Camarillo, California, October 16, 2023 – AskGene Pharma Inc. announces that the Center for Drug Evaluation (CDE) of the Chinese National Medicinal Product Administration (NMPA) has granted clearance for the initiation of a Phase III clinical trial to evaluate the efficacy and safety of ASKB589 (anti-CLDN18.2 monoclonal antibody) in combination with CAPOX (capecitabine and oxaliplatin) and a PD-1 inhibitor for the first-line treatment of CLDN18.2 positive, inoperable, locally advanced, recurrent or metastatic gastric and esophagogastric junction (G&GEJ) cancer in China. The Phase III initiation marks AskGene’s entry into the first tier of pivotal clinical studies for anti-claudin 18.2 antibody targeted therapy for gastric cancer.
ASKG589 Clinical Progress
ASKB589 is a second generation anti-CLDN18.2 humanized monoclonal antibody with ADCC enhancement. To support the Phase III study, more than 200 patients have been enrolled into a number of Phase I/II studies, including ASKB589 monotherapy, combination with chemotherapy, and combination with PD-1 inhibitor and chemotherapy. No dose limiting toxicity (DLT) has been observed so far, with monotherapy up to 20 mg/kg, and combination therapy up to 15 mg/kg. Thus, a maximum tolerated dose (MTD) has not yet been reached, indicating that ASKB589 is well-tolerated.
The Phase I/II clinical results were first presented at ASCO GI (the American Society of Clinical Oncology Gastrointestinal Cancer Symposium) in January 2023, and later at IGCC (the International Gastric Cancer Congress) in June 2023. For those patients in the Phase II dose expansion study with measurable lesions, at least one post-treatment tumor assessment, medium to high CLDN18.2 expression, and treatment with 6 or 10 mg/kg ASKB589 in combination with CAPOX (capecitabine and oxaliplatin), the investigator-confirmed objective response rate (cORR) was 79.2%, and the disease control rate (DCR) was 95.8%.
In order to better identify patients who can benefit from the treatment, AskGene has also developed a CLDN18.2 immunohistochemistry-based companion diagnostic kit. With its high sensitivity and selectivity, the diagnostic kit will become an essential component of the ASKB589 Phase III program.
The approval of Phase III clinical trial is a major milestone for ASKB589 as an innovative patient-centered first-line treatment of G&GEJ cancer. The combination therapy targets both CLDN18.2 and PD-1, and could provide a more effective treatment by boosting both innate and adaptive immune responses.
Barbara Hickingbottom, J.D., M.D., Chief Medical Officer of AskGene, commented: “Claudin 18.2 has recently been validated as a new molecular target that demonstrates the potential for clinical benefit for patients with gastric and gastroesophageal cancer. Our Phase I/II clinical trial shows that ASKB589, particularly in combination with chemotherapy or PD-1 plus chemotherapy, can be administered safely in patients with these types of cancer and results in a high rate of deep and durable responses, as well as a remarkable disease control rate. The clearance for starting the registrational trial marks a major milestone for the clinical development ASKB589. We look forward to conducting an efficient and successful Phase III trial and advancing ASKB589 to meet the significant unmet medical needs of gastric and gastroesophageal cancer patients in China and beyond.”
About Gastric Cancer
Gastric cancer, also known as stomach cancer, is one of the most common cancers in the world, with more than 1 million new cases and 769,000 deaths each year worldwide. It ranks fifth in incidence rate among malignant tumors and fourth in mortality. According to data from the World Health Organization, there were approximately 480,000 new gastric cancer cases and 370,000 deaths in China in 2020, accounting for 44% and 48.6% of the global gastric cancer new cases and deaths, respectively.
ASKB589 is an innovative biological drug discovered and developed by AskGene. It is a recombinant humanized monoclonal antibody targeting CLDN18.2. ASKB589 is among the top 3 most advanced therapies against this target with no marketed drugs yet. ASKB589 mediates antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) through high-affinity binding to cancer cells. Enrollment in dose escalation for ASKB589 as monotherapy and in combination with CAPOX chemotherapy was completed in 2022. Enrollment continues in expansion cohorts of first-line advanced or metastatic patients with CLDN18.2-positive G&GEJ cancers that are being treated with ASKB589 in combination with chemotherapy. In addition to G&GEJ cancers, ASKB589 is being tested in clinical trials for other CLDN18.2-positive solid tumors such as pancreatic cancer. A pivotal study of ASKB589 in the treatment of gastric cancer has received CDE approval and is under way.
About AskGene Pharma
AskGene Pharma, founded in 2012 in Los Angeles, California, is dedicated to the discovery and development of novel antibody and fusion protein therapeutics. It has established the proprietary SmartKine® cytokine prodrug platform, which significantly improves the developability of cytokines for oncology and inflammation indications. AskGene has multiple programs in clinical and preclinical developments. In addition to the first-in-class cytokine prodrug programs in clinical state, AskGene is actively advancing several programs with the potential of being best-in-class or first-in-class into late-stage or mid-stage clinical development.
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