abbvie, PPD Development, Protagonist Therapeutics, Janssen: Consultancy; Astex Pharmaceuticals, Ryvu, PTC Therapeutics: Research Funding; Pacylex, Novartis, Cytomx, Bio Ascend:: Membership on an entity's Board of Directors or advisory committees. Kadia: AstraZeneca: Research Funding; Iterion: Research Funding; Glycomimetics: Research Funding; Hikma Pharmaceuticals: Speakers Bureau; Cellenkos Inc.: Research Funding; Cure: Speakers Bureau; Astellas Pharma Global Development: Research Funding; Biologix, Cure, Hikma Pharmaceuticals: Speakers Bureau; Genentech: Consultancy, Research Funding; Jazz Pharmaceuticals, Pfizer, Pulmotect, Inc, Regeneron Pharmaceuticals, SELLAS Life Sciences Group: Research Funding; Celgene: Research Funding; Novartis: Consultancy; Liberum: Consultancy; Janssen Research and Development: Research Funding; Pinotb-Bio: Consultancy; BMS: Consultancy, Research Funding; Astex: Honoraria; Genzyme: Honoraria; Amgen, Inc.: Research Funding; Agios: Consultancy; Servier: Consultancy; AbbVie, Amgen, Inc, Ascentage Pharma Group, Astellas Pharma Global Development, Astex, AstraZeneca, BMS, Celgene, Cellenkos Inc, Cyclacel, Delta-Fly Pharma, Inc, Genentech, Inc., Genfleet, Glycomimetics, Iterion, Janssen Research and Development: Research Funding; Daiichi Sankyo, Genentech, Inc., Genzyme, Jazz Pharmaceuticals, Liberum, Novartis, Pfizer, PinotBio, Inc, Pulmotect, Inc, Sanofi-Aventis, Servier: Consultancy; Ascentage Pharma Group: Research Funding; GenFleet Therapeutics: Research Funding; Cyclacel: Research Funding; Delta-Fly Pharma, Inc.: Research Funding; Pfizer: Consultancy, Research Funding; Pulmotect, Inc.: Consultancy, Research Funding; Regeneron Pharmaceuticals: Research Funding; Sanofi-Aventis: Consultancy; SELLAS Life Sciences Group: Research Funding. Ravandi: Xencor: Research Funding; Astex/taiho: Membership on an entity's Board of Directors or advisory committees, Research Funding; Biomea fusion: Honoraria, Research Funding; Syros: Consultancy, Honoraria, Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding; Abbvie: Consultancy, Honoraria, Research Funding; Astellas: Consultancy, Honoraria, Research Funding; Prelude: Research Funding; Amgen: Honoraria, Research Funding. Pemmaraju: Menarini Group: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karger Publishers: Other: Licenses; ASCO Cancer.Net Editorial Board: Other: Leadership; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Intellisphere: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Magdalen Medical Publishing: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Physician Education Resource (PER): Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ASH Committee on Communications: Other: Leadership; Aplastic Anemia & MDS International Foundation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Harborside Press: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Imedex: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Pacylex: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; OncLive: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Dan's House of Hope: Membership on an entity's Board of Directors or advisory committees; Neopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; EUSA Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PharmaEssentia: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; United States Department of Defense (DOD): Research Funding; Curio Science: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Stemline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Dava Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CareDx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; PeerView Institute for Medical Education: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Protagonist Therapeutics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; ImmunoGen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Medscape: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Patient Power: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; National Institute of Health/National Cancer Institute (NIH/NCI): Research Funding; CancerNet: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Aptitude Health: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astellas: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Cimeio Therapeutics AG: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ClearView Healthcare Partners: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; CTI BioPharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; HemOnc Times/Oncology Times: Other: Uncompensated; Bristol Myers Squibb Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Kantarjian: Pfizer: Research Funding; Novartis: Research Funding; Jazz Pharma: Research Funding; Orsinex: Honoraria; Daiichi-Sankyo: Research Funding; Cyclacel: Research Funding; BMS: Research Funding; Actinium: Honoraria; Astex: Research Funding; Immunogen: Honoraria, Research Funding; Ariad: Research Funding; Amgen: Honoraria, Research Funding; Agios: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Takeda: Honoraria. Garcia-Manero: Genentech: Research Funding; Bristol Myers Squibb: Other: Medical writing support, Research Funding; AbbVie: Research Funding.

*signifies non-member of ASH