"Clinical evidence shows that, given the genetic characteristics of a patient, a simple genetic test can fairly accurately predict how they might respond to treatment," he said.
About 25 to 35 per cent of patients respond to the currently available treatment. With use of boceprevir, the response rate increases to 70 to 75 per cent. Victrelis is the first new hepatitis C treatment made available to New Zealanders in the past decade.
Hepatitis C genotype 1 is the most common form of the condition, and affects about 50 per cent of all known sufferers.
If left untreated, hepatitis C can cause serious liver disease including cirrhosis, liver cancer and even death.
Professor Ed Gane, chief hepatologist and deputy director of the New Zealand Liver Transplant Unit at Auckland City Hospital, said Victrelis was a protease inhibitor and worked directly on the hepatitis C virus to stop it replicating.
"It is used in combination with other drugs - peginterferon alfa and ribavirin - which prevent the virus from becoming resistant to Victrelis."
The drug could almost double cure rates for patients who had never been treated before, and for patients who had failed previous therapies it could treble the cure rate, Professor Gane said. "This can be life-changing, especially for patients who have been the hardest to treat."
Patients will be genetically tested to determine whether they qualify for the new medicine. About 300 patients are expected to start the triple therapy within the next year.
Pharmac has also negotiated a price reduction for the Pegasys brand of the current treatment, pegylated interferon with ribavirin.
Together, total funding of these hepatitis C treatments will cost $17.8 million over five years.
Hepatitis C
• Viral infection of the liver.
• Affects about 50,000 New Zealanders.
• Genotype 1 is the most common form of the condition.
• Pharmac will start funding a new drug, Victrelis, from September.