Oxford BioMedica PLC (OXBDF)

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In most cancers, tumour-specific antigens are not well defined, but in B cell cancers (such as CLL
and ALL) the CD19 antigen is an attractive target that has been validated by a number of
approaches. Expression of CD19 is highly restricted to B cells and not detected on other normal
tissues, including hematopoietic stem cells, thus making it a safe tumor antigen. The approach is to
modify T cells with a CAR that mimics the signaling of the natural T cell receptor (TCR) when
encountering tumor antigen. This creates a universal tumor-specific TCR that can be used across
patients with a common tumor antigen.
With CAR immunotherapy, the T cells are drawn from a patient's blood then transduced ex vivo so
they are able to identify and bind to cells that express the CD19 antigen present on a patient's
cancerous cells. When the modified T cells are re-introduced into the patient's blood, they seek out
and destroy the targeted cancer cells.
The activation and re-targeting of the patient’s T cells is achieved by genetically modifying them
using a lentiviral vector, which expresses an antibody-like protein that is the basis of the CAR. It is
at this stage that Oxford BioMedica’s expertise with lentivirus vector in general and production in
particular is expected to come into play. Oxford BioMedica will initially be responsible for
manufacturing several batches of a lentiviral vector encoding CTL019 technology. This is the vector
that will be used to transduce patients’ immune cells (T-cells) in an ex vivo process before they are
re-infused back into the patients.
The University of Pennsylvania says these re-engineered T-cells currently cost about $20,000 per
patient, much less than a bone-marrow transplant, and believes the higher volumes of production
scale-up will be likely to reduce the price tag. Such pricing assumptions are, in our view, realistic
and fall in a similar range to those we envisage for Oxford BioMedica’s own proprietary lentivirus
vector based gene therapy products (RetinoStat, StarGen and UshStat).