Foregoing Prophylaxis: Better Safe Than Sorry?
This begs the question: Should I continue taking prophylaxis medications against opportunistic infections if my T-cells continue to rise?
From last year's ICAAC, we learned that it may be safe for people to discontinue taking such preventative medications against PCP if their T-cells climb over 200mm3. This year, we saw more information supporting this hypothesis as well as new information concerning discontinuation of MAC (mycobacterium avium complex) prophylaxis.
PCP Incidence Shows
In a late-breaker session, Dr. J.M. Miro, from Barcelona detailed a study in which 488 participants who had a history of T-cell counts less than 200 or a prior episode of PCP, had a history of ongoing PCP prophylaxis, and had a consistent response to HAART (over three months of T-cells greater than 200mm3 and a viral load less than 5,000 copies), were randomized into Group 1, which discontinued prophylaxis, or Group 2, which continued prophylaxis (LB-24).
After almost a year, there were no episodes of PCP in either group, no new AIDS diagnoses, and one participant died from each group of causes unrelated to AIDS. This study supported earlier reports that indicated the safety of discontinuing PCP prophylaxis if a person experiences a sustained response to HAART.
Since studies of this sort are fairly new, it is important to note that further studies with long-term follow-up may be necessary before applying these results to the general population.
A number of presentations focused on MAC in the age of HAART.
A poster presentation from France detailed the use of a hospital database to determine the incidence and risk of MAC (Abstract 131). Patients in the study were required to have a T-cell count less than 100. The study looked at pre-HAART and HAART eras (from 1992-1995 and from 1996-1998, respectively). The researchers concluded that there was a dramatic decrease in the incidence of MAC in the HAART era and a decrease in the interest of the patients to continue MAC prophylaxis.
A late-breaker presentation by Dr. Judith Currier of UCLA detailed a study supported by the National Institute of Allergy and Infectious Diseases (NIAID) to determine whether or not a person on antiviral medications could safely discontinue MAC prophylaxis if he or she experienced a rebound in T-cells (LB-23).
This randomized, placebo-controlled study enrolled 643 patients for a median follow-up of 56 weeks. At enrollment, the average T-cell count was 226 and 66 percent of the patients had a viral load of less than 500 copies. Participants were divided into a placebo arm or an arm containing the MAC prophylaxis drug, Zithromax (azithromycin).
As of July, no incidences of MAC were reported in the Zithromax arm and two incidences of MAC were reported in the placebo arm. It is important to note that both MAC incidences were atypical, in that MAC was isolated from bone and paraspinal masses and not from blood.
Researchers concluded that there was no statistical difference between the two study arms, and that those who experience a sustained increase in T-cells while on antiviral medications have a minimal risk of developing MAC if prophylaxis is discontinued.
This article has been reprinted at The Body with the permission of AIDS Project Los Angeles (APLA).
This article was provided by AIDS Project Los Angeles. It is a part of the publication Positive Living.