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Switching Drug Regimens Every Three Months May Benefit HIV-Positive People, Study Says

July 23, 2003

HIV-positive people may be less likely to develop a resistance to antiretroviral drugs if they switch drug regimens every three months, according to a study published in the July 15 issue of the Annals of Internal Medicine, the Los Angeles Daily News reports. Javier Martinez-Picado, a researcher at the University Germans Trias i Pujol in Badalona, Spain, and colleagues examined 161 HIV-positive people in Spain and Argentina who started antiretroviral therapy between 1999 and 2000 (Los Angeles Daily News, 7/21). The researchers split the patients into three groups, and the first two groups received their respective drug regimen continuously until their viral load began to increase -- the standard method of drug treatment. The first group received stavudine, didanosine and efavirenz, and the second group received zidovudine, lamivudine and nelfinavir. The third group alternated between the two treatment regimens every three months. The researchers chose this time period because doctors' appointments and prescription changes commonly occur at three-month intervals. The researchers found no difference between the standard drug regimens taken continuously by the first and second groups (Martinez-Picado et al., Annals of Internal Medicine, 7/15). However, in the third group, it took four times longer for participants to show detectable viral levels, according to Martinez-Picado. Researchers concluded that further research must be conducted because it is "too early" to change treatment regimens based only on this study, the Daily News reports (Los Angeles Daily News, 7/21).

'Subtleties' Raise Questions, Editorial Says
In an accompanying editorial, Dr. Michael Saag, a professor of medicine at the University of Alabama-Birmingham, says that although "[a]t first glance, the results of this study seem straightforward ... there are many subtleties in the study design and analysis that raise questions about the meaning and generalizability of the findings." The drugs used in the study, which were popular in 1999 and 2000, are not as effective as newer antiretroviral drugs. Also, the alternating therapy group may have had a "subtle advantage" because at the end of every three-month interval, the nonnucleoside reverse transcriptase inhibitor or protease inhibitor of the previous regimen was continued for an additional week. Therefore, the patient was receiving a four-drug regimen for one week every three months, Saag writes. In addition, the results of the study could have been affected because the participants and investigators were not blinded, meaning that patients and physicians were aware of the treatment regimen. Saag concludes that "further study of proactive switching seems warranted" (Saag, Annals of Internal Medicine, 7/15).

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