Additional Relevant Details Study Design
This above referenced Phase 3 study was a randomized, multicenter, double-blinded, active-controlled study (study number 20120283) that evaluated safety and efficacy of ABP 980 compared to trastuzumab in adult female patients with HER2-positive early breast cancer. There were 725 patients randomized, with 364 patients in the ABP 980 group and 361 patients in the trastuzumab group.In the neoadjuvant phase, enrolled patients received run-in chemotherapy consisting of epirubicin and cyclophosphamide (EC) every three weeks (Q3W) for four cycles. Once run-in chemotherapy was completed, patients with adequate cardiac function were randomized 1:1 to receive investigational product (ABP 980 or trastuzumab), plus paclitaxel, Q3W for four cycles. Surgery (breast and sentinel node or axillary lymph node resection) was complete three to seven weeks after the last dose of investigational product in the neoadjuvant phase, and pCR was analyzed.In the adjuvant phase, following surgery, patients received investigational product (ABP 980 or trastuzumab) Q3W for up to one year from the first day of investigational product administered in the neoadjuvant phase. Patients who received ABP 980 during the neoadjuvant phase continued to receive ABP 980 Q3W for the adjuvant phase. Patients who received trastuzumab during the neoadjuvant phase received either ABP 980 or trastuzumab Q3W for the adjuvant phase. The allocation to a treatment group during the neoadjuvant or adjuvant phase occurred at randomization.The primary analysis was conducted when the last patient completed the surgery following the neoadjuvant therapy. Clinical equivalence was assessed by comparing the confidence interval of the risk difference and risk ratio of the pCR in breast tissue and axillary lymph nodes with the prespecified equivalence margins. The final analysis of safety will be conducted when the last patient has completed their last study assessment in the adjuvant phase.