Tenofovir to Prevent HIV Infection in Western China: Pragmatic Randomized Controlled Trial

Area of Science:

• Public Health
• Infectious Disease Epidemiology
• Clinical Pharmacology

Background:

• Pre-exposure prophylaxis (PrEP) is crucial for HIV prevention, yet optimizing regimens and minimizing adverse effects remain key considerations.
• While combination therapies are common, the efficacy and safety of tenofovir disoproxil fumarate (TDF) alone for PrEP require further evaluation, particularly regarding optimal dosing strategies.
• Existing PrEP trials often use daily dosing, but alternative regimens like event-driven prophylaxis warrant investigation for improved adherence and reduced drug exposure.

Purpose of the Study:

• To systematically evaluate the preventive efficacy and safety of TDF-based PrEP in the Chinese population.
• To explore medication compliance, behavioral changes, and HIV infection risk factors associated with TDF-based PrEP.
• To compare the effectiveness of daily versus event-driven TDF dosing regimens for HIV prevention.

Main Methods:

• A pragmatic randomized controlled trial (RCT) involving 1914 participants assigned to daily TDF, event-driven TDF, or a control group.
• Primary outcomes assessed the effectiveness and safety of TDF, while secondary outcomes focused on efficacy with good medication compliance.
• Tertiary outcomes included analysis of HIV infection risk factors and behavioral changes throughout the study period.

Main Results:

• No significant difference in HIV seroconversion rates was observed between daily TDF, event-driven TDF, and control groups.
• Post hoc analysis revealed that good medication compliance reduced HIV infection risk by 53%, with event-driven dosing and good compliance reducing risk by 62%.
• Low adherence, sexual role, inconsistent condom use, and a higher number of sexual partners were significant risk factors for HIV infection.

Conclusions:

• TDF-based PrEP is ineffective for HIV prevention without consistent medication adherence.
• Event-driven dosing of TDF is recommended as an optimal PrEP regimen when high medication compliance is achieved.
• Adherence remains a critical factor for the success of TDF-based PrEP, highlighting the need for adherence support interventions.