Effects of antiretroviral combination therapies F/TAF, E/C/F/TAF and R/F/TAF on insulin resistance in healthy volunteers: the TAF-IR Study.

BACKGROUND: Increased insulin resistance (IR), associated with specific antiretroviral drugs or drug classes, is an established risk factor for type 2 diabetes in HIV patients, ultimately increasing morbidity and mortality. To date, data on the risk of IR in tenofovir alafenamide (TAF)-based protocols are unavailable. METHODS: This prospective randomized, open-label study evaluated the effects of IR on 30 healthy volunteers receiving fixed-dose combinations (FDCs) of emtricitabine/tenofovir alafenamide (F/TAF), elvitegravir/cobicistat/emtricitabine/tenofovir alafenamide (E/C/F/TAF) or rilpivirine/emtricitabine/tenofovir alafenamide (R/F/TAF). IR was measured before and after 14-day treatments using the hyperinsulinemic-euglycaemic clamp technique (HEGC). Changes in IR in each group were evaluated using the mean glucose disposal rate, normalized with body weight (MBW [mg glucose/(min×kg)]). RESULTS: A total of 30 subjects underwent randomization: one subject in the F/TAF arm withdrew consent after randomization and one in the R/F/TAF arm had to be excluded because of technical failure during HEGC, resulting in 28 subjects in the per-protocol population (F/TAF, n=9 subjects; E/C/F/TAF, n=10 subjects; R/F/TAF n=9 subjects). No significant differences were detected on the baseline characteristics. IR did not differ among the groups before treatment. None of the studied antiretroviral combinations resulted in a significant change in IR after 14 days compared with baseline values, as measured by MBW (F/TAF, 11.42 ±3.04 mean [±sd] versus 11.43 ±3.23, P=0.49; E/C/F/TAF, 10.04 ±2.49 versus 10.95 ±4.26, P=0.30; R/F/TAF, 11.03 ±1.96 versus 13.01 ±4.11, P=0.13). CONCLUSIONS: Short-term treatment for F/TAF, E/C/F/TAF or R/F/TAF did not increase IR in healthy male volunteers.

When food can make the difference: The case of elvitegravir-based co-formulation.

Stribild should be administered under fed conditions to optimize drugs exposure. Here we assessed to what extent this advice is applied in the real life scenario by therapeutic drug monitoring in 75 HIV-infected patients given Stribild-based antiretroviral therapy. Fifty-three percent of our patients took Stribild at lunch/supper time, 23% in the morning with breakfast, and 24% middle in the morning or late in the evening. Twelve out of the 75 patients had unquantifiable elvitegravir concentrations, whereas in the remaining the levels were largely distributed. Wide inter-individual variability in the tenofovir, cobicistat and darunavir trough concentrations was also observed. In real life settings a significant proportion of patients took Stribild without food, namely in the mid-morning or late in the evening. This resulted in a wide inter-individual variability of antiretroviral drug trough concentrations. To avoid the risk for patients to experience suboptimal drug exposure, it is important that health professionals more convincingly advise their patients to take Stribild in fed conditions. On the other hand, the role of patient education and patient responsibility to correctly take the therapy should not be underestimated.

Pharmacokinetics of Co-Formulated Elvitegravir/Cobicistat/Emtricitabine/Tenofovir Disoproxil Fumarate After Switch From Efavirenz/Emtricitabine/Tenofovir Disoproxil Fumarate in Healthy Subjects.

BACKGROUND: Elvitegravir (EVG), a HIV integrase inhibitor, is metabolized primarily by CYP3A, and secondarily by UGT1A1/3; Efavirenz (EFV), a HIV non-nucleoside reverse transcriptase inhibitor, is metabolized by Cytochrome P450 (CYP) 2B6 and induces CYP3A and uridine diphosphate glucuronosyltransferase (UGT) with residual effects post discontinuation because of long T1/2 (40-55 hours). This study evaluated the pharmacokinetics after switching from efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF) to elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF). METHODS: Healthy subjects (n = 32 including n = 8 CYP2B6 poor metabolizers) received EVG/COBI/FTC/TDF (150/150/200/300 mg) on days 1-7, and after a washout, received EFV/FTC/TDF (600/200/300 mg) on days 15-28 and switched to EVG/COBI/FTC/TDF (150/150/200/300 mg) for 5 weeks (days 29-62). Pharmacokinetic assessments occurred on days 7, 28, 35, and 42; trough samples (Ctrough) were collected periodically until day 63. Safety was assessed throughout the study. RESULTS: Twenty-nine subjects completed with 3 adverse events leading to discontinuation; no grade ≥3 adverse events were reported. Post-EFV/FTC/TDF, mean EVG area under concentration (AUCtau) was 37% and 29% lower and mean Ctrough ∼3- and ∼5-fold above IC95, respectively, on days 35 and 42, and 7-8-fold above IC95 by 5 weeks. COBI AUCtau returned to normal by day 42. EVG glucuronide, GS-9200, AUCtau was higher (46% and 32% on days 35 and 42, respectively) postswitch. CYP2B6 poor metabolizers displayed higher EFV AUCtau and Cmax (125% and 91%, respectively) versus non-poor metabolizers, and lower EVG and COBI exposures. EFV Ctrough was >IC90 (10 ng/mL) in all subjects postswitch. FTC and tenofovir (TFV) exposures were unaffected. CONCLUSIONS: After EFV/FTC/TDF to EVG/COBI/FTC/TDF switch, EVG and/or EFV exposures were in an active range. These findings support further evaluation of switching regimens in HIV-1 patients.

Pharmacokinetic and bioequivalence evaluation of single-tablet and separate-tablet regimens for once-daily cobicistat-boosted elvitegravir in healthy Japanese male subjects: A randomized, two-way crossover study.

This randomized, two-way crossover study evaluated the bioavailability of elvitegravir administered as the new individual tablet containing 150 mg and a cobicistat 150 mg tablet, concomitantly with a fixed-dose combination tablet containing 200 mg of emtricitabine and 300 mg of tenofovir disoproxil fumarate (EVG + COBI + FTC/TDF), in comparison with a single-tablet regimen containing the same dose of each component (EVG/COBI/FTC/TDF). Twenty-four healthy Japanese male subjects received the two different elvitegravir treatments, the separate-tablet or single-tablet regimen, once-daily for 10 days in each. The pharmacokinetic parameters (Cmax , AUCtau , and Ctau ) of elvitegravir were investigated at Day 10 after each treatment, together with safety and tolerability. Relative to EVG/COBI/FTC/TDF, the geometric least-squares mean ratios (GMR) and 90% confidence intervals (CIs) for elvitegravir Cmax and AUCtau were within the boundary of 0.8-1.25, while the upper limit of the 90% CI of GMR for Ctau was narrowly below the lack of bioequivalence boundary (0.79). No deaths, serious AEs, or drug-related AEs occurred. In conclusion, Cmax and AUCtau of elvitegravir met the strict definition of bioequivalence, indicating that the two regimens were essentially bioequivalent. Treatment with both regimens for 10 days appeared to be safe and well tolerated.