Darunavir has a high genetic barrier to resistance. Across a diverse population of HIV-1-infected subjects treated with darunavir 800 mg QD regimens, the development of darunavir resistance was rare (<0.1%).

(2020) 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,

BackgroundRapid initiation of ART requires that clinicians start therapy prior to having baseline laboratory Results. High rates of virologic suppression and retention were reported in the DIAMOND trial. Efficacy and safety are presented, according to baseline disease characteristics.MethodsDIAMOND (ClinicalTrials.gov: NCT03227861), a phase 3, single-arm, open-label, prospective, multicenter study, assessed efficacy/safety of D/C/F/TAF in rapid initiation. Adults enrolled within 14 days of diagnosis and started D/C/F/TAF without baseline laboratory results; investigators reviewed results as they became available. Primary endpoint was virologic suppression (HIV-1 RNA < 50 copies[c]/mL; intent-to-treat (ITT); Food and Drug Administration [FDA] snapshot) at Week 48. Virologic suppression <50 c/mL and <200 c/mL were also assessed via an observed analysis, excluding patients with missing data.ResultsOverall, 109 patients were enrolled; 25% had HIV-1 RNA ≥100,000 c/mL and 21% had CD4+ < 200 cells/μL (Table 1). 21% of patients started therapy within 24 hours of diagnosis. At Week 48, 84%, and 88% of patients had HIV-1 RNA <50 c/mL and <200 c/mL (FDA snapshot), respectively. In the observed analysis, 96% and 100% of patients had HIV-1 RNA <50 c/mL and <200 c/mL, respectively, at Week 48. Earlier ART initiation, HIV-1 RNA <100,000 c/mL, and CD4+ >200 cells/μLwere associated with numerically higher virologic suppression rates (ITT-FDA snapshot; Table 2). No patient discontinued due to lack of efficacy or met protocol-defined virologic failure (PDVF) criteria. In the observed analysis, virologic suppression rates were consistent across all subgroups; all patients were suppressed <200 c/mL at Week 48. One patient discontinued due to an adverse event (AE); incidences of grade 3/4 (10%) and serious (9%) AEs were low, with no serious AEs related to study drug and no deaths.ConclusionIn the first phase 3 study of an STR in a rapid initiation model, no patients rapidly starting D/C/F/TAF discontinued therapy due to lack of efficacy or had PDVF through 48 weeks. High rates of virologic suppression were achieved and maintained with a variety of baseline characteristics, and treatment was safe and well tolerated, indicating D/C/F/TAF as a preferred ART option for patients rapidly starting treatment. Disclosures All Authors: No reported Disclosures.

Gastrointestinal intolerance has been associated with ritonavir-boosted protease inhibitors. This post hoc analysis evaluated gastrointestinal adverse events of interest (AEOIs; diarrhea, nausea, abdominal discomfort, flatulence [MedDRAv21]) through Wk96 among patients enrolled in the phase 3 AMBER (treatment-naïve) and EMERALD (virologically suppressed) studies of darunavir/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg. 362 and 763 patients initiated D/C/F/TAF in AMBER and EMERALD, respectively. All D/C/F/TAF-related gastrointestinal AEOIs were grade 1/2 in severity; none were serious. Across studies, incidence of D/C/F/TAF-related diarrhea and nausea were each ≤5% in Wk1 (≤1% post-Wk2); prevalence of each decreased to <5% post-Wk2. In each study, there was 1 case of D/C/F/TAF-related abdominal discomfort during Wk1 and none thereafter. Incidence of D/C/F/TAF-related flatulence was <1% throughout. Median duration of D/C/F/TAF-related gastrointestinal AEOIs was 16.5 (AMBER) and 8.5 (EMERALD) days. In conclusion, in treatment-naïve and virologically suppressed patients, incidences and prevalences of D/C/F/TAF-related gastrointestinal AEOIs were low and tended to present early.

BackgroundDRV has demonstrated high efficacy and barrier to resistance development across diverse populations, from TN to heavily TE patients. We evaluated resistance data from 10 clinical studies of different DRV 800 mg QD–based antiretroviral regimens and formulations.MethodsThe analysis included patients from 10 phase 2/3 studies (48–192 weeks in duration) of ritonavir- and cobicistat-boosted DRV 800 mg QD–based regimens in TN and virologically failing or suppressed TE patients with HIV-1 (table). Three were phase 3 studies of the DRV/cobicistat/emtricitabine/tenofovir alafenamide (D/C/F/TAF) 800/150/200/10 mg single-tablet regimen (STR). Post-baseline resistance was evaluated in patients experiencing protocol-defined virologic failure (PDVF); definitions and criteria for resistance testing varied slightly among studies. Resistance-associated mutations (RAMs) were based on respective International Antiviral Society–USA mutation lists over time.ResultsOf the 3,635 patients evaluated, 250 met PDVF criteria and 205 had post-baseline genotypes/phenotypes. Overall, 4 (0.1%) patients developed (or had identified [switch studies]) ≥1 DRV and/or primary protease inhibitor (PI) RAM (table), and only 1 (< 0.1%, ODIN) patient lost DRV phenotypic susceptibility; this TE patient had prior VF with lopinavir. Among those who used a nucleos(t)ide reverse transcriptase inhibitor (NRTI) backbone (mostly emtricitabine [FTC] + tenofovir [TFV]), 12 (0.4%) patients had ≥1 NRTI RAM, including 10 with M184I/V associated with FTC resistance. No TFV RAMs were observed. Among patients receiving D/C/F/TAF (n = 1,949), none had post-baseline DRV, primary PI, or TFV RAMs; only 2 (0.1%) patients developed an FTC RAM.ConclusionAcross a large, diverse population using DRV 800 mg QD–based regimens and formulations, resistance development remains rare; 0.1% of patients had ≥1 DRV and/or primary PI RAM post-baseline. Among 3 trials of the D/C/F/TAF STR, no patients developed a DRV or primary PI RAM. After > 10 years of investigating DRV 800 mg QD–based regimens in clinical trials, loss of phenotypic susceptibility to DRV has never been observed in TN or TE virologically suppressed patients and was only once observed in a TE patient with prior VF on multiple antiretrovirals, including a PI. Disclosures All authors: No reported disclosures.