Secondary sclerosing cholangitis: a lesser known side effect of pembrolizumab therapy

Introduction/Objective Immune check-point inhibitors have increasingly taken hold as mainstays of various cancer treatments, revolutionizing outcomes for individuals diagnosed with terminal malignancy. Hepatotoxicity is reported to occur in 2-10% patients, predominantly manifesting as a mixed cholestatic hepatitis pattern of injury. Cholangitis is a rare immune-mediated adverse event (irAE). We present a case of pembrolizumab-induced secondary sclerosing cholangitis presenting with multiple biliary strictures. Early recognition is crucial as these cases are resistant to treatment with steroids. Methods/Case Report 82-year-old woman with recurrent, metastatic, high grade urothelial carcinoma status post cystectomy and neoadjuvant chemotherapy, presented with new onset obstructive jaundice (alkaline phosphatase 958 U/L, aspartate aminotransferase of 331 U/L, alanine aminotransferase of 422 U/L, and total bilirubin of 19.8 mg/dL) following two weeks of pembrolizumab therapy. MRCP suggested intrahepatic biliary ductal dilation. ERCP showed multiple strictures involving hepatic bifurcation, left, right and intrahepatic ducts with beaded intrahepatic bile ducts. Liver biopsy showed expanded portal tracts with mixed inflammatory infiltrate, extensive bile duct injury, neutrophilic cholangitis, ductular proliferation, and perivenular cholestasis (10% dropout) concerning for mechanical obstruction. CK7 did not show ductopenia and immunostain IgG4 was negative. All autoimmune work-up was negative. Liver enzymes continued to rise despite multiple therapeutic stents, drains, high-dose corticosteroids, ursodiol and mycophenolate mofetil. The patient died five months later. Results (if a Case Study enter NA) NA Conclusion Pemrolizumab-induced secondary sclerosing cholangitis is a rare, hence under-recognized, adverse effect of check point inhibitor-mediated hepatotoxicity. It is important to recognize this association, as it has limited benefit from steroid therapy. Our finding of pembrolizumab-related SC adds to the growing body of literature of immune check-point inhibitor-related hepatobiliary injury and calls for further characterization of PD-1/PD-L1 inhibitor SC and its clinical implications.