Scientists have reported the successful eradication of hepatitis C in patients using two new antiviral drugs, raising hopes of a possible cure.

In the trial, the virus was eliminated from almost all the patients involved, including those who had not previously responded to existing drugs.

Hepatitis C is caused by a virus that spreads via bodily fluids and ends up damaging the liver. Unlike other forms of hepatitis, there is no vaccine and the only treatments include powerful combinations of drugs known as interferons and protease inhibitors. But the treatments have many side-effects, are complex to administer and, in the common type of hepatitis C known as genotype 1, the drugs do not work. If an infection cannot be cured, it can lead to liver cancer.

The new treatment, reported in medical journal the Lancet on Tuesday , consists of the experimental drugs sofosbuvir and ledipasvir. In the trial, 100 patients with genotype 1 hepatitis C were split into groups and given the drugs in a single pill for either eight or 12 weeks. Forty of the participants had previously failed to respond to drugs and half of this group had cirrhotic livers.

After 12 weeks, 97% of the participants had what scientists called a "sustained virological response", which meant that the hepatitis C virus was not replicating inside them. The patients suffered varying amounts of side-effects, including nausea, anaemia, respiratory tract infections and headaches, but none were considered to be serious.

Professor Eric Lawitz of the University of Texas, who led the study, said the results offered hope to people currently without treatment options: "The results of this trial suggest that the fixed-dose combination of sofosbuvir and ledipasvir could offer patients a short, all-oral treatment that might be highly effective and safe in patients who tend not to respond well to existing therapies, including individuals with cirrhosis, or black race, resistant strains of the virus."

Charles Gore, chief executive of the Hepatitis C Trust, said the new drug combination was great news. "We were concerned that those with advanced hepatitis C would remain difficult to treat, but these new direct antivirals are incredibly potent. The results suggest that even the most difficult to treat people will in fact be extremely treatable. It now looks as if almost no one will be excluded from benefiting from treatment, which is an incredible achievement.

"There are a number of exciting new drugs on the horizon. However, of the 215,000 people estimated to be living with the virus in the UK, less than half have been diagnosed. In England, only 3% of hepatitis C patients receive treatment each year. There is no point having these treatments if we can't use them, so we must ensure that we diagnose more people who can avail of them."

In 2010, a total of 7,834 new hepatitis C cases were reported in England, though the true figure is probably much higher. Rates of infection are greater in people of African descent than in other ethnic groups.

The virus is present in the blood and, to a much lesser extent, the saliva and semen or vaginal fluid of an infected person.

It is most likely to be transmitted through blood-to-blood contact. Intravenous drug users who share their needles are known to be especially vulnerable.

Professor Margaret Hellard of the Burnet Institute in Melbourne, Australia, who co-authored a linked comment on the research published in the Lancet, said: "As a proof of concept study, [this] demonstrates very high response rates, regardless of the presence of cirrhosis, prior treatment failure, or [resistant] genotype."

She cautioned, however, that the study was small, based at a single location and only had a short follow-up, which she said raised concerns about how representative the sample was and whether early clinical trial results could be generalised to real-world settings. "Whilst giving cause for optimism, the full implications of these results need to be tempered for now," she wrote.