BAO PHARMA-B (02659) has announced that on August 21, 2026, its independently developed KJ015 injection, a subcutaneous formulation of a bispecific antibody targeting HER2, received Investigational New Drug (IND) approval from the US Food and Drug Administration (FDA). This clearance permits the company to initiate clinical trials in the United States.

KJ015 is an innovative bispecific anti-HER2 antibody subcutaneous formulation derived from common light chain technology. It is engineered with two Fab arms featuring a common light chain, forming a structure closely resembling natural IgG1. By simultaneously maintaining high affinity for two epitopes, KJ015 can target the clinically validated epitopes recognized by Herceptin (trastuzumab) and Perjeta (pertuzumab), thereby inhibiting HER2 homodimerization as well as heterodimerization of HER2 with EGFR, HER3, and HER4.

Compared with existing anti-HER2 bispecific antibodies, KJ015 features more refined affinity and structural optimization, enabling more effective inhibition of dimerization between HER2 and ERBB family members, leading to attenuated downstream signaling pathways such as MAPK and PI3K/Akt. This dual binding also induces antibody-antigen clustering, promoting internalization and recognition of tumor antigens, distinguishing it from combinations of monoclonal antibodies. The company's preclinical studies indicate that KJ015 demonstrates enhanced overall efficacy compared with conventional anti-HER2 monoclonal antibody combinations in preclinical stages.

KJ015's near-natural structure, combined with deamidation site design, contributes to its stable physicochemical properties and high yield in large-scale manufacturing. Its stability at high concentrations also facilitates formulation as a subcutaneous preparation with the company's recombinant human hyaluronidase. The design of KJ015 enables convenient subcutaneous administration, reducing drug onset time, improving patient convenience, and lowering risks associated with intravenous delivery, thereby offering a safer and more patient-friendly alternative.

The company is developing KJ015 internally and holds global rights for its development and commercialization. In December 2024, KJ015 received IND approval from China's National Medical Products Administration (NMPA), and Phase I clinical trials commenced in China in June 2025, with completion expected in the second half of 2026.