Clinical Characteristics and Outcomes of Pembrolizumab Induced Gastritis: A Systematic Review of the Literature

Pembrolizumab is associated with the development of gastritis, but its clinical features have not been characterized. To explore the clinical features of pembrolizumab induced gastritis and provide reference for the prevention and treatment of gastritis.

Case reports and case series related to pembrolizumab induced gastritis were retrospectively analyzed by searching the database from inception to September 30, 2023.

Thirty-nine patients with gastritis entered the study with a median age of 63 years (range 34, 81). The median time to gastritis was 11.1 months (range 0.3, 60) and 7 cycles (range 1, 27) after administration. Epigastric pain (24 cases, 61.5%), nausea (17 cases, 43.6%), and vomiting (16 cases, 41.0%) were the most frequently complained symptoms. Esophagogastroduodenoscopy mainly showed erythematous (16 cases, 41.0%), hemorrhage (14 cases, 35.9%) and erosions (11 cases, 28.2%). Gastric mucosal biopsy shows chronic active gastritis with lymphocytic infiltration. These patients' symptoms and gastric mucosa improved or recovered after receiving systemic steroid and proton pump inhibitor therapy regardless of whether pembrolizumab was discontinued. These patients' symptoms and gastric mucosa improved or recovered after treatment with systemic steroids, proton pump inhibitors, and biological agents.

Gastritis is an extremely rare adverse effect of pembrolizumab. When patients receiving pembrolizumab complain of abdominal symptoms, endoscopy, tissue biopsy, and immunohistochemical staining should be actively performed for early identification and diagnosis of gastritis.