Dr. Montero Discusses PERTAIN Study in HER2-Positive Breast Cancer

Alberto J. Montero, MD, Department of Hematology and Oncology at Cleveland Clinic, discusses the PERTAIN study in postmenopausal women with hormone receptor-positive, HER2-positive, locally advanced or metastatic breast cancer. The study looks at the impact of adding pertuzumab (Perjeta) to trastuzumab (Herceptin) in aromatase inhibitor (AI) therapy.

PERTAIN is randomized phase II trial that combined either pertuzumab with trastuzumab or trastuzumab with an AI with or without induction chemotherapy. Pertuzumab was administered initially at 840 mg followed by 420 mg every 3 weeks, while trastuzumab was administered at 8mg/kg at first dose, followed by 6mg/kg every 3 weeks. AI therapy was either anastrozole at 1 mg per day or letrozole at 2.5 mg per day. Out of the 258 patients participating in this study, most of them received chemotherapy, but there was a subset of patients that received an antibody and aromatase inhibitor alone.

The addition of pertuzumab to trastuzumab in AI therapy has a significant impact, says Montero, with a 35% reduction in risk of progression or death with the addition of pertuzumab.

According to Montero, this study is important because it provides clinical data that looks at dual-antibody blockade and an AI in a triple-positive subset that is without any sort of cytotoxic chemotherapy in patients in the metastatic stage, in consideration of side effects and quality of life.

Cardiac toxicity was considered, but there was nothing unexpected as the risk of heart failure with the combination of pertuzumab and trastuzumab is low.