In the Carraguard vaginal gel efficacy trial, product adherence was assessed through self-reports, counting returned applicators and a staining test that was meant to show which applicators had been vaginally inserted [7], [8], [9].
This counter-intuitive result suggests that participants who consistently report 100% product adherence are, in fact, likely to be over-reporting adherence.
One study showed product adherence was more difficult for women whose partners were not aware of their participation and product use (Sahin-Hodoglugil et al., 2006).
In the FEM-PrEP trial, product adherence was too low to assess the efficacy of daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC, Truvada) in preventing HIV acquisition in the study population [ 5].
Although higher rates of study product adherence were observed among women enrolled in the Botswana TDF2 PrEP trial [ 14], as well as those in the Partners PrEP trial [ 10], some have suggested that low study product uptake and use in trials may signal regional differences in the acceptability of drug delivery strategies used (eg, pills, gel, ring).
Understanding the relative contribution of cultural and community perspectives on clinical trials and biomedical agents to low study product uptake and adherence is critically important in setting agendas for ongoing and future research [ 31].
Although we recognize these concerns, we simply do not yet know whether open-label PrEP adherence will show patterns similar to those seen in blinded RCTs, or whether determinants of study product adherence will be generalizable to individuals who are seeking out and opting to use open-label PrEP as a prevention strategy.
Study product adherence has been cited as an important factor in the mixed results seen in recent antiretroviral (ARV -based microbicide ARV -basedevention trials.
One factor that influences adherence is the ability of trial participants to attend regular clinic visits at which trial products are dispensed, adherence counseling is administered, and participant safety is monitored.
Poor adherence is understandable.
