Activity of the triazole SCH 56592 against disseminated murine coccidioidomycosis.
SCH 56592 (SCH) is a new triazole antifungal with a broad spectrum of activity. In vitro susceptibility testing against five strains of Coccidioides immitis revealed MICs from 0.39 to 3.13 microg/ml and minimal fungicidal concentrations from 1.56 to 3.13 microg/ml. A murine model of systemic coccidioidomycosis was established in female CD-1 mice. Groups received either no treatment or oral therapy with fluconazole at 10 or 100 mg/kg of body weight; itraconazole at 10 or 100 mg/kg; SCH at 0.5, 2, 10, or 25 mg/kg; or its methylcellulose diluent alone. Therapy began 2 days postinfection and continued once daily for 19 days. Surviving mice were euthanized 49 days postinfection, and infectious burdens were determined by culture. All drugs were superior to no-treatment or diluent-treatment controls (P < 0.001) in prolonging survival but were not significantly different from one another. Itraconazole at 100 mg/kg was superior to fluconazole in reduction of CFU in the spleen, liver, and lung (P < 0.01 to 0.001). SCH at 0.5 mg/kg was superior to either fluconazole or itraconazole at 10 mg/kg in reduction of CFU in all three organs (P < 0.05 to 0.001). SCH at 2 mg/kg was not significantly different from itraconazole at 100 mg/kg in all three organs. SCH at 10 and 25 mg/kg was superior to either dose of fluconazole or itraconazole in all three organs (P < 0.05 to 0.001). In terms of reduction of CFU, SCH was > or = 200-fold as potent as fluconazole and > or = 50-fold as potent as itraconazole. There was a clear dose-responsive relationship for SCH in each of the organs. It is noteworthy that SCH effected cures (no detectable C. immitis in any organ) in 1 of 9, 6 of 10, or 9 of 9 surviving mice in animals given 2, 10, or 25 mg/kg, respectively. Neither fluconazole nor itraconazole cured any survivor. SCH has potent, fungicidal activity in vivo against C. immitis. It should be considered for clinical trials in patients with coccidioidomycosis.
Lutz
J E
JE
Department of Medicine, Santa Clara Valley Medical Center, and California Institute for Medical Research, San Jose 95128, USA.
Clemons
K V
KV
Aristizabal
B H
BH
Stevens
D A
DA
D000666:Amphotericin B / Q000494:pharmacology; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology*; D003045:Coccidioides / Q000187:drug effects; D003047:Coccidioidomycosis / Q000188:drug therapy*; D004353:Drug Evaluation, Preclinical; D005260:Female; D017964:Itraconazole / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D008826:Microbial Sensitivity Tests; D014230:Triazoles / Q000494:pharmacology*
D000935:Antifungal Agents; D014230:Triazoles; D017964:Itraconazole; C101425:posaconazole; D000666:Amphotericin B