HIV/AIDS Research

Multiple drug therapy for HIV clinic patients is only half as successful as it is for clinical trial patients

Highly active antiretroviral therapy (HAART), an intense combination drug therapy for patients who have HIV infection, is only half as successful in reducing HIV viral load in patients treated at a typical urban HIV clinic compared with those in clinical trials. Failure to keep clinic appointments is the principal reason for this failure to suppress HIV levels, according to a study supported in part by the Agency for Health Care Policy and Research (HS07809). Missed appointments may simply be a marker for poor compliance with drug therapy, which is more easily controlled in clinical trials, suggests Richard D. Moore, M.D., M.H.Sc., of Johns Hopkins University School of Medicine.

HAART has been able to reduce HIV blood levels to less than 500 copies/mL in 60 to 90 percent of clinical trial patients. It is usually a combination of drugs: protease inhibitors, nucleoside analogs, and non-nucleoside reverse transcriptase inhibitors. In this study, Dr. Moore and colleagues analyzed the success of a broad range of HAART regimens in 273 patients receiving care at an urban HIV clinic. The patients took a protease inhibitor regimen containing at least one other antiretroviral drug that they had not taken before; 87 percent took at least three drugs. The patients were similar in sex, age, injection drug use, baseline CD4 lymphocyte count (indicator of immune system function), and HIV levels.

Of these clinic patients, 37 percent receiving HAART had undetectable HIV levels 1 year after starting therapy, and only 23 percent experienced viral suppression in all three time periods: 1 to 90 days, 3 to 7 months, and 7 to 14 months. This was half the rate of viral suppression seen in patients participating in clinical trials involving similarly potent therapy. Adverse drug reactions were more common among women and twice as common in patients receiving regimens including the protease inhibitor ritonavir than in those taking the protease inhibitors indinavir or nelfinavir. Higher rates of missed clinic appointments was the factor most strongly associated with failure to suppress HIV viral load at 1 year. Minority patients, injection drug users, and those younger than 41 years were more likely to miss clinic appointments.

See "Highly active antiretroviral therapy in a large urban clinic: Risk factors for virologic failure and adverse drug reactions," by Gregory M. Lucas, M.D., Richard E. Chaisson, M.D., and Dr. Moore, in the July 20, 1999, Annals of Internal Medicine 131(2), pp. 81-87.

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