In well-suppressed, treatment-experienced adults with HIV, decreasing the dose of ritonavir-boosted darunavir (darunavir/r) from the standard dose is associated with a high rate of virologic suppression and was found to be safe over a 48-week period, according to research published in the Journal of Antimicrobial Chemotherapy.
Once-daily darunavir/r at a dose of 800 mg/100 mg is effective for both treatment-naive individuals and those who have used other therapies but who do not harbor darunavir resistance-associated mutations (RAMs). It also has a better tolerability profile than ritonavir-boosted atazanavir. In this study, the authors investigated the use of a lower dose of darunavir (400 mg) in combination with ritonavir in well-suppressed patients who are currently being treated with a standard dose of once-daily darunavir/r plus 2 nucleoside reverse transcriptase inhibitors (NRTIs).
The cohort included 100 HIV-1-infected adults without darunavir or NRTI RAMs and a plasma HIV RNA level 50 copies/mL who received once-daily darunavir/r (800/100 mg) for 12 or more months and 2 NRTIs for 6 or more months, and their regimen was then changed to darunavir/r 400 mg/100 mg with the same NRTIs.
At week 48, 87 out of 95 patients (5 were excluded from the analysis) maintained a plasma HIV RNA level <50 copies/mL, and the success rate of reduced-dose therapy was 91.6% (95% CI, 84.1%-96.3%). A moderate increase in median CD4 cell count of 40 cells/mm3 was noted from baseline to week 48 (P= 0.049).
A randomized trial evaluating reduced-dose darunavir is currently ongoing, and “should this trial confirm our findings, this strategy could lead to significant savings for second-line therapy in low- and middle-income countries,” wrote the authors.
Molina J-M, Gallien S, Chaix M-L, et al; on behalf of the ANRS 165 Darulight Study Group. Low-dose ritonavir-boosted darunavir in virologically suppressed HIV-1-infected adults: an open-label trial (ANRS 165 Darulight) [published online June 1, 2018]. J Antimicrob Chemother. doi: 10.1093/jac/dky181