Dr. Rugo Discusses the Equivalency of Trastuzumab Biosimilars

Hope Rugo, MD, professor of medicine, director of the Breast Oncology Clinical Trials Program, UCSF Helen Diller Family Comprehensive Cancer Center, discusses the equivalency that has been demonstrated with biosimilars for trastuzumab (Herceptin).

In an analysis of abstracts discussing trastuzumab biosimilars, efficacy was assessed to see if there was an optimal setting to study this agent. Safety information was assessed across trials, and in the neoadjuvant studies, pathologic complete response was evaluated.

Only 1 trial included in this analysis looked at longer-term disease-free survival, according to Rugo. This was added as an endpoint once patients got to the 1-year mark. Rugo says that most patients on these trials will be evaluated for 5 years. Still, there is no established endpoint.

A trial of a trastuzumab biosimilar in the metastatic setting ran by Rugo stopped at 24 weeks, increasing the patient’s exposure to the drug in terms of safety evaluation. Progression-free survival (PFS) and overall survival (OS) were also evaluated since they are shorter-term endpoints in this setting, she explains. After a specified number of events, Rugo then evaluated PFS and OS. In the metastatic setting, there is the advantage of giving chemotherapy plus an antibody, says Rugo.