Polyvalent Breast-Cancer-Vaccination with Antigen-loaded Dendritic Cells: Study-Design and GMP-Conformity of Vaccine-Preparation

Abstract

Aims: First: Evaluation of toxicity under Dendritic-Cell (DC) dosis-escalation. Secondary: clin. response and induction of T-cell mediated immunity, quality of life; evaluation of feasibility. Methods: Study-design: Bicentric phaseI/II study. In vitro prepared autologous mature DCs are loaded with 14 tumorantigen-derived HLA-A*0201-restricted epitopes. A dosis-escalation will be undertaken in 3 groups with 9 patients each. All patients receive 8 vaccinations of the same dosis. Patients: HLA-A*0201+ breast cancer patients with low-risk metastases. DC-vaccination is offered additionally to standard-therapy-regimes (letrozol and/or zometa). Production and quality control of DCs: DC preparation was performed in a cleanroom (A in B) from monocytes after leucapheresis. DCs are loaded fractionated with peptides in three groups according to their binding-affinity. The loaded DCs are cryopreserved and have to meet the following criteria after thawing: dendritic morphology, no contamination with bystander cells and expression of DC-markers. Functionality of DC is examined by acitvation of autologous viral-specific T-cells (Elispot) and activation of alloreactive T-cells (MLR). Results: 4 DC-Preparations have been completed and 3 patients are already vaccinated. DCs were of high quality (CD83 68–97%) and showed high explorations in cell number. Stability of DC-markers was maintained after withdrawal of cytokines. No loss of function was detected using cryopreserved peptide-loaded DC vs. peptide loading after thawing. No toxicity or side-effects were observed in the first patients. Conclusion: high-quality DC preparation according to GMP-guidelines from only 1 leucapheresis per patient for all vaccinations is feasible with no loss of function after thawing. Application for approval of the vaccine at the “Regierungspräsidium“ has been initiated.