Exploring the impact of combining radiation with immunotherapy

The development of drugs that work together with the immune system to kill cancer (immunotherapy) represents a major advance in oncology.

Building upon clinical trials led by Dr. Hans Hammers, Associate Professor of Internal Medicine and Co-Leader of the Kidney Cancer Program, and others, the Food and Drug Administration recently approved a dual immunotherapy drug combination (ipilimumab and nivolumab) for advanced kidney cancer. The combination induces significant tumor shrinkage in 40 percent of patients, and in 10 percent of patients all tracers of the cancer vanish.

Investigators at the Kidney Cancer Program of UT Southwestern Medical Center’s Harold C. Simmons Comprehensive Cancer Center are looking for new ways to improve the odds.

A promising strategy involves the addition of radiation therapy to immunotherapy. The idea behind the approach is to induce the release of contents from cancer cells using focal radiation treatment, which may alert the immune system to recognize other cancer cells.

Dr. Raquibul Hannan, Associate Professor, Radiation Oncology and Immunology, along with his team reviewed the UT Southwestern experience combining radiation and immunotherapy in 59 patients. The majority of patients had kidney cancer or melanoma. Most often radiation was administered using stereotactic techniques also known as SAbR.

Their first report (see press release) focused on evaluating the safety of the approach. “This is one of the largest single institution reported experiences of concurrent radiation and immunotherapy,” said Dr. Hannan.

The researchers found that the combination was associated with some side effects, which could be significant in 25% of the patients. The most common was inflammation of the lung or pneumonitis. However, the rates and types of side effects were comparable to those with immunotherapy alone, and the side effects were generally reversible with expert medical treatment.

“Even though this study primarily focused on the safety of the combination, we also made some interesting observations about responses,” stated Dr. Hannan, who found that metastases in the lung respond particularly well to the approach. As a result, several clinical trials looking at the combination of SAbR and immunotherapy are on the way.

For more information about clinical trials ongoing at UT Southwestern Kidney Cancer Program, please see KCP Clinical Trials.