Patient compliance and drug failure in protease inhibitor monotherapy

To the Editor. —We conducted a 2-dose study of saquinavir in which 40 human immunodeficiency virus type 1 (HIV-1)positive patients received either three or six 200-mg capsules of saquinavir (Roche Products, Welwyn, United Kingdom) 6 times daily (total dose, 3600 mg/d or 7200 mg/d).1Analysis of an early cohort of patients enrolled in the study demonstrated that the duration of the response as measured by HIV-1 plasma RNA copy number varied widely within the 2 groups. This variation was not accounted for by the development of resistant mutations alone. To investigate whether decreased patient compliance with this intensive regimen could explain the observed variation in viral responses, we monitored drug-taking behavior in the remaining patients on their enrollment into the high-dose group for the initial 24 weeks of therapy using medication container closures or caps that record the precise date and time of the opening and closing of the