Background HIV Incidence in PURPOSE 1 and 2 PrEP Trials

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Clinical Trials

Background:

• Pre-exposure prophylaxis (PrEP) is a key HIV prevention strategy.
• Evaluating new HIV prevention methods requires robust comparators.
• Placebo arms in prevention trials raise ethical concerns.

Purpose of the Study:

• To assess background HIV incidence (bHIV) in relation to oral PrEP use with low adherence.
• To determine the suitability of bHIV as a comparator in HIV prevention trials.
• To support ethical and efficient evaluation of novel HIV prevention strategies.

Main Methods:

• Analysis of HIV incidence data from the PURPOSE 1 and 2 clinical trials.
• Comparison of HIV incidence rates between low-adherence oral PrEP users and background incidence.
• Statistical evaluation of bHIV as a conservative comparator.

Main Results:

• HIV incidence among low-adherence oral PrEP users in PURPOSE 1 and 2 closely matched or slightly exceeded bHIV.
• This indicates that bHIV is a conservative and appropriate comparator.
• The findings validate the use of bHIV in lieu of placebo arms.

Conclusions:

• Background HIV incidence serves as a valid and conservative comparator in PrEP trials.
• Utilizing bHIV enables more ethical and efficient clinical trials for new HIV prevention strategies.
• This approach streamlines the evaluation process, potentially accelerating the availability of effective interventions.