A phase 1B dose escalation trial of Scutellaria barbata (BZL101) for patients with metastatic breast cancer

Abstract

The purpose of this study was to determine the safety and maximum tolerated dose (MTD) of BZL101 (FDA IND# 59,521), an orally delivered aqueous extract from the herb Scutellaria barbata, in women with metastatic breast cancer (MBC). The trial was an open-label, phase 1B, multicenter, dose escalation study. Eligible patients had histologically confirmed breast cancer and measurable stage IV disease. The standard phase 1 “3 + 3” study design was used to determine the MTD. Primary endpoints were toxicity and MTD of BZL101. Secondary outcomes included efficacy based on RECIST criteria. A total of 27 women with a median of 2 prior chemotherapy treatments for metastatic disease were treated in four different dose cohorts. Grade 3 and 4 adverse events (AEs) were uncommon. Dose-limiting toxicities included the following: grade 4 AST elevation, grade 3 diarrhea, grade 3 fatigue, and grade 3 rib pain. Fourteen patients were evaluable according to Response Evaluation Criteria in Solid Tumors. Investigator assessment classified three patients with stable disease for >120 days (21%). One patient was on BZL101 for 449 days and remains stable for 700 + days. Independent radiology review identified three patients with objective tumor regression (>0% and <30%). The MTD was not reached, thus per protocol, the MTD was defined as the maximum administered dose of BZL101 40 g/day. In conclusion, oral administration of BZL101 was safe, well tolerated, and showed promising clinical evidence of anticancer activity in this heavily pretreated population of women with MBC.