Breast Cancer Biosimilar Shows Comparable Efficacy to Herceptin

Biosimilar trastuzumab antibody (MYL-1401O) comparable in efficacy and safety to targeted cancer drug in women with HER2-positive advanced breast cancer.

The biosimilar MYL-1401O was found comparable in safety and efficacy to the FDA-approved drug trastuzumab (Herceptin) in women with HER2-positive advanced breast cancer.

A study phase 3 randomized trial was conducted in 95 states across Asia, Africa, Europe, and Latin America and the results were presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Meeting.

As a first line treatment, 500 women with metastatic HER2-positive breast cancer were given taxane chemotherapy with either MYL-1401O or trastuzumab for a minimum of 8 cycles, followed by trastuzumab administered alone until the disease progressed. The response rates were assessed at 24 weeks after treatment.

The results of the study showed an objective response rate of 69.6% at 24 weeks in patients given MYL-1401O compared with 64% administered trastuzumab. The safety and immunogenicity was found comparable between the treatment arms and the rates of serious adverse events was 36% in the trastuzumab arm and 38% in the MYL-1401O arm.

The most common serious adverse event was neutropenia, with no difference in measures of cardiac function between the 2 groups. Additionally, there were 4 treatment-related deaths in either group.

Overall MYL-1401O was found to be equivalent to trastuzumab in safety and efficacy and did not cause low immunogenicity.

“To our knowledge, this is one of the first clinical trials to show equivalency of a trastuzumab biosimilar to the branded cancer drug,” said lead study author Hope S. Rugo, MD.

Researchers hope that future clinical trials will examine the use of biosimilars or combinations of biosimilars to help improve global access to these agents.

“Trastuzumab has markedly improved survival of women with HER2-positive breast cancer, but many women around the world can’t benefit from trastuzumab due to its high cost,” Rugo said. “We hope that the introduction of biosimilars will expand patient access to this effective drug, which has already benefited the lives of thousands of people across the globe.”