TAIPEI, Taiwan, April 22, 2025 — AP Biosciences, a biopharmaceutical company focused on clinical development and dedicated to revolutionizing cancer treatment through innovative bispecific antibodies, announced the first patient has been dosed in its Phase 1 study of AP402. AP402 is a potential first-in-class, next-generation T cell engager targeting CD137 and p95HER2 in patients with HER2+ cancers that have relapsed or are refractory to anti-HER2 treatments. The Phase 1 clinical trial, currently underway in Australia, aims to assess the safety, tolerability, and early efficacy of AP402 in HER2+ patients with advanced solid tumors, including breast cancer. The subsequent dose expansion phase may include clinical sites in Taiwan, South Korea, and the United States.
According to Dr. Jeng Her, Ph.D., Founder and CEO of AP Biosciences, AP402 targets p95HER2, a truncated form of HER2 found in 30-40% of HER2-positive cancers. This form is linked to a particularly poor prognosis and cannot be treated with conventional anti-HER2 therapies. Dr. Her states that AP402 is the only T-cell engager in human trials that connects activated T cells and p95HER2-expressing cancer cells within the tumor, a unique mechanism that could generate a strong immune response while minimizing systemic toxicity. AP402, therefore, presents a promising potential therapeutic option for patients with difficult-to-treat cancers, potentially improving efficacy and safety where other treatments are insufficient.
AP402-101 is a multi-center, open-label Phase 1 trial enrolling up to 85 patients in two stages: a dose-escalation phase to determine the maximum tolerated dose and recommended Phase 2 dose (RP2D), followed by a dose-expansion phase targeting specific HER2-positive tumor types. The study’s primary endpoints include safety and tolerability, while secondary endpoints will evaluate objective response rate (ORR), disease control rate (DCR), and pharmacokinetic (PK) parameters. Exploratory endpoints will assess pharmacodynamic biomarkers and immunogenicity.
The company has announced that preclinical data supporting AP402’s therapeutic potential will be presented as a poster at this year’s American Association of Cancer Research (AACR) conference.
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About AP402
AP402 is a first-in-class bispecific antibody discovered and developed by AP Biosciences to target p95HER2, a truncated version of HER2 that is present in 30-40% of HER2-positive cancers resistant to treatment. AP402 utilizes T-cube bispecific antibody technology, combining p95HER2 targeting with a CD137 activation domain to enable target-dependent T-cell activation specifically within the tumor microenvironment. The antibody design promotes the clustering of HER2 variants, effectively triggering CD137-mediated T-cell activation while reducing potential side effects associated with systemic cytokine release. The binding domains for p95HER2 and CD137 are designed to improve the connection between HER2 variant-expressing cancer cells and CD137-expressing T-cells, ensuring efficient immune cell recruitment without spatial hindrance. This innovative mechanism positions AP402 as a potentially promising therapeutic approach for addressing tumors that have developed resistance to traditional anti-HER2 therapies, offering renewed hope for patients with refractory/recurrent cancers.
About AP Biosciences
AP Biosciences, based in Taiwan, is a clinical-stage biopharmaceutical company dedicated to developing innovative antibody-based therapies for cancer and other diseases. Utilizing its proprietary Omni-Mab and T-cube platforms, AP Biosciences is pioneering next-generation bispecific antibodies that precisely activate the immune system where needed, for both established and treatment-resistant cancers.
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