Dendritic cell therapy with CD137L-DC-EBV-VAX in locally recurrent or metastatic nasopharyngeal carcinoma is safe and confers clinical benefit.

INTRODUCTION: Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC), and provides a target for a dendritic cell (DC) vaccine. CD137 ligand (CD137L) expressed on antigen presenting cells, costimulates CD137-expressing T cells, and reverse CD137L signaling differentiates monocytes to CD137L-DC, a type of DC, which is more potent than classical DC in stimulating T cells. METHODS: In this phase I study, patients with locally recurrent or metastatic NPC were administered CD137L-DC pulsed with EBV antigens (CD137L-DC-EBV-VAX). RESULTS: Of the 12 patients treated, 9 received full 7 vaccine doses with a mean administered cell count of 23.9 × 106 per dose. Treatment was well tolerated with only 4 cases of grade 1 related adverse events. A partial response was obtained in 1 patient, and 4 patients are still benefitting from a progression free survival (PFS) of currently 2-3 years. The mean pre-treatment neutrophil: lymphocyte ratio was 3.4 and a value of less than 3 was associated with prolonged median PFS. Progressors were characterized by a high frequency of naïve T cells but a low frequency of CD8+ effector T cells while patients with a clinical benefit (CB) had a high frequency of memory T cells. Patients with CB had lower plasma EBV DNA levels, and a reduction after vaccination. CONCLUSION: CD137L-DC-EBV-VAX was well tolerated. The use of CD137L-DC-EBV-VAX is demonstrated to be safe. Consistent results were obtained from all 12 patients, indicating that CD137L-DC-EBV-VAX induces an anti-EBV and anti-NPC immune response, and warranting further studies in patients post effective chemotherapy. PRECIS: The first clinical testing of CD137L-DC, a new type of monocyte-derived DC, finds that CD137L-DC are safe, and that they can induce an immune response against Epstein-Barr virus-associated nasopharyngeal carcinoma that leads to tumor regression or prevents tumor progression.

Large-scale Isolation of Highly Pure "Untouched" Regulatory T Cells in a GMP Environment for Adoptive Cell Therapy.

Adoptive cell therapy is an emerging treatment strategy for a number of serious diseases. Regulatory T (Treg) cells represent 1 cell type of particular interest for therapy of inflammatory conditions, as they are responsible for controlling unwanted immune responses. Initial clinical trials of adoptive transfer of Treg cells in patients with graft-versus-host disease were shown to be safe. However, obtaining sufficient numbers of highly pure and functional Treg cells with minimal contamination remains a challenge. We developed a novel approach to isolate "untouched" human Treg cells from healthy donors on the basis of negative selection using the surface markers CD49d and CD127. This procedure, which uses an antibody cocktail and magnetic beads for separation in an automated system (RoboSep), was scaled up and adapted to be compatible with good manufacturing practice conditions. With this setup we performed 9 Treg isolations from large-scale leukapheresis samples in a good manufacturing practice facility. These runs yielded sufficient numbers of "untouched" Treg cells for immediate use in clinical applications. The cell preparations consisted of viable highly pure FoxP3-positive Treg cells that were functional in suppressing the proliferation of effector T cells. Contamination with CD4 effector T cells was <10%. All other cell types did not exceed 2% in the final product. Remaining isolation reagents were reduced to levels that are considered safe. Treg cells isolated with this procedure will be used in a phase I clinical trial of adoptive transfer into leukemia patients developing graft-versus-host disease after stem cell transplantation.