Junshi Biosciences' bispecific ADC JS212 gains U.S. FDA clearance for clinical trials

On December 14, Junshi Biosciences announced that the Investigational New Drug (IND) application for its in-development EGFR/HER3 bispecific antibody-drug conjugate (ADC) (code-named: JS212) for the treatment of advanced solid tumors has been approved by the U.S. Food and Drug Administration (FDA).

JS212 is a recombinant humanized bispecific antibody-drug conjugate (ADC) targeting both the epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 3 (HER3), intended primarily for the treatment of advanced malignant solid tumors. Both EGFR and HER3 are highly expressed on the surface of various tumor cells, such as those found in lung cancer, colorectal cancer, and head and neck cancer. There is interaction between EGFR and HER3 signaling pathways, collectively promoting tumor cell proliferation, survival, migration, and angiogenesis. Furthermore, HER3 is implicated in resistance mechanisms to various anti-tumor agents, including EGFR-targeted therapies and chemotherapy.

Compared to single-target ADCs, JS212 can exert anti-tumor effects by binding to either EGFR or HER3. This is expected to broaden its potential efficacy against a wider range of tumors while potentially overcoming drug resistance issues. Preclinical studies have demonstrated that JS212 exhibits high-affinity, specific binding to both EGFR and HER3 and has shown significant tumor suppression in multiple animal models. Additionally, JS212 has demonstrated an acceptable and favorable safety profile.

In January 2025, the clinical trial application for JS212 was accepted by China's National Medical Products Administration (NMPA), and approval was granted in March 2025. To date, JS212 is undergoing an open-label, dose-escalation and dose-expansion Phase 1/2 clinical trial in mainland China. This trial aims to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of JS212 in patients with advanced solid tumors. Furthermore, the clinical trial application for multi-cohort combination therapy studies involving JS212 received approval from the NMPA in November 2025, with related clinical research planned to commence in the near term.