Acute pancreatitis (AP) is a rare adverse event of pembrolizumab with unclear clinical features. This study investigated the clinical features of pembrolizumab-induced AP to provide a reference for prevention and treatment. Case reports, case series and clinical studies of pembrolizumab-induced AP were collected by searching Chinese and English databases up to January 31, 2024. Thirty-one patients were included, with a median age of 59 years (range 39, 82). The median time from administration to onset of AP was 5.05 months (range 0.5, 16) and the median cycle was 7 cycles (range 1, 35). Twenty-two (71.0%) patients had elevated pancreatic amylase with a median value of 860 IU/L (range 105-12562), and 16 (51.6%) patients had elevated lipase with a median value of 282 IU/L (range 153–1034). Pancreatic biopsy showed neutrophil infiltration (9.7%) and lymphocyte infiltration (6.5%). Immunohistochemical staining showed CD8 dominated inflammatory infiltration (6.5%). The computed tomography showed diffuse enlargement (51.6%) and focal enlargement (51.6%) of the pancreas. Endoscopic ultrasound showed enlarged hypoechoic pancreas(16.1%). PET/CT showed increased FDG uptake (16.1%). The magnetic resonance cholangial pancreatography showed narrowing of main pancreatic duct (12.9%). AP symptoms and pancreatic enzymes improved after discontinuation of pembrolizumab and administration of steroids and infliximab. Clinicians should be aware that AP is a rare adverse reaction to pembrolizumab. Pembrolizumab induced AP can be initiated with steroids for control, and infliximab can be initiated with steroid-refractory AP.
