Dr. Mittendorf on the Impact of Pertuzumab in HER2+ Breast Cancer

Elizabeth A. Mittendorf, MD, PhD, associate professor in the Department of Surgical Oncology at The University of Texas MD Anderson Cancer Center, discusses the impact of pertuzumab (Perjeta) on the treatment landscape of HER2-positive breast cancer.

In December 2017, the FDA approved pertuzumab in combination with trastuzumab (Herceptin) and chemotherapy as an adjuvant treatment for patients with HER2-positive breast cancer, based on the results from the APHINITY trial.

In the phase III trial, adjuvant treatment with pertuzumab, trastuzumab, and chemotherapy demonstrated a 3-year invasive disease-free survival (iDFS) rate of 94.1% versus 93.2% for those who received trastuzumab plus chemotherapy and placebo. This represented an 18% reduction in the risk of developing invasive disease or death (HR, 0.82; 95% CI, 0.67-1.00, P = .047). The 4-year iDFS rates were 92.3% versus 90.6%, respectively.

The most common grade 3/4 adverse events (AEs) in the pertuzumab and placebo groups, respectively, were neutropenia (16% vs 16%), febrile neutropenia (12% vs 11%), diarrhea (10% vs 4%), and anemia (7% vs 5%). Fatal AEs occurred in 0.8% of patients in each group. AEs led to dose discontinuations for 7.3% of patients in the pertuzumab group versus 6.4% with placebo.

APHINITY is getting a lot of attention, but neratinib (Nerlynx) has also been approved, making the HER2-positive setting more interesting and exciting, explains Mittendorf.