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# Pfizer Positive Trial Results with Herceptin Biosimilar
- URL: https://www.fdaweb.com/pfizer-positive-trial-results-with-herceptin-biosimilar/
- Published: 2016-11-30T12:00:00.000Z
- Updated: 2026-09-14T21:51:39.000Z
- Author: David McFarland
- Tags: Drugs, #legacy-id-D5137456

Pfizer says its pivotal REFLECTIONS B3271002 study, a comparative safety and efficacy study of biosimilar candidate PF-05280014 versus Genentech’s Herceptin (trastuzumab), met its primary endpoint. “The trial demonstrated equivalence in the primary endpoint of objective response rate (ORR) of PF-05280014 versus Herceptin, taken in combination with paclitaxel, in first line patients with HER2-positive metastatic breast cancer,” the company says. ORR was defined as the proportion of patients with tumor size reduction of a predefined amount and for a minimum period of time. A separate comparative, randomized, double-blind clinical trial \[REFLECTIONS B3271004\] in early breast cancer patients also met its primary endpoint of steady-state concentrations in patients treated with PF-05280014 and Herceptin. PF-05280014 is a monoclonal antibody that is in development as a potential biosimilar for all currently approved Herceptin indications — HER2-positive breast cancer and gastric cancer.