ASH2024|Poster on Global Study of Olverembatinib in CML

The ASH Annual Meeting is one of the largest gatherings of the international hematology community, bringing together the most cutting-edge scientific research and latest data of investigational therapies that represent leading scientific and clinical advances in the global hematology field. Garnering growing interest from the global research community, results from multiple clinical and preclinical studies on four of Ascentage Pharma’s drug candidates (olverembatinib, lisaftoclax, APG-2449, and APG-5918) have been selected for presentations, including two Oral Reports , at this year’s ASH Annual Meeting. Furthermore, this is the seventh consecutive year for studies of olverembatinib to be selected for Oral Reports at the meeting .

After releasing the preliminary results from the global study of olverembatinib in an Oral Report at ASH 2022 and the updated results from a larger patient sample at ASH 2023, this year Ascentage Pharma presented the 1.5-year follow-up data in patients with heavily pretreated CML-CP. In the latest data, olverembatinib showed strong, durable and consistent antileukemic activity, the ability to overcome resistance/intolerance to the third-generation tyrosine kinase inhibitor (TKI) ponatinib or the allosteric STAMP inhibitor asciminib , as well as favorable tolerability in patients with heavily pretreated CML-CP.

As the first approved third-generation BCR-ABL inhibitor in China, olverembatinib has already been approved for the treatment of adult patients with tyrosine kinase inhibitor (TKI)-resistant CP-CML or accelerated-phase (AP-) CML harboring the T315I mutation; and adult patients with CP-CML resistant to and/or intolerant of first- and second-generation TKIs. In January 2024, olverembatinib was cleared by the US Food and Drug Administration (FDA) to enter a global registrational Phase III trial in previously treated adult patients with CML-CP.

Olverembatinib (HQP1351) Overcomes Resistance/Intolerance to Asciminib and Ponatinib in Patients (pts) with Heavily Pretreated Chronic-Phase Chronic Myeloid Leukemia (CP CML): A 1.5-Year Follow-up Update with Comprehensive Exposure-Response (E-R) Analyses

Format: Poster Presentation

Abstract#: 3151

Session: 632. Chronic Myeloid Leukemia: Clinical and Epidemiological: Poster II

Highlights:

Introduction : New treatment options are needed for patients with CP-CML resistant/intolerant to third-generation (3G) TKI ponatinib and/or asciminib, a specifically targeting the ABL myristoyl pocket (STAMP) inhibitor. Olverembatinib is a well-tolerated TKI with potential to overcome resistance. This update presents efficacy and safety data of olverembatinib in patients with heavily pretreated CP-CML.

Enrolled Patients and Study Methods :

• Adults with CP-CML previously treated with ≥2 TKIs and/or a STAMP inhibitor, adequate organ function, and no major molecular response (MMR) were eligible.

• As of July 28, 2024, 67 pts with CP-CML were enrolled; median (range) follow-up was 74.3 (0.1-217.1) weeks; median (range) age, 50 (21-80) years; and 38 (56.7%) patients were male.

• Patients were randomly allocated to receive olverembatinib at doses of 30, 40, or 50 mg orally every other day (QOD) in 28-day cycles, with stratification based on T315I mutation status. Comprehensive E-R analyses were performed.

Efficacy Results :

• No patient had efficacy at baseline. 35 of 60 (58.3%) evaluable patients achieved CCyR and 29/64 (45.3%) achieved MMR. At 12 months, the overall MMR rate was 61.4% (27/44). CCyR was achieved by 66.7% of patients with the T315I mutation vs 54.8% without it, and MMR was achieved by 50.0% vs 43.5%, respectively.

• Of 28 cytogenetic response-evaluable patients with ponatinib-failed CP-CML, 15 (53.6%) achieved CCyR. The CCyR rates in patients with prior ponatinib resistance and intolerance were 52.2% (12/23) and 75.0% (3/4), respectively. In the 30 molecular response-evaluable patients who were previously treated with ponatinib, 12 (40.0%) achieved MMR, including 47.8% (11/23) of those with prior resistance and 16.7% (1/6) with intolerance. No patient above had efficacy at baseline.

• In evaluable patients with asciminib treatment failure, 37.5% (6/16) achieved CCyR and 30% (6/20) achieved MMR, including a CCyR rate of 30.8% (4/13) and an MMR rate of 26.7% (4/15) in those with prior resistance, and a CCyR rate of 50.0% (1/2) and an MMR rate of 25.0% (1/4) in those with intolerance. No patient had efficacy at baseline.

Safety Results : Among 66 subjects receiving olverembatinib, a total of 62 (93.9%) reported treatment-emergent adverse events (TEAEs) of any grade, with 44 (66.7%) experiencing grade ≥ 3 TEAEs. In addition, 60 (90.9%) patients reported TRAEs of any grade. Common TRAEs (≥20%) were elevated creatine phosphokinase (37.9%), thrombocytopenia (24.2%), and increased alanine aminotransferase (22.7%).

Conclusions : Olverembatinib was well tolerated and showed strong and durable antileukemic activity in patients with heavily pretreated CP-CML. The registrational study is recruiting.

* Olverembatinib is an investigational drug that has not been approved for any indication outside China.