ESTRO 2016: Radiation and L19-IL2 Immunotherapy Combination Shows Activity in Preclinical Models

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Radiation therapy not only targets and destroys cancer cells, but also helps to activate the immune system against their future proliferation. However, this immune response is often not strong enough to be able to completely eradicate tumors, and even when it is, its effect is limited to the area that has been irradiated. Now, however, research presented at the European Society for Radiotherapy & Oncology (ESTRO) 35 Conference on May 1 (Abstract OC-0234)1 has shown that the addition of an immune system–strengthening compound can extend the radiation therapy–induced immune response against the tumor sites, and that this response even has an effect on tumors outside the radiation field.

Nicolle Rekers, MSc, from the Department of Radiation Oncology, Maastricht University Medical Centre, Maastricht, The Netherlands, described how a combination of radiation therapy and L19-IL2, an immunotherapy agent, can increase significantly the immune response when given to mice with primary colorectal tumors. L19-IL2 is a combination of an antibody that targets the tumor blood vessels and cytokines.

The researchers found not only that the mice were tumor-free following treatment, but also that when reinjected with cancer cells 150 days after cure, they did not form new tumors. There was also an increase in the number of cells with an immunologic memory.

“Radiation therapy damages the tumor, creating a...