September 23, 2012
Stribild (elvitegravir/cobicistat/emtricitabine/tenofovir) performs similarly among people over 50 years old as with younger people, according to the results of a two-study sub-analysis presented at ICAAC 2012. The presentation marks part of an emerging trend in research that reflects the aging of the HIV-infected population in the U.S., and the need for more studies on antiretrovirals specifically within older groups.
The parent study of this presentation was a 48-week snapshot analysis looking at data from three pre-approval trials. It showed that, in terms of virologic suppression (defined here as a viral load below 50 copies/mL) and tolerability in treatment-naive patients, Stribild was easily non-inferior to Atripla (efavirenz/tenofovir/emtricitabine) as well as a regimen comprised of ritonavir (Norvir)-boosted atazanavir (Reyataz) and Truvada (tenofovir/emtricitabine).
This sub-analysis looked at data from two of the same studies at 48 weeks, but specifically compared Stribild's safety and efficacy among people over 50 against those who were younger. The first study (study 102) followed 49 HIV-infected, treatment-naive individuals over 50 years old and 299 under 50 who were started on Stribild. The second study (study 103) followed 50 HIV-infected, treatment-naive individuals over 50 years old and 305 under 50 years old who started on Stribild.
Overall, people over 50 did well on Stribild, showing high rates of virologic suppression (86% in study 102 and 94% in study 103), which were similar to that of participants under 50 (88% in study 102 and 89% in study 103). Average CD4+ cell count gains were lower in the over-50 group (199 cells/mm3 in study 102 and 176 cells/mm3 in study 103) than in the under-50 group (246 cells/mm3 in study 102 and 212 cells/mm3 in study 103), but this difference is not atypical when comparing CD4+ cell gains between older and younger patients in general.
In terms of adverse events, the over-50 group reported a trend toward a reduced rate of events compared to the under-50 group. The difference extended to several types of events, including diarrhea (8% in the over-50 group vs. 25% in the under-50 group), nausea (14% vs. 22%), abnormal dreams (14% vs. 15%), fatigue (10% vs. 12%), insomnia (4% vs. 9%), depression (4% vs. 10%), dizziness (4% vs. 7%) and rash (4% vs. 7%). However, among these complications, the only statistically significant difference was for diarrhea (P = .006). Upper respiratory infection and headache rates were the same for both groups (14%).
In study 102, a higher rate of those in the over-50 group than the under-50 group discontinued treatment (6.1% vs. 3.3%). By contrast, in study 103, the over-50 group had a lower rate of discontinuation (2.1% vs. 3.9%).
When comparing changes in lipid values, there were similar median increases of total, LDL and HDL cholesterol levels among both age groups in study 103 while on Stribild.
Warren Tong is the research editor for TheBody.com and TheBodyPRO.com.
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