Neratinib given as 1-year extended adjuvant therapy significantly reduced the rate of relapse among patients with breast cancer treated with chemotherapy and trastuzumab, according to a study published in Lancet Oncology.

A previous 2-year analysis of the ExteNET phase 3 study demonstrated that extended adjuvant treatment with 1 year of neratinib — compared with placebo — significantly improved the rate of 2-year invasive disease-free survival among 2840 women who had completed neoadjuvant and adjuvant chemotherapy plus trastuzumab.

After a median follow-up of 5.2 years, patients who received neratinib vs placebo (116 vs 163, respectively) experienced significantly fewer incidences of invasive disease-free survival events (stratified hazard ratio [HR], 0.73; 95% CI, 0.57-0.92; P =.0083). The 5-year invasive disease-free survival was 90.2% (95% CI, 88.3-91.8) and 87.7% (95% CI, 85.7-89.4) in the neratinib group and placebo group, respectively.

The most frequently reported grade 3 to 4 adverse events (AEs) were diarrhea, vomiting, and nausea. Treatment-emergent serious AEs occurred in 7% of women in the neratinib and group and 6% of women in the placebo arms.  There was no evidence for increased risk of long-term toxicity or consequence associated with neratinib-correlated diarrhea compared with placebo.

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The authors concluded “[e]xtended adjuvant neratinib after chemotherapy and trastuzumab should be considered a new therapeutic option for this patient population,” and added that an overall survival analysis will be conducted after 248 events.

Reference

  1. Martin M, Holmes FA, Ejlertsen B, et al. Neratinib after trastuzumab-based adjuvant therapy in HER2-positive breast cancer (ExteNET): 5-year analysis of a randomised, double-blind, placebo-controlled, phase 3 trial [published online November 13, 2017]. Lancet Oncol. doi: 10.1016/S1470-2045(17)30717-9