Biosimilar Trastuzumab Shows Promise in Phase 3 Trial

MYL-1401O improves overall response rate compared with branded product

Phase 3 results have confirmed the efficacy, safety, and immunogenicity of MYL-1401O (Mylan/Biocon), a proposed biosimilar trastuzumab, in comparison with that of branded trastuzumab (Herceptin, Genentech). Branded trastuzumab is indicated for the treatment of patients with certain human epidermal growth factor receptor 2 (HER2)-positive breast and gastric cancers.

The HERITAGE trial was a double-blind, randomized study designed to compare MYL-1401O with branded trastuzumab in patients with centrally confirmed, measurable HER2-positive metastatic breast cancer who had not received chemotherapy or trastuzumab for metastatic disease. The patients were treated with either MYL-1401O or branded trastuzumab plus docetaxel or paclitaxel for a minimum of eight cycles. Trastuzumab was continued until disease progression. The primary endpoint was the overall response at week 24. Secondary endpoints included safety, progression-free survival (PFS), and overall survival (OS) at week 48.

A sample size of 456 patients was calculated to demonstrate equivalence in the overall response at week 24 for MYL-1401O compared with branded trastuzumab.

The results showed an overall response rate of 69.6% for MYL-1401O compared with 64.0% for branded trastuzumab. Tumor progression, PFS, and OS were not statistically different between MYL-1401O and branded trastuzumab at week 48.

The HERITAGE data were submitted to the FDA in November as part of a biologics license application for MYL-1401O.

The study was published in the Journal of the American Medical Association.

Source: Mylan; December 27, 2016.