By Ed Susman

UPI 10 July 2001

A controversial treatment in which patients infected with the virus that causes AIDS are allowed to only take medications on alternate weeks appears to hold the deadly virus at bay -- and after a year has not resulted in the creation of a drug resistant virus.

"Our results seem to be indication that small cyclical treatment interruption could be a feasible option," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, Bethesda, Md. Fauci said that more than a year after the treatment program began with 10 selected patients, he has seen no evidence of the two most feared complications -- a rebound of the level of virus in the bloodstream and emergence of a resistant virus.

The patients in the program had all previously shown that, when treated with a cocktail of antiretroviral drugs, the virus could be suppressed to undetectable levels, preventing the disease from attacking the patients' immune system and making them susceptible to the opportunistic infections -- cancers, pneumonias, dementias and diarrheas -- that often prove fatal.

During the one-week period in which the patients were off drug, Fauci said no patient recorded an increase in virus. That is, assays which detect the level of virus in the blood did not spot human immunodeficiency virus during the period when drugs to suppress the virus are not being used. No mutated form of HIV that could escape medication has appeared either, Fauci said Tuesday at the first International AIDS Society Conference on HIV Pathogenesis and Treatment in Buenos Aires, Argentina.

Fauci noted that other structured treatment interruption (STI) programs have been tried, including one that involved a two-month-on treatment followed by no medication for one month. But that strategy did show a worrisome ability of the virus to rebound above detectable levels. Fauci is now concentrating on the one-week-on and one-week-off regimen. "the short period of time off drugs does not appear to give the virus enough time to rebound," he said.

The goal of STI, Fauci said, would:

Give the patients relief from having their lives controlled by pills, up to 20 or more on some complex regimens.

Reduce costs by as much as 50 percent, important when one considers that some antiretroviral regimens cost upwards of $20,000 a year.

Make it easier for patient to adhere to the regimens which appear to be required during lifelong treatment.

Reduce the possibility of the adverse side effects seen with the triple combination of drugs used in most of the successful treatments. Those side effects include metabolism changes that increase cholesterol levels and increase the risk of diabetes, as well as unsightly fat redistribution that thins the face, but can create humps on the back or protruding stomachs.

Dr. Franco Lori, a researcher at Georgetown University who is also involved in STI, said that the immune systems in some patients under STI treatment regimes may be able to recognize the virus and attack it during periods when it rebounds. However, Lori noted, in such cases when the virus rebounds it can destroy some of the key immune cells that are slowly regenerating. "There is a cost to allowing this rebound," he said.

Researchers were also concerned that patients might try their own form of STI and have disastrous results. Dr. Joseph Eron, associate professor medicine at the University of North Carolina-Chapel Hill, said the concept of STI is something that doctors and their patients should discuss. However, Eron said he wasn't convinced that the STI would make it easier for patients to adhere to a regimen. "I don't think there is any evidence that taking alternate days off is more effective than once-a-day dosing," he said.

Eron also noted that while the results shown by Fauci were interesting and impressive, "no one should be surprised if resistance occurs among these patients." Before jumping into STI, Eron said, researchers should also recognize that the Fauci study involved just 10 patients, which is not a sample large enough so that the program can be put into general use.

Fauci said a larger trial is being prepared to see how well STI works in a greater population of patients.