Trial in Progress: Phase 1b Bridging Study of the Pharmacokinetics (PK), Safety, and Efficacy of Orally Administered Olverembatinib (HQP1351) in Patients with Refractory Chronic Myeloid Leukemia (CML) and Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia (Ph⁺ ALL)

Abstract Background: Management of CML using tyrosine kinase inhibitors (TKIs) is often constrained by treatment failure, which portends a poor prognosis, particularly among patients who fail second-generation TKIs because of resistance. Treatment failure may be due to therapeutic resistance (whether BCR-ABL1 mutation-dependent or independent), intolerance, and/or suboptimal adherence. The BCR-ABL1 T315I ("gatekeeper") genotype is insensitive to first- and second-generation TKIs, and compound mutations complicate management with all members of the class (including third-generation TKI ponatinib). Olverembatinib (HQP1351) is a novel, potent, orally active BCR-ABL1 TKI with promising activity against CML, including antitumor activity regardless of genotype, and a preliminarily favorable safety profile. Methods: This open-label bridging trial is evaluating the PK, efficacy, and safety of olverembatinib administered orally every other day (QOD) in adults who have chronic-phase, accelerated-phase, or blast-phase CML (CP-CML, AP-CML, or BP-CML) and Ph⁺ ALL, with or without the T315I mutation, and have experienced resistance to or intolerance (including NCI CTCAE v5.0 grade ≥ 2 adverse events) of at least 3 TKIs. Eligible patients have no residual grade ≥ 2 adverse events (other than alopecia or skin pigmentation change) due to prior treatments, a maximum ECOG performance status of 2, and a minimum life expectancy of 3 months. Study participants are being randomly allocated in a 1:1:1 ratio to 3 dose cohorts: 30, 40, or 50 mg of oral olverembatinib QOD over a cycle length of 28 days, with 10 patients per cohort and randomization stratified according to CML phase (CP-CML, AP-CML, or BP-CML) or Ph⁺ ALL and T315I mutational status. Study endpoints comprise the PK profile of olverembatinib at Cycle 1 Day 1 and Day 27; efficacy endpoints of major cytogenetic and hematologic responses; and safety. The recommended phase 2 dose of olverembatinib will be determined based on a comprehensive assessment of PK, safety, and efficacy data in US and Chinese patients. As of July 14, 2021, 14 of 30 patients have been enrolled. Internal study identifier HQP1351-CU-101. Clinicaltrial.gov identifier: NCT04260022. Disclosures Jabbour: Amgen, AbbVie, Spectrum, BMS, Takeda, Pfizer, Adaptive, Genentech: Research Funding. Kantarjian: Aptitude Health: Honoraria; Daiichi-Sankyo: Research Funding; Ascentage: Research Funding; Astra Zeneca: Honoraria; Ipsen Pharmaceuticals: Honoraria; Immunogen: Research Funding; Pfizer: Honoraria, Research Funding; KAHR Medical Ltd: Honoraria; BMS: Research Funding; NOVA Research: Honoraria; Astellas Health: Honoraria; Novartis: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Jazz: Research Funding; AbbVie: Honoraria, Research Funding; Precision Biosciences: Honoraria; Taiho Pharmaceutical Canada: Honoraria. Issa: Kura Oncology: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Syndax Pharmaceuticals: Research Funding. Mukherjee: Genentech: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees; Acceleron: Membership on an entity's Board of Directors or advisory committees; Partnership for Health Analytic Research: Honoraria; AbbVie: Membership on an entity's Board of Directors or advisory committees; BioPharm: Consultancy; AAMDS in Joint Partnership with Cleveland Clinic Taussig Cancer Institute: Honoraria; Eusa Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Teaching and Speaking; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Research/Independent Contractor, Research Funding; McGraw Hill: Honoraria, Other: Editor of Hematology Oncology Board Review (ongoing); Bristol-Myers Squibb Co.: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene Corporation: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Research/Independent Contractor, Research Funding; Jazz Pharmaceuticals: Research Funding. Oehler: OncLive: Honoraria; Pfizer: Research Funding; Takeda: Consultancy; BMS: Consultancy. Chen: Ascentage Pharma (Suzhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company. Lu: Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company. Fu: Ascentage Pharma Group Inc: Current Employment, Current equity holder in publicly-traded company. Zhai: Ascentage Pharma (Suzhou) Co., Ltd.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding; Ascentage Pharma Group Inc.: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding. Yang: Ascentage Pharma (Suzhou) Co., Ltd: Current Employment, Current equity holder in publicly-traded company, Other: Leadership and other ownership interests, Patents & Royalties, Research Funding.