Efficacy and safety of neoadjuvant pertuzumab and trastuzumab in women with locally advanced, inflammatory, or early HER2-positive breast cancer (NeoSphere) a randomised multicentre, open-label, phase 2 trial

SUMMARY: PERJETA® (Pertuzumab) is a recombinant, humanized, monoclonal antibody that binds to the HER2 dimerization domain and prevents the dimerization of HER2 with other HER receptors, ie. HER3, HER1 and HER4. HERCEPTIN® (Trastuzumab) is a monoclonal antibody that specifically targets the HER2 receptor and blocks the downstream signalling pathways. The accelerated approval of PERJETA® for the neoadjuvant treatment of breast cancer was based on a randomized, multicenter, open-label, phase II trial, in which 417 patients with HER2-positive, operable, locally advanced or inflammatory breast cancer (T2-4d), were randomly assigned to receive preoperative therapy with either HERCEPTIN® plus TAXOTERE® (Docetaxel), PERJETA® plus HERCEPTIN® and TAXOTERE®, PERJETA® plus HERCEPTIN® or PERJETA® plus TAXOTERE®. Patients in the three drug group received preoperative therapy with PERJETA®, HERCEPTIN® and TAXOTERE® every 3 weeks for a total of 4 cycles and following surgery, all patients received 3 cycles of Fluorouracil, ELLENCE® (Epirubicin), and CYTOXAN® (Cyclophosphamide) – (FEC) IV every 3 weeks and HERCEPTIN® was continued every 3 weeks for a total of one year of therapy. The primary endpoint was pathological Complete Response (pCR) rate defined as the absence of invasive cancer in the breast. The FDA definition of pCR is the absence of invasive cancer in the breast and lymph nodes. All treatment groups were well balanced. Seven percent of patients had inflammatory breast cancer, 32% had locally advanced cancer and 70% had clinically node-positive breast cancer. Forty-seven percent of the patients had hormone receptor-positive disease. The FDA defined pCR rates were 39.3% in the PERJETA® plus HERCEPTIN® and TAXOTERE® group and 21.5% in the HERCEPTIN® plus TAXOTERE® group P=0.0063). Of Interest, the pCR rates in the three drug group were lower in patients with hormone receptor positive tumors compared to patients with hormone receptor negative tumors. The most common adverse events in the three drug group were alopecia, diarrhea, nausea and neutropenia. The accelerated approval by the FDA was based solely on the improved pCR rate with the three drug combination with no demonstrable improvement in event-free survival or overall survival. A confirmatory phase III trial is underway, with results expected in 2016. Gianni L, Pienkowski T, Im YH, et al. Lancet Oncol. 2012;13:25-32