Novel Hepatitis B Drug May Improve Long-Term Treatment

Phase 3 study results show high efficacy and improved renal and bone safety parameters with tenofovir alafenamide regimen.

An investigational therapy for hepatitis B showed promising results during a recent clinical trial.

Gilead Sciences found during a pair of phase 3 clinical trials that tenofovir alafenamide (TAF) worked equally as well as tenofovir disoproxil fumarate/TDF (Viread) among patients with chronic hepatitis B.

When looking at the percentage of patients at 48 weeks of therapy with HBV who had DNA levels that were below 29 IU/mL, researchers discovered TAF worked just as well as TDF, and contributed to the improvement of renal and bone laboratory safety compared to TDF

“We are pleased that the TAF Phase 3 study results reflect high efficacy and improved renal and bone safety parameters similar to those seen in clinical studies evaluating TAF-based regimens for HIV,” said Executive Vice President at Gilead Sciences Norbert Bischofberger, PhD. “Like HIV, HBV is a chronic condition that requires prolonged therapy and we look forward to the opportunity to offer patients an improved option that has the potential to advance the long-term treatment of HBV.”

The results of the first study showed 94% (n=268/285) of HBeAg-negative patients administered TAF and 92.9% (n=130/140; CI -3.6% to +7.2%, p=0.47) of patients administered Viread achieved HBV DNA below 29 IU/mL at week 48.

The second study found 63.9% (n=371/581) of HBeAg-positive patients administered TAF and 66.8% (n=195/292; CI -9.8% to +2.6%, p=0.25) of patients administered Viread achieved HBV DNA below 29 IU/mL at week 48.

Normalization of serum ALT levels were evaluated using 2 criteria: a central laboratory cut-off value and the American Association for the Study of Liver Diseases (AASLD) criteria. Across both studies, patients receiving TAF showed a statistically significant increase in ALT normalization compared with the Viread cohort measured by AASLD criteria.

The central laboratory cut-off value did not show statistically significant ALT normalization.

The most common adverse events were similar across both studies and included headache, upper respiratory tract infection, nasopharyngitis, and cough.

Gilead plans to submit applications for TAF to be used for chronic hepatitis B in the United States and European Union in 2016.