Pooled resistance analyses of darunavir once-daily regimens and formulations across 10 clinical studies of treatment-naïve and treatment-experienced patients with human immunodeficiency virus-1 infection.

Background: The efficacy and high barrier to resistance of darunavir have been demonstrated across diverse populations with HIV-1 infection.

Objective: To evaluate post-baseline resistance among patients in studies of once-daily (QD) darunavir-based regimens and formulations.

Methods: The analysis included treatment-naïve and virologically failing or suppressed patients from 10 phase 2/3 studies (48-192 weeks in duration) of boosted darunavir 800 mg QD-based regimens. Three were phase 3 studies of the QD darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg single-tablet regimen. Post-baseline resistance was evaluated upon protocol-defined virologic failure (PDVF). Resistance-associated mutations (RAMs) were identified using International Antiviral Society-USA mutation lists. Phenotypic analyses varied across studies.

Results: Overall, 250 of 3635 patients in the analysis met PDVF criteria; 205 had post-baseline genotypes/phenotypes. In total, four (0.1%) patients developed (or had identified) ≥1 darunavir and/or primary protease inhibitor (PI) RAM; only one (<0.1%) patient (with prior lopinavir virologic failure) lost darunavir phenotypic susceptibility. Among 3317 patients using nucleos(t)ide reverse transcriptase inhibitors (N[t]RTIs; mostly emtricitabine and tenofovir), 13 (0.4%) had ≥1 N(t)RTI RAM (10 with M184I/V). Among patients receiving D/C/F/TAF ( = 1949), none had post-baseline darunavir, primary PI, or tenofovir RAMs; only two (0.1%) patients developed an emtricitabine RAM, M184V/I.

Conclusions: Across a large, diverse population using darunavir 800 mg QD-based regimens and formulations, resistance development remains rare. After clinical trials that span >10 years, loss of phenotypic susceptibility to darunavir was only observed once in a PI-experienced patient and has never been observed in treatment-naïve patients, treatment-experienced PI-naïve patients, or treatment-experienced virologically suppressed patients.