Although long-term cancer survival rates have been significantly improved by the implementation of screening programmes and new therapies, many cancers remain incurable.

The improvements in cancer treatment include the availability of targeted cancer therapies that block the growth of cancer by interfering with specific molecules involved in tumour progression, and are designed to be more effective and less harmful to normal cells than traditional chemotherapy. There is a trend towards more individual diagnosis and treatment and a developing field of targeted immunotherapies trying to boost the immune system’s ability to control cancer. However, the first immunotherapies, such as cancer vaccines and immune modulating antibodies, have to date not lived up to expectations.

Overcoming cancer antigen down-regulation

The immune system often fails to clear tumours, even those presenting cancer specific antigens on the cell surface, a phenomenon known as tumour tolerance.  Cancers escape immuno-surveillance via a variety of mechanisms, including up-regulation of inhibitory proteins and down-regulation of surface HLA. Naturally occurring tumour-specific T cells, in addition to those induced by cancer vaccines, tend to have low avidity and fail to recognise low levels of cancer associated antigens, typically 20 to 150 epitopes per tumour cell.  Immunocore’s ImmTACs, however, have been designed to work optimally across the antigen presentation window of cancer cells, and are therefore potentially able to break tumour tolerance.

Pipeline of candidates

Immunocore has is developing a number of ImmTACs targeting different cancers. The lead candidate, ImmTAC-gp100, targeting metastatic melanoma, entered clinical trials in 2010 and a second candidate is expected to follow within 18 months. Pipeline projects are available for partnering.