New Agent Could Enhance Effectiveness of Radiotherapy

Scientists have demonstrated the potential of a drug to enhance the effectiveness of radiotherapy in stopping tumor growth.

There is increasing interest in using the body’s own immune system to attack tumor cells—an approach that can be very effective without the side effects linked with traditional chemotherapy.

Skin cancers have been effectively treated using a topical cream, imiquimod, which recruits immune cells through a molecule called toll-like receptor 7 (TLR7), a protein that recognizes foreign and potentially damaging substances. Earlier, researchers from the University of Manchester (part of the Manchester Cancer Research Centre; UK) have shown that they can also trigger the immune system into producing an immune response against non-skin cancers by injecting an agent similar to TLR7 into the blood.

Working with AstraZeneca (London, UK) and Dainippon Sumitomo Pharma (Osaka, Japan), the British group of investigators have examined at another molecule that activates TLR7, known as DSR-6434. Using mouse models of two different types of cancer, they evaluated DSR-6434 on its own and in combination with radiotherapy and gauged the effect on the primary tumor and the number of secondary tumors in the lungs.

Prof. Ian Stratford, from Manchester Pharmacy School, who, with Prof. Tim Illidge, who led the study, which was published online January 2014 in the International Journal of Cancer, said, “We have already seen a strong immune system response from other immunotherapy agents in combination with radiation--this new agent appears to be even more potent.”

The investigators revealed that giving DSR-6434 combined with radiotherapy led to tumor shrinkage and increased long-term survival. They discovered that the combination treatment also reduced the occurrence of secondary lung tumors. “It looks like there’s good reason to use radiotherapy alongside immunotherapy agents in the treatment of solid tumors. These results strongly suggest that this sort of combination therapy should be evaluated in clinical trials with cancer patients,” added Prof. Stratford.

Related Links:
Manchester Cancer Research Center
AstraZeneca
Dainippon Sumitomo Pharma