Boston: An experimental hepatitis C drug combination from Gilead Sciences Inc. wiped out multiple strains of the virus in a large clinical trial, giving the company an advantage against AbbVie Inc. in the race to treat as many patients as possible.

In a trial of 624 patients with any of six strains or genotypes of hepatitis C, Gilead’s experimental combination of velpatasvir and sofosbuvir was effective at clearing the virus 99% of the time after 12 weeks of therapy. Three related trials also showed the drug was successful in treating multiple strains, the company said in a statement on Monday.

“This is a big step forward to proving they’re going to have a pan-genotypic option here," said Asthika Goonewardene, an analyst at Bloomberg Intelligence. In hepatitis C, “you have a very fragmented market," Goonewardene said, because of the genetic diversity of the virus, which causes the liver disease.

Gilead shares rose less than 1% to $108.76 at 10:18 am in New York.

Gilead and AbbVie already have drugs on the market for hepatitis C, though they’ve mostly focused on patients with genotype 1, the most common strain in the US. Other strains are more common in different parts of the world. Globally, almost a third of patients suffer from genotype 3, which is more common in India and Southeast Asia.

In a study of patients with genotype 3, 95% of those on the experimental combination were free of the virus after 12 weeks, compared with 80% under an older treatment approach.

Gilead’s existing hepatitis C drugs brought in $12.4 billion last year, even as the company faced criticism over list prices for the medicine that exceed $1,000 a day. Actual prices dropped after Abbvie entered the market and health insurers began inking exclusive deals with the drugmakers in exchange for rebates.

Gilead, based in Foster City, California, said it plans to file for regulatory approval of the combination in the fourth quarter this year. Bloomberg