Switching to a Single-Tablet Combination of Rilpivirine/Emtricitabine/Tenofovir DF Improves Outcomes in Virologically Suppressed HIV-positive Patients

Presenters at the 2013 United States Conference on AIDS shared results from the SPIRIT Study during a poster session titled “SPIRIT Study: Switching to the Singlet-Tablet Regimen (STR) Rilpivirine/Emtricitabine/Tenofovir DF (RPV/FTC/TDF; Complera®) from a Ritonavir-Boosted Protease Inhibitor (PI+RTV) Regimen Maintains Virologic Suppression and Improves Patient Satisfaction.”

This is the first study to evaluate the safety and efficacy of switching from a PI+RTV-based therapy to a single daily treatment regimen, RPV/FTC/TDF. The study demonstrates that individuals treated with RPV/FTC/TDF had higher patient satisfaction, lower rates of treatment failure, lower rates of side effects, and similar control of viral loads.

It is well known that simplifying medication regimens can improve quality of life, increase medication adherence, reduce treatment failure, and often reduce long-term toxicities of drugs. With these goals in mind, the study authors sought to evaluate this simplification in the standard treatment for HIV. Researchers from several institutions and countries participated, including Kaiser Permanente, the Northwestern University Feinberg School of Medicine, University of Pennsylvania, Brighton and Sussex University Hospital in the UK, the Universitaetsklinikum Hamburg-Eppendorf in Germany, and the Chelsea and Westminster Hospital Foundation Trust in London.

This multicenter, randomized, open-label, Phase 3b study looked at patients at two endpoints: after 24 and 48 weeks of treatment. All patients were taking a stable boosted protease inhibitor plus two nucleosides for greater than six months prior to the study, and all had undetectable viral loads. They had no prior history of non-nucleoside reverse transcriptase inhibitor (NNRTI) use and no known resistance of any of the drugs in the study. Those in the treatment group took RPV/FTC/TDF; those in the control group took a boosted protease inhibitor plus nucleosides for 24 weeks, then shifted to the RPV/FTC/TDF regimen.

At 24 weeks, those in the treatment group (n=317) showed a similar percentage of individuals with undetectable viral loads as the control group (n=159), at 93.7% versus 89.9%, respectively. These levels were similar at 48 weeks of treatment with RPV/FTC/TDF (89.3%). Moreover, those treated with RPV/FTC/TDF had lower rates of treatment failure—only 0.9% for the RPV/FTC/TDF group compared to 5.0% of those on the standard medication regimen.

The researchers also analyzed the impact of the drug on side effects and other health indicators. Individuals treated with RPV/FTC/TDF showed positive changes in their fasting blood fats, total cholesterol, LDL, triglycerides and TC:HDL ratio at both 24 and 48 weeks.

The individuals on RPV/FTC/TDF also complained of fewer medication side effects. These patients had significantly lower rates of diarrhea, stomach pain, fatigue, memory problems, headache, depression, and anxiety (all p<.05). Additionally, many patients in the RPV/FTC/TDF group reported improvement of HIV symptoms, like muscle aches, weight loss, and fever, none of which improved in the control group (all p<0.5).

The researchers also tracked participants’ satisfaction with their treatments. Given the improved side effect profile and the less complicated regimen, it is perhaps not surprising that those treated with RPV/FTC/TDF reported higher satisfaction with their treatment.