The Efficacy and Safety of Chidamide, Anti-PD-1 Antibody in Combination With Pegaspargase Versus DDGP in the Treatment of Newly Diagnosed, Stage III to IV Extranodal Natural Killer/T-Cell Lymphoma

6 cycles of pegaspargase 2500IU/m2 intramuscularly on day1, anti-PD1 antibody 200mg intravenously on day 2, chidamide 30mg biw orally, every 21 days.

6 cycles of pegaspargase 2500IU/m2 intramuscularly on day1, cisplatin 20mg/m2 intravenously on days 1 through 4, dexamethasone 15mg/m2 intravenously on days 1 through 5, gemcitabine 800mg/m2 on day 1 and day 8, every 21 days.