You may have heard of post-exposure prophylaxis for HIV (PEP). This has shown some success and there are studies underway to further prove it is an effective public health measure. But planning ahead is sometimes more effective and easier than cleaning up a mess afterward. Women using vaginal Truvada gel as PrEP, pre-exposure prophylaxis, have had some success in preventing HIV transmission. PrEP is a hot topic with strong feelings on both sides of the issue.
Now comes a study concerning PrEP, taking medications to prevent catching HIV. There was a large, high quality study of MSMs (men who have sex with men) who were thought to be at high risk for catching HIV, in 11 sites in 6 countries: Peru, Ecuador, South Africa, Brazil, Thailand, and the United States. There were some transgender participants who had changed from male to female participating in the study.
The 2,499 participants were given counseling, pill counts, and condoms monthly, and either took Truvada or a placebo pill once a day, had lab tests, and had STD checks as needed. They were followed for as long as 2.8 years (average of 1.2 years). 64 of those in the placebo arm converted to HIV and 36 in the Truvada arm. Those who took the Truvada more faithfully had a higher chance of not getting HIV. Some of them got drug levels to document that they were taking they had effective amounts of the medication in their bodies.
Even though the medication was supplied by the pharmaceutical company, Gilead, they had no say on how to conduct the trial nor what to say in the published paper. Those who guessed which medication they were on, were only 50% correct in both the placebo and Truvada group; so the blinding was successful. Double blinding means that no one in contact with the subject knew if they were taking active drug or placebo. They didn’t always bring in their bottles to count pills; which makes this part of the data weaker.
Side effects occurred in small numbers: 43 patients had temporary kidney damage from the medication; 10 of them had to be taken off the drug. Only 22 subjects had nausea in the Truvada group and 10 in the placebo group. Placebos have no activity but the placebo effect (belief in the medication) can be strong. The two groups did not differ in using condoms. 2 subjects developed resistance to one of the medications in Truvada. Resistance could develop in more as more time goes by.
The study authors mention that perhaps thinking they might be on a placebo might have caused some to not take the medicine more faithfully. This study did not have women in it so the application to women is unknown.
Is the cup half full or half empty?
Project Inform, a national HIV advocacy group with very smart people, sees the study as having saved 35 people from converting over to HIV. They want people to sign a petition urging the FDA to approve and recommend using Truvada as PrEP. Preventing HIV in these will prevent transmission to others.Condom education has had its maximal effect; it is time for something new and effective.
AIDS Healthcare Foundation, the largest provider of HIV medical services in the state, nation, and world, also filled with very smart people, want others to sign a petition to the FDA with the opposite message. They feel more studies need to be done so that people won’t trade their condoms for Truvada: exchanging a wonderful prevention for a much weaker one. Also, taking a pill daily is unconnected to the sex act, whereas a condom is and therefore maybe easier to remember. They say this detailed study, as are many, represents an artificial, ideal, intensive, treatment that is not available in most real-world situations. Will the money for PrEP be taken from other prevention or treatment efforts? HIV providers can now prescribe PrEP for those few cases where the partner refuses to wear condoms, but a general recommendation is premature. How dangerous is taking this incomplete HIV medication combination, and not daily, so that in some it might cause resistance if they catch HIV?
The CDC has issued interim guidelines before the final FDA decision whether to approve Truvada for this use. It stresses that this study shows that PrEP helps somewhat in only MSMs; its safety is not proven in HIV negative people or women; it is expensive; it should be given with counseling, condoms, and periodic monitoring for side effects and STDs.
The Academy of HIV Medicine (of which many HIV specialists are members, including me) is performing a survey of HIV specialists about PrEP to see what they think about the particulars of the issue.
Conclusion: This is a well done, helpful study. It does not have all the answers. Both sides have great arguments and I understand where they are coming from. I await the opportunity to study the FDA’s opinion document and hear more on this controversy. If I see a patient in the office who’s partner won’t wear condoms, then I might consider prescribing Truvada as a PrEP. Research/Clinical Trials are expensive, and tedious, but they are invaluable in getting closer to the correct answers to important questions. I applaud the subjects who participated and the scientists who help make this huge effort happen.
These are the pertinent web pages:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm6003a1.htm?s_cid=mm6003a1_w
http://www.aidshealth.org/advocacy-policy/current-issues/prep-sign-on.html
http://projectinform.org/news/2011/032211.html
Disclaimer: I am employed by AIDS Healthcare Foundation as a part-time HIV Specialist. I have been a member and am credentialed as an HIV Specialist by the Academy. I have performed studies paid for by Gilead and have been a paid speaker and advisor, but am not connected currently. I have not signed the AHF petition. I respect Project Inform and the CDC.
By Daniel Pearce, D.O., FACOI, AAHIVMS