Hepatitis B drug boosts HIV-drug resistance

[cezene]

An antiviral drug widely used to treat hepatitis B causes some people with HIV to become rapidly resistant to their medication, a new study suggests.

The finding could have major implications for over four million people worldwide who are jointly infected with hepatitis B and HIV.

Chloe Thio and colleagues at Johns Hopkins University in Baltimore, Maryland, US, investigated the drug entecavir, a leading treatment for hepatitis B. Thio had heard reports that the drug – sold as Baraclude – had demonstrated anti-HIV activity in two HIV patients who were taking the drug for hepatitis B.

Working in the lab, the researchers combined the drug with healthy blood samples and a non-virulent form of HIV. At low concentrations of entecavir, the drug dramatically slashed the number of newly infected cells by 50%.

But the drug also caused a mutation in the virus, they found. This so-called "M184V mutation" inhibited further HIV suppression, even when higher doses of the drug were used. Worse, the mutation stopped other anti-HIV drugs from treating the immunological disease, including lamivudine – the mainstay of many HIV drug-combination therapies.