Sintilimab in Combination With Chemoradiotherapy in High-risk Locoregionally-advanced Nasopharyngeal Carcinoma

This study is testing whether adding an immunotherapy drug called sintilimab to standard chemotherapy and radiation improves outcomes for people with a specific type of throat/nasal cancer called nasopharyngeal carcinoma. **You may be eligible if...** - You have been diagnosed with a specific type of nasopharyngeal (nasal throat) cancer confirmed by biopsy - Your cancer is stage III or IVA (has spread to nearby tissue or lymph nodes but not distant organs) - You are between 18 and 70 years old - You are generally well enough to carry out daily activities with minimal limitations - Your liver, kidney, and blood counts are within acceptable ranges - You are willing to use contraception during treatment and for 1 year after **You may NOT be eligible if...** - You have active hepatitis B with high viral load, or hepatitis C - You have an active autoimmune disease (besides controlled type 1 diabetes, thyroid conditions, or minor skin conditions) - You have a history of serious lung disease such as interstitial lung disease - You have recently used high-dose steroids or immune-suppressing medications - You are pregnant, breastfeeding, or planning pregnancy during the study Talk to your doctor to see if this trial is right for you.