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Isavuconazole Drug Interaction — SCE Infectious Diseases MCQ

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HardFungal InfectionsIsavuconazole Drug InteractionSCE Infectious Diseases

A 60-year-old man on Ibrutinib for CLL develops invasive aspergillosis. His haematologist needs to manage the interaction between Voriconazole and Ibrutinib. Instead of Voriconazole, which azole has a more favourable CYP3A4 interaction profile for Ibrutinib co-administration?

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Correct answer: A — Isavuconazole — a weaker CYP3A4 inhibitor with a more manageable interaction profile

Isavuconazole is a moderate CYP3A4 inhibitor (compared to Voriconazole and Posaconazole which are strong inhibitors) and is increasingly preferred for invasive aspergillosis in patients on CYP3A4-sensitive drugs like Ibrutinib. Isavuconazole has non-inferior efficacy to Voriconazole for invasive aspergillosis (SECURE trial). The Ibrutinib dose still requires reduction when co-administered with Isavuconazole, but the interaction is more manageable than with Voriconazole or Posaconazole.

Reference: BSAC 2024 – Antifungal guidelines; SECURE trial 2016; BNF 2024 – Isavuconazole