Pertuzumab, trastuzumab, and docetaxel are antineoplastic drugs used in the chemotherapy treatment of HER2-positive metastatic breast cancer. The objective of this study is to evaluate the overall and progression-free survival in breast cancer patients receiving antineoplastic drugs.

This is a double-blind, randomized, placebo-controlled phase-3 trial conducted in 204 centers across 25 countries. The study included a total of 808 eligible patients aged 18 years or older who had HER2-positive, metastatic breast cancer, and had not received previous chemotherapy or biological treatment. Out of 808 participants, 402 were assigned to receive docetaxel plus trastuzumab plus pertuzumab, and 406 to receive docetaxel plus trastuzumab plus placebo. The primary outcome was overall survival, and the secondary outcome was adverse events.

The median follow-up in the pertuzumab group was 57.1 months, compared to 40.8 months in the placebo group. The overall survival after eight years was 37% in the pertuzumab and 23% in the placebo group. Neutropenia was the most common adverse event, occurring in 49% of patients in the pertuzumab group and 46% in the placebo group. 1.0% of patients in the pertuzumab group and 2.0% of patients in the placebo group had treatment-related death.

The research concluded that patients in the pertuzumab–trastuzumab–docetaxel group had higher overall survival than those in the placebo–trastuzumab–docetaxel.