Ascentage Pharma Releases Updated Data of Bcl-2 Inhibitor Lisaftoclax in MDS that Demonstrates Potential Clinical Benefits and Favorable Safety

Ascentage Pharma (6855.HK), a global biopharmaceutical company engaged in discovering, developing, and commercializing therapies to address global unmet medical needs primarily for malignancies, today announced that it has released the follow-up safety and efficacy data of the company's investigational Bcl-2 selective inhibitor, lisaftoclax (APG-2575), in combination with azacitidine (AZA) for the treatment of patients with myelodysplastic syndrome (MDS), in a Poster Presentation at the 66th American Society of Hematology (ASH) Annual Meeting, taking place in San Diego, CA, the United States.

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.

Prof. Jie Jin, the principal investigator of the study from the First Affiliated Hospital, Zhejiang University School of Medicine, noted, "For a long time, there has not been much progress in the treatment of higher-risk MDS and the outcome of the current standard treatment with hypomethylating agents has been disappointing. In patients with MDS, the investigational novel Bcl-2 inhibitor lisaftoclax in combination with AZA has demonstrated clinical benefit and manageable safety that support continued treatment. These observations suggest that the regimen can potentially offer a new standard treatment in MDS."

Prof. Huafeng Wang, the presenter of this study from the First Affiliated Hospital, Zhejiang University School of Medicine, commented, "Patients with higher-risk MDS often have inadequate marrow function and low tolerance for therapeutic agents. The investigational novel Bcl-2 inhibitor lisaftoclax in combination with AZA has shown encouraging clinical benefit, manageable safety, and low suppression on bone marrow function. More importantly, the regimen showed a low rate of treatment-related infections that were mostly mild, and a low rate of mortalities in early treatment, thus overcoming some of the biggest clinical challenges in this patient population."

Dr. Yifan Zhai, Chief Medical Officer of Ascentage Pharma, said, "These updated efficacy and safety data of lisaftoclax in combination with AZA are very encouraging as they reaffirmed the therapeutic potential of this novel drug candidate. A global registrational Phase III study of lisaftoclax in combination with AZA for the first-line treatment of MDS is currently ongoing and an NDA for lisaftoclax in R/R chronic lymphocytic leukemia/small lymphocytic lymphoma has already been accepted and granted the Priority Review designation in China. Fulfilling our founding mission of addressing unmet clinical needs in China and around the world, we will expedite the global clinical development of our key drug candidates to bring more safe and effective therapies to patients as soon as possible."

Highlights of the data this study reported at ASH 2024 are as below:

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.

About Ascentage Pharma

Ascentage Pharma (6855.HK) is a global, integrated biopharmaceutical company engaged in discovering, developing and commercializing therapies to address global unmet medical needs primarily in malignancies. On October 28, 2019, Ascentage Pharma was listed on the Main Board of the Stock Exchange of Hong Kong Limited with the stock code 6855.HK.

The company has built a rich pipeline of innovative drug candidates that includes novel, highly potent Bcl-2 and dual Bcl-2/Bcl-xL inhibitors, as well as candidates aimed at IAP and MDM2-p53 pathways, and next-generation TKIs. Ascentage Pharma is also the only company in the world with active clinical programs targeting all three known classes of key apoptosis regulators. The company has conducted more than 40 clinical trials in the US, Australia, Europe, and China, including 13 registrational studies (completed/ ongoing/planned).

Olverembatinib, the company's first lead asset developed for the treatment of drug-resistant chronic myeloid leukemia (CML) and the company's first approved product in China, has been granted Priority Review Designations and Breakthrough Therapy Designations by the Center for Drug Evaluation (CDE) of China National Medical Products Administration (NMPA). To date, the drug had been included into the China National Reimbursement Drug List (NRDL). Furthermore, olverembatinib has been granted Orphan Drug Designations (ODDs) and a Fast Track Designation (FTD) by the US FDA, and an Orphan Designation by the EMA of the EU.

To date, Ascentage Pharma has obtained a total of 16 ODDs from the US FDA and 1 Orphan Designation from the EMA of the EU for 4 of the company's investigational drug candidates. Leveraging its robust R&D capabilities, Ascentage Pharma has built a portfolio of global intellectual property rights and entered into global partnerships and other relationships with numerous leading biotechnology and pharmaceutical companies such as Takeda, AstraZeneca, Merck, Pfizer and Innovent; and research and development relationships with leading research institutions such as Dana-Farber Cancer Institute, Mayo Clinic, National Cancer Institute and the University of Michigan.

The company has built a talented team with a wealth of global experience in the discovery and development of innovative drugs and fully functional commercial manufacturing and Sales & Marketing teams. One pivotal aim of Ascentage Pharma is to continuously strengthen its R&D capabilities and accelerate its clinical development programs, in order to fulfil its mission of addressing unmet clinical needs in China and around the world for the benefit of more patients.

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