Durable Response to Nivolumab Combined With Metformin in Advanced Pancreatic Cancer: A Case Report With Seven Years of Follow-Up.

We report a case of poorly differentiated pancreatic cancer that showed an exceptional response to combination therapy with nivolumab and metformin. A 58-year-old man presented with epigastric pain and was diagnosed with locally advanced pancreatic cancer with para-aortic lymph node metastasis. After disease progression following modified FOLFIRINOX therapy (a combination of fluorouracil, leucovorin, irinotecan, and oxaliplatin), the patient was enrolled in a phase Ib clinical trial of nivolumab (3 mg/kg biweekly) combined with metformin (750 mg/day). Post-treatment imaging showed marked tumor shrinkage with normalization of the tumor markers. During treatment, the patient was diagnosed with early-stage lung cancer and underwent successful left S1+S2 segmentectomy with temporary suspension of immunotherapy. The therapeutic response of pancreatic cancer has been sustained for seven years, with minimal residual disease. This unprecedented response duration is particularly noteworthy considering his microsatellite stability, which typically predicts a limited response to immune checkpoint inhibition. This case demonstrates an exceptional response to nivolumab and metformin combination therapy in poorly differentiated pancreatic cancer. The remarkable durability of the response suggests the need for further investigation to identify patients most likely to benefit from this therapeutic approach.