Labeling for HBV medication updated following new safety, efficacy data
The FDA has approved changes to the labeling for Viread, a treatment for chronic hepatitis B, following the results of a 96-week study.
Updated labeling for tenofovir disoproxil fumarate (Viread, Gilead Sciences) reflects that the indication was the product of trials of treatment-experienced, lamivudine-resistant adult patients with chronic HBV and chronic liver disease who were naive to nucleoside-based therapy. Adverse events observed among these patients during treatment were similar to those observed in other HBV-related clinical trials.
In a randomized, double blind, active-controlled study, 141 patients with chronic HBV, HBV DNA of 1,000 IU/mL (mean 6.4 log10 copies/mL) or more and resistance to lamivudine received Viread for 96 weeks. Forty-six percent of the cohort were HBeAg-positive, and 56% had abnormal serum ALT levels at baseline (mean 71 U/L).
Upon completion of treatment, 89% had HBV DNA below 400 copies/mL, and 62% of those with abnormal ALT had normalized. HBeAg loss occurred in 15% of the HBeAg-positive patients, and 11% experienced anti-HBe seroconversion through the final treatment week.
The labeling also indicates a potentially significant drug-drug interaction between Viread and didanosine. A didanosine dose reduction is recommended upon coadministration with Viread: to 250 mg once daily among patients weighing more than 60 kg and 200 mg among those weighing less than 60 kg. The drugs should be taken under fasting conditions or with a light meal containing fewer than 400 kcal and 20% fat.