Abacavir Versus Zidovudine Combined with Lamivudine and Efavirenz for Treatment-naïve Patients

Preliminary results of this trial were first presented at the 43th ICAAC (September 14-17, 2003, Chicago, IL). Final results, summarized here, appear in the current issue of Clinical Infectious Diseases (October 1, 2004).

Zidovudine (Retrovir), lamivudine (Epivir), and efavirenz (Sustiva) comprise a highly effective and well-tolerated triple regimen for antiretroviral-naive patients. Evaluating other unique nucleoside reverse-transcriptase inhibitor (NRTI) combinations for long-term viral suppression is desirable.

This multicenter, randomized, double-blind non-inferiority clinical trial compared the efficacy and safety of abacavir (Ziagen) with that of zidovudine plus lamivudine and efavirenz in 649 antiretroviral-naive HIV-infected patients.

The primary objective was a comparison of proportions of patients achieving plasma HIV-1 RNA levels ≤50 copies/mL through week 48 of the study.

Results

At study week 48, 70% of patients in the abacavir group, compared with 69% in the zidovudine group, maintained confirmed plasma HIV-1 RNA levels of ≤50 copies/mL (in the intent-to-treat exposed population).

Virologic failure was infrequent (6% in the abacavir group and 4% in the zidovudine group).

There was a significant CD4⁺ cell response (209 cells/mm³ in the abacavir group and 155 cells/mm³ in the zidovudine group). Safety profiles were as expected.

Conclusions    

The authors conclude, “ Abacavir provided an effective and durable antiretroviral response that was non-inferior to zidovudine, when combined with lamivudine and efavirenz.”

IDC Research, Altamonte Springs, Florida; North Texas Center for AIDS and Clinical Research, Dallas, Texas; GlaxoSmithKline, Research Triangle Park, North Carolina; Hospital CIMA San Jose, San Jose, Costa Rica; Hospital de Santo Antonio dos Capuchos, Lisbon, Portugal; Rigshospitalet, Blegdamsvej, Demark; and Hospital Barros Luco Trudeau, Santiago, Chile.

10-08-04