Who would find a daily pill to prevent HIV “too inconvenient” to bother?

Much of the information presented here is from “AIDS 2014″ International AIDS Conference taking place in Melbourne, Australia.

iPrEx was one of the studies done on using the PrEP (Pre-exposure Prophylaxis) drug combination of tenofovir-emtricitabine. iPrEx OLE was an extension of that study.

IPrEx OLE is unusual in a couple of ways. In general, most research trials enroll a number of patients. About 50% of the enrollees are randomly assigned to be given the study drug, the other 50% get a placebo. Almost always, neither the patients nor the investigators know which patients are getting the drug and which are getting placebo.

In iPrEx OLE there were two important differences. About 1700 participants were enrolled worldwide. These were either men who had sex with men (MSMs) or transgender people who had sex with men. All participants were allowed to choose which arm of the study (medication or placebo) that they wanted to be in. About 75% chose to take PrEP and the remaining 25% chose to not take PrEP. So all of the volunteers and investigators knew who was getting the drug and who wasn’t. So they weren’t blinded to that fact.

Researchers monitored how frequently the participants used condoms. Interestingly, the non-PrEP group began to use condoms more frequently than they had before enrolling in the trial. And the group that was taking PrEP? They started using condoms more frequently, as well. So both those taking tenofovir-emtricitabine and those not taking the drug increased condom use. So, in spite of fears to the contrary, it seems that those who use PrEP also increase condom use, not decrease condom use as was hypothesized.

Researchers also found that the people who chose to try PrEP and took it on a regular basis (if not daily, as directed) had the following characteristics:

  • They tended to be older (not necessarily much older) than those who didn’t take PrEP.
  • They had more schooling.
  • They had a history of having more sexual partners.
  • They had a history of having had either herpes, syphilis of both.
  • They had a higher incidence of having been receptive to anal intercourse (they bottomed) without condom use.

Data from this, and a previous study showed that “effective” PrEP use was defined as volunteers taking their antiretroviral combination 4 or more days per week. So, even when patients didn’t take PrEP daily, as they should, most took it frequently so that they had high enough blood levels of the drug to prevent infection.

One other interesting fact. Investigators asked those who chose not to take PrEP, why they made that choice. About 50% said that they were worried about side effects of the drug. 14% said that they preferred other methods or prevention (e.g., condoms) — though the question remains, why did they prefer other methods? And about 25% said that taking a daily pill was too inconvenient.

After having seen the history of HIV/AIDS as it occurred I’m amazed that people would think that a single daily pill, that can prevent a terrible disease, would be “too inconvenient.” I can only imagine what those lived (or died) through the three decades when HIV was virtually unstoppable, would have given to have had access to an “inconvenient” medication like this.

Mark Thoma, MD, is a physician who did his residency in internal medicine. Mark has a long history of social activism, and was an early technogeek, and science junkie, after evolving through his nerd phase. Favorite quote: “The most exciting phrase to hear in science... is not 'Eureka!' (I found it!) but 'That's funny.'” - Isaac Asimov

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