By Toni Clarke
(Reuters) - Gilead Sciences Inc's sofosbuvir drug is safe and effective when used in combination with other therapies to treat hepatitis C, according to reviewers with the U.S. Food and Drug Administration.
Their review was posted on the FDA website on Wednesday ahead of an October 25 meeting of an outside panel of medical experts who will recommend whether or not the agency should approve the drug.
"The currently available data support a favorable benefit-risk assessment for the use of sofosbuvir as part of a combination regimen for the treatment of chronic hepatitis C," the reviewers said. "No major safety issues associated with sofosbuvir use have been identified to date."
Gilead is seeking approval to market the drug in combination with an existing treatment, ribavirin, for patients with two variants of the liver-damaging disease: genotype 2 and genotype 3, and for patients awaiting a liver transplant.
If approved, this would be the first all-oral treatment for genotypes 2 and 3. Current therapies typically include ribavirin, a pill, and the once-weekly injectable drug interferon. Both can cause debilitating side effects.
Gilead is also seeking to market sofosbuvir in combination with ribavirin and interferon for patients with genotype 1, regardless of prior treatments, and for patients with genotypes 4, 5 and 6 who have not previously been treated.
Bristol-Myers Squibb Co and Abbvie Inc have advanced all-oral clinical trial programs in late-stage development, using a variety of so-called direct acting antivirals, which directly interfere with the virus's ability to replicate, but Gilead is widely seen to be in the lead.
Chronic hepatitis C affects at least 3 million people in the United States, according to the U.S. Centers for Disease Control. Genotype 1 is the most common form, accounting for about 70 percent of cases.
Analysts on average expect Gilead's drug to generate sales of $1.73 billion in 2014, according to Thomson Reuters data.
Current standard treatments for genotype 1 often include a protease inhibitor. These are oral drugs that include Merck & Co Inc's Victrelis and Vertex Inc's Incivek.
Gilead acquired sofosbuvir, known as a nucleotide analogue inhibitor, with its $11 billion purchase of Pharmasset Inc in 2012.
(Reporting by Toni Clarke in Washington; Editing by Gerald E. McCormick and Lisa Von Ahn)