Without insurance, the HIV antiretroviral drug Truvada — the only medication approved for pre-exposure prophylaxis (PrEP) in the U.S. — costs around $1,600 a month, without accompanying office visits and lab work. But activists say it costs Gilead Sciences, the California-based company that produces the drug, a mere six dollars to produce a month's supply. Today, on National HIV Prevention Day, they ask the question: Why is it so expensive? Break the Patent, an activist campaign with a goal of making PrEP more accessible for those who can't afford it, is looking for the answer. According to its website, the cost barrier has resulted in less than 10 percent of at-risk populations — gay and bisexual men, especially of color, who account for most new HIV infections — taking the medication. It also says that under the Bayh-Dole Act of 1980, the government could break Gilead's patent over the drug at any time and allow generic PrEP to come to the American market, which would dramatically reduce the price.