The Food and Drug Administration has approved neratinib, an oral tyrosine kinase inhibitor, for the extended adjuvant treatment of patients with early-stage, HER2-positive breast cancer who have previously been treated with trastuzumab.
Approval was based on improved invasive disease-free survival (iDFS) in the phase 3 ExteNET trial of 2,840 women with early-stage HER2-positive breast cancer who were within 2 years of completing adjuvant trastuzumab. Patients were randomized to receive either neratinib or placebo daily for 1 year. After 2 years of follow-up, iDFS was 94.2% in patients treated with neratinib, compared with 91.9% in those receiving placebo (hazard ratio, 0.66; 95% confidence interval, 0.49, 0.90; P = .008), according to the FDA statement.
The most common adverse reactions to neratinib in ExteNET were diarrhea, nausea, abdominal pain, fatigue, vomiting, rash, stomatitis, decreased appetite, muscle spasms, dyspepsia, AST or ALT increase, nail disorder, dry skin, abdominal distention, weight loss, and urinary tract infection. Diarrhea was observed in 16.8% of neratinib-treated patients.
The recommended dose of of neratinib is 240 mg (six 40 mg tablets) given orally once daily with food, continuously, for 1 year. Patients should be given antidiarrheal prophylaxis for the first 56 days of treatment with neratinib and as needed thereafter to help manage diarrhea, the FDA said.