- Gandhi, Monica;
- Bacchetti, Peter;
- Greenblatt, Ruth;
- Grant, Robert;
- Liu, AY;
- Yang, Q;
- Huang, Y;
- Anderson, PL;
- Jin, C;
- Goggin, K;
- Stojanovski, K;
- Buchbinder, SP
Background: Pre-exposure prophylaxis (PrEP) trials using tenofovir-based regimens have demonstrated that high levels of adherence are required to evaluate efficacy; the incorporation of objective biomarkers of adherence in trial design has been essential t