ORIENT-15 was a multicentre, double blind, randomised, phase 3 clinical trial conducted at 79 sites in five countries (China, France, Spain, US, and Australia; table S2). The ORIENT-15 trial was started in China in December 2018. While our study was ongoing, other studies that enrolled patients with oesophageal squamous cell carcinoma globally reported that anti-PD-1 monoclonal antibodies prolonged overall survival in those who progressed after first line chemotherapy,8 (link)
9 (link) and therefore we expanded our trial to include western countries. Based on communications with the US Food and Drug Administration, the chemotherapy regimen of cisplatin plus 5-fluorouracil, used globally, was added as a chemotherapy option in our trial. In February 2020, our trial was amended to a multiregional trial and the number of patients enrolled was increased to 676. We enrolled 62% of patients (420/676) before February 2020 but the first patient outside of China was enrolled on 25 November 2020 because of the covid-19 pandemic. At that time, 95% of the target number of patients (640/676) had been enrolled in China.
In January 2021, one of the primary endpoints of the trial was changed from overall survival in patients with tumour proportion scores ≥10% for expression of programmed cell death ligand 1 (PD-L1 TPS), to overall survival in patients with combined positive scores ≥10 for expression of programmed cell death ligand 1 (PD-L1 CPS). This change was based on the results of KEYNOTE-181 (A Phase III Randomized Open-label Study of Single Agent Pembrolizumab vs Physicians' Choice of Single Agent Docetaxel, Paclitaxel, or Irinotecan in Subjects With Advanced/Metastatic Adenocarcinoma and Squamous Cell Carcinoma of the Esophagus That Have Progressed After First-line Standard Therapy) and KEYNOTE-590, suggesting that the combined positive score might be better associated with the benefits of anti-PD-1 treatment than the tumour proportion score.8 (link)
19 (link) Up to January 2021, 95% of patients (644/676) had been enrolled in the trial based on the tumour proportion score as one of the stratification factors, and therefore the stratification factor during enrolment could not be changed from the tumour proportion score to the combined positive score. After January 2021, enrolment outside of China was ongoing whereas enrolment in China had ended when one of the primary endpoints of the trial was changed from overall survival in patients with PD-L1 TPS≥10% to overall survival in patients with PD-L1 CPS≥10.
Based on the positive results of the interim analysis, sintilimab in combination with chemotherapy significantly prolonged the overall survival of patients compared with placebo in combination with chemotherapy. But only 19 patients outside of China had been randomised before 9 April 2021 (cut-off date of the interim analysis). Enrolment in the randomisation phase was still ongoing outside of China. To further evaluate the efficacy and safety of sintilimab in combination with chemotherapy in patients representing western populations with advanced or metastatic oesophageal squamous cell carcinoma, a single arm open label extension phase will be conducted outside of China after completion of enrolment in the randomisation phase. Seventy patients will receive sintilimab combined with chemotherapy in the open label phase. The protocol was amended after the interim analysis in August 2021.
The trial was done according to Good Clinical Practice and the Declaration of Helsinki. The protocol and amendments were approved by the institutional review board or ethics committee at each site.
9 (link) and therefore we expanded our trial to include western countries. Based on communications with the US Food and Drug Administration, the chemotherapy regimen of cisplatin plus 5-fluorouracil, used globally, was added as a chemotherapy option in our trial. In February 2020, our trial was amended to a multiregional trial and the number of patients enrolled was increased to 676. We enrolled 62% of patients (420/676) before February 2020 but the first patient outside of China was enrolled on 25 November 2020 because of the covid-19 pandemic. At that time, 95% of the target number of patients (640/676) had been enrolled in China.
In January 2021, one of the primary endpoints of the trial was changed from overall survival in patients with tumour proportion scores ≥10% for expression of programmed cell death ligand 1 (PD-L1 TPS), to overall survival in patients with combined positive scores ≥10 for expression of programmed cell death ligand 1 (PD-L1 CPS). This change was based on the results of KEYNOTE-181 (A Phase III Randomized Open-label Study of Single Agent Pembrolizumab vs Physicians' Choice of Single Agent Docetaxel, Paclitaxel, or Irinotecan in Subjects With Advanced/Metastatic Adenocarcinoma and Squamous Cell Carcinoma of the Esophagus That Have Progressed After First-line Standard Therapy) and KEYNOTE-590, suggesting that the combined positive score might be better associated with the benefits of anti-PD-1 treatment than the tumour proportion score.8 (link)
19 (link) Up to January 2021, 95% of patients (644/676) had been enrolled in the trial based on the tumour proportion score as one of the stratification factors, and therefore the stratification factor during enrolment could not be changed from the tumour proportion score to the combined positive score. After January 2021, enrolment outside of China was ongoing whereas enrolment in China had ended when one of the primary endpoints of the trial was changed from overall survival in patients with PD-L1 TPS≥10% to overall survival in patients with PD-L1 CPS≥10.
Based on the positive results of the interim analysis, sintilimab in combination with chemotherapy significantly prolonged the overall survival of patients compared with placebo in combination with chemotherapy. But only 19 patients outside of China had been randomised before 9 April 2021 (cut-off date of the interim analysis). Enrolment in the randomisation phase was still ongoing outside of China. To further evaluate the efficacy and safety of sintilimab in combination with chemotherapy in patients representing western populations with advanced or metastatic oesophageal squamous cell carcinoma, a single arm open label extension phase will be conducted outside of China after completion of enrolment in the randomisation phase. Seventy patients will receive sintilimab combined with chemotherapy in the open label phase. The protocol was amended after the interim analysis in August 2021.
The trial was done according to Good Clinical Practice and the Declaration of Helsinki. The protocol and amendments were approved by the institutional review board or ethics committee at each site.