PHILADELPHIA, PA—Switching to single-tablet co-formulated elvitegravir, cobicistat, emtricitabine, and tenofovir (EVG/COB/FTC/TDF) from a multi-tablet ritonavir-boosted protease inhibitor (PI + RTV) with emtricitabine and tenofovir DF (FTC/TDF) regimen significantly increased rates of virologic suppression and declined fasting triglycerides in patients with HIV-1 infection, results of an ongoing open-label Phase 3b study reported at IDWeek 2014.
Previously, results from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study found a higher triglyceride concentration to be “marginally independently associated with a increased risk of myocardial infarction,” noted Douglas Cunningham, DO, of Pueblo Family Physicians, Phoenix, AZ, and colleagues. One of the benefits of the ritonavir-boosted PI regimen simplification “may include improvement in fasting lipid parameters, including triglycerides,” he added.
In the STRATEGY-PI study, patients are randomized 2:1 to EVG/COB/FTC/TDF or to continue their PI + RTV + FTC/TDF regimen. The primary endpoint is proportion of patients who maintain HIV-1 RNA <50 copies/mL at Week 48; secondary endpoints are tolerability and safety of the two regimens through Week 96. Subanalysis of the effect of switching antiretroviral therapy on fasting lipids through Week 48 focused on absolute changes in fasting lipid parameters and National Cholesterol Education Program-defined changes in proportion of subjects with optimal or desirable triglyceride concentration.
Of the 433 patients enrolled, 293 were switched to EVG/COB/FTC/TDF and 140 continued PI + RTV. At screening, the distribution of PIs was atazanavir (ATV), 40%; darunavir (DRV), 40%; lopinavir (LPV), 17%; and other PIs, 3%.
At Week 48, the switch to EVG/COB/FTC/TDF maintained HIV suppression, “particularly in those switched from LPV or ATV,” Dr. Cunningham stated. High rates of virologic suppression were observed across PI subgroups, with no treatment-emergent resistance. EVG/COBI/FTC/TDF was well tolerated; small and nonprogressive increases in serum creatinine were seen but there were no cases of proximal renal tubulopathy.
“Switching to EVG/COBI/FTC/TDF versus continuation of PI + RTV resulted in statistically significant decrease from baseline in fasting triglyceride concentrations at Week 48,” Dr. Cunningham reported, which was statistically significant (P=0.001). This was “driven primarily by decreases in triglycerides when switched to EVG/COB/FTC/TDF from LPV (P=0.003) or ATV (P=0.014),” he added.
Improvements in treatment adherence, virologic outcomes, and health-related quality of life have been shown with antiretroviral therapy simplification to reduce pill burden and/or dosing frequency, researchers concluded.