Pfizer has announced positive findings from REFLECTIONS B327-02 (n=707), a pivotal phase 3 randomized, double-blind comparative safety and efficacy study of the company’s investigational trastuzumab biosimilar (PF-05280014) versus Herceptin (trastuzumab), at the European Society for Medical Oncology (ESMO) 2017 Congress in Madrid. Positive data from a supplemental study, REFLECTIONS B327-04 (n=226), were also presented at the meeting. PF-05280014 is being developed by Pfizer as a potential biosimilar to Herceptin.

“Biosimilars are poised to revolutionize the oncology treatment landscape by expanding patient access to high quality and effective therapies,” said Dr. Mark Pegram, associate director for clinical research at the Stanford Comprehensive Cancer Institute, and director of the Breast Oncology Program at the Stanford Women’s Cancer Center. “These data are encouraging, and reinforce the future potential of Pfizer’s investigational trastuzumab biosimilar to help meet the needs of cancer patients and their treating physicians as a potentially lower cost option to Herceptin, across all indications.”

The REFLECTIONS B327-02 study achieved the primary objective for equivalence in the objective response rate (ORR) of PF-05280014 versus Herceptin in patients receiving first-line treatment, in combination with paclitaxel, for HER2-positive metastatic breast cancer [risk ratio of 0.940; within the pre-specified equivalence margin of 0.8–1.25]. ORR is defined as the proportion of patients with tumor size reduction of a predefined amount and for a minimum period of time. Additionally, rates of one year progression-free survival and one year survival were similar across groups (56% and 88.84% vs. 52% and 87.96% for PF-05280017 and Herceptin, respectively).

The REFLECTIONS B327-04 study found there were no clinically meaningful differences between PF-05280014 and Herceptin in terms of efficacy, safety, immunogenicity, and noninferiority in pharmacokinetics, as neoadjuvant treatment taken in combination with docetaxel and carboplatin for patients with operable HER2-positive breast cancer.

“Pfizer is committed to driving significant improvements in patient care through the development of high quality, effective biosimilars. Including PF-05280014, Pfizer’s biosimilars pipeline consists of eight distinct biosimilar molecules in mid to late stage development, with three of these in oncology,” said Salomon Azoulay, MD, senior vice president, chief medical officer, Pfizer Essential Health. “By continuing to grow our oncology and supportive care presence through both novel therapies and biosimilars, we are able to provide an array of important treatment options for patients, physicians and healthcare systems.”

As part of Pfizer’s commitment to expanding its oncology biosimilars pipeline, the company is progressing its biosimilar trastuzumab marketing applications, which have been accepted for review by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA).