The median DOR was 15.2 months. Patients with PD-L1 expression (≥10%) or high tumor mutational burden (TMB) had better ORR than PD-L1 <10% (50.0% vs. 10.7%, P = 0.019) and TMB-low patients (75.0% vs. 16.1%, P = 0.03). Three of 8 (37.5%) responders harbored ARID1A mutations...Toripalimab had antitumor activity and safety in treating recurrent or metastatic NENs...Patients with positive PD-L1 expression, TMB-H (top 10%), and/or microsatellite instable (MSI-H) might preferentially benefit from the treatment.

The patient then received toripalimab (Shanghai Junshi Bioscience Co., Ltd in China), a programmed death receptor‐1 (PD‐1) monoclonal antibody, 240 mg every 3 weeks, and achieved a PR (Figure 1G)....As of the last follow‐up on September 3, 2020 (BMI 17.58), no significant adverse effects were observed and CT scans revealed stable diseases at the primary PanNET and liver metastases (Figure 1H)...we described a PanNET G3 case, with increasing TMB induced by TMZ‐related alkylation, which presented a favorable clinical response to anti‐PD‐1 treatment.