� 1999 Medical Tribune News Service

When placing patients on highly active antiretroviral therapy (HAART), doctors can increase the odds of therapeutic success by using drugs to which patients previously have not been exposed, according to a new study. The Swiss study focused on 2,674 outpatients who started HAART between 1995 and 1998. At 12 months, 81.2 percent of patients had undetectable viral load, defined as a plasma HIV-RNA concentration of 400 copies/ml or less. Among treatment-naive subjects, 90.7 percent achieved undetectable levels of virus after 12 months, compared with 70.3 percent of pretreated subjects who received one new agent, 74 percent of participants who received two new drugs and 78.7 percent of pretreated patients who received three new drugs, researchers led by Bruno Ledergerber, M.D., of University Hospital in Zurich, reported in The Lancet (1999;353:863-868). Findings suggest that the virus develops resistance more easily to one drug than to three new medications, as suggested by other studies, according to the researchers. Triple regimens are the most popular therapy for HIV infection. These regimens usually consist of a protease inhibitor such as indinavir (Crixivan, Merck) or ritonavir (Norvir, Abbott) and two nucleoside-analogue reverse-transcriptase inhibitors, such as zidovudine (AZT, Retrovir, Glaxo Wellcome) and lamivudine (3TC, Epivir, Glaxo Wellcome). Confirming results of earlier studies, the Swiss team found that subjects whose virus was never lowered to undetectable levels were 2.5 times more likely to die from AIDS than other patients. Among the study patients who were naive to antiretroviral agents prior to receiving HAART and whose viral loads sank to undetectable levels at 12 months, less than 10 percent contracted AIDS or died within the next 18 months. Jonathan Kaplan, M.D., of the Centers for Disease Control and Prevention in Atlanta, called the finding �exciting news� that �confirms results we�ve been hearing [from] all over the world.� The death rate from AIDS in the United States has fallen by 80 percent since the introduction of triple combination therapies, he added. In addition, the Swiss study, which looked at patients taking four different protease inhibitors in various combinations with other drugs, shows that there is flexibility in antiretroviral treatment, said Oren Cohen, M.D., an HIV researcher at the National Institute of Allergy and Infectious Diseases. Many possible combinations of antiretroviral agents exist, so doctors do not have to be concerned about running out of treatment options, according to Dr. Cohen. April 8, 1999 � 1999 Medical Tribune medtrib@medtrib.com