- The DISCOVER trial assessed if F/TAF, approved as HIV treatment, can also reduce risk of acquiring HIV.
- Update: researchers say F/TAF has faster onset and longer sustained duration of HIV protection vs F/TDF.
Why this matters
- The only drug approved for HIV preexposure prophylaxis (PrEP) is F/TDF.
- F/TAF is reported to be noninferior to F/TDF as PrEP among 5387 participants.
- Randomized, double blind, safety and efficacy noninferiority trial, 92 study sites, United States, Canada, Western Europe.
- Compared HIV risk, sexually transmitted infection incidence, adherence, pharmacokinetics.
- Relationship between adherence and efficacy assessed in nested case-control study.
- Noninferiority confirmed with sensitivity analysis; incident rate ratio: 0.55 (95% CI, 0.20-1.48).
- Bayesian analysis showed a 96% (95% credible interval) probability that F/TAF is more effective than F/TDF.
- Tenofovir diphosphate levels in peripheral blood mononuclear cells were 6.3-fold higher with F/TAF vs F/TDF and achieved 90% effective concentration faster.
- 98% receiving F/TAF had intracellular drug concentrations above the threshold considered protective from HIV vs 65% receiving F/TDF.
- Estimating duration of protection with a range of trial and historic data, F/TAF provided a 60% longer duration.
- Preliminary data, no cost analysis, conference presentation without peer review.