The safety and immunological effects of rAd5-EBV-LMP2 vaccine in nasopharyngeal carcinoma patients: A phase I clinical trial and two-year follow-up

Abstract

Epstein-Barr virus (EBV)-encoded latent membrane protein 2 (LMP2) promotes nasopharyngeal carcinoma (NPC) progression. Previously, we reported that the dendritic cells (DCs) transfected with EBV-LMP2 recombinant serotype 5 adenoviruses (rAd5) induced anti-tumor effect by eliciting cytotoxic T lymphocytes (CTLs)-mediated immune response in vitro and the adenoviral vaccine of EBV-LMP2 (rAd5-EBV-LMP2) stimulated antigen-specific cellular immunity in mice. However, the safety and immunological effect of rAd5-EBV-LMP2 vaccine in human still remained unknown. Here we conducted a single-center, non-randomized, open-label, single-arm phase I clinical trial to clarify this unsolved issue. A total of 24 patients with regional advanced NPC were sequentially enrolled into three dose level groups (2×109, 2×1010, 2×1011 vp). The rAd5-EBV-LMP2 vaccines were intramuscularly injected for four times within 28 d (D0, D7, D14, D28). Blood samples were harvested immediately before every vaccination, one week and one month after the last vaccination (D0, D7, D14, D28, D35, D58). All the vaccine inoculation-related toxicities presented as grade I/II adverse events. The most frequent systemic adverse reactions were fatigue (33.0%, 8/24), myalgia (29.2%, 7/24) and cough (29.2%, 7/24), while the most common regional adverse reaction was tenderness in the inoculation site (54.2%, 13/24). In addition, proportion of CD3+CD4+ cells in peripheral blood was significantly increased in the high dose group (2×1011vp). The rAd5-EBV-LMP2 vaccine was generally well-tolerated and the high dose (2×1011vp) is recommended to be adopted in phase II studies. The long-term outcome of rAd5-EBV-LMP2 vaccine inoculation is required to be determined in following placebo-controlled trials.