Amgen and Allergan PLC have announced the results from a Phase 3 study evaluating efficacy and safety of ABP 980 compared with trastuzumab in patients with human epidermal growth factor receptor 2-positive (HER2-positive) early breast cancer. The results ruled out inferiority compared to trastuzumab but could not rule out superiority based on its primary efficacy endpoint of the difference of the percentage of patients with a pathologic complete response (pCR). The primary endpoint had a prespecified equivalence margin of +/- 13 percent and the observed upper end of the confidence interval was 13.4 percent.
Overall, adverse events were comparable between ABP 980 and trastuzumab. In the neoadjuvant phase of the study, which included chemotherapy, there were more serious adverse events reported in the ABP 980 group, the majority of which were reported by the investigators as unlikely related to investigational product. In the adjuvant phase of the study, which did not include chemotherapy, serious adverse events were comparable between treatment groups. The overall results also showed comparable immunogenicity.
"We believe this study confirms no clinically meaningful differences between ABP 980 and trastuzumab, and we look forward to continued discussions with regulatory authorities," said Sean E. Harper, M.D., executive vice president of Research and Development at Amgen. "Biosimilars are approved based on the analytical, nonclinical and clinical data, and we believe that the totality of the evidence we've generated supports ABP 980 as highly similar to the reference product."
"These results provide significant clinical evidence that ABP 980 could be an important biosimilar treatment option for patients with HER2-positive early breast cancer," said David Nicholson, chief research and development officer, Allergan. "Allergan is committed to the continued development of ABP 980 and other biosimilars that provide safe, high-quality and effective therapies in key disease areas."
ABP 980 is being developed as a biosimilar to trastuzumab, a recombinant DNA-derived humanized monoclonal immunoglobulin G1 kappa antibody which targets HER2. Trastuzumab is approved in many regions for the treatment of HER2-positive early breast cancer, metastatic breast cancer and metastatic gastric cancer.
Amgen and Allergan are collaborating on the development and commercialization of four oncology biosimilars. Amgen has a total of nine biosimilars in development. Allergan is also independently developing biosimilars.