In Vitro Antifungal Activity of Ibrexafungerp (SCY-078) Against Contemporary Blood Isolates From Medically Relevant Species of Candida: A European Study

BackgroundIbrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis. ObjectiveThe aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida. MethodsIbrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated. ResultsIbrexafungerp MICs ranged from 0.016 to >= 8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016-0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06->= 8 mg/L). Modal MICs/MIC(50)s (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis. ConclusionIbrexafungerp showed a potent in vitro activity against Candida.This study received funding from SCYNEXIS. The funder was not involved in the study design, collection, analysis, interpretation of data, the writing of the article, or the decision to submit it for publication. CM-A is a recipient of a grant from Fundació n ONCE (Oportunidad al Talento). EE, AG, NJ, CM-A, and GQ have received grant support from Consejerı́a de Educación, Universidades e Investigación del Gobierno Vasco (GIC15 IT-990-16), Fondo de Investigación Sanitaria del Gobierno de España (FIS PI11/00203), and UPV/EHU (UFI 11/25). All authors declare no other competing interests

In Vitro Antifungal Activity of Ibrexafungerp (SCY-078) Against Contemporary Blood Isolates From Medically Relevant Species of Candida : A European Study

Ibrexafungerp (SCY-078) is the newest oral and intravenous antifungal drug with broad activity, currently undergoing clinical trials for invasive candidiasis. The aim of this study was to assess the in vitro activity of ibrexafungerp and comparators against a collection of 434 European blood isolates of Candida. Ibrexafungerp, caspofungin, fluconazole, and micafungin minimum inhibitory concentrations (MICs) were collected from 12 European laboratories for 434 blood isolates, including 163 Candida albicans, 108 Candida parapsilosis, 60 Candida glabrata, 40 Candida tropicalis, 29 Candida krusei, 20 Candida orthopsilosis, 6 Candida guilliermondii, 2 Candida famata, 2 Candida lusitaniae, and 1 isolate each of Candida bracarensis, Candida catenulata, Candida dubliniensis, and Candida kefyr. MICs were determined by the EUCAST broth microdilution method, and isolates were classified according to recommended clinical breakpoints and epidemiological cutoffs. Additionally, 22 Candida auris from different clinical specimens were evaluated. Ibrexafungerp MICs ranged from 0.016 to ≥8 mg/L. The lowest ibrexafungerp MICs were observed for C. albicans (geometric MIC 0.062 mg/L, MIC range 0.016-0.5 mg/L) and the highest ibrexafungerp MICs were observed for C. tropicalis (geometric MIC 0.517 mg/L, MIC range 0.06-≥8 mg/L). Modal MICs/MICs (mg/L) against Candida spp. were 0.125/0.06 for C. albicans, 0.5/0.5 for C. parapsilosis, 0.25/0.25 for C. glabrata, 0.5/0.5 for C. tropicalis, 1/1 for C. krusei, 4/2 for C. orthopsilosis, and 0.5/0.5 for C. auris. Ibrexafungerp showed activity against fluconazole- and echinocandin-resistant isolates. If adopting wild-type upper limits, a non-wild-type phenotype for ibrexafungerp was only observed for 16/434 (3.7%) isolates: 11 (4.6%) C. parapsilosis, 4 (5%) C. glabrata, and 1 (2.5%) C. tropicalis. Ibrexafungerp showed a potent in vitro activity against Candida