Clinical trials show that a combination of pills, one still in the experimental phase and one just approved for the US market, are effective at curing hepatitis C, researchers said.
However, the cost of the treatment is expected to be at least US$80,000 per year, making it out of reach to many of the 150 million people chronically infected with the liver disease worldwide.
The New England Journal of Medicine published the latest data from a phase II clinical trial on daclatasvir and sofosbuvir. Sofosbuvir, made by Gilead Sciences in California, was approved by the US Food and Drug Administration in December. It has been given the brand name Sovaldi. The trial involved 211 people at 18 medical centres across the US and Puerto Rico.
People in the study took a daily combination of 60 milligrams of daclatasvir - which has not been approved for market - and 400 milligrams of sofosbuvir, with or without a third drug called ribavirin that can cause anemia.
A full 98 per cent of participants were considered cured, showing no detectable virus in their blood three months after the treatment ended.
Results were similar for people with the virus genotype 1, which is common in the United States, and those with genotypes 2 and 3 which are more common elsewhere.
The study was also the first to show that hepatitis C could be cured without the use of ribavirin.
Side effects of the combination included fatigue, headache and nausea.
Dr Mark Sulkowski, medical director of the Johns Hopkins Centre for Viral Hepatitis, said the research could soon transform treatments for hepatitis patients, who currently must get weekly injections of peginterferon.
"Standard treatments for the disease are going to improve dramatically within the next year, leading to unprecedented advances for the treatment of patients infected with the hepatitis C virus," he said.