A new study led by Keck Medicine of USC researchers found that corticosteroids, a commonly prescribed medication to alleviate cancer-related symptoms for non-small cell lung cancer patients treated with immunotherapy, are the main reason certain immunotherapies may fail in treating the disease.

The study, published in Cancer Research Communications, showed that high doses of steroids, when given before and/or during a specific type of immunotherapy, caused patients’ tumors to shrink less than those of patients not on steroids. Those patients also did not live as long.

Additionally, researchers believe they have found the mechanism behind why steroids and some immunotherapies may not mix.

Read more about this study.