PD-1 Antibody Combined With COX Inhibitor in MSI-H/dMMR or High TMB Colorectal Cancer: a Single Arm Phase II Study
PD-1(programmed death protein 1)antibody has been to approved in patients with MSI-H/dMMR advanced cancer and has achieved significant efficacy. It is reported that the objective response rate of Pembrolizumab and Nivolumab are 40% and 31.1% in MSI-H/dMMR (microsatellite instability-high/deficiency mismatch repair )colorectal cancer. What's more, most of the patients who had response for PD-1 antibody achieved a long duration of disease control. However, not all patients with MSI-H/dMMR was sensitive to PD-1 antibody despite it is a biomarker for PD-1 antibody treatment. There were about 50-60% of patients with MSI-H/dMMR were insensitive and we don't know why. What's more, it's reported that tumor mutation burden (TMB) may be another biomarker of response to PD-1 therapy. COX (cyclooxygenase)inhibitor has been proved to prevent adenomas in colorectal and it is safe for most of the patients. Preclinical models also showed that COX inhibitor could act with PD-1 antibody in mice and control disease progress. So, this study aims to evaluated efficacy and safety of combination of PD-1 antibody and COX inhibitor in patients with MSI-H/dMMR or high tumor mutation burden colorectal cancer.
• Signed informed consent; able to comply with study and/or follow- up procedures;
• Age:18-75 years old;
• Histological or cytological documentation of colorectal cancer;
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1;
• There must be documentation by CT scan, MRI, or intraoperative palpation that tumor is unresectable;
• Have had at least one lines of chemotherapy fail or refuse to receive chemotherapy;
• Histologically confirmed metastatic or primary colorectal cancer as dMMR/MSI-H or whole exon sequence confirmed tumor mutation burden higher than 1000;
• Adequate bone marrow, hepatic and renal function as assessed by the following laboratory requirements conducted within 7 days of starting study treatment: Hemoglobin (Hb) ≥ 90g/ L, absolute neutrophil count (ANC) ≥ 1.5×109/ L, platelet count ≥ 100×109/ L; Total bilirubin ≤ 1.5×the upper limit of normal (ULN), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5 ×ULN; Serum creatinine ≤1.5×the ULN.