On-Again, Off-Again HIV Treatment May Work
Aug. 29, 2000 -- Researchers say they may have found a way to enlist a person's immune system in the fight against HIV infection. If so, it may be possible to take a vacation from rigorous AIDS drug regimens that save lives but drain time, energy, and money.
The strategy is based on patients studied in a small trial at the Wistar Institute in Philadelphia. One of these patients, according to a report in the September issue of the Journal of Infectious Diseases, is keeping the virus under control four months after he stopped taking his anti-HIV drugs.
"We are in the stage of saying to ourselves, 'What if?'" senior author Luis J. Montaner, PhD, DVM, tells WebMD. "Everyone is very excited here and wondering how far you can push this."
The admittedly dangerous strategy is known as structured treatment interruption. Montaner and many other AIDS experts are quick to warn patients not to try this on their own. The concept emerged after the report of a now-famous patient from Germany called the "Berlin patient," who stopped taking his HIV drugs and then developed potent immune responses able to control his HIV infection. Several trials of different treatment interruption strategies are ongoing but are proceeding cautiously because of the dangers involved.
Researchers fear that the rebound of HIV and the subsequent loss of immune system cells seen when a patient stops treatment will reverse the hard-won gains of treatment. There are also well-grounded fears that repeated drug holidays will open the door to drug-resistant virus.
Montaner and colleagues recruited 10 HIV-infected individuals by word of mouth from a community HIV treatment center. Five of the people had never been on HIV drugs and did not develop an immune response against HIV. But the five others who started treatment and then stopped were able to mount an immune response against the virus.
In patients who had several treatment interruptions, with each interruption there was a smaller rebound of HIV and a greater increase in immunity against HIV. For one patient, this immunity appears to be controlling his HIV infection in the absence of drugs.
"There are two interpretations," Montaner says. One is that the patient was able to develop an immune response against HIV with the treatment interruptions. "That is very exciting," he says. But the other possibility may be that this patient just happened to be one of the rare people who naturally control HIV, and all this was just a smoke screen for what would have happened anyway.
Franco Lori, MD, at the Institute for Genetic and Human Therapy in Pavia, Italy, is one of the researchers who originally reported the Berlin patient. He agrees that the immune response can control the viral load and is actively seeking a way to elicit HIV-specific immunity as an "extra drug" to fight the virus.