Weekends off for HIV drugs appears safe in pilot study (Medical Post)

Weekends off for HIV drugs appears safe in pilot study

But 'holidays' may not apply to protease inhibitor-based treatments

By Ed Susman

BANGKOK – An experiment to give patients on highly active antiretroviral therapy a little relief from the burden of taking pills for the rest of their lives appears to be safe and allows control of infection from human immunodeficiency virus.

"We have been able to show in this pilot program that patients can take their medication for five days and then stop taking the medication for two days—or over the weekend—and maintain virologic control," said Dr. Calvin Cohen, director of research for the Community Research Initiative of New England in Boston.

"The study," said Dr. Anthony Fauci, director of the U.S. National Institute on Allergy and Infectious Diseases, "shows similar results to what we have seen over the years—that short-term holidays in drug treatment seem safe and reduce the amount of drugs people need to take. I think it is a good thing."

Year-long study

In reporting results at the 15th International AIDS Conference here, Dr. Cohen said he recruited 23 men for the year-long study—one of several structured treatment interruption trials that have been attempted among patients with HIV infection who have maintained undetectable viral loads.

"In our study, the participants had to have their viral loads below the 50-copy detection level for at least three months before entering the trial," Dr. Cohen said at his poster presentation.Â

While most of the men chose to take medication Monday through Friday, a few built their drug schedule around mid-week days off.

"The patients didn't have any problem remembering when they were supposed to take their medication. They knew that if they went to work it was time to take their pills," he said.

In the FOTO (five days on, two days off) study, patients were on a variety of regimens. Those who were taking non-nucleoside reverse transcriptase based regimens with efavirenz (Sustiva) or with nevirapine (Viramune) as the backbone drug showed consistent ability to keep the virus suppressed throughout the study. However, patients taking a protease inhibitor-based regimen exhibited some viral rebound that was detected in standard tests.

"These patients were taking a lopinavir (Kaletra)/saquinavir (Invirase)-based regimen," he said. "When we saw the blips of viral recovery, we took these patients off the intermittent therapy and put them back on seven-day regimens. Their viral loads again became undetectable."

One new mutation was seen in the patients on the protease inhibitor regimen, but that did not affect the ability of the regimen to suppress the virus.

Dr. Cohen said the protocol is favoured by patients because it gives them some relief from the burden of taking pills every day and it actually represents a 28% reduction in the amount of medication being taken.

"I think the latter point is why only Boehringer Ingelheim was willing to sponsor our study," he said. "Reduction in the amount of medicine being taken by patients is not a popular concept with drug companies."

Limited by small numbers

He said the study was limited by its small numbers—typical of a pilot trial—and its applicability to different regimens is uncertain. He noted the fact that rebound occurred in the protease inhibitor-based regimens has uncertain implications.

"The impact of complications from this type of program over the longer term is also unclear." Dr. Cohen said this type of FOTO regimen warrants further study.

Dr. Fauci said the study was similar to one he and other researchers at his institute performed in which there was a seven-day on, seven-day off period. "We didn't see any rebound with that regimen and so that seemed safe, too," he said in an interview. That regimen resulted in a year-long 50% reduction in medication.

However, Dr. Fauci said the week-on, week-off regimen was fraught with the danger that a patient might forget which week he was in and allow viral rebound and development of resistance.

He said the simpler regimen of not taking drugs over the weekend might be easier for patients to handle without deleterious effects occurring.

"We need more of these user-friendly regimens that can reduce the pill burden without getting the patients into trouble with the virus."

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