Faculty, Staff and Student Publications

Language

English

Publication Date

6-1-2024

Journal

Cancer

DOI

10.1002/cncr.35251

PMID

38340331

Abstract

Background: Ivosidenib is primarily metabolized by CYP3A4; however, it induces CYP450 isozymes, including CYP3A4 and CYP2C9, whereas it inhibits drug transporters, including P-glycoprotein. Patients with acute myeloid leukemia are at risk of invasive fungal infections, and therefore posaconazole and voriconazole are commonly used in this population. Voriconazole is a substrate of CYP2C9, CYP2C19, and CYP3A4; therefore, concomitant ivosidenib may result in decreased serum concentrations. Although posaconazole is a substrate of P-glycoprotein, it is metabolized primarily via UDP glucuronidation; thus, the impact of ivosidenib on posaconazole exposure is unknown.

Methods: Patients treated with ivosidenib and concomitant triazole with at least one serum trough level were included. Subtherapeutic levels were defined as posaconazole < 700 ng/mL and voriconazole < 1.0 µg/mL. The incidences of breakthrough invasive fungal infections and QTc prolongation were identified at least 5 days after initiation of ivosidenib with concomitant triazole.

Results: Seventy-eight serum triazole levels from 31 patients receiving ivosidenib-containing therapy and concomitant triazole were evaluated. Of the 78 concomitant levels, 47 (60%) were subtherapeutic (posaconazole: n = 20 of 43 [47%]; voriconazole: n = 27 of 35 [77%]). Compared to levels drawn while patients were off ivosidenib, median triazole serum levels during concomitant ivosidenib were significantly reduced. There was no apparent increase in incidence of grade 3 QTc prolongation with concomitant azole antifungal and ivosidenib 500 mg daily.

Conclusions: This study demonstrated that concomitant ivosidenib significantly reduced posaconazole and voriconazole levels. Voriconazole should be avoided, empiric high-dose posaconazole (>300 mg/day) may be considered, and therapeutic drug monitoring is recommended in all patients receiving concomitant ivosidenib.

Keywords

Humans, Leukemia, Myeloid, Acute, Triazoles, Male, Female, Middle Aged, Aged, Myelodysplastic Syndromes, Pyridines, Glycine, Voriconazole, Aged, 80 and over, Drug Interactions, Adult, Antifungal Agents, Antineoplastic Agents, CYP450 inducer, QTc prolongation, drug‐drug interactions, ivosidenib, posaconazole, venetoclax, voriconazole

Published Open-Access

yes

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