Successful treatment of eosinophilic cystitis with benralizumab

Eosinophilic cystitis is a rare form of interstitial cystitis. It can be chronic and debilitating due to urinary frequency, dysuria, incontinence, and frequent urinary tract infections. Prior attempts at treatment have included oral and intravesical steroids, antispasmodics, and antibiotics when indicated. Treatment of eosinophilic disorders has recently been improved with the use of monoclonal antibodies directed at interleukin 5. We report here a case of eosinophilic cystitis treated with the interleukin 5 antagonist, benralizumab. The patient had significant improvement in both quality of life measures and biopsy findings.