Simpler, Less Expensive Methods of Controlling HIV Progression Possible, Studies Suggest

There might be a simpler and less expensive method of controlling the progression of HIV, according to several preliminary studies presented Thursday at the XVI International AIDS Conference in Toronto, the Los Angeles Times reports (Chong, Los Angeles Times, 8/18). In one study, published Monday in the Journal of the American Medical Association, Susan Swindells of the University of Nebraska Medical Center and colleagues for 24 weeks followed the progress of 34 HIV-positive people whose viral levels had been lowered for 48 weeks or longer and who were given a combination of atazanavir and ritonavir instead of a three-drug antiretroviral regimen to determine whether the former could be used as a maintenance therapy. The study finds that the simplified antiretroviral combination sustains virologic suppression and might be an effective maintenance therapy for some HIV-positive people. Researchers reported that after 24 weeks, 91% of the people who had switched to the simplified combination therapy continued to have suppressed viral loads (Kaiser Daily HIV/AIDS Report, 8/14). Another study, conducted in Spain and presented Thursday, shows that 85% of HIV-positive people who changed from a combination therapy to a single protease inhibitor lopinavir, which is produced by Abbott Laboratories and sold under the brand name Kaletra, maintained undetectable viral levels for a year. The study compared the viral loads of 100 HIV-positive people taking the lopinavir regimen with 98 HIV-positive people who took the combination therapy. Another study, presented Thursday and conducted by French researchers, examines the efficacy of using lopinavir alone at the beginning of HIV treatment. The HIV-positive participants taking lopinavir alone developed undetectable viral levels at comparable rates to those who began their HIV treatment on a three-drug combination that included lopinavir, the study finds. The French researchers also found that two of the 83 participants taking lopinavir alone developed a virus that was resistant to protease inhibitors, compared with one of the 53 participants taking the three-drug combination that included lopinavir.

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A single-drug regimen could help reduce drug costs and prevent some side effects that result from combination therapies, the Times reports. It also could allow physicians to save the stronger antiretroviral treatment for HIV-positive people who become resistant to first-line therapy, according to Joseph Gathe, a Houston-based infectious diseases specialist who was involved with one of the studies. But many physicians at the conference said that a single-drug regimen could make HIV-positive people quickly become resistant to the drug, which was what had motivated researchers to develop a three-drug combination therapy. A single-drug therapy is "potentially viable for the future, but I wouldn't use it routinely in practice now," Scott Hammer, an infectious diseases specialist at Columbia University Medical Center who led the development of new AIDS treatment guidelines for the International AIDS Society-USA, said. He added that data presented Thursday support prescribing the drugs for HIV-positive people who cannot tolerate certain types of HIV treatment or for those who do not want to take the standard therapy. Many physicians at the conference said they thought further studies involving hundreds of people were needed, the Times reports. "I need more convincing," Chinkholal Thangsing, a physician from India who serves as Asia-Pacific bureau chief for the AIDS Healthcare Foundation, said (Los Angeles Times, 8/18).

Kaisernetwork.org is serving as the official webcaster of the conference. View the guide to coverage and all webcasts, interviews and a daily video round up of conference highlights at www.kaisernetwork.org/aids2006.

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