Aseptic cystitis induced by nivolumab and ipilimumab combination for metastatic melanoma.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced melanoma. Combination of ICI with ipilimumab cytotoxic T-lymphocyte antigen-4 and nivolumab [anti-programmed cell death-1 (PD-1)] improves tumoral response compared to anti-PD1 monotherapy in melanoma patients, but is associated with more severe and multiple immune-related adverse events. We report the first case of aseptic cystitis induced by ipilimumab and nivolumab combination in a 61-year-old melanoma patient. She described after two infusions, diarrhea, pollakiuria, intense bladder pain, urinary urgency, and nocturia. Repeated negative urine culture tests led to perform cystoscopy. Mucosal bladder biopsies showed lymphocytic T-cells infiltration in intraepithelial and in subepithelial connective tissue, which were consistent with the diagnosis of immune-related aseptic cystitis. Aseptic cystitis is a rare and poorly known side-effect related to ICI. Only four other cases with anti-PD1 monotherapy were found in literature, only in Japanese patients. It simulates bacterial cystitis with negative urinary tests, and is often associated with atypical symptoms like diarrhea, which may delay the diagnosis. Oral steroids appear to be the most efficient therapeutic options.