Recurrent Cystitis Associated With 2 Programmed Death 1 Inhibitors: A Rare Case Report and Literature Review.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced cancer, however, often with immune-related adverse events (irAEs). Adverse events involving the bladder were extremely rare with only few cases. Herein, we described a rare, recurrent cystitis associated with 2 programmed death 1 inhibitors (pembrolizumab and toripalimab) in 1 patient with advanced liver cancer. Cystitis associated with toripalimab, a novel humanized programmed death 1 monoclonal antibody, was first presented in our case. Cystitis is an extremely rare irAE associated with ICIs, especially anti-programmed death 1 antibodies. With widening indications of ICIs in clinical practice, physicians should be also aware of this rare irAE.