Efficacy and Safety of Cell-based Immunotherapy in The Treatment of Recurrent or Metastatic Nasopharyngeal Carcinoma – A Systematic Review and Meta-analysis

Recurrent/Metastatic Nasopharyngeal Carcinoma (RM-NPC) remains difficult to treat and contributes to considerable mortality. The first-line treatment for RM-NPC is Gemcitabine and Cisplatin and second-line treatment options differ. The endemic variant of NPC is associated with Epstein-Barr Virus (EBV). Therefore, Cell-based Immunotherapy (CBI) targeting EBV-specific RM-NPC may be effective. We systematically searched PubMed, Embase and the Cochrane Library for randomised or observational studies investigating the efficacy and safety of CBI in the treatment of RM-NPC. We performed all meta-analyses using the random-effects model. Studies were further stratified by endemicity, nature of disease and drug type to investigate for potential between-study heterogeneity and additional pre-specified tests were employed to assess for publication bias. We screened 1,671 studies and included 13 studies with 403 participants in the systematic review, of which nine studies were eligible for meta-analysis. The use of CBI monotherapy as second or subsequent line treatment for EBV-positive RM-NPC revealed an ORR of 10 % (95 %CI = 3 %–29 %), median PFS of 2.37 months (95 %CI = 1.23–3.51) and median OS of 10.16 months (95 %CI = 0.67–19.65). For EBV-specific Cytotoxic T-Lymphocyte monotherapy, the pooled PD rate was 54 % (95 %CI = 9 %–93 %), SD rate was 22 % (95 %CI = 2 %–75 %) and incidence rate of any grade adverse events was 45 %. For Dendritic Cell monotherapy, a PD rate of 80 % (95 % CI = 29 %–98 %), SD rate of 11 % (95 % CI = 0 %–82 %) and incidence rate of any grade adverse events of 29 % was achieved. CBI monotherapy demonstrates some activity in pre-treated RM-NPC. More trials are needed to better understand how to integrate CBI into RM-NPC care.