Switching from twice-daily raltegravir plus tenofovir disoproxil fumarate/emtricitabine to once-daily elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate in virologically suppressed, HIV-1-infected subjects: 48 weeks data

Abstract

Background: Pill burden, dosing frequency, and concerns about safety and tolerability are important obstacles to maintaining adequate medication adherence. Raltegravir (RAL) is indicated for twice-daily dosing and when taken with emtricitabine (FTC)/tenofovir disoproxil fumarate (TDF), it becomes a twice-daily multiple-tablet regimen. Elvitegravir (EVG)/cobicistat (COBI)/FTC/TDF, STB, is the first approved once-a-day integrase strand transfer inhibitor (INSTI) containing single-tablet regimen that combines EVG, an INSTI, and COBI, a novel pharmacoenhancer, with the preferred nucleos(t)ide backbone of FTC/TDF.

Methods: This was a 48-week prospective, single-arm open-label study of the switch to STB in virologically sup-pressed HIV-1-infected adult patients on FTC/TDF and twice-daily RAL for at least 6 months. Objectives were to evaluate the tolerability and safety of a regimen simplification to once-a-day STB, while maintaining viral suppression through 48 weeks.

Results: Forty-eight individuals in the United States were enrolled. The median age was 44 years, 96% were male, and 83% were White. The median time on RAL + FTC/TDF treatment prior to enrollment was 34 months. Ninety-six percent of participants cited regimen simplification as the reason to enroll in the switch study. At base-line, the median CD4 count was 714 cell/µL and estimated glomerular filtration rate (eGFR) was 105 mL/min. At week 48, all assessed study participants remained viro-logically suppressed to the lower limit of quantification (HIV-1 RNA<50 copies/mL) and maintained high CD4 cell count (median, 751 cells/mL) and stable eGFR (median, 100.5 mL/min). STB was well tolerated with no discontinuations, no study drug-related serious adverse events, and no study drug-related grade 3/4 adverse events.

Conclusions: All participants switching to 1 tablet once-a-day STB from a twice-daily RAL + FTC/TDF regimen remained virologically suppressed. STB was well tolerated. Switching to STB may be a viable option for virologically suppressed patients wanting to simplify from a twice-daily RAL-containing regimen.

Keywords: HIV-1; antiretroviral regimen simplification; single-tablet regimen; treatment experienced.