LAUSR

OBJECTIVE To examine the effect of anti-B cell therapy (rituximab) on cardiac inflammation and function in corticosteroid-refractory cardiac sarcoidosis. BACKGROUND Cardiac sarcoidosis (CS) is a rare cause of cardiomyopathy characterized by granulomatous inflammation involving the myocardium. While typically responsive to corticosteroid treatment, there is a critical need for identifying effective steroid-sparing agents for disease control. Despite growing evidence on the role of B-cells in the pathogenesis of sarcoidosis, there is limited data on the efficacy of anti-B cell therapy, specifically rituximab, for controlling CS. METHODS We reviewed the clinical experience at a tertiary care referral center of all patients with CS who received rituximab after failing to improve with initial immunosuppression therapy, which included corticosteroids. Fluorodeoxyglucose positron emission tomography (FDG-PET/CT) images before and after rituximab treatment were evaluated. All images were interpreted by 2 experienced nuclear medicine trained physicians. RESULTS We identified seven patients, (5 men, 2 women; mean age at diagnosis, 49.0±7.9 years) with active cardiac sarcoidosis who were treated with rituximab. The median length of follow-up was 5.1 years. All individuals, but 1, had received prior steroid-sparing agents in addition to corticosteroids. Rituximab was administered either as 1000 mg IV x 1 or x 2 doses, separated by 2 weeks. Repeat dosing, if appropriate, was considered after 6 months. All tolerated the infusions well.Inflammation as assessed by maximum SUV on cardiac FDG PET/CT uptake significantly decreased in 6 of 7 patients (median 6.0 to 4.5, Wilcoxon signed rank z: -1.8593, W: 3), whereas left ventricular ejection fraction improved or stabilized in 4 patients but decreased in 3. Mean left ventricular ejection fraction (LVEF) was 40.1% and 43.3% before and after treatment respectively (p=0.28). Three patients reported improved physical capacity, and 5 patients showed improved arrhythmic burden on Holter monitoring or ICD interrogation. One patient subsequently developed fungal catheter-associated infection and sepsis requiring discontinuation. CONCLUSIONS Rituximab was well tolerated and appeared to decrease inflammation, as assessed by cardiac FDG PET/CT scan, in all but 1 patient with active CS. These data suggest that rituximab may be a promising therapeutic option for CS, which deserves further study.