SystImmune Inc.  announced that its parent company, Sichuan Biokin Pharmaceutical Co., Ltd. (Biokin), has received regulatory approval from China's National Medical Products Administration (NMPA) for iza-bren (izalontamab brengitecan) for the treatment of adult patients with recurrent or metastatic esophageal squamous cell carcinoma (ESCC) whose disease has progressed following prior platinum-based chemotherapy and PD-1/PD-L1 inhibitor therapy.

This marks the second approved indication for iza-bren in China following its recent approval for recurrent or metastatic nasopharyngeal carcinoma (NPC), further establishing iza-bren as a first-in-class EGFR × HER3 bispecific antibody-drug conjugate (ADC) with broad clinical potential across multiple solid tumors.

The approval is supported by results from the pivotal PANKU-Esophagus01 (BL-B01D1-305) study. The study met both dual primary endpoints of progression-free survival (PFS) and overall survival (OS), demonstrating statistically significant and clinically meaningful improvements versus chemotherapy, while maintaining a manageable safety profile. The results were previously presented during an oral presentation at the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting.

Key results from the PANKU-Esophagus01 study included:

• Median overall survival of 9.8 months with iza-bren versus 7.2 months with chemotherapy (HR=0.64, 95% CI: 0.49–0.83; p=0.0004).
• Median progression-free survival by BICR of 4.2 months with iza-bren versus 2.0 months with chemotherapy (HR:0.50; 95% CI: 0.40-0.63; p<0.0001).
• Low treatment discontinuation due to treatment-related adverse events (2.0%), with a safety profile consistent with previous studies.
• The rates of all grade and grade 3 or higher ILD were low in the iza-bren arm (1.6% / 0.8%) and chemotherapy arm (0.4% / 0%).

"Today's approval represents another important milestone for iza-bren and validates the potential of our EGFR × HER3 bispecific ADC platform to address significant unmet needs across multiple difficult-to-treat cancers," said Dr. Yi Zhu, Chairman and Chief Executive Officer of Biokin.  "Following the first global approval ofiIza-bren in nasopharyngeal carcinoma, this second approval in esophageal squamous cell carcinoma further demonstrates the meaningful clinical benefit this medicine can provide to patients.  We are grateful to the patients, investigators, healthcare professionals, and regulatory authorities whose contributions made this achievement possible."

"Patients with recurrent or metastatic ESCC who progress after first-line therapy have historically faced limited treatment options and poor clinical outcomes," said Dr. Jonathan Cheng, Chief Medical Officer of SystImmune.  "The BL-B01D1-305 study demonstrated significant improvements in both progression-free and overall survival compared to chemotherapy, supporting iza-bren as a new treatment option for these patients.  We look forward to continuing the global development of iza-bren across a wide range of tumor types."

Iza-bren is currently being evaluated in multiple global clinical studies across several solid tumor indications, including non-small cell lung cancer, breast cancer, urothelial cancer, and other EGFR/HER3-expressing malignancies.