Gradually ramping up promotion of its HIV-prevention pill, Gilead Sciences has turned to humor, dating apps, and social-media sites like Tumblr and Snapchat to raise awareness about HIV prevention.

The drugmaker markets Truvada for pre-exposure prophylaxis, also called PrEP. The drug is currently the only therapy approved by the FDA to prevent HIV infections. It first received FDA approval for this indication in 2012, but it wasn’t until last year that Gilead began to market Truvada for PrEP.

The latest campaign, developed by Digitas Health LifeBrands, uses Tumblr, Snapchat, and YouTube, as well as gay dating apps like Grindr, Jack’d, and Hornet. Posts on Gilead’s Healthysexual Tumblr page say things like: “From HIV testing to threads, coordinate with your partner. Being on the same page means you’re in position…for any position.”

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The campaign targets young black and Latino men, transgender women, and serodiscordant couples, in which one partner is HIV positive  — all of whom are at high risk for HIV, according to Ryan McKeel, a Gilead spokesperson. “The campaign is designed to engage sexually active, at-risk people with sex-positive public health messages,” he wrote in an email.

It’s rare for drugmakers to decline to use their marketing arms to promote branded drugs or to delay these promotions to this degree. While most pharmaceutical companies wait six months before launching branded direct-to-consumer ads, in order to quell concerns that patients learn about a drug before their physicians, it took four years for Gilead to launch the first branded ad for PrEP, in late 2016.

“In any other kind of FDA approval, there would have been beautiful ads, lots of TV, and lots of press touting the fact that this was the new thing to keep people protected from HIV. Gilead chose not to do that,” the San Francisco AIDS Foundation’s Ernest Hopkins told The New Yorker in 2013.

Gilead, which has long marketed HIV therapies, was in this instance “very ambivalent to be seen as promoting” Truvada for PrEP, said Mitchell Warren, executive director of AVAC, a nonprofit that advocates for PrEP usage and doesn’t accept funding from drugmakers. Warren credits local organizations and nonprofits for creating awareness about PrEP during the absence of a pharmaceutical marketing push. He noted, however, that Gilead’s resources would be useful in creating awareness.

“They have the biggest reach and have bigger pockets than other organization,” Warren said from Nairobi, where a government-awareness campaign about PrEP is expected to kick off this week. “That’s just a reality.”

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To date, most of the awareness of PrEP has been driven by campaigns developed by local government agencies. In New York, for example, the health department in 2015 created the #PlaySure campaign, which features ads in subway stations, on MTA buses, and online. It provides free kits, which hold condoms, lubricant, and prevention medications ranging from Truvada to birth-control pills. Health departments in San Francisco and other cities have also launched campaigns.

However, despite the clinical promise of Truvada to treat PrEP, there have been several obstacles to adoption. The influential AIDS Healthcare Foundation has been critical of the drug, arguing that if people stop using condoms that may lead to an increase in other types of sexually transmitted infections, including HIV. The term “Truvada whore,” which refers to people who see PrEP as a means to stop using condoms and engage in risky sexual behavior, cropped up several years ago, creating a debate within the gay community.

There are similar questions within the physician community. A poll conducted in 2015 by SERMO, a social network for physicians, found that 59% of roughly 1,200 doctors were concerned that PrEP usage would lead to less cautious sexual behavior among patients. But 91% also said they would still prescribe the medication to an at-risk individual.

This may be one reason why Gilead launched an unbranded campaign in mid-2016 to raise awareness about PrEP among healthcare providers. That campaign used medical publications, digital advertising, and a website; the first branded ads went live last fall.

Still, Gilead’s advertising spending for Truvada is fairly low. Last year the drugmaker spent $450,000 advertising Truvada, up from $260,000 in 2015, according to Kantar Media. In comparison, Gilead spent $101 million in 2016 to advertise Harvoni, its blockbuster hepatitis-C treatment.

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The company began to incorporate sites like Tumblr into its marketing strategy for PrEP in late 2016, as part of an effort to raise awareness among patient populations that traditionally don’t engage with the health system. “We’ll be using social media and dating sites and Tumblr and Snapchat and things like that, that…are much more, I would say, likely media to reach this type of population,” James Meyers, EVP of commercial operations at Gilead, said during an investor call in February.

About 125,000 people are currently taking Truvada, up from the 110,000 people taking the preventative medication at the end of 2016. “Truvada for PrEP also continues to be an important growth driver for Gilead,” Meyers told investors this week. “We’ve seen a significant uptick in PrEP usage in 2017.”

That uptick, though, hasn’t translated into higher sales. U.S. sales of Truvada, which include revenue for Truvada as both HIV treatment and HIV prevention, fell 19% to $464 million in the first quarter of 2017, down from $576 million in the same quarter a year ago. Globally, sales also dropped by roughly 20%, to $714 million in the first quarter of 2017, compared to $898 million in the same quarter last year.