ABSTRACT
BACKGROUND: The ability of elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) to maintain virologic suppression in participants with M184V and/or M184I resistance mutations from historical genotypic reports when switching from a tenofovir disoproxil fumarate-based or abacavir (ABC)-based regimen was investigated. SETTING: Phase IIIb, 48-week, open-label, single-arm, multicenter, clinical trial (NCT02616029). METHODS: Virologically suppressed adults with HIV and documented M184V/I on historical genotypic records switched to E/C/F/TAF from a tenofovir disoproxil fumarate-based or ABC-based regimen. The primary end point was HIV-1 RNA of <50 copies per milliliter at week 12 using pure virologic response (PVR). Secondary end points included HIV-1 RNA of <50 copies per milliliter at weeks 24/48 (PVR) and at weeks 12, 24, and 48 (Food and Drug Administration snapshot algorithm), and change in CD4+ count at weeks 12, 24, and 48. RESULTS: M184V alone was reported in 82.8% of 64 participants; 9.4% and 7.8% had M184I and M184V/I, respectively, and 43.8% had archived M184V/I (baseline DNA). All (62/62 with available data, 100%, 95% confidence interval 94.2% to 100%) participants maintained PVR at weeks 12, 24, and 48. By Food and Drug Administration snapshot algorithm, one participant had HIV-1 RNA of ≥50 copies per milliliter (week 12); confirmatory HIV-1 RNA was <50 copies per milliliter. No significant changes were observed in CD4+ cell count. Drug-related adverse events (AEs) were reported by 10 (15.6%) participants. Six (9.4%) and 5 (7.8%) participants had grade 3-4 AEs or serious AEs, respectively (none drug related). CONCLUSIONS: The presence of the resistance mutations M184V/I did not jeopardize the efficacy of switching to E/C/F/TAF in virologically suppressed adults. High rates of virologic suppression were maintained throughout 48 weeks of therapy and treatment was well tolerated.