Alphamab oncology's JSKN003 shows promise, earns second breakthrough designation

Alphamab Oncology has announced new research updates for JSKN003, a biparatopic HER2-targeting ADC, presented at the ESMO Congress 2025. In primary platinum-refractory ovarian cancer (PROC), JSKN003 achieved an Objective Response Rate (ORR) of 32.0% and a Disease Control Rate (DCR) of 72.0% in 25 evaluable patients. Median Progression-Free Survival (PFS) was 4.1 months, with a 9-month Overall Survival (OS) rate of 65.4%. Grade 3 or higher treatment-related adverse events (TRAEs) occurred in 15.4% of patients.

For HER2+ metastatic colorectal cancer (CRC), JSKN003 demonstrated an ORR of 68.8% and a DCR of 96.9% in 32 evaluable patients. BRAF V600E wild-type patients showed an ORR of 71.0%, DCR of 100%, median Duration of Response (DoR) of 9.89 months, and median PFS of 11.04 months. Grade 3 or higher TRAEs occurred in 21.2% of patients. Additionally, JSKN003 received Breakthrough Therapy Designation from the CDE for HER2+ advanced CRC that failed prior oxaliplatin, fluorouracil, and irinotecan treatments, building on a prior breakthrough designation for PROC.