Combination Antifungal Therapy Experience at an Academic Health System

PURPOSE

Invasive fungal infections are becoming increasingly prevalent, particularly in the immunocompromised population.  The development of new antifungal agents with novel mechanisms of action has sparked interest in combination antifungal therapies.  This study seeks to characterize combination antifungal use at a large academic health system.

METHODS 

We conducted a retrospective observational study of adult inpatients with the intent of characterizing combination systemic antifungal utilization between the dates of July 1, 2012 and June 30, 2013.  Combination antifungal therapy was defined as administration of two or more target systemic antifungals (liposomal amphotericin B, fluconazole, voriconazole, posaconazole, micafungin or terbinafine) for five or more days.

RESULTS

Twenty nine patients received combination antifungal therapy and 36 unique treatment courses were identified.  Ten of the 29 patients (35%) were BMT patients.  Pneumonia was the most common disease indication (20/29; 69%).  Unknown was the most common organism indication overall (11/29; 38%) and within the BMT patient population (6/10; 60%).  Among the 36 unique treatment courses the most common combination therapy by drug class was an azole and an echinocandin (53%; 19/36) followed by a polyene and an azole (31%; 11/36).

CONCLUSION

A significant proportion of the study population both overall (35%) and among BMT patients (60%) received combination antifungal therapy with no identified infecting fungal organism.  There is no data to support such a practice.  However, in the setting of severe invasive fungal infections, particularly in immunocompromised hosts, using additional antifungal agents may seem less risk-prone than invasive diagnostics like tissue biopsy.  These findings suggest that earlier diagnostic methods including tissue biopsy are warranted to avoid unnecessary use of combination antifungal therapy when no pathogen has been identified.