Epstein-Barr virus (EBV) is associated with many cancers, including nasopharyngeal carcinoma (NPC). Induction of an immune response against EBV could potentially be employed for elimination of NPC and other EBV-associated cancers. Dendritic cells (DC) are potent induces of immune responses, and are being tested for cancer immunotherapy.
Prof Schwarz and his team developed a new type of DC, that are being generated by a CD137 ligand (CD137L) agonist, and these cells display enhanced potency. In a phase I study, 12 NPC patients were administered CD137L-DC that were pulsed with EBV antigens (CD137L-DC-EBV-VAX). Treatment was well tolerated. A partial response (PR) was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2 to 3 years. Patients with clinical benefit had lower plasma EBV DNA levels, and a reduction after vaccination, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies.
Further strategies to enhance DC vaccine efficacy will be discussed.