Subcutaneous Mepolizumab Injection: An Adjunctive Treatment for Recalcitrant Allergic Fungal Rhinosinusitis Patients With Asthma

Background Allergic Fungal Rhinosinusitis (AFRS) is a non-invasive fungal disease that results from chronic allergic inflammation of the sinonasal mucosa. Failure to respond to mainstay medical therapies and sinus surgery leaves AFRS patients with limited alternatives and a decreased quality of life. Mepolizumab is a known IL-5 antagonist for patients with severe eosinophilic asthma. Objective To identify the efficacy of mepolizumab on improving Modified Lund-Kennedy (MLK) endoscopic scores in recalcitrant AFRS patients with asthma. Methods Retrospective chart review of 27 recalcitrant AFRS patients with asthma receiving a monthly mepolizumab injection between January 2017 and July 2019. Patients were evaluated endoscopically at baseline and at each follow-up visit every 6–8 weeks until their third visit. Secondary outcomes included SNOT-22 scores, serum eosinophil counts and the rate of prednisone rescues required in patients receiving mepolizumab compared to a retrospective control arm. Results Total median MLK scores improved significantly for all patients over three follow-up visits (6[4,7], 4[2,6], 5[2,6], 3.5[2.25,5]; p = 0.04). Amongst patients with a baseline polyposis score of 1 or more, combined MLK edema and polyposis sub-scores significantly improved (6[5.25,6], 3.5[2.25,5,75], 4[2.75,5.25], 4[3,4]; p = 0.02) versus patients with no polyposis (4[3,4], 3[1,4], 4[2,4], 3[0,4]; p = 0.90). Total SNOT-22 scores (56 vs 43; p = 0.04) and eosinophil counts (0.40 × 109/L vs 0.00 × 109/L; p