July 17, 2012
PrEP Talk 101
by Trenton Straube
Who would be a good candidate for PrEP?
In short, Beaten says, “a patient with ongoing potential HIV risk would be a person to talk to about PrEP.” More specifically, he points to the different at-risk populations who were studied in the clinical trials: men who have sex with men (MSM, like the hypothetical Joe mentioned above), trans women, and HIV-negative heterosexuals whose partner is positive but not taking medication yet.
“It is the medical provider’s job to match the intervention to the person correctly and to evaluate that intervention over time,” Mayer adds.
Mayer, who primarily works with gay men, lists a few qualities his ideal PrEP patients would possess: They’d understand the key to successful prevention is adherence; they’d undergo frequent monitoring with their medical provider to ensure the meds weren’t harmful; and “importantly, [they’d] also have insurance that covers this use of Truvada. With a monthly cost of over $1,000, it would be impossible for most people to take PrEP without appropriate insurance coverage.”
Who is contracting HIV in the United States nowadays?
Perhaps another way to frame the “who’s a good PrEP candidate” is to look at who is contracting HIV in the United States today. According to the Centers for Disease Control and Prevention (the CDC), about 1.2 million people are living with HIV in the United States, with nearly 50,000 people becoming positive each year (and one in five don’t know they’re living with the virus). Here are specific breakdowns of the main population groups who contracted HIV in 2009, the latest data available:
When you consider that African Americans represent only 14 percent of the U.S. population but account for 44 percent of new infections—and similarly, that Latinos represent 16 percent of the population but comprise 20 percent of new infections—you can see that the epidemic is hitting minority populations (and poor people) particularly hard.
- White MSM — 11,400 infections
- Black MSM — 10,800
- Latino MSM — 6,000
- Black Heterosexual Women — 5,400
- Black Heterosexual Men — 2,400
- Latina Heterosexual Women — 1,700
- White Heterosexual Women — 1,700
- Black Male Injection Drug Users — 1,200
- Black Female Injection Drug Users — 940
But MSM share the brunt. (“MSM,” or “men who have sex with men,” is a term researchers use; it refers to behaviors that transmit HIV and does not delve into self-identities and labels such as “gay” or “bisexual.”) MSM account for 2 percent of the U.S. population and yet make up 61 percent of new infections—and more and more of those diagnoses are happening to young MSM and to MSM of color. Why is HIV becoming more and more a gay epidemic again? Mayer thinks the answer is condom fatigue. Gay men “don’t want to become infected with HIV,” he says, “but those of us with the most condom fatigue are losing the battle. Because it’s an effective prevention that isn’t a condom, PrEP can play a major role in preventing new infections in the gay community.”
How long should a person be on PrEP?
PrEP is appropriate for periods of time when people have greater risk for contracting HIV, Baeten explains. Those periods may be short or long or recurrent, depending on the individual. He likens it to the way women use oral contraceptives at different times in their lives depending on their risk of pregnancy at those times. “That discussion—when to use, and when not to use—is a discussion patients should be having with health care providers,” he says. “The general goal is that PrEP is not lifelong. When you have HIV, treatment is lifelong. But PrEP is not.”
Mayer refers again to his hypothetical patient, Joe: “Ideally, I would like to use PrEP as a stopgap measure to protect Joe while we work toward addressing the obstacles that stand between him and regular condom use. For example, there are plenty of patients out there who will use condoms more consistently if they sober up. PrEP might be a wonderful way to keep them safe as they get treatment, but they may not need it after they get sober.”
What have we learned from PrEP studies?
Seven major studies have been done, or are currently being done, involving PrEP: one with MSM and trans women, two with straight couples, three with women-only and one that’s underway with injection drug users. They’ve been making headlines for a few years now, often with confusing and seemingly contradictory findings. The big picture? “Taken together, these data suggest that PrEP can be effective for both men and women at risk for HIV infection,” Liu says. “People who take PrEP consistently are able to achieve higher levels of protection. Medication adherence (taking the pill regularly) appears to be an important factor.” Further studies are needed, and several are ongoing. For now, here’s a general summary of the results we do have:
iPreX: This study looked at Truvada as PrEP among men who have sex with men and trans women. “The overall protection was around 42 percent,” explains Mayer, “meaning that among all the participants receiving PrEP there were 42 percent fewer HIV infections than in the participants receiving placebo. However, not everyone receiving PrEP was taking it correctly. Hair and blood tests for Truvada could tell the researchers who was taking it. And it turned out that most of the infections in the group receiving Truvada were, in fact, in participants with negative hair and blood samples—in other words, participants who were not taking the medication correctly. When [researchers] compared the number of new HIV infections in the group who were not only receiving PrEP, but also taking it correctly, the efficacy rose to 92 percent This is a fantastic result, when you compare it to condoms being 90 to 95 percent effective at stopping HIV transmission.”
Partners PrEP and TDF2: These were among heterosexual couples in which one partner was positive for HIV and the other was negative for the virus. “In both studies, HIV protection was strong in men and women [who took the pills consistently],” Baeten says. TDF2 involved Truvada. In Partners PrEP, some participants received Truvada, some got only Viread (tenofovir, which is one component of Truvada), and some placebo. The best results—73 percent fewer infections—were among the Truvada arm.
CAPRISA 004: This was a vaginal microbicide study of a topical tenofovir gel. Depending on how you crunch the data and during what time period, it offered between 50 and 35 percent reduction. But it’s a gel, and therefore difficult to compare with oral Truvada as PrEP.
Fem-PrEP: This involved Truvada pills as PrEP for women. It was stopped because it was not offering protection. However, only a minority of participants took the meds as directed, so no firm conclusions could be drawn.
VOICE: This study, among women, has many components. The tenofovir gel study was stopped because of a lack of efficacy. (It seems that tenofovir by itself doesn’t work as well as Truvada, which is tenofovir plus emtricitabine.) The Truvada pill component of the study is still going on. Many women across the globe are not in relationships in which they can force their partners to wear condoms—or to be monogamous. A prophylaxis in the form of a pill or gel would arm these women with valuable protection.
Were there any caveats or strings attached to the FDA approval?
“As part of PrEP, HIV-uninfected individuals who are at high risk will need to take Truvada daily to lower their chances of becoming infected with HIV should they be exposed to the virus,” the FDA said. “Truvada for PrEP is meant to be used as part of a comprehensive HIV prevention plan that includes risk reduction counseling, consistent and correct condom use, regular HIV testing, and screening for and treatment of other sexually transmitted infections. Truvada is not a substitute for safer-sex practices.”
As part of its approval requirement, Gilead will provide a medication guide along with training and education for health care providers. Specifically, it will address the issues of drug resistance along with the potential dangers for people living with hepatitis B (tenofovir and emtricitabine also work against hep B, and for this population, the meds can cause serious liver problems if not taken as directed). In addition, Gilead will study women who become pregnant while taking Truvada for PrEP. And the company will provide vouchers for free condoms and testing for HIV and hep B. For more info, see the AIDSmeds article “FDA Approves Truvada as PrEP.”
What are the next steps, now that Truvada as PrEP has been approved?
“The immediate next steps,” Baeten says, “are understanding who will take it, who is interested, who starts it, who continues to take it, who takes it with high adherence. Because each of those steps will determine how big of an impact PrEP will have in preventing HIV.”
Liu underscores an obvious point: “It’s important to remember that PrEP should be taken under the care of a clinician.”
If you think you’re a candidate for Truvada as PrEP, talk to your health care provider or local AIDS service organization for more info (you can locate one near you on the POZ Health Services Directory). Also keep your eyes on AIDSmeds for information regarding PrEP demonstration projects—programs to study PrEP in different geographic areas and communities, which may potentially offer Truvada free of charge.
“Matching PrEP to the right patient and appropriate monitoring will be, in my opinion, key to making PrEP a success in the real world,” says Mayer, adding that it’s also important for everyone taking PrEP to be screened for HIV and hepatitis B before starting. PrEP also requires that health care providers monitor blood work, urine samples and HIV and STI tests every three to six months. “That might be a challenging model for primary care providers to adopt,” Mayer acknowledges, “but I think being cautious at this preliminary stage is appropriate. We really want to keep an eye on our patients to make sure we’re not causing more harm than benefit as PrEP rolls out.”
Editor's note: Following the publication of this article, data from the Fem-PrEP clinical trial indicated a few cases of resistance to the emtricitavine among some women who became infected with HIV while prescribed Truvada in the study.
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Search: Pre-exposure prophylaxis, PrEP, Albert Liu, Jared Baeten, Gal Mayer, MSM, gay, bisexual, truvada, tenofovir, emtricitabine
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