Phase III Study for Gilead's Viread meets primary endpoint

Gilead Sciences has announced that Study 103, a Phase III clinical trial evaluating the company's once-daily anti-HIV drug Viread (300mg) as a potential treatment for chronic hepatitis B virus (HBV) infection, met its primary efficacy endpoint.

Results show that Viread is non-inferior to the company's once-daily antiviral drug Hepsera among patients with 'e' antigen (HBeAg)-positive chronic hepatitis B. The primary efficacy endpoint, the proportion of patients with a complete response at week 48, was defined by serum HBV DNA levels below 400 copies/mL and histologic improvement characterized by at least a two point reduction in the Knodell necroinflammatory score (a measure of necro-inflammation - an inflammatory process in the liver including or leading to death of liver cells) with no concurrent worsening of fibrosis (scarring of liver tissue).

At 48 weeks, 66.5 percent of patients in the Viread arm (n=176) had a complete response compared to 12.2 percent in the Hepsera arm (n=90; p<0.001). The most commonly observed treatment-emergent adverse events of moderate intensity or higher were abdominal pain, back pain, headache, respiratory infections and transaminase elevations. The incidence of these events was comparable between the Viread and Hepsera arms of the study.

In addition, the most frequently observed grade 3 or 4 laboratory abnormalities were elevations in transaminase and serum amylase and were comparable between the two arms. Full study results will be submitted for presentation at an upcoming scientific meeting, the company says.

Study 103 is the second of two Phase III pivotal studies evaluating the efficacy, safety and tolerability of Viread for the treatment of chronic hepatitis B to have met its primary efficacy endpoint. Earlier this month, the company announced that Study 102 met its primary 48-week efficacy endpoint showing that Viread is non-inferior to Hepsera among patients with HBeAg-negative/anti-HBe positive (presumed pre-core mutant) chronic hepatitis B.

'The preliminary data observed in both Phase III trials evaluating Viread as a potential treatment option for chronic hepatitis B are very encouraging,' said Franck Rousseau, vice president of clinical research at Gilead.

'We look forward to reviewing these data with regulatory authorities and are working quickly to file a New Drug Application in the United States and Marketing Authorisation Application in Europe in the fourth quarter of this year,' Rousseau added.