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 a New Drug Application (NDA) for its inhouse developed investigational novel Bcl-2 selective inhibitor, lisaftoclax (APG-2575), for the treatment of patients with relapsed or refractory (r/r) chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has been accepted and recommended the Priority Review designation by the Center for Drug Evaluation (CDE) of China's National Medical Products Administration (NMPA). This NDA, the first for a domestically developed Bcl-2 inhibitor in China, could potentially lead lisaftoclax to become the second Bcl-2 inhibitor approved anywhere in the world.

This NDA is based on results from a pivotal registrational Phase II study in China (APG2575CC201) that evaluated the efficacy and safety of lisaftoclax in patients with r/r CLL/SLL. The primary endpoint of the study is the overall response rate (ORR).

CLL/SLL is a hematologic malignancy caused by mature B-cell neoplasms. It primarily affects older populations and is among the most common leukemia subtypes in the Western World, with over 100,000 new diagnoses reported globally each year1. In China, where the incidence rate of CLL/SLL is lower than that of the western countries, the disease is occurring at a rapidly rising rate, with a younger age of onset and higher aggressiveness2. SLL and CLL are two different manifestations of the same disease and approximately 20% of all SLL cases would progress to CLL3. Treatments such as immunotherapies and Bruton's tyrosine kinase inhibitors (BTKis) have significantly improved patients' responses to initial treatment. However, due to the limitations of existing treatment options, the poor prognosis of patients, severe impact on patients' quality of life and high complexity of the disease, patients with r/r CLL/SLL are in desperate need for new treatment options that are safe and effective.

The introduction of Bcl-2 inhibitors has further revolutionized the treatment of CLL/SLL. Bcl-2 is an apoptosis suppressor factor that regulates cell survival by controlling mitochondrial membrane permeability. It suppresses apoptosis by inhibiting the release of cytochrome C from mitochondria or by binding to apoptotic activators to inhibit the activity of caspase. The overexpression of Bcl-2, found in a variety of hematologic malignancies, particularly CLL/SLL, is a key mechanism by which tumor cells evade apoptosis.

However, the development of Bcl-2 as a therapeutic target is challenging mainly because its mechanism of action is based on the protein-protein interaction (PPI). The binding interface of Bcl-2 is relatively large, making it difficult for small-molecule inhibitors to exert blocking effects. Additionally, the Bcl-2 protein is located on the mitochondrial membrane, and mitochondria, with its double-membrane structure, is among the most complex and challenging cellular components. Drugs must first penetrate the cell membrane before they can further act on the mitochondrial membrane. In nearly 40 years since the discovery of this target, only one Bcl-2 inhibitor has been approved globally, a reality highlighting the immense difficulty and challenges in this field of research and development. In western countries, the treatment of CLL/SLL has entered a new era of chemotherapy-free and fixed-duration regimens, while no Bcl-2 inhibitor has been approved in China in this therapeutic area. Therefore, patients in China have an urgent unmet need for such novel therapies that can offer both efficacy and safety.

Lisaftoclax is a novel, investigational orally administered small-molecule Bcl-2 selective inhibitor being developed by Ascentage Pharma to treat patients with malignancies by selectively blocking the antiapoptotic protein Bcl-2 and hence restoring the normal apoptosis process in cancer cells. Lisaftoclax is the first Bcl-2 inhibitor in China and the second anywhere globally that has demonstrated compelling clinical benefit and entered a pivotal registrational study. Lisaftoclax has broad therapeutic potential for a variety of hematologic malignancies and solid tumors, particularly as a single agent and in combinations in CLL/SLL. Lisaftoclax is a potential drug that may offer patients a safe, effective, and easy to use treatment option.

Lisaftoclax is being evaluated in multiple registrational Phase III studies, including a global registrational Phase III study of lisaftoclax in combination with a BTKi in previously treated patients with CLL/SLL (cleared by the US FDA); a global registrational Phase III study of lisaftoclax in combination with acalabrutinib for the first-line treatment of treatment-na?ve patients with CLL/SLL; a global registrational Phase III study of lisaftoclax in combination with azacitidine (AZA) for the first-line treatment of elderly/unfit treatment-na?ve patients with acute myeloid leukemia (AML) who were intolerant of standard induction chemotherapies; and a global registrational Phase III study of lisaftoclax in combination with AZA for the first-line treatment of newly-diagnosed patients with higher-risk myelodysplastic syndrome (MDS).

"Ascentage Pharma's founding team has over 20 years of deep experience in developing apoptosis-targeted therapies and has made significant strides with the Bcl-2 target," said Dr. Dajun Yang, Chairman & CEO of Ascentage Pharma. "To date, only one Bcl-2 inhibitor has been approved globally, which is a reality underscoring the immense difficulty and challenges in this field of research and development. This NDA submission for lisaftoclax could potentially pave the way for lisaftoclax to become the first approved China-developed Bcl-2 inhibitor, thus marking another major milestone that is a culmination of the Ascentage Pharma's deep commitment and perseverant work in the past 15 years."

Dr. Yang continued, "Globally, r/r CLL/SLL represents an area of urgent unmet clinical needs. To have successfully advanced lisaftoclax to this point, it is a true testament to Ascentage Pharma's robust capabilities in global pharmaceutical innovation. Moving forward, we will accelerate the global development of lisaftoclax in other indications to bring benefit to patients as quickly as possible. Remaining steadfastly committed to our mission of addressing unmet clinical needs in China and around the world, we will strive to develop more novel therapeutics for patients in need."

References:

1.Yao, Y., Lin, X., Li, F., et al. The global burden and attributable risk factors of chronic lymphocytic leukemia in 204 countries and territories from 1990 to 2019: analysis based on the global burden of disease study 2019. Biomed Eng Online. 2022 Jan 11;21(1):4. DOI: 10.1186/s12938-021-00973-6

2.Liu Peng. Practice guidelines for the diagnosis and treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma in Zhongshan Hospital, Fudan University (v1.2018). [J]. Chin J Clin Med, 2018, 25(1): 157-160. DOI 10.12015/j. issn. 1008-6358. 2018. 20180

3. Li Jianyong, Qiu Lugui. Hematology Committee of Chinese Medical Association; Hematological Oncology Committee of China Anti-Cancer Association; Chinese Working Group for Chronic Lymphocytic Leukemia. The guidelines for diagnosis and treatment of chronic lymphocytic leukemia/small lymphocytic lymphoma in China (2022). Zhonghua Xue Ye Xue Za Zhi. 2022 May 14;43(5):353-358. DOI: 10.3760/cma.j.issn.0253-2727.2022.05.001

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, MD Anderson Cancer Center, 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.