ONT-380: Additional Phase Ib data

Data from 34 evaluable patients with HER2-positive metastatic breast cancer who were heavily pretreated with Herceptin trastuzumab and a taxane in an open-label, dose-escalation, U.S. and Canadian Phase Ib trial showed that twice-daily 300 mg oral ONT-380 plus Kadcyla ado-trastuzumab emtansine ( T-DM1) led to an overall response rate (ORR) of 41%, including 14 confirmed partial responses, plus 15 cases of stable disease. In 12 evaluable patients with assessable CNS metastases, ONT-380 plus Kadcyla led to an ORR of 33%, including 1 complete response and 3 partial responses, plus 8 cases of stable disease. The MTD was twice-daily 300 mg ONT-380 plus Kadcyla. The most common adverse events reported were nausea, vomiting, diarrhea and constipation. Data were presented at the San Antonio Breast Cancer Symposium. Oncothyreon has previously reported interim data from the trial (see BioCentury, Jan. 5). ...