Scientists target tumours with 'magic bullet' antibodies

A new cancer therapy which uses ultra-violet light to turn the cells of the body's own immune system into "ultra-specific magic bullets" for attacking tumours is revealed today by British scientists.

The team from Newcastle University have found a way of preventing antibodies from prompting a reaction until they are next to the tumour and can be activated by shining a light probe on to the appropriate area of the body.

The technique has been tested successfully on mice with ovarian cancer and Professor Colin Self, who led the research team, hopes to start clinical trials in patients next year.

The treatment has already taken 11 years to develop and it could be another decade before it is available as a matter of routine. In principle it could be used against cancers of the lung, prostate, bladder and eye, the team say.

They coated antibodies, used by the immune system to tackle disease and infection, with a light-sensitive organic oil that prevents them from reacting as normal within the body. The antibodies are then injected into the patient, who must wait until they have reached the tumour.

When a UV-A probe is shone on to the body, the antibody is re-activated and can bind to T-cells, which form the body's own defence mechanism, prompting them to attack the surrounding tissue.

Professor Self said: "I would describe this development as the equivalent of ultra-specific magic bullets. This could mean that a patient coming in for treatment of bladder cancer would receive an injection of the cloaked antibodies. She would sit in the waiting room for an hour and then come back in for treatment by light. Just a few minutes of the light therapy directed at the region of the tumour would activate the T-cells causing her body's own immune system to attack the tumour."

The researchers' work is detailed in two papers, by Professor Self and Dr Stephen Thompson, published online today in the journal ChemMedChem.

Unlike chemotherapy and radiotherapy, which also kill off healthy tissue, the new procedure maximises the destruction of the tumour while minimising damage to surrounding cells. BioTransformations Ltd, a company set up by Professor Self to develop the technology, wants to start clinical trials on patients with secondary skin cancers early next year.