CD4+ Cell Count Useful Guide to HAART Interruption

In HIV-infected patients showing a good response to highly active antiretroviral therapy (HAART), the use of CD4+ cell counts is a safe and effective means of guiding interruption, according to Italian researchers.

This approach along with "clear predetermined criteria for resuming therapy, is a safe therapeutic strategy," lead investigator Dr. Andrea Boschi told Reuters Health.

An aim of treatment interruption is to decrease the drug burden and attendant toxicity without jeopardizing the efficacy of treatment, Dr. Boschi, of the Division of Infectious Diseases AUSL Rimini, and colleagues note in the December 3rd issue of AIDS.

To determine whether CD4+ cells counts might be useful in selecting a suitable point for treatment interruption, the researchers prospectively evaluated 71 patients with chronic HIV infection.

They stopped HAART when their CD4+ cell counts were higher than 500 cells per microliter and returned to the regimen before the count dropped below 200 cells per microliter. Once the level rose higher than 500, they were again eligible to interrupt treatment.

The median nadir CD4+ count before interruption was 352 cells per microliter and the median count at the time of the first interruption was 790 cells per microliter.

After a median follow-up of more than 2 years after the first treatment interruption, 22 patients remained off therapy and 49 restarted. Overall, 24 have interrupted therapy twice and, nine have done so three times and six have done so four times.

No AIDS-defining illnesses have been encountered. The median duration of the first interruption was 15 months and time on therapy was cut by more than 71%. Both of these parameters were related to nadir CD4+ cell count.

The researchers conclude that if carefully monitored, such interruptions "are clinically safe, decrease exposure to drugs and do not reduce the efficacy of therapy."

01/31/05

AIDS 2004;18:2381-2389.