Background: Previous studies (FOTO, BREATHER) have given encouraging results with a 5/7days efavirenz-based maintenance regimen. Based on pilot experience (Leibowitch, FASEBJ-2015), we conducted a 48-week multicenter, open-label, single-arm prospective study evaluating efficacy and safety of a 4/7days maintenance therapy in HIV infected patients with controlled VL.
Methods: The main inclusion criteria were age>18 years; current regimen with 2 nucleoside analogs and either a boosted protease inhibitor PI/r or a NNRTI; no treatment modification in the last 6 months; VL< 50 c/ml for at least one year; no resistance mutation to the drugs in current regimen. Maintenance therapy used the same regimen, taken 4 consecutive days of each week. Virological failure (VF) was defined as VL>50 c/ml confirmed within 4 weeks between D0-W48. Patients were evaluated at D0, W4, W8, W12, W16, W24, W32, W40, and W48. The study was designed to show that the efficacy of the strategy >80%, assuming a success rate > 90%, with a power of 87% and a 5% type-one error. Values are presented as median [range]. Adherence to therapy was assessed by questionnaires, pill count, drug concentrations, and MEMS caps for a subgroup of patients.
Results: One hundred patients were included in the study, 82 men and 18 women, median age 47[25-75], CD4 nadir 282[7-1044] cells/µl, and receiving ARV therapy since 5.1[1.3-25.2] years with VL< 50 since 4.1[0.5-15.5] years. Current regimen included tenofovir-DF+FTC (89 patients) or abacavir+3TC (11 patients), combined with a PI/r for 29 (lopinavir/r:1, atazanavir/r:13, darunavir/r:15) or a NNRTI for 71 (EFV:41, RPV:25, ETV:5). After 48 weeks, 96% [95%CI 90-98, Kaplan-Meier estimate] were still under maintenance 4/7days regimen without failure; 1 patient returned to 7/7 regimen and left the study at W4, VF was confirmed in 3/100 patients at W4, W8, W40, with VL 785, 124, and 969 c/ml respectively. These 3 patients returned to 7/7 regimen and VL was subsequently suppressed in all 3.
Conclusions: Over 48 weeks, maintenance ARV therapy with a 4 days a week regimen was effective in these patients with suppressed VL under 2 nucleosides and either a PI/r or a NNRTI, resulting in a success rate of 96%.

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