During the last decade, immune checkpoint inhibition (ICI) emerged as an important therapeutic pillar across a broad range of cancer types. Given the high incidence of DNA mismatch repair deficiency (dMMR) in endometrial tumours, this treatment modality has also been studied in the treatment of patients with recurrent or advanced endometrial cancer (EC). These studies have revealed that particularly tumours with dMMR or a high level of microsatellite instability (MSI-H) are sensitive to ICI-based therapies. While ICI monotherapy initially proved its worth in recurrent or advanced dMMR/MSI-H EC patients with failure after platinum-based chemotherapy, more recent studies have successfully evaluated combinations of an ICI and chemotherapy in the first-line treatment of these patients. Based on the results of the ENGOT-en6/RUBY trial, NRG-GY018, AtTEnd and DUO-E studies it is safe to say that ICI-chemotherapy combinations should be the new standard first-line treatment for recurrent or advanced dMMR/MSI-H EC patients. Several studies are currently underway to evaluate ICI monotherapy as first-line treatment for these patients and the results of these trials are eagerly awaited.
