Isavuconazole Concentration in Real-World Practice: Consistency with Results from Clinical Trials

Area of Science:

• Medical Mycology
• Pharmacokinetics
• Clinical Pharmacy

Background:

• Voriconazole, posaconazole, and itraconazole require therapeutic drug monitoring (TDM) due to variable plasma concentrations.
• This necessity for TDM was not apparent during their respective clinical trials.
• The need for TDM in isavuconazole, another important antifungal, remained undetermined.

Purpose of the Study:

• To determine if routine therapeutic drug monitoring (TDM) is necessary for isavuconazole.
• To compare isavuconazole plasma concentrations in clinical practice with those from clinical trials.

Main Methods:

• Analysis of 283 patient plasma samples from real-world isavuconazole use.
• Comparison of observed concentration distributions with data from isavuconazole clinical trials.

Main Results:

• Plasma concentration distributions for isavuconazole in clinical practice were nearly identical to those in clinical trials.
• Over 90% of patients in both settings achieved concentrations above 1 μg/ml.

Conclusions:

• Routine therapeutic drug monitoring (TDM) is likely not necessary for isavuconazole in most clinical situations.
• Isavuconazole exhibits predictable pharmacokinetics, unlike some other azole antifungals.
• Clinical trial data adequately predict real-world isavuconazole exposure.