Innovent's IBI354 Records 95% Response Rate in 20-Patient Breast Cancer Study

Innovent Biologics' experimental HER2-targeted drug IBI354 had a 95% confirmed response rate when paired with pertuzumab in a 20-patient study of advanced HER2-positive breast cancer.

The Phase 2 study enrolled patients with unresectable locally advanced or metastatic disease. They received 9 milligrams of IBI354 per kilogram of body weight every three weeks alongside pertuzumab. The disease-control rate was 100% after a median follow-up of 9.6 months, and median treatment duration was 42.21 weeks. The results were presented at the 2026 European Society for Medical Oncology Congress in Madrid.

The survival analysis remained immature, with one progression-free survival event and no overall survival events. Four of 20 patients (20%) had Grade 3 or higher treatment-related adverse events; one discontinued because of a treatment-related adverse event. No treatment-related deaths were reported.

A separate Phase 1 trial tested IBI3001 alone, an experimental antibody-drug conjugate targeting EGFR and B7H3, in advanced solid tumors. Fifty-seven patients received doses from 1 to 10 mg/kg. They included 21 patients with non-small cell lung cancer, 15 with pancreatic cancer, eight with small cell lung cancer and 13 with other tumors; 78.9% had received at least two prior treatments.

Among 53 patients evaluable for efficacy, the objective response rate was 30.2% and the disease-control rate was 88.7%. In the 8 mg/kg dose group, the rates were 45% and 100%, respectively.

Among 16 patients with EGFR-mutant non-small cell lung cancer, the objective response rate was 31.3%, the disease-control rate was 93.8% and median progression-free survival was 7.7 months. The listed 15-patient pancreatic group had response and disease-control rates of 15.4% and 92.3%, respectively, and median progression-free survival of 6.9 months; the response-evaluable denominator for those rates was not specified. Fourteen of the 15 pancreatic cancer patients had received irinotecan, and 13 were in third-line treatment or later.

Across the IBI3001 study, 47.4% of patients had Grade 3 or higher treatment-related adverse events. One patient permanently discontinued treatment because of a treatment-related adverse event, and no treatment-related deaths were reported.

Professor Yi Hu of Chinese PLA General Hospital said the findings support further dose optimization and study expansion to explore IBI3001's potential for patients with limited treatment options. IBI354 has advanced to Phase 3, and IBI3001 to Phase 1b dose optimization.