ALPHAMAB-B (09966): IND for Phase I Clinical Study of JSKN021 Approved by FDA

ALPHAMAB-B (09966) announced that the U.S. Food and Drug Administration (FDA) has approved the Investigational New Drug (IND) application for JSKN021 (a dual-payload antibody-drug conjugate (ADC(s)) targeting epidermal growth factor receptor (EGFR)/human epidermal growth factor receptor 3 (HER3) independently developed by the Company) for a Phase I clinical study (Study No.: JSKN021-101), marking the official launch of overseas clinical development of JSKN021. JSKN021-101 is an open-label, multicenter Phase I clinical study planned to enroll patients with locally advanced or metastatic solid tumors who have relapsed or are refractory after standard treatment, or for whom no approved therapy exists, to evaluate the safety, tolerability, pharmacokinetic profile, and preliminary antitumor activity of JSKN021. The study was previously approved in China, and the first patient was dosed in June 2026. The clinical study in China is currently progressing in an orderly manner, and preliminary efficacy has been observed during dose escalation. The approval of this U.S. IND marks another key milestone in the internationalization of the Company's innovative product pipeline. JSKN021 is a "2-in-1" bispecific dual-payload ADC targeting EGFR/HER3, featuring differentiated product design and unique technological advantages. The drug utilizes glycoengineering-based site-specific conjugation technology to site-specifically and quantitatively conjugate two different cytotoxic payloads onto the glycan chains of the antibody Fc region. The process is simple, stable, and efficient, and the resulting antibody-drug conjugate product has high stability and low hydrophobicity. Preclinical studies showed that JSKN021 has significantly superior tumor inhibition efficacy compared with single-payload ADCs and has good tolerability. The approval of the U.S. IND is an important part of the global development strategy for JSKN021. In recent years, the Company has continued to deepen its globalization strategy, with multiple core products successively obtaining overseas regulatory designations and clinical breakthroughs. Going forward, the Company will steadily advance the clinical development of JSKN021 in China and the United States, while relying on its proprietary technology platforms to continuously enrich its innovative pipeline, bringing more treatment hope to cancer patients worldwide.