Dr. Hope Rugo on Trastuzumab Biosimilar in HER2-Positive Breast Cancer

Hope Rugo, MD, a professor of Medicine and director of the Breast Oncology Clinical Trials Program at the UCSF Helen Diller Family Comprehensive Cancer Center, discusses the Heritage study, which evaluated MYL-1401O, a proposed biosimilar for trastuzumab (Herceptin), in patients with HER2-positive metastatic breast cancer.

The trial was designed with a primary endpoint of overall response rate (ORR) at 24 weeks. Patients with treatment-naïve metastatic HER2-positive breast cancer were randomized to receive either Herceptin or the proposed trastuzumab biosimilar in combination with a taxane of choice. The institution had to choose their taxane and 75% chose docetaxel and 25% chose paclitaxel, explained Rugo.

In 450 patients with metastatic HER2-positive disease in the first-line setting, response rates were close to equivalent and the hazard ratio fell within an equivalency ratio, said Rugo. The FDA and the European Medicines Agency (EMA) had different requests for the way they wanted to see data. The FDA wanted to look at the ORR ratio, and the EMA wanted to look at the response difference between the two arms. This trial fell well within all of those guidelines, said Rugo.