Efficacy and Tolerability of Isavuconazole versus Posaconazole for Fungal Prophylaxis after Lung Transplantation

PURPOSE Azole antifungals are commonly prescribed for fungal prophylaxis (ppx) following lung transplant, but have many side effects and drug interactions. Isavuconazole, a new broad-spectrum azole antifungal, may obviate these issues. METHODS We retrospectively reviewed all lung transplant recipients (LTR) from February 2018 through September 2019 who received either ISA or POS for fungal ppx for 3 months post-transplant. Prior to February 2019 all patients received POS for ppx. Starting February 2019, POS was replaced by ISA at standard dosing. All patients received basiliximab induction and standard triple immunosuppression post-transplant. Surveillance bronchoscopies were performed at 1, 3, 6, and 12 months post-transplant. RESULTS In total, we reviewed 24 LTR who received ISA and 29 who received POS. Baseline characteristics were similar between groups. Median duration of follow-up was significantly shorter for the ISA group (137 vs. 340 days, p<0.01). Breakthrough fungal infections occurred in 3 (13%) and 2 (7%) patients in the ISA and POS groups, respectively (p=0.65). All ISA patients developed oropharyngeal candidiasis; in the POS group there was one each of candida empyema and mold colonization. Post-ppx fungal infections occurred in 1 (4%) and 5 (17%) patients in the ISA and POS groups, respectively (p=0.20). All of these were mold colonization except for one case of oropharyngeal candidiasis. There was no difference between fungal-infection free survival based on Kaplan-Meier analysis (p=0.69). POS was held in two cases and discontinued in 1 patient due to a drug interaction causing hepatotoxicity compared to zero patients receiving ISA (p=0.24). CONCLUSION Breakthrough fungal infections were similar between LTR receiving ISA or POS for fungal ppx. Longer follow-up of ISA patients is needed for definitive comparison of long-term infection risk. POS was discontinued in more patients due to drug interactions. ISA is a reasonable choice for primary fungal ppx in LTR.