Withdrawal of Antifungal Treatment for Histoplasmosis in Patients After Improved Immune Response to Anti-HIV Drugs

Histoplasmosis is a serious opportunistic infection in persons with AIDS that demonstrates an excellent response to antifungal therapy. However, until the advent of highly active antiretroviral therapy (HAART), patients with histoplasmosis required lifelong suppressive antifungal therapy. It is thought that immune reconstitution as a result of HAART may diminish the need for chronic therapy. Histoplasmosis offers an opportunity to examine the concept of discontinuation of maintenance therapy as it is rapidly diagnosed and effectively treated with itraconazole [AS PER AMENDMENT 9/27/00: or other appropriate therapy for disseminated histoplasmosis] should relapse occur.

Patients discontinue antifungal maintenance therapy. Patients are seen for routine visits every 8 weeks and urine and serum specimens are collected for real time Histoplasma antigen testing and immunologic parameters. Patients with suspected recurrence, as determined by clinical or routine laboratory findings consistent with recurrent histoplasmosis, are reevaluated within 1 week of onset of these findings. Patients with suspected recurrence based on a serum or urine Histoplasma antigen rise of 2 units or more, in the absence of clinical or routine laboratory findings consistent with histoplasmosis, are reevaluated within 2 weeks. All patients with suspected recurrence have more frequent evaluations and additional laboratory tests. Those with negative studies resume bimonthly follow-up. All patients who develop proven (positive culture or positive fungal stain of tissues or body fluids) or probable relapse (clinical findings of relapse with an increase in antigen of 4.1 units or more, or no clinical findings but increases in antigen levels on repeated testing with the most recent antigen test demonstrating an increase in antigen of 4.1 units or more) or who experience persistent reduction of CD4 cell count to below 100/mm3 have antifungal induction therapy reinstituted. Patients remain on study for at least 12 months with regular follow-up/evaluations.