TORONTO -- A clinical trial has found that a simple drug regimen delivered over 12 weeks achieved sustained eradication of several strains of hepatitis C in 99 per cent of patients treated with the medications, researchers reported Monday.

Their study, published in the New England Journal of Medicine, showed that receiving a once-daily combination of sofosbuvir-velpatasvir for a 12-week period was effective in both previously treated and never-treated patients with hepatitis C genotypes 1, 2, 4, 5 or 6.

"This drug regimen changes the standard of care in treating patients with HCV. We can now cure almost everyone with a very simple treatment," said lead researcher Dr. Jordan Feld, a liver specialist at Toronto Western Hospital.

Current approved treatments for chronic HCV are not equally effective in combating the virus' different forms. Testing to determine the particular genetic makeup -- or genotype -- of the virus has been required before treatment could be started.

But Feld said the combination of sofosbuvir-velpatasvir has been shown to work on all strains of hepatitis C virus, effectively eliminating the need for this testing, which often delayed treatment.

The drug combination was investigated in a randomized, placebo-controlled trial at 81 sites in eight different countries. After 12 weeks, 99 per cent of the 624 patients given sofosbuvir-velpatasvir were virus-free three months after completing treatment. None of the 116 patients receiving a placebo had the same result.

"This is truly a one-size-fits-all treatment that is very easy to administer and extremely well-tolerated," said Feld. "Our challenge now is getting treatment to those who need it. Over half of people living with hepatitis C remain undiagnosed."

Chronic HCV is known as a silent killer because symptoms often don't appear until the liver is severely damaged. Left undiagnosed, the infection can lead to cirrhosis, which can progress to liver failure or liver cancer.

The virus is primarily spread through blood and is associated with IV drug use, contact with poorly sterilized medical equipment, and blood transfusions before 1992.

"Knowing which treatment to use for which patient required expertise, which made it much more difficult for non-specialists to treat hepatitis C," Feld said by email. "There are simply not enough specialists to treat all of the 250,000 to 400,000 infected Canadians."

With the single tablet that is effective for all strains of the virus, it's hoped that family doctors, internists and nurses will step in to treat hepatitis C, particularly in rural and under-served areas, he said.

"We are now on a path where elimination of hepatitis C from Canada actually starts to become a realistic goal."