Study results show that patients treated with Stribild had significantly reduced viral load and increased CD4 counts after 96 weeks, with fewer patients discontinuing treatment due to side effects.
The single-tablet regimen Stribild (STB) has greater efficacy and fewer adverse events than Atripla (ATR) in treating human immunodeficiency virus (HIV)-positive African American patients after 96 weeks of treatment, according to a recent retrospective analysis by David Hardy, MD, from the David Geffen School of Medicine at University of California, Los Angeles, and colleagues.
The findings were presented on October 4, 2013, at IDWeek 2013, a joint meeting of the Infectious Diseases Society of America (IDSA), the Society for Healthcare Epidemiology of America (SHEA), the HIV Medicine Association (HIVMA), and the Pediatric Infectious Diseases Society (PIDS), in San Francisco, CA.
A previous randomized controlled trial indicated that STB, a combination of elvitegravir, cobicistat, emtricitabine, and tenofovir DF, was as effective as ATR, a combination of efavirenz, emtricitabine, and tenofovir DF, after 48 and 96 weeks of treatment. HIV affects African Americans at a disproportionately high rate. A previous meta-analysis indicated that antiretroviral therapy is less effective in African Americans compared to other patients. The goal of the present study was to compare the efficacy and safety of STB versus ATR treatment in African American and non-African American patients with HIV.
The researchers used HIV-1 RNA, an indicator of the viral load, and change in CD4 cell count to assess treatment efficacy. Eighty-one percent of African American patients achieved the efficacy endpoint (defined by the researchers as less than 50 copies/mL) after 96 weeks of STB treatment, whereas 73% of African American patients taking ATR reached this endpoint. CD4 cell count increased similarly with both treatments. Total and HDL cholesterol had significantly smaller increases with STB treatment in African American individuals. The proportion of non-African American patients who reached the efficacy endpoints was similar between the two treatments.
A significantly greater proportion of side effects occurred with ATR treatment compared to STB in both African American and non-African American subjects. A significantly greater proportion (10%) of African American patients taking ATR discontinued the treatment due to side effects as compared to African American patients taking STB (less than one percent discontinued treatment due to side effects). According to Hardy, genetic differences in liver metabolism may cause some African Americans to metabolize the efavirenz component of ATR differently than their non-African American counterparts, although more research is needed to clarify this. The proportion of non-African American patients that discontinued therapy due to side effects was similar between the STB and ATR treatments.
Serum creatinine increased significantly by week four of STB treatment in the African American patients and remained elevated through week 96. This elevation is likely due to cobicistat, which inhibits renal tubular secretion according to Hardy and colleagues. However, neither treatment caused renal problems that required African American individuals to discontinue treatment, whereas the STB treatment caused seven drug-related renal incidents that caused non-African American patients to stop treatment. Therefore, STB may be an effective drug for treating HIV in African American patients without increasing the risk of treatment-related renal problems, according to Hardy.
All authors listed financial disclosures.