Why the IPERGAY (Yes, That's Its Name) Study Could Substantially Increase Use of PrEP

Yesterday, the French IPERGAY study of intermittent pre-exposure prophylaxis (PrEP) was stopped early by the Data Safety Monitoring Board, and for the best reason -- the evidence demonstrating that it prevented HIV was overwhelming.

For those who read French, here's the official announcement. (Scroll down for the English.) And for those who can't believe the name, it stands for "Intervention Prophylactique pour Et avec les Gays". Of course.

Here's a short English version of the study: IPERGAY was a randomized trial of intermittent, "on demand" PrEP vs placebo done in high risk, HIV negative, men who have sex with men (MSM) in France and Canada. The specific strategy tested was:

  • Two tablets of tenofovir/emtricitabine (Truvada) from 2-24 hours before sex
  • One tablet 24 hours later
  • Another tablet 24 hours after that one

So a total of 4 tablets over 3 days for episodic sexual activity, with an option for daily use for more frequent exposures.

We saw the pharmacokinetic data from IPERGAY in Melbourne, which showed that this strategy generated blood levels of tenofovir highly predictive of protection, and that appears to be borne out in these results. The full study detail are not yet available, but encouragingly they are reported to be better than iPrEx (the first study of PrEP in MSM). These results, along with the PROUD trial done in Britain -- also stopped early for efficacy -- substantially strengthen the data for PrEP in MSM.

So will the results increase the prescribing of PrEP? Even though the FDA has only approved tenofovir/FTC for daily use for prevention? I say it will, and here's why:

  1. Patients have been asking about intermittent "on demand" dosing since the first day people were even thinking about PrEP.
  2. Even though iPrEx was a study of daily PrEP, it appears that many study subjects were taking it intermittently -- and still were protected if they got drug levels correlating with 4 or more pills/week.
  3. Compared with daily dosing, this IPERGAY strategy will cost less.
  4. It will also reduce drug exposure, and hence likely toxicity.
  5. No one can say "IPERGAY" without smiling. Said with a French accent, of course.

Just like this film clip (it's Monty Python week). Roll 'em!

Paul Sax is Clinical Director of Infectious Diseases at Brigham and Women's Hospital. His blog HIV and ID Observations is part of Journal Watch, where he is Editor-in-Chief of Journal Watch AIDS Clinical Care.