Single Tablet Fixed-Dose Antiretroviral Combinations Improve Virologic Outcomes

SAN FRANCISCO, CA—Single tablet fixed-dose antiretroviral combination regimens, or STRs, “may offer improved virologic outcomes among urban populations of HIV-infected persons” compared with multiple tablet regimens, or MTRs, the first study to compare virologic outcomes concluded at IDWeek 2013.

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“Single tablet fixed dose STRs for HIV treatment simplify therapy and assure all regimen components are taken at once,” Shashi Kapadia, MD, of the Department of Medicine, UMDNJ-New Jersey Medical School, Newark, NJ, and colleagues reported.

“While STRs have potential to improve adherence resulting in better outcomes, there are limited data supporting this hypothesis,” he noted. This is especially important in that as components of branded STRs go off-patent, less expensive generic MTRs become available.

Using insurance claims, previous studies have assessed hospitalization rates among patients on STRs compared with MTRs. In this study, Dr. Kapadia and colleagues compared virologic suppression rates among HIV-infected patients initiating antiretroviral therapy with either STRs or MTRs.

The retrospective chart review study included 186 patients who were HIV-positive receiving care at the medical school's infectious disease practice between 2008 and 2012 and had completed 6 months on their first antiretroviral (ARV) regimen.

The investigators collected data on ARV regimen and on CD4 and HIV RNA viral load both prior to and 6 months after initiation of ARV. Primary outcome was defined as undetectable HIV RNA viral load after 6 months of therapy (+/- 4 weeks).

Of the 186 patients, 44% (n=81) were taking STRs and 56% (n=105) were taking MTRs. Mean age was 41 years in the STR group and 44 years in the MTR group. Significantly more women were in the MTR vs. the STR group, 49% vs. 26%; P=0.002). African American patients comprised 54% of the STR group and 68% of the MTR group.

Mean baseline HIV RNA viral load was 190,165 copies/mL in the STR group and 176,543 copies/mL in the MTR arm (P=0.375). Mean baseline CD4 was 224 cells/mm3 and 227 cells/mm3 in the STR and MTR groups, respectively (P=0.432).

After approximately 6 months on therapy, 77% of patients on the STRs achieved undetectable viral load compared with 60% of patients on MTRs (P=0.009). Mean CD4 count was 411 cells/mm3 in the STR group vs. 362/mm3 (P=0.09) in the MTR group and mean CD4 change from baseline was +143 cells/mm3 and +122 cells/mm3 (P=0.17), respectively, they concluded.

“Further study is needed to characterize differences in virologic response in specific sub-populations, particularly amongst persons with mental illness or substance abuse,” added Dr. Kapadia. “Cost-effectiveness of STRs amongst persons of color residing in low-income areas also needs to be evaluated.”

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