PhosImmune Inc: exploiting tumour associated phosphopeptide antigens for cancer immunotherapy
A new spin out company called PhosImmune Inc, involving researchers based at the University of Virginia in the US, and the University of Birmingham, UK, is aiming to develop novel cancer vaccines targeting phosphopeptide antigens expressed on cancer cells.
The company is focusing on commercializing a proprietary library of over 700 phosphopeptide antigens that are derived from proteins aberrantly phosphorylated in cancer, and are ultimately presented at the cancer cell surface bound to major histocompatibility complex molecules. Traditional cancer vaccines have typically targeted antigens whose overexpression in cancer is not necessarily linked to the process of tumour formation. In contrast, up-regulation of kinase pathways is one of the hallmarks of cancer, and presentation of phosphopeptide antigens on tumour cells appears to be tightly linked to cellular transformation and/or metastasis, potentially providing an immunologically targetable signature of “transformed self” that reflects upregulated signaling pathways critical to the tumour.
According to CEO Thomas Haag, these features, combined with results showing phosphopeptide antigens can elicit robust memory T cell responses against tumours in similar to viral peptides in healthy human donors, represent advantages compared to traditional cancer vaccine approaches. One such advantage may be a decreased likelihood of tumour cell escape, as University of Birmingham-based PhosImmune co-founder Dr Mark Cobbold explains: “The chances a tumor will escape immune control are likely to be much lower if you are targeting the very processes that it needs to maintain its existence.”