New data indicates that the use of Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP) is on the upswing in the United States, with the demographic of users trending increasingly male. Gilead Sciences, which manufactures Truvada, conducted an analysis of pharmacy data from January 2012 through March 2014 and found that 3,253 people went on PrEP during that period, including 1,057 new prescriptions filled during the first nine months of 2013 and an additional 880 between October 2013 and March 2014.

These data have critical limitations. They are drawn from only about 55 percent of U.S. pharmacies, reflect only a limited proportion of prescriptions filled through Medicaid, and do not factor in people taking PrEP as part of a study. Further, given the accelerating national interest in PrEP, the figures are already well out of date. The Gilead analysis can, however, help give a decent impression of changing trends over time.

By comparison, a single clinic, Kaiser Permanente Medical Center in San Francisco, reported having more than 500 patients on PrEP in December, compared with 250 during midsummer of 2014 and 40 in 2013.

The proportion of men taking PrEP has increased since Gilead’s previous report, which covered PrEP use through September 2013. During the first half of 2012, 46 percent of new PrEP prescriptions were among men, compared with 73 percent from October 2013 through March 2014.

Characterizing Gilead’s figures as “an interesting snapshot,” Jim Pickett, director of prevention advocacy at AIDS Foundation of Chicago, says, “It does make sense that men are making up a bigger proportion. I would expect that to continue. Where are the numbers going up? They’re going up in one population.”