Positive phase III results for Pfizer’s trastuzumab biosimilar

Biosimilars/Research | Posted 22/09/2017 post-comment0 Post your comment

Pharma giant Pfizer announced on 10 September 2017 positive results from the pivotal phase III study of its candidate trastuzumab biosimilar. Pfizer says that ‘data from the REFLECTIONS B327-02 study demonstrates equivalence in objective response rate (ORR) for patients with HER2-positive metastatic breast cancer’.

Clinician indications V17A13

Trastuzumab is a monoclonal antibody that interferes with the human epidermal growth factor receptor 2 (HER2)/neu receptor. In some cancers, notably certain types of breast cancer, HER2 is overexpressed, and causes cancer cells to reproduce uncontrollably. Trastuzumab is therefore used to treat certain breast cancers.

The phase III REFLECTIONS B327-02 study evaluated the efficacy, safety, pharmacokinetics and immunogenicity of PF-05280014 in combination with paclitaxel compared to the originator biological, Roche’s Herceptin (trastuzumab), in female patients with HER2-positive (HER2+), metastatic breast cancer in the first-line treatment setting. The study tested the hypothesis that the efficacy [objective response rate (ORR)] of PF‑05280014 is similar to Herceptin.

The REFLECTIONS B327-02 study was started in February 2014 and enrolled 707 adult females with HER2+ metastatic breast cancer. It was carried out at 221 centres in Argentina, Brazil, Chile, Czech Republic, Greece, Hungary, India, Japan, Korea, Latvia, Mexico, Peru, Philippines, Poland, Portugal, Romania, Russia, Serbia, Slovakia, South Africa, Thailand, Turkey, Ukraine and the US.

The REFLECTIONS B327-02 study, according to Pfizer ‘achieved the primary objective for equivalence in the ORR of PF‑05280014 versus Herceptin in patients receiving first-line treatment, in combination with paclitaxel, for HER2+ metastatic breast cancer [risk ratio of 0.940; within the pre-specified equivalence margin of 0.8–1.25]. ORR was defined as the proportion of patients with tumour 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)’.

Pfizer added that the study also found that ‘there were no clinically meaningful differences between PF‑05280014 and Herceptin in terms of efficacy, safety, immunogenicity, and non-inferiority in pharmacokinetics, as neoadjuvant treatment taken in combination with docetaxel and carboplatin for patients with operable HER2+ breast cancer’.

The results of the study were presented at the European Society for Medical Oncology (ESMO) 2017 Congress in Madrid, Spain. 

Pfizer also said in its press statement that the marketing applications for its trastuzumab biosimilar had been ‘accepted for review by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA)’.

Neither FDA nor EMA have yet approved a trastuzumab biosimilar. However, Amgen, Biocon/Mylan, Celltrion and Samsung Bioepis/Merck have all submitted applications for their trastuzumab biosimilars to EMA. Amgen, Biocon/Mylan and Celltrion have also submitted applications to FDA [1].

Editor’s comment
It should be noted that data of the study presented in this article was published as an abstract and presented at a conference. These data and conclusions should be considered as preliminary until published in a peer-reviewed journal.

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1. GaBI Online - Generics and Biosimilars Initiative. Biosimilars of trastuzumab [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2017 Sep 22]. Available from: www.gabionline.net/Biosimilars/General/Biosimilars-of-trastuzumab

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Source: Pfizer

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