Mimotopes are peptides that mimic the effects of specific B-cell epitopes in stimulating an immune response. Immunization with such mimotopes would be expected to induce an immune response directed at the target disease related antigen. As such they have great utility as potential immunotherapeutic approaches for various cancers in much the same way as HER-Vaxx is being used to stimulate an immune response to the tumour antigen HER2 in breast or gastric cancer.
Using a proprietary screening platform (see below), it has been possible to screen libraries of peptides using monoclonal antibodies for candidates that mimic the effect of target epitopes. Imugene has acquired an option to continue this research and development of Mimotope Vaccines with the Company’s scientific team in Austria.
As of February 2018, we have completed early development of a new mimotope vaccine that will target and compete in the billion-dollar blockbuster anti-PD-1 immuno-oncology market.
The check-point inhibitor market is dominated by two monoclonal antibody drugs, Opdivo (marketed by BMS) and Keytruda (marketed by Merck). Sales reported for Opdivo and Keytruda in 2017 were USD4.95b and USD3.81b respectively with double digit annual growth. Both drugs target PD-1, a key switch of the immune system’s ability to find and eliminate cancerous cells.
The research is being conducted under the leadership of Imugene’s CSO Professor Dr Ursula Wiedermann, and has identified mimotope peptides that when incorporated into Imugene’s proprietary immunotherapeutic vaccine delivery platform, generate antibodies that bind to the PD-1 biomarker. PD-1 antibodies block a protective mechanism on cancer cells, and allow the immune system to destroy those cancer cells.
The following publications cover some of the research to date on Mimotope Vaccines:
Riemer AB, Klinger M, Wagner S, Bernhaus A, Mazzucchelli L, Pehamberger H, Scheiner O, Zielinski CC, Jensen-Jarolim E: Generation of Peptide mimics of the epitope recognized by trastuzumab on the oncogenic protein Her-2/neu. J Immunol 2004, 173(1):394-401.
The mimotopes targeting Trastuzamab and Her-2 are protected in the following USA granted and owned by Imugene patent; "Vaccine against cancerous diseases which is based on mimotopes of antigens expressed on tumour cells", Zielinski, C etal. US patent no. 7,166,694
Vaccination with a Human High Molecular Weight Melanoma-Associated Antigen Mimotope Induces a Humoral Response Inhibiting Melanoma Cell Growth In Vitro
Stefan Wagner, Christine Hafner, Dorothee Allwardt, Joanna Jasinska, Soldano Ferrone, Christoph C. Zielinski, Otto Scheiner, Ursula Wiedermann, Hubert Pehamberger and Heimo Breiteneder
J Immunol 2005; 174:976-982
Epitope-Specific Antibody Response to Mel-CAM Induced by Mimotope Immunization
Christine Hafner, Stefan Wagner, Joanna Jasinska, Dorothee Allwardt, Otto Scheiner, Klaus Wolff, Hubert Pehamberger, Ursula Wiedermann, and Heimo Breiteneder
J Invest Dermatol 2005;124:125–131