The United States is suing Gilead, the manufacturer of Truvada and Descovy, the two drugs approved for use in PrEP regimens. The news was announced late Wednesday evening in a release.

“Today, the United States, on behalf of [the Department of Health and Human Services,] filed a complaint in federal district court against Gilead seeking damages for Gilead’s infringement of HHS patents related to pre-exposure prophylaxis (or PrEP) for HIV prevention,” HHS Secretary Alex M. Azar II tweeted, linking to a department press release. “Gilead must respect the U.S. patent system, the groundbreaking work by [Center of Disease Control] researchers, and the substantial taxpayer contributions to the development of [Truvada and Descovy.] The complaint filed today seeks to ensure that they do.”

PrEP, or pre-exposure prophylaxis, is a drug regimen that makes it almost impossible to contract HIV through sex. In the U.S., the CDC has approved it as a pill-a-day system that utilizes either Truvada or Descovy.

According to the complaint, CDC researchers developed PrEP and the U.S. government owns four patents for that innovation. The activist group PrEP4All made this information public for the first time in March. At the time they questioned why the U.S. was not enforcing its own patents and allowing Gilead to price gouge communities who need the drug. Senators including Bernie Sanders and Richard Blumenthal highlighted those same concerns in a letter that referenced PrEP4All’s findings. This suit is the first substantive public move that has resulted from it.

HHS alleges that “Gilead has willfully and deliberatively induced infringement of the HHS patents. The complaint further alleges that, as a result of such infringement, Gliead has provided from research funded by hundreds of millions of taxpayer dollars and reaped billions from PrEP through the sale of Truvada and Descovy.” This lawsuit, logged in federal courts, will attempt to recoup some of that.

“PrEP is not Gilead’s invention, it’s the American taxpayer’s invention and because [the CDC] invented it and owns four patents protecting that invention, Gilead needs to in some way pay back the American taxpayers,” PrEP4All co-founder James Krellenstein tells Out. “That can be in monetary royalties — the Financial Times estimates that Gilead owes at least a billion dollars back to the American taxpayer — but it can also be other things. Like commitments to increase access and make sure PrEP is universally available.” Whatever the decision is, this is the first step in calling to heel a company that made a reported $3 billion last year off of Truvada alone.

While litigation can be a lengthy process, Krellenstein says the move also can provide leverage over Gilead. “I think one of the things we have been highlighting since we founded our organization, is that the amount of money that Gilead either owes us for backpay or the amount of money we are paying because of Gilead’s price gouging, if we could redirect all of that money to a universal PrEP program, we can ensure that every single person that needs PrEP in this country, gets it, for free,” he says. In theory, this lawsuit could move the country in this direction, and widen access. But that’s only if handled right.

“We should be really clear that if the federal government is just going to use these lawsuits and whatever money they recover to just redistribute them back into the general fund and not do anything to help the most impacted communities who need access to PrEP, then it won’t do anything,” Krellenstein explains. “We need a commitment from the Department of Health and Human Services to include communities in all of the discussions about how this leverage and this money is going to be utilized.”