Structured Intermittent Antiretroviral Therapy Explored as Treatment Option

A 7-day-on, 7-day-off approach to highly active antiretroviral therapy (HAART) may provide some treatment-experienced, HIV-infected patients with an alternative to daily dosing, Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, reported here on Wednesday.

At the 8th annual Conference on Retroviruses and Opportunistic Infections, Dr. Fauci updated an earlier report presented last year in Durban (see Reuters Health report, July 12, 2000). At that time, Dr. Fauci reported findings for five patients ; now data for 10 subjects are available.

Of the 10 treatment-experienced patients now enrolled in the protocol of 7 days on HAART, followed by 7 days off, 3 subjects have completed 22 cycles, reflecting a total of 44 weeks.

"The virus does not rebound," Dr. Fauci told conference participants. "There is no negative impact on the immune system and we have not seen the emergence in any of them of phenotypic or genotypic resistance."

He cautioned that these data reflect less than 1 year’s treatment and include only 10 patients — and that no treatment recommendations can be made on this basis. "However, what it does tell you is that it is feasible to pursue [this approach]."

He added that not all antiretroviral drugs are appropriate to use in this protocol. For example, efavirenz should not be used, and the dosage of the ritonavir/indinavir combination must be modified.

"The next step will be to see if we can prolong that period of a week," he said. "This may be possible by the addition of immunological enhancement, or any of a number of other means."

The 7-on, 7-off regimen allows patients to be off drugs 50% of the time, Dr. Fauci pointed out. "This is a big deal to people — I don’t think you can underestimate that."

"The concept of ’hitting hard and hitting early’ — and this relates to modification of the guidelines [see Reuters Health report, February 1]— was predicated on the assumption that we would be able to eradicate the virus and discontinue therapy," Dr. Fauci told conference participants.

Although previously recognized, "short-term and long-term toxicities have now become a major issue in the approach and management of an HIV-infected individual," he noted. Therefore, for this reason and others, alternatives to reducing patients’ antiretroviral drug exposure will continue to be explored.