A clinical trial of GlaxoSmithKline's anti-HIV drug Trizivir--a combination of Ziagen, AZT, and 3TC--was halted this week after the medication was shown to be inferior to other combinations of anti-HIV drugs, according to the National Institutes of Health unit conducting the study. The HIV/AIDS division of the National Institute of Allergy and Infectious Diseases wrote in a letter on Monday to doctors that Trizivir was less effective in reducing HIV viral loads than two other treatment regimens being evaluated in the study.
The study--involving 1,147 previously untreated HIV patients--compared Trizivir alone with a combination of Trizivir and Sustiva and with a combination of Sustiva and Combivir. After 32 weeks of treatment, 21% of study volunteers in the group receiving Trizivir had levels of HIV that exceeded the study's preset threshold viral levels of 200 copies per milliliter of blood, compared with 10% in each of the other two groups. The researchers also said viral failure occurred sooner in patients on Trizivir. Based on this data, the clinical trial was halted. Researchers plan to study the trial data before deciding whether to proceed with similar tests.