Purpose: To determine the long-term efficacy of a simplification strategy in the clinical setting when used to improve adherence.
Method: Prospective study of 70 patients included in a regimen with ddI plus 3TC plus an NNRTI, after viral suppression with a PI-containing regimen, due to decreasing adherence. Adherence to PI was calculated as the percentage of doses taken last week before inclusion, and patients were stratified as high and low adherence (95% and <95% of doses).
Results: Overall, 19 patients (27%) related adherence to PI <95% at inclusion (6 patients [9%], with adherence <80%). Mean adherence improved, with only 8% of patients presenting values <95%. At 104 weeks, 88% of patients on therapy had viral load suppression, but only 43% by ITT analysis. The main cause of therapy change or withdrawal was toxicity or drug interactions (26%). Notably, 16% of patients were lost to follow-up or left therapy, especially in the group of initially low adherent (26% vs. 12%, p = .02).
Conclusion: The use of a simplification strategy could be associated with long-term high risk of treatment failure, when used to improve adherence in the clinical setting.