Preventive vaccination against infectious diseases has been a major milestone for the health of modern society. The development of therapeutic vaccination against established diseases is much more difficult. For more than 100 years researchers have already tried to develop cancer vaccines and now first promising clinical results raise hopes. A summary of the most attractive new approaches gave Professor Carmen Scheibenbogen, Institut für Medizinische Immunologie, Charité-Universitätsmedizin, at a press conference in Berlin.
A new approach based on recent knowledge of peptide-based vaccination will be presented by Cees Melief, Leiden at thee ECI: A vaccine based on synthetic long peptides derived from oncogenic proteins of the human papillomavirus (HPV) was tested in patients with a form of genital cancer, so called intraepithelial neoplasia of the vulva in a clinical phase II study. A complete tumor regression could be observed in a substantial number of patients. (C Melief et al, 2008).
Similarly the Berliner group of Carmen Scheibenbogen and Anne Letsch developed a peptide-based vaccine using the transcription factor WT1 in patients with acute myeloid leukemia (AML). WT1 is strongly expressed in various types of cancer and supports the growth of cancer cells. In earlier studies the authors could show that WT1-specific T cells are able to attack leukemia cells. The results of a clinical phase II study will be presented by Anne Letsch. With support from the Jose Carreras Leukämie Foundation they developed a vaccine which was able to control leukemia in a substantial proportion of patients with non-curable leukemia (Keilholz et al. 2009). Based on this study a multi-center trial will be performed in Germany.
Licia Rivoltini from the Instiuto Nazionali Tumori in Milano has also been working on the field of cancer vaccination for many years. She will present recent studies on the role of immunoregulatory mechanisms for the T cell response against cancer and how these findings are implemented into the development of cancer vaccination (Filipazzi P, 2007).
A different approach to engage T cells against cancer, will be presented by Gerd Riethmüller, Munich. Using a newly developed synthetic bispecific antibody molecule, firm bridges can be built between T cells and cancer cells. Based on the specially selected target molecules the close contact of the cells results in the activation of cytotoxicity of T cells to kill the tumor cells. In a clinical trial in patients with advanced lymphoma and acute lymphatic leukemia complete or partial regression was achieved in 90% of patients (Bargou et al. 2008). Remarkably these results could be achieved by continouus infusion of only 15 - 60 microgramm per patient and day.