This page provides an independent statistical analysis and educational interpretation of publicly reported results. ClinicalTrials.gov provides the official trial registry record.
1. Trial at a Glance
IPERGAY was a phase 3 randomized, quadruple-masked, parallel-design prevention trial evaluating on-demand antiretroviral pre-exposure prophylaxis for HIV infection.
| Feature | IPERGAY |
|---|---|
| Condition | HIV Infection |
| Primary purpose | Prevention |
| Allocation | Randomized |
| Design model | Parallel |
| Masking | Quadruple |
| Lead sponsor | ANRS, Emerging Infectious Diseases |
2. Clinical Question
Population
Men who have sex with men evaluated for prevention of HIV infection.
Intervention
Truvada (drug).
Comparator
Placebo (drug).
Primary Question
Does on-demand antiretroviral pre-exposure prophylaxis affect the occurrence of HIV-1 or HIV-2 infection?
3. Trial Design
Randomization
Participants were assigned using a randomized allocation.
Masking
The trial used quadruple masking.
Study Arms
The trial included two intervention arms: Truvada and placebo.
Follow-up
The trial end date was set by the scientific committee when the necessary number of primary endpoints had been reached without exceeding 5 years of follow-up.
4. Endpoints
| Endpoint | Definition | Time Frame |
|---|---|---|
| Contamination with HIV-1 or -2 | First diagnostic proof of infection: positive HIV serum test using combined latest-generation tests HIV-1 + 2 or positive HIV-1-RNA Polymerase Chain Reaction (PCR) in plasma. | From randomization to the end of the trial. The trial end date was set by the scientific committee when the necessary number of primary endpoints had been reached without exceeding 5 years of follow-up. |
5. Planned Analysis
The registry identifies contamination with HIV-1 or HIV-2 as the primary endpoint but does not report posted statistical analyses or trial results.
For a randomized prevention trial with an infection endpoint, the statistical analysis would typically compare the incidence of infection between randomized groups using methods appropriate for time-to-event or risk-based outcomes. The choice of analysis depends on the prespecified statistical analysis plan, including event definitions, follow-up structure, censoring rules, and hypothesis framework.
6. Statistical Methodology
The key statistical principle in this trial is the randomized comparison of infection outcomes between two groups. Randomization creates the framework for estimating the effect of the intervention while balancing measured and unmeasured factors on average.
Event-based analysis
The primary outcome is an infection event. Analyses of this type commonly focus on the difference in infection occurrence between randomized groups over follow-up, accounting for the timing of events and participants who do not experience infection during observation.
7. Statistical Methods Explained
Why is randomization important?
Randomization allows the comparison between intervention and placebo groups to be interpreted as a comparison created by the study design rather than by participant selection.
Why does the endpoint definition matter?
The primary endpoint depends on a specific diagnostic confirmation of HIV-1 or HIV-2 infection. Clear endpoint definitions prevent inconsistent classification of outcomes.
Why is follow-up time important?
Prevention trials measure events occurring over time. The length and structure of follow-up determine how much information is available for statistical comparison.
What does a confidence interval provide?
A confidence interval describes uncertainty around an estimated treatment effect. It does not describe the outcomes of individual participants.
Why are p-values not enough?
A p-value addresses compatibility of the observed data with a statistical model and null hypothesis. It does not measure clinical importance or the size of an effect.
8. Limitations
- The registry does not report posted statistical analyses, effect estimates, confidence intervals, or p-values.
- The ClinicalTrials.gov record does not report subgroup analyses, baseline characteristics, or safety results by arm.
- The registry does not provide details of missing-data handling, interim analyses, multiplicity procedures, stratification factors, or Bayesian methods.
- Interpretation of prevention outcomes depends on the prespecified statistical analysis plan and complete follow-up information.
9. Why This Trial Matters Statistically
| Concept | How it appears in IPERGAY |
|---|---|
| Randomized design | Randomized comparison of Truvada and placebo. |
| Blinding | Quadruple masking. |
| Binary clinical outcome | HIV-1 or HIV-2 infection as the primary endpoint. |
| Prevention trial methodology | Evaluation of infection occurrence over follow-up. |