Abstract
INTRODUCTION: Immunotherapy is limited in efficacy for glioblastoma (GBM). The objective of this study was to evaluate the efficacy and immune effects of the pp65 mRNA dendritic cell (DC) vaccine with the use of lysosomal-associated membrane protein (LAMP) in two different formulations (full-length (fl) and short-length (sh). METHODS: Patients who underwent resection of newly diagnosed GBM were enrolled and randomized to one of 3 arms: Arm 1) pp65-shLAMP mRNA DC with GM-CSF, Arm 2) pp65-flLAMP mRNA DC with GM-CSF, Arm 3) Unpulsed peripheral blood mononuclear cells (PBMC). After surgery, patients underwent leukapheresis for PBMC isolation and vaccines generation. Patients were treated with standard radiation and temozolomide followed by dose intensified adjuvant temozolomide at 75-100 mg/m2 x 21 days (aged less than 70) or standard dose at 150-200 mg/m2 x 5 days (patients 70 and older). Immunization started days 22-24 of cycle #1 with vaccines 1-3 delivered at 2 week intervals. All patients received tetanus-toxoid booster prior to vaccine 1. Patients continued to receive monthly vaccines for up to 10 vaccines with tetanus-diphtheria toxoid skin prep prior to vaccines 3, 6 and 9 (arms 1 and 2). Safety, efficacy and immune labs were evaluated. RESULTS: Overall DC vaccines were well-tolerated with 2 SAEs possibly attributed to DC vaccination that met criteria as DLTs. Of recorded grade 2 or lower AEs, 2 were possibly attributable to DC vaccination. One patient was removed from the study due to failure to produce DC vaccines that met QA/QC release criteria. CONCLUSION: In a large randomized and blinded patient cohort, delivery of CMV LAMP pp65 mRNA DC vaccines is feasible and safe in a multi-institutional setting. The primary endpoint of survival will be analyzed at the conclusion of the study.