547   Successful Discontinuation of MAC Therapy Following Effective HAART.

S. D. Shafran*¹, M. J. Gill², R. G. Lalonde³, S. L. Walmsley⁴, E. Toma⁵, B. Conway⁶, I. W. Fong⁷, A. R. Rachlis⁸, K. E. Williams⁹, G. E. Garber¹⁰, W. F. Schlech III¹¹, and F. Smaill¹².
¹Univ. of Alberta, Edmonton;²Univ. of Calgary, Alberta;³McGill Univ., Montreal, Quebec;⁴Toronto Hosp., Ontario;⁵Hotel Dieu, Montreal, Quebec;⁶Univ. of British Columbia, Vancouver;⁷St. Michael's Hosp., Toronto, Ontario;⁸Sunnybrook Med. Ctr., Toronto, Ontario;⁹Univ. of Saskatchewan, Saskatoon;¹⁰Univ. of Ottawa, Ontario;¹¹Dalhousie Univ., Halifax, Nova Scotia; and¹²McMaster Univ., Hamilton, Ontario, Canada.

Background:HAART is associated with improvement or resolution of several opportunistic infections. Successful discontinuation of CMV retinitis therapy has been achieved following HAART. Although MAC prophylaxis may be stopped following a favorable response to HAART, the U.S. Public Health Service guidelines presently recommend against discontinuing therapy for disseminated MAC infection, even following a favorable response to HAART. Accordingly, we examined the outcomes of patients with DMAC infection whose antimycobacterial therapy (AMBT) was discontinued following a favorable response to HAART.

Methods:A retrospective study was undertaken at 12 Canadian HIV clinics to examine the clinical and mycobacterial outcomes of patients with DMAC in whom successful AMBT was discontinued following a favorable response to HAART.

Results:33 subjects (26 male) were identified, with a mean age of 37 years and a median CD4 count of 19 cells/ mm³at the time of DMAC diagnosis. They received a median of 29 months of AMBT, including ethambutol plus either clarithromycin or azithromycin. Patients were followed for a median of 17 months after stopping AMBT. Only one patient relapsed with MAC disease, 37 months after stopping AMBT. This patient had uncontrolled HIV disease and had stopped HAART. At the most recent assessment of the other 32 patients, the median CD4 count was 225 cells/mm³

72% had an "undetectable" pVL, and only 4 had pVL >1000 copies/mL.

Conclusions:Discontinuation of successful DMAC therapy following a successful response to HAART is safe, reduces patients' pill burdens, and reduces costs of therapy.