ASH2024|Poster on Updated Data of Lisaftoclax in MDS

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.

Thes data underscored the potential clinical benefit and manageable safety of lisaftoclax in combination with AZA in MDS. In the results, the combination regimen demonstrated an overall response rate (ORR) of 75% in patients with treatment-naïve (TN) or relapsed/refractory (R/R) MDS, and no patient withdrew from the study due to intolerable toxicities.

Lisaftoclax (APG-2575), a Novel BCL-2 Inhibitor, in Combination with Azacitidine in Treatment of Patients with Myelodysplastic Syndrome (MDS)

Format: Poster Presentation

Abstract#: 3202

Session: 637. Myelodysplastic Syndromes: Clinical and Epidemiological: Poster II

Highlights:

Background: Hypomethylating agents (HMAs) remain the standard of care in higher-risk MDS. However, its clinical efficacy is limited, and patients who have failed or are resistant to HMAs have a poor prognosis, leaving them in need of new therapeutic options.

Introduction : Preclinical data have shown that novel investigational Bcl-2 inhibitor lisaftoclax combined with an HMA can synergistically induce apoptosis in cancer cells in AML and MDS. Reported here are the follow-up safety and efficacy data from a Phase Ib/II clinical trial evaluating lisaftoclax combined with azacitidine in adults (≥18 years) with MDS.

Enrolled Patients and Study Methods :

• This study enrolled patients with higher-risk MDS (IPSS-R score > 3.5; blasts > 5%), including those with TN or R/R disease. Lisaftoclax at an assigned dose (400, 600, or 800 mg) was administered orally once daily from Days 1 to 14 and combined with azacitidine (75 mg/m2/day) on Days 1 to 7 in repeated 28-day cycles. A daily ramp-up was used before the first cycle to prevent TLS. The primary objectives of the study were to assess the efficacy and safety of the combination regimen in patients with MDS and establish the recommended Phase III dose for lisaftoclax. Complete response (CR) and marrow CR (mCR) rates were evaluated in accordance with 2006 International Working Group (IWG) criteria.

• As of July 1, 2024, 49 patients were enrolled: 8 had R/R MDS (lisaftoclax 600 mg [n=5] and 800 mg [n=3]) and 41 had TN MDS (lisaftoclax 400 mg [n=16], 600 mg [n=23], and 800 mg [n=2]). The median (range) age was 66 (22-83) years, and 55.1% of patients were male. IPSS-R risk categories were intermediate (12/49 [24.5%]), high (24/49 [49.0%]), and very high (13/49 [26.5%]). Among the 39 patients with genetic mutational profile data, 9 (23.1%) had TP53 mutations; 11 (28.2%) had TET2 mutations; 10 (25.6%) had ASXL1 mutations; and 10 (25.6%) had RUNX1 mutations. At baseline, 70.8% of patients reported grade ≥ 3 anemia; 54.2% had grade ≥ 3 neutropenia; and 45.8% had grade ≥ 3 thrombocytopenia.

Efficacy Results :

In 8 patients with R/R MDS, the median (range) duration of treatment (DOT) was 3.2 (1.2-9.4) months. The ORR (CR[12.5%]+marrow CR[62.5%]) was 75.0% (95% CI, 34.9-96.8). In 40 efficacy-evaluable patients with TN MDS, the median DOT (range) was 4.5 (0.5-12.1) months; the ORR was 77.5% (95% CI, 61.5-89.2); and the CR rate was 25.0% per IWG 2006 criteria. Furthermore, the ORR and CR rate in 23 patients with TN MDS treated with lisaftoclax 600 mg combined with azacitidine were 73.9% and 30.4%, respectively; because these patients had a relatively longer median DOT (6.01 months), we conducted further analyses per IWG 2023 criteria. The composite CR rate (CR2023 = CR [52.2%] + CRL [17.4%]) was 69.6%, and the median time to CR (range) was 2.84 (1.1-8.7) months. Both the median progression-free survival and overall survival rates were not reached.

Safety Results :

• Grade ≥ 3 infections were reported in 46.9% of patients, of which 26.5% were treatment related. Treatment delays between cycles due to AEs occurred in 11 (22.4%) patients, with a median delay time (range) of 12 (1-63) days.

• A total of 95.9% of patients reported TRAEs, of which 87.8% were grade ≥ 3 AEs and 28.6% were serious AEs. Common grade ≥ 3 hematologic TRAEs included leukocyte count decreased (71.4%), neutropenia (65.3%), thrombocytopenia (65.3%), anemia (20.4%), and febrile neutropenia (12.2%).

• Neither 60-day mortality nor TLS was reported.

Conclusions : The clinical data support an emerging role for lisaftoclax in combination with azacitidine for treatment of patients with higher-risk TN or R/R MDS. The combination therapy was efficacious and well tolerated, resulting in no 60-day mortality, few dose modifications, and low infection rates, supporting further clinical development of this combination in patients with higher-risk MDS.

* Lisaftoclax is an investigational drug that has not been approved in any country or region.