The Safety and Efficacy of Sintilimab Combined With Hypofractionated Radiotherapy in MSI-H/dMMR Rectal Cancer: a Prospective, Single-arm, Multicenter, Phase Ib Study
This prospective, single-arm study is conducted to investigate the safety and efficacy of Sintilimab combined with hypofractionated radiotherapy in patients with microsatellite instability-high (MSI-H)/ DNA mismatch repair-deficient (dMMR) non-metastatic rectal cancer.
• Histologically confirmed rectal adenocarcinoma;
• With DNA mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) status, whether or not being Lynch syndrome;
• Not received any anti-rectal cancer treatment previously; for patients with Lynch syndrome, not received any anti-tumor therapy about rectal cancer diagnosed this time;
• No distant metastasis except for lateral lymph nodes on thoracic and abdominal enhanced computed tomography (CT) scans; the distance between tumor's lower edge and anus within 15cm; clinical T stage ≥T2 on high-resolution pelvic magnetic resonance imaging (MRI)；
• Men and women ≥18 years of age;
• Eastern Cooperative Oncology Group performance status score 0 or 1;
• Adequate hematologic, hepatic, renal, thyroid and cardiac function: hemoglobin ≥90 g/L, neutrophils ≥1500/mm3, platelets ≥75,000/mm3; aspartate aminotransferase and alanine aminotransferase ≤3.0 × upper limit of normal (ULN), bilirubin ≤1.5 × ULN; creatinine ≤1.5 × ULN, creatinine clearance ≥50 mL/min; activated partial thromboplastin time, prothrombin time and international normalized ratio ≤1.5 × ULN; serum albumin ≥28 g/L；thyroid stimulating hormone and free thyroxine within ±10% of normal levels; no obvious abnormality in electrocardiogram;
• Not received blood, blood products and hematopoietic growth factor (e.g. granulocyte colony-stimulating factor) within 2 weeks before inclusion;
• Informed consent form signed;
⁃ Life expectancy of ≥3 months.