In Vitro activity of isavuconazole (BAL4815) and voriconazole against 443 Isolates of aspergillus spp

J. Guinea, J. Jensen, T. Peláez, M. Torres-Narbona, E. Bouza

Author address: 

Hospital Gregorio Marañón, MADRID, Spain


Background: Isavuconazole (BAL4815) is a novel broad-spectrum triazole in latestage clinical development for treatment of invasive aspergillosis. It is administered IV and PO as a water-soluble prodrug. We studied the antifungal activity of isavuconazole and compared it with voriconazole against a large collection of Aspergillus spp. isolates. Methods: We analyzed 443 Aspergillus spp. isolates: 256 from outdoor air (province of Madrid), 43 from hospital air, and 144 from clinical samples of hospitalized patients. The MICs of isavuconazole (Basilea Pharmaceutica, Basilea, Switzerland) and voriconazole (Pfizer Pharmaceutical Group, New York, NY) were determined following CLSI M-38A microdilution procedures, with a concentration range of 0.015 to 16 μg/ml, and 48 hours’ incubation at 35ºC. The MIC endpoint was defined as the lowest concentration producing complete visual inhibition of growth (MIC-0). For isavuconazole, we also calculated the MFC (minimal fungicidal concentration), defined as the lowest drug concentration that killed 99% of the spores. Results: As shown in the table, there were no significant differences in activity between isavuconazole and voriconazole or between the different species of Aspergillus evaluated. Isavuconazole showed a potent fungicidal effect. Conclusions: Isavuconazole and voriconazole showed comparable, potent in vitro activity against all major Aspergillus species. Isavuconazole is a promising antifungal agent with fungicidal effect. J. Guinea is contracted by FIS CM05/00171. This study was financed by grants from CIBER RES CD06/06/0058 and from Basilea Pharmaceutica.

abstract No: 


Full conference title: 

3rd Trends in Medical Mycology
    • TIMM 3rd (2011)