ALPHAMAB-B (09966.HK): JSKN003 data at ESMO 2026, Cohort B ORR 100%, PROC median OS 23.5 months

NewTimeSpace News: ALPHAMAB-B (09966.HK) released a voluntary announcement that the latest research updates of JSKN003 were presented during poster sessions at the 2026 ESMO Congress, covering the efficacy and safety of JSKN003 combination regimens as first-line treatment for HER2+ advanced or metastatic gastric/gastroesophageal junction cancer (GC/GEJ), and an updated overall survival analysis of JSKN003 in platinum-resistant recurrent epithelial ovarian cancer (PROC).

In the JSKN003-003 phase II study, a total of 25 patients were treated as of 9 May 2026, including 7 in Cohort A, 14 in Cohort B and 4 in Cohort C. Confirmed ORRs were 71.4%, 100% and 50.0% in Cohorts A, B and C respectively, with all 14 patients in Cohort B achieving PR. Cohort B showed a clear safety advantage, with grade 3 or above TRAEs of 28.6%, lower than 57.1% in Cohort A and 100% in Cohort C; no TRAEs led to death.

For PROC, 47 patients had received JSKN003 monotherapy as of 10 July 2026, with a median follow-up of 20.8 months. The ORR was 63.8%, confirmed ORR 55.3% and DCR 93.6%, with a median DoR of 9.2 months, median PFS of 8.3 months and median OS of 23.5 months. Grade 3 or above TRAEs occurred in 19.1% of patients, and ILD was reported in 6 patients (12.8%), all grade 1 or 2. A phase III study of JSKN003 in PROC irrespective of HER2 expression is ongoing.