Project: Development of an innovative immunotherapy against melanoma

Melanoma, the most malignant form of skin cancer in man with an alarming increasing incidence and death toll worldwide is generally resistant to chemotherapy and radiation. The unique immunological properties of melanoma lend support to developing innovative therapies via strengthening the patients` immune system to combat cancer. Immunotherapies against melanoma have been established in several clinical trials but with low efficacy based upon heterologous expression pattern of targeted antigens during melanoma progression and even between individual lesions._x000D__x000D_AVIR Green Hills Biotechnology (AGHB), a biotech company based in Vienna, Austria, has identified an unique tumor associated antigen for melanoma disease that arises from melanoma associated endogenous retrovirus (MERV). This endogenous retrovirus is activated during melanoma progression and leads to a stable expression of specific MERV proteins in melanoma tumors during the whole process of melanoma development – a fact that makes MERV an attractive melanoma tumor antigen that can be targeted by an immunotherapeutic approach. _x000D__x000D_To efficiently present the tumor-associated melanoma antigen MERV to the immune system, AGHB will use its established influenza virus technology in a recombinant vaccine design. Different properties of influenza virus make this vaccine vector very attractive: First, genetically modified influenza viruses (delNS1) are available that were shown to be safe and induce a protective immune response in humans. Importantly, delNS1 influenza vectors are potent inducers of cellular immune responses. Secondly, there are different subtypes of influenza virus available that allow to circumvent pre-existing immunity to the vector in the host._x000D__x000D_The fact that tumor cells are notoriously poor immunogens is a major obstacle in tumor immunology. For example, tumor cells frequently downregulate the expression of MHC class I and MHC class II molecules. As a result, the host’s T-cell responses against tumor cells are impaired. One of interferon’s many effects is to induce the expression of both MHC class I and MHC class II molecules. In this regard, AGHB generated an influenza A virus lacking the interferon-antagonist NS1 (delNS1 virus) that induces high levels of interferon. The broad objective of this proposal is to explore the immunogenic properties of a chimeric influenza delNS1 virus that additionally expresses MERV-T-cell epitopes (FLU/MERV). The final aim is to analyze the potential of the resulting recombinant FLU/MERV viruses as new melanoma vaccine. _x000D__x000D_To ensure that this knowledge will be translated into a marketable product, this project brings together the highly specialized and complementary expertise of two individual SMEs (AGHB, Austria and IBA, Germany) and a highly experienced research institute (DKFZ, German ) into a consortium. In the proposed project AGHB takes the lead in the development of the FLU/MERV vaccine based upon its profound experience in MERV antigens and influenza virus vector design. Epitope prediction will be subcontracted to Emergentec, Vienna. With DKFZ a P joins the project that is highly experienced in tumor antigen T-cell epitope identification and epitope validation. The potency of candidate FLU/MERV vaccines to induce T-cell mediated immunity will be evaluated in vitro and in vivo at DKFZ with the use of IBA´s unique reversible MHC staining technology enabling functional testing of vaccine-induced T-cell populations._x000D__x000D_Over the next ten years, immunotherapy is likely to take the lead among the innovative drugs. Several agents for treating various tumor types are now on the market. Due to the rising economic value of the cancer market, innovative oncology technologies will be an important business area for pharmaceutical industries that want to keep their market potential. With FLU/MERV vaccine addressing melanoma, AGHB and its project Ps expect to play a major role in the emerging market of immunotherapy and plan to gain a substantive market share. Proof of concept for the efficacy of FLU/MERV vaccine which is obtained in this project will be crucial for its application in clinical trials and subsequent market introduction._x000D_

Acronym MELVAX (Reference Number: 4286)
Duration 01/01/2009 - 31/12/2011
Project Topic We aim to generate a vaccine for malignant melanoma based on melanoma-associated endogenous retrovirus (MERV) antigens. Predicted and validated antigens are inserted into an influenza virus vector and the resulting vaccine (MelFlu) is tested in preclinical assays.
Project Results
(after finalisation)
In this project, a novel type of vaccine was developed in preclinic experiments. Based on identification of retroviral epitopes (MERV) in tumor samples, these antigens were validated for vaccination use in animal systems. Then, optimal stretches of antigens were introduced into a vector that is based on genetically modified influenza viruses. These novel vaccine viruses were again validated in an animal system and compared to other immunization methods. _x000D_Specifically, immunogenic MERV T-cell epitopes were defined by bioinformatics and validated in an experimental setting. Final epitope selection for the Env and Gag proteins was performed and selected epitopes were confirmed in a human system. Based upon stability issues, the most promising vaccine vector for final FLU/MERV vaccine candidates (SHgag, FUgag, FUenv) were chosen. The three FLU/MERV vaccine viruses were generated by reverse genetics, tested for stability and antigen expression, titrated and sequenced. These viruses were then analyzed in the HLA-transgenic mouse system._x000D_In the HHDtg mice, specific T-cell resposes were found against the influenza matrix peptide that was included as control peptide, whereas responses against the MERV-specific candidate epitopes was weak. The induction of GAG and ENV specific helper T-cells in DR3tg und DR4tg mice was also rather weak._x000D_To summarize, out of the three tested FLU/MERV constructs, the FuGAG construct produced best results. However the results using FLU/MERV constructs were not substantially better than the results obtained using DNA vaccination._x000D_
Network Eurostars
Call Eurostars Cut-Off 1

Project partner

Number Name Role Country
4 Universitätsklinikum Essen Partner Germany
4 Deutsches Krebsforschungszentrum - German Cancer Research Center Observer Germany
4 IBA GmbH Partner Germany
4 Avir Green Hills Biotechnology Research Development Trade AG Coordinator Austria