European regulators have issued a green light for the use of Gilead's Truvada to cut the risk of HIV infection in adults.

The once-daily pill has been cleared for a strategy known as pre-exposure prophylaxis (PrEP), under which the drug is prescribed alongside safer-sex practices to help prevent HIV infection in adults at high risk.

"The approval of Truvada for PrEP represents an important step forward in addressing the incidence of HIV in Europe" said Norbert Bischofberger, PhD, chief scientific officer at Gilead. "When taken as directed and used in combination with other prevention strategies, Gilead believes Truvada for PrEP can have a meaningful impact on public health by helping to reduce HIV transmission rates across Europe."

Recent evidence indicates that the PrEP approach can be highly effective in preventing transmission of the disease as long as the drugs are taken regularly; data from the pilot phase of the PROUD study show that PrEP using Truvada cut the incidence of HIV infection by 86 percent.

The once-daily pill costs around £360 a month, according to the AIDS charity the Terrence Higgins Trust, but it points out that this is still cheaper than the cost of treating HIV, which has been estimated at around £360,000 over a life-time.

But NHS England is currently appealing a recent High Court ruling that it does have the legal power to commission the PrEP service, because it argues that, being a preventative measure, the service falls under the remit of local authorities.

Truvada (emtricitabine/tenofovir disoproxil) was cleared by the European Medicines Agency in 2005 for use alongside other antiretroviral agents for the treatment of HIV-1 infection in adults, and, according to Gilead, is currently the most prescribed antiretroviral medicine in the region as part of combination therapy.