Objectives
In VOICE, a phase IIB trial of daily oral and vaginal tenofovir for HIV prevention, ≥50% of women receiving active products had undetectable tenofovir in all plasma samples tested. MTN-003D, an ancillary study using in-depth interviews (IDIs) and focus group discussions (FGDs), together with retrospective disclosure of plasma tenofovir pharmacokinetic (PK) results, explored adherence challenges during VOICE.
Methods
We systematically recruited participants with PK data (median 6 plasma samples), categorized as low (0%, N=79), inconsistent (1%-74%, N=28), or high (≥75%; N=20) based on frequency of tenofovir detection. Following disclosure of PK results, reactions were captured and adherence challenges systematically elicited; IDIs and FGDs were audio-recorded, transcribed, coded, and thematically analyzed.
Results
We interviewed 127 participants from South Africa, Uganda, and Zimbabwe. The most common reactions to PK results included surprise (41%; low PK), acceptance (39%; inconsistent PK), and happiness (65%; high PK). Based on participants’ explanations, we developed a typology of adherence patterns: noninitiation, discontinuation, misimplementation (resulting from visit-driven use, variable taking, modified dosing or regimen), and adherence. Fear of product side effects/harm was a frequent concern, fueled by stories shared among participants. Although women with high PK levels reported similar concerns, several described strategies to overcome challenges. Women at all PK levels suggested real-time drug monitoring and feedback to improve adherence and reporting.
Conclusions
Retrospective provision of PK results seemingly promoted candid discussions around nonadherence and study participation. The effect of real-time drug monitoring and feedback on adherence and accuracy of reporting should be evaluated in trials.