Gilead Sciences’ updated version of Viread (tenofovir disoproxil fumarate, or TDF), tenofovir alafenamide (TAF), combats hepatitis B virus (HBV) comparably to and is safer than the older drug. Researchers conducted two randomized, double-blind, 96-week Phase III trials, called Studies 108 and 110, which included 1,298 treatment-naive and treatment-experienced people with hep B who were given TAF or TDF.

Findings were presented at the 51st International Liver Congress in Barcelona.

In Study 108, 425 HBeAg-negative participants were randomized two to one to receive TAF or TDF. In Study 110, 873 HBeAg-positive participants were randomized two to one to receive TAF or TDF.

The researchers found that, after 48 weeks of treatment, TAF suppressed hepatitis B as well as TDF, based on the percentage of those with a hep B viral load below 29. Various laboratory tests indicated that TAF was less harmful to the bones and kidneys than TDF.

Few people discontinued either drug because of adverse health “events.” The most commonly reported side effects in both studies included headache, upper respiratory tract infection and cough. The rates of these side effects were similar between those taking TAF and TDF.

To read a press release about the study, click here.