The FDA has announced approval for a generic version of Truvada, a popular and very effective HIV drug that was first approved by the agency in 2012. The approval is several years earlier than expected.

Truvada is an antiretroviral medication used to treat those infected with HIV, but it’s also effective as a pre-exposure prophylaxis, or PrEP. That means people who are not HIV-positive can reduce their odds of infection by up to 100 percent by taking the medication daily.

Though pricing information is not yet available, the FDA estimates that on average, a generic prescription drug costs between 80 and 85 percent less than a brand name one.