[Incidence of Immune-Related Adverse Events after Switching from a Conventional Regimen of Nivolumab and Pembrolizumab to the Extended Dosing Interval Regimen].

A new nivolumab and pembrolizumab monotherapy regimen with double the conventional dose and longer dosing intervals( the new regimen)has been approved. Here, we report the incidence of immune-related adverse events(irAEs)in the early phase of switching from the conventional regimen to the new regimen at Ogaki Municipal Hospital. Thirty-seven patients switched to the new regimen between October 2020 and February 2021: 7(18.9%)switched to nivolumab and 5 (14.3%)to pembrolizumab. Two of the 7 patients treated with nivolumab developed irAEs. One patient developed Grade 3 colitis on day 51 following the switch to the new regimen, and the treatment was discontinued. The other patient developed Grade 3 adrenal insufficiency on day 72 and was hospitalized. No irAEs were observed with pembrolizumab treatment. These results suggest that high-severity grade irAEs may occur early after switching to the new regimen.