A Study of Nitazoxanide in Patients With AIDS and Diarrhea Caused by Cryptosporidium

There is no proven therapy for cryptosporidiosis in persons with AIDS. Nitazoxanide appears to be a good candidate drug for further evaluation because of its effectiveness in preclinical models, the data from early clinical trials and its safety profile. Cooperation between clinical researchers and basic scientists in clinical trials of agents for HIV infection and its complications is a high priority for the ACTG, the NIAID, and the NIH. Thus, it is important to design a clinical trial of NTZ that includes cooperation with basic scientists. Patients will be randomized to the active drug or placebo in a 2:1 ratio. Patients will be stratified by presence or absence of dual infection with microsporidiosis and screening CD4+ count (\<= 50/mm3, \> 50/mm3). Days 1 - 21, Arm I will receive oral NTZ and Arm II will receive NTZ placebo po bid (blinded). With the approval of the protocol chair, patients may switch to open-label NTZ after two weeks of blinded therapy if there is a clinical worsening of diarrhea due to cryptosporidiosis accompanied by either weight loss \>= 5% or the requirement for intravenous fluids to maintain body weight and/or intravascular volume despite the use of appropriate antidiarrheal agents. Days 22 - 42, Arm I and Arm II will receive oral NTZ (open-label). Days 43 - 63, Arm I will begin the maintenance phase and Arm II will receive oral NTZ (open-label). On Day 63 Arm II will start the maintenance phase. In maintenance phase patients will be randomized to 1 of 2 doses of NTZ 24 weeks. Patients who are not complete or marked responders at Day 42 (Arm I) or Day 63 (Arm II) may receive a higher dose of NTZ for an additional three weeks. Patients who have a complete or marked response at the higher dose may initiate maintenance therapy. Patients who continue to have only a partial response or who fail to respond will discontinue therapy.