(568) Clinical Outcomes of Different Micafungin Dosing Strategies in Obese Patients With Candidemia

Introduction: Candidemia is a common bloodstream infection in the U.S. Echinocandins, like micafungin, are the primary treatment due to azole-resistant Candida species. Recent studies evaluating pharmacokinetic shifts that occur in obese patients found reduced serum concentrations of micafungin, raising concern for maintaining the area under the curve: minimum inhibitory concentration (AUC:MIC) ratio required for appropriate fungicidal activity. The goal of this study is to assess the clinical outcomes of standard-dose versus high-dose micafungin in obese patients with culture-proven candidemia.

Methods: Retrospective, cohort analysis of obese and morbidly obese patients with culture-proven candidemia who received micafungin from October 1, 2018 – October 1, 2023. Primary outcome was clinical stabilization as measured by resolution of systemic inflammatory response syndrome (SIRs) criteria, time to defervescence, and normalization of white blood cells (WBCs). Key secondary outcomes included time to blood culture clearance, the financial impact of different dosing strategies, workflow impact, and echinocandin resistance development.

Results: Seventy-one patients were included in this study with forty patients receiving standard-dose micafungin (100 mg daily) and thirty-one patients receiving high-dose (≥150 mg daily). Resolution of SIRS was seen in 84.2% in the standard-dose group compared to 83.3% in the high-dose group. Median time to defervescence was less than one day in both groups, and median time to WBC normalization was one day and less than one day in the standard-dose and high-dose groups, respectively. Median time to culture clearance was three days in the standard-dose arm compared to five days in the high-dose arm.

Conclusions: The results suggest that high-dose micafungin in obese patients does not result in statistically significant changes in clinical outcomes when compared to standard-dose micafungin for the treatment of culture-proven candidemia. While our study is one of the largest to date to assess the clinical outcomes of high-dose micafungin in obese patients, our findings fall in line with previous studies and further elucidate the need for larger clinical studies to determine the differences, if they exist, between the two dosing regimens in obese and morbidly obese patients.