New hepatitis C treatment

This combination works less than half the time in people co-infected with HIV and the most common types of hepatitis C, and can cause unpleasant side-effects.

However, there are new drugs and new treatment regimens in development or recently released that offer more options.

Last year, two protease inhibitors that work directly against hepatitis C were licensed. Telaprevir (Incivo) and boceprevir (Victrelis) are currently only licensed for people with hepatitis C mono-infection. However, doctors are allowed to prescribe them to anyone who, in their judgement, needs them urgently.

These new drugs improve treatment response rates, but they must still be used in combination with pegylated interferon and ribavirin.

A large number of other drugs which work directly against hepatitis C are in development.

In studies on these drugs presented at CROI, those taking part had the difficult-to-treat hepatitis C genotype 1. Rates of sustained virological response (an undetectable hepatitis C viral load which is considered a cure) were measured 12 weeks after finishing treatment. Studies found that 74 per cent of people taking telaprevir had a sustained virological response (compared to 45 per cent of those on standard treatment) as did 61 per cent of those on boceprevir (compared to 27 per cent on standard treatment). But the new drugs did increase the number of side-effects.

While further research will be needed, the findings are very encouraging. They suggest that triple therapy of a protease inhibitor, pegylated interferon and ribavirin may be an important option for people with HIV and hepatitis C co-infection.

However, as with all medications, there is a risk of interactions. Interactions between antiviral agents for hepatitis C and some anti-HIV drugs are common, but they are often modest and can be managed by adjusting doses of one or both types of drug.

Researchers have been looking at potential interactions between the new protease inhibitors developed to treat hepatitis C with anti-HIV drugs. While interactions with telaprevir were studied early in this drug’s development, drug/drug interaction studies were not conducted until later with boceprevir.

Researchers have been looking at potential interactions between the new protease inhibitors developed to treat hepatitis C and anti-HIV drugs. While interactions with telaprevir were studied early in this drug’s development, drug/drug interaction studies were not conducted until later with boceprevir.

It is already known that efavirenz (Sustiva) causes substantial decreases in boceprevir levels and now another study has shown that boceprevir also decreases blood levels of atazanavir, darunavir and lopinavir, as well as decreasing levels of their 'booster' drug ritonavir.

At the same time, lopinavir/ritonavir (Kaletra) and darunavir/ritonavir reduced blood levels of boceprevir. The pharmaceutical company Merck, which makes boceprevir, has issued advice recommending that boceprevir not be taken at the same time as anti-HIV protease inhibitors. However, another study presented at CROI suggested boceprevir was safe and effective for people taking boosted HIV protease inhibitors. These conflicting results mean there isn’t agreement on whether people can safely take boceprevir with other protease inhibitors. Indications are that it is safe to take boceprevir with raltegravir (Isentress).

Future developments

Development continues on other hepatitis C treatments. Researchers presenting at CROI said that hepatitis C treatment that doesn’t include interferon 'is not a dream', after a study showed that a two-drug combination consisting of an experimental drug GS-7977 with ribavirin, but no interferon, had a fast and potent effect against the virus.

However, researchers were disappointed when viral load rebounded once treatment was stopped. The study involved hepatitis C mono-infected patients. It is thought that a longer duration of therapy, or the addition of another drug that works directly against hepatitis C, could improve response rates. Findings from this work, as well as from the studies described above, emphasise the need to look carefully at possible interactions for people who are co-infected with HIV and hepatitis C.

The combined findings of this research suggest that an HIV treatment regimen that can be safely and effectively used with new hepatitis C drugs can be found for most co-infected people, and that people who need this treatment urgently now have a much better chance of being cured of hepatitis C.

However, we are at a very early stage of knowing how to use these new drugs with co-infected patients. Many doctors recommend that people without active liver damage may do better to wait until simpler, more effective drugs are available. The pace of hepatitis C drug development means that hopefully that wait won’t be too long.