Amid ongoing efforts to thwart HIV, AIDS activists are growing increasingly frustrated with the Centers for Disease Control and Prevention for failing to reach a deal with Gilead Sciences (GILD) over royalties on its sales of the Truvada prevention pill. Although the agency has refused to publicly discuss the subject, the activists hope any funds that could become available will be used for combating the virus.

The activists argue that because American taxpayers funded some of the basic research, the CDC should force Gilead to take a license and then collect royalties that could be used to promote wider use of the pill, which is also known as PrEP. The number of new HIV infections in the U.S. each year stabilized at around 39,000 through 2016, according to the CDC. And only 10% of those eligible for treatment that year were using Truvada.

Meanwhile, though, STAT has learned that the CDC is collecting a “small” royalty for its Truvada patents from Mylan, which sells a generic version, for sales in high-income countries in Europe, as well as Australia. A spokeswoman for the generic drug maker told us the agreement with the CDC was made after Mylan three years ago lost a bid to challenge the CDC patent in the European Patent Office.

The CDC declined to comment on collecting royalties from Gilead, other than to say that the agency is “not able to discuss any negotiations that may or may not be ongoing with drug manufacturers.” But the dichotomy has AIDS activists fuming, especially since Truvada sales are so substantial. Last year, the medicine generated $3 billion in worldwide sales, of which $2.6 billion was notched in the U.S. Read more via STAT