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Abacavir/Lamivudine Noninferior to Tenofovir/Emtricitabine as Backbone to Lopinavir/Ritonavir HIV Therapy: Presented at CROI
Doctors reported that the combination of the nucleoside reverse transcriptase inhibitors abacavir/lamivudine appears to be noninferior to the nucleotide/nucleoside reverse transcriptase inhibitor combination of tenofovir/emtricitabine as a backbone regimen with the protease inhibitor lopinavir/ritonavir in treating antiretroviral-naive patients.
"Abacavir/lamivudine is comparable to tenofovir/emtricitabine in virologic efficacy when combined with lopinavir/ritonavir through 48 weeks," said Kimberly Smith, MD, Infectious Disease Specialist, Rush University Medical Center, Chicago, Illinois. "Both treatment regimens were well tolerated with few discontinuations due to adverse events in either arm."
Dr. Smith reported on the interim results of the 96-week Abacavir/Lamivudine Versus Emtricitabine/Tenofovir Both In Combination With Lopinavir/Ritonavir for the Treatment of HIV (HEAT) study in her poster presentation here on February 5 at the 15th Conference on Retroviruses and Opportunistic Infections (CROI).
The HEAT study investigators enrolled 688 antiretroviral-naive patients infected with HIV and assigned 343 patients to treatment with abacavir/lamivudine and 345 patients to treatment with tenofovir/emtricitabine.
There was no human leukocyte antigen (HLA)-B*5701 testing performed to rule out abacavir hypersensitivity reactions. In the study, 4% of patients experienced reactions if they were on abacavir; 1% of patients on tenofovir/emtricitabine experienced reactions.
Overall, Dr. Smith said that 68% of abacavir/lamivudine patients achieved an undetectable viral load using the 50-copies/mL assay compared with 67% of patients on tenofovir/emtricitabine. Switches in medication were allowed but were counted as treatment failures.
Median CD4-positive cells increased by 201 cells in the abacavir/lamivudine patients compared with a 173-cell increase in the tenofovir/emtricitabine arm of the study, Dr. Smith said.
"A blinded analysis of the data was performed at week 48 to protect the integrity of this 96-week study," she said.
Funding for the study was provided by GlaxoSmithKline.