비인두암 신보조 요법으로서 펨브롤리주맙 + MRG003

The goal of this clinical trial is to evaluate efficacy and safety of neoadjuvant of the anti PD1 agent Pembrolizumab combined with MRG003 and adjuvant treatment of Pembrolizumab in patients with Epstein-Barr virus (EBV) - associated locoregionally advanced nasopharyngeal carcinoma. The expected sample size is 35 patients. Participants will receive 3 cycles of neoadjuvant pembrolizumab 200mg Q3W plus MRG003 2.3mg/kg Q3W followed by the standard concurrent chemoradiotherapy. Then participants will receive 14 cycles of adjuvant Pembrolizumab 200 mg Q3W after the standard concurrent chemoradiotherapy. The estimated average length of treatment per patients is 1 year.