The Food and Drug Administration (FDA) has approved the supplemental New Drug Application (sNDA) for Vemlidy® (tenofovir alafenamide; Gilead Sciences) to include efficacy and safety data from the phase 3 GS-US-320-4018 trial, along with updates to the Pregnancy section of the labeling. Vemlidy is a HBV nucleoside analog reverse transcriptase inhibitor that is indicated for the treatment of chronic hepatitis B virus (HBV) infection in adults with compensated liver disease.

The Clinical Trials section now includes data from a 48-week, randomized, double-blind, active-controlled trial that evaluated the efficacy and safety of switching from tenofovir disoproxil fumarate to tenofovir alafenamide (TAF) in 488 virologically suppressed adults with chronic HBV infection. Patients were randomized 1:1 to receive either TAF 25mg once daily (n=243) or remain on TDF 300mg once daily (n=245). The primary end point was the proportion of patients with plasma HBV DNA levels ≥20 IU/mL at week 48. 

Results showed that both TAF and TDF treatment arms had less than 1% of patients with HBV DNA ≥20 IU/mL with no treatment difference at week 48 (95% CI, -1.9, 2.0). Moreover, 96% of patients in both treatment arms demonstrated plasma HBV DNA levels of <20 IU/mL at week 48 (0.0% treatment difference; 95% CI, -3.7, 3.7). With regard to safety, changes in renal function, bone mineral density and lipid parameters were found to be similar to those observed in previous trials. 

The new labeling also includes updated data based on prospective reports to the Antiretroviral Pregnancy Registry (APR) of exposures to TAF-containing regimens. The prevalence of birth defects in live births was determined to be 5.2% (95% CI, 2.7% to 8.8%) and 1.2% (95% CI, 0% to 6.5%), following first and second/third trimester exposure, respectively. This does not include outcomes for births at <20 weeks gestation.

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