FDA Approves Neratinib for Extended Adjuvant Treatment of Early-Stage HER2-Positive Breast Cancer

Approval was based on the ExteNET trial (NCT00878709), a multicenter, randomized, double-blind, placebo-controlled trial of neratinib following adjuvant trastuzumab treatment. Women (n = 2,840) with early-stage HER2-positive breast cancer and within two years of completing adjuvant trastuzumab were randomized to receive either neratinib (n = 1,420) or placebo (n = 1,420) for one year.

The major efficacy outcome measure was invasive disease-free survival (iDFS) defined as the time between the randomization date to the first occurrence of invasive recurrence (local/regional, ipsilateral or contralateral breast cancer), distant recurrence, or death from any cause, within two years and 28 days of follow-up. After two years, iDFS was 94.2% in patients treated with neratinib compared with 91.9% in those receiving placebo (HR + 0.66; 95% CI = 0.49, 0.90; p = 0.008).

The most common adverse reactions (more than 5%) 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. The most common adverse reaction leading to discontinuation was diarrhea, observed in 16.8% of neratinib-treated patients. Hepatotoxicity or increases in liver transaminases led to drug discontinuation in 1.7% of neratinib-treated patients.

The recommended dose is 240 mg (six tablets) given orally once daily with food, continuously for one year. Antidiarrheal prophylaxis should be initiated with the first neratinib dose and continued during the first two cycles (56 days) of treatment and as needed thereafter.

Full prescribing information (https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/208051s000lbl.pdf) is available.

Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System by completing an online form (http://www.fda.gov/medwatch/report.htm), by faxing (800-FDA-0178) or mailing the postage-paid address form provided online, or by telephone (800-FDA-1088).

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