PD-1 Blockade in a Liver Transplant Recipient With Microsatellite Unstable Metastatic Colorectal Cancer and Hepatic Impairment

Immune checkpoint inhibitors represent a newly established standard of care in patients with refractory metastatic colorectal cancer with mismatch repair deficiency and microsatellite instability. However, the use of immunotherapy is unclear in recipients of liver transplants with or without concurrent liver function abnormalities. Clinical trials investigating immunotherapy have mostly excluded liver transplant recipients and patients with abnormal liver function. This report presents the first case, to our knowledge, of a liver transplant patient with mismatch repair-deficient colon adenocarcinoma with liver metastases and concurrent abnormal liver function who safely responded to immunotherapy. We also review the literature on checkpoint inhibitor use in patients with other metastatic solid tumors after liver transplant and those with baseline liver function abnormalities. An increasing body of evidence supports the safety of checkpoint inhibition in patients with cancer and solid organ transplants, but further prospective studies are warranted. Use of immunotherapy in liver transplant recipients who have metastatic colorectal cancer with microsatellite instability is feasible but should be performed in a multidisciplinary team setting.