Hanmi Pharmaceutical said on the 13th that BH3120, an investigational immuno-oncology drug candidate co-developed with Beijing Hanmi Pharmaceutical, showed initial efficacy and safety in a phase 1 trial.
The results were presented as a poster at the ESMO Immuno-Oncology Congress 2025, held in London, England, from the 10th to the 12th of last month.
BH3120 is a bispecific antibody-based anticancer therapy in which a single antibody binds two targets simultaneously. It is designed to simultaneously target PD-L1 on the surface of cancer cells and 4-1BB on immune cells, helping immune cells recognize and attack cancer cells more easily.
PD-L1 is a protein cancer cells use to evade immune attack, and 4-1BB is a target that transmits signals activating immune cells. BH3120 aims to link these two targets at the same time to selectively enhance immune responses at tumor sites.
Existing 4-1BB–targeting antibodies have been flagged for the challenge of balancing anticancer effect and safety. In preclinical studies, BH3120 appeared to activate immune responses around tumors while suppressing excessive immune responses in normal tissue.
These preclinical findings were additionally disclosed at the American Association for Cancer Research (AACR) last year. At the time, Beijing Hanmi Pharmaceutical presented a study assessing liver toxicity risk and nonclinical results analyzing BH3120's effects on immune responses in the tumor microenvironment.
BH3120 is currently in a global phase 1 trial in Korea and the United States for patients with advanced or metastatic solid tumors who failed standard therapies, including prior immuno-oncology agents. The study is evaluating safety and tolerability both as monotherapy and in combination with Keytruda.
According to the clinical progress disclosed at this congress, dose-escalation testing is proceeding as planned in both the monotherapy and combination arms, and no dose-limiting toxicities have been reported to date. Early antitumor responses were also observed in some patients who had failed prior treatments.
Hanmi Pharmaceutical believes these results could serve as evidence suggesting a new treatment possibility even for patient groups that did not respond to existing immuno-oncology therapies.
Meanwhile, Hanmi Pharmaceutical signed a collaboration agreement with MSD in Apr. 2024 for a combination clinical study of BH3120. In Sept. of the same year, the company received approval for the combination clinical trial plan from the U.S. Food and Drug Administration (FDA) and the Ministery of Food and Drug Safety in Korea. Hanmi Pharmaceutical oversees the trial, and MSD supplies Keytruda.