A new drug has been developed for the treatment of hepatitis C, a infection linked to liver cirrhosis and cancer.
The new drug, called Telaprevir, offers new hope to the 170 million people worldwide who are currently infected with hepatitis C, which is transmitted by blood contact, needle sharing, blood products and occasionally during sex. Of those exposed to the virus, 80% develop a chronic infection, leading to persistent liver injury, cirrhosis and liver cancer.
The only proven treatment is with a drug called ribavirin, which is administered together with an immune-boosting chemical called alpha-interferon. Given for 12 months, this cocktail, which produces severe side effects including flu-like symptoms, weight loss, anaemia and depression, can clear the virus from the bloodstreams of only about 40% of patients with the most common form of the disease, known as genotype 1.
Now, according to a trial of published this week in the New England Journal of Medicine, it should be possible to almost double that cure rate.
The phase 3 trial, which was conducted by John McHutchinson and his colleagues at the Duke Clinical Research Institute in the US, looked at 453 hepatitis C-infected patients who had failed to respond to existing treatment with ribavirin and interferon.
These patients were randomly split into groups and given either 24 or 48 weeks therapy with ribavirin and interferon with or without 12 or 24 weeks of Telaprevir. A control group received ribavirin and interferon together with a placebo. The results were striking.
Over 50% of the patients given telaprevir cleared the virus and continued to test negative six months after the trial was completed, compared with only 14% given the standard treatment of ribavirin and interferon.
Telepravir achieves its antiviral action by blocking a key viral protease enzyme which is used by hepatitis C to copy itself inside infected cells. It reflects an entirely new way to target the virus, but was associated with some significant side effects including causing rashes and anaemia.
Further phase 3 investigations are now planned to identify more optimal treatment strategies aimed at minimising side effects.