Effective treatment of metastatic forms of Epstein-Barr virus-associated nasopharyngeal carcinoma with a novel adenovirus-based adoptive immunotherapy

Abstract

Nasopharyngeal carcinoma (NPC) is endemic in China and Southeast Asia where it is tightly associated with infections by Epstein-Barr virus (EBV). The role of tumor-associated viral antigens in NPC renders it an appealing candidate for cellular immunotherapy. In earlier preclinical studies, a novel adenoviral vector-based vaccine termed AdE1-LMPpoly has been generated that encodes EBV nuclear antigen-1 (EBNA1) fused to multiple CD8(+) T-cell epitopes from the EBV latent membrane proteins, LMP1 and LMP2. Here, we report the findings of a formal clinical assessment of AdE1-LMPpoly as an immunotherapeutic tool for EBV-associated recurrent and metastatic NPC. From a total of 24 patients with NPC, EBV-specific T cells were successfully expanded from 16 patients with NPC (72.7%), whereas six patients with NPC (27.3%) showed minimal or no expansion of virus-specific T cells. Transient increase in the frequencies of LMP1&2- and EBNA1-specific T-cell responses was observed after adoptive transfer to be associated with grade I flu-like symptoms and malaise. The time to progression in these patients ranged from 38 to 420 days with a mean time to progression of 136 days. Compared with patients who did not receive T cells, the median overall survival increased from 220 to 523 days. Taken together, our findings show that adoptive immunotherapy with AdE1-LMPpoly vaccine is safe and well tolerated and may offer clinical benefit to patients with NPC.