Herceptin Biosimilar Succeeds in Key Breast Cancer Trial

PF-05280014 and trastuzumab show comparable response rates

Pfizer has announced that its pivotal REFLECTIONS B3271002 trial, a comparative safety and efficacy study of PF-05280014 versus Herceptin (trastuzumab, Genentech), met its primary endpoint. PF-05280014 is a monoclonal antibody that is in development as a potential biosimilar for all approved indications of Herceptin. Currently, Herceptin is indicated for the treatment of human epidermal growth factor receptor-2 (HER2)-positive breast cancer and gastric cancer.

The randomized, double-blind trial demonstrated equivalence in the primary endpoint of the objective response rates (ORRs) for PF-05280014 and Herceptin, administered in combination with paclitaxel, in first-line patients with HER2-positive metastatic breast cancer after 25 weeks of treatment. ORR was defined as the proportion of patients with a reduction in tumor size of a predefined amount and for a minimum period.

A separate comparative, randomized, double-blind study (REFLECTIONS B3271004) in 226 patients with early breast cancer also met its primary endpoint of steady-state Ctrough concentrations (PK) in patients treated with PF-05280014 and Herceptin.

PF-05280014 is an investigational compound and has not received regulatory approval in any country.

Source: BusinessWire; November 30, 2016.