We can do better: a fresh look at echinocandin dosing

Area of Science:

• Pharmacology
• Mycology
• Infectious Diseases

Background:

• Echinocandins are preferred antifungals due to lower toxicity compared to azoles and polyenes.
• Emergence of echinocandin-resistant Candida species necessitates re-evaluation of dosing strategies.
• Pharmacometric approaches were not standard during the development of current echinocandins.

Purpose of the Study:

• To review pharmacokinetic/pharmacodynamic (PK/PD) evaluations of approved and investigational echinocandins.
• To assess PK/PD-optimized dosing regimens for treating resistant Candida isolates.
• To compare the efficacy of existing echinocandins with novel agents against resistant fungal strains.

Main Methods:

• Pharmacokinetic/pharmacodynamic (PK/PD) modeling and simulation.
• Evaluation of approved echinocandins (anidulafungin, caspofungin, micafungin) and rezafungin.
• Analysis of target attainment probabilities against Candida species with varying minimum inhibitory concentrations (MICs).

Main Results:

• Optimized regimens for existing echinocandins showed benefits but were insufficient for highly resistant isolates.
• Anidulafungin and micafungin demonstrated low probabilities of target attainment for resistant strains.
• Rezafungin exhibited high probabilities of PK/PD target attainment over 4 weeks with a single dose, even at higher MICs.

Conclusions:

• Current echinocandin dosing may not be optimal for treating resistant Candida infections.
• Anidulafungin and micafungin are unlikely to be effective against highly resistant isolates, even with dose adjustments.
• Rezafungin represents a promising new echinocandin with potential for improved efficacy against resistant fungal pathogens.