A widely used antiretroviral drug - entecavir - used to treat Hepatitis B infection can lead to cross-resistance to other anti-viral drugs in patients co-infected with HIV.

Such were the findings of a Johns Hopkins study presented recently at the at the 2007 Conference on Retroviruses and Opportunistic Infections (CROI) in Los Angeles.

According to senior study author and infectious disease specialist Chloe Thio, M.D.:

"Our results show that entecavir is no different from any other that has been shown to be active against HIV - it breeds resistance rapidly, despite its ability to reduce the amount of HIV in the body.

The good news is that co-infected patients already on HIV therapy can still use entecavir to treat their hepatitis B, but the bad news is that there are now fewer options for treating hepatitis B first."

First marketed in March 2005, entecavir is sold under the brand name Baraclude by Bristol-Myers Squibb and the drug's label information currently states that is has no clinical effects on HIV.

Authors of the said study have already informed the USFDA of their findings so that prescribing physicians will be notified and that the product's labelling can be changed.

The findings have serious implications for the more than 4 million people worldwide believed to be infected with both viral illnesses but who need to treat their hepatitis B and are not yet on anti-HIV drugs.

Find more details from the full report.

[Photo Credit: drugs.com]