There has been welcome excitement in the cancer field lately about immune-based treatments, which co-opt the body’s own immune system to fight tumors. The so-called immunotherapies have transformed everything from solid cancers like melanoma and lung, to blood cancers like lymphoma and leukemia.
In the latest study involving one of the first immunotherapies approved by the Food and Drug Administration, researchers report that an immune-based approach can even help people with advanced melanoma, which has spread to the brain, to live longer.
The study, published in Cancer Immunology Research, included more than 2,700 cases of stage 4 melanoma that were recorded in the National Cancer Database, a national repository of newly diagnosed cancer cases in the U.S. Of these, about 40% involved metastasis of the melanoma to the brain (the remainder had metastases to the brain as well as other parts of the body). Immunotherapies have been approved since 2011 to treat advanced melanoma and have dramatically improved overall survival; the immune-based treatment is so effective that chemotherapy is no longer used as first-line treatments for these patients. Still, few studies have looked specifically at the role these anti-cancer medications might have in people with disease that has spread to the brain. Many metastatic cancers are treated with steroids, which doctors thought would interfere with the effectiveness of the immune therapies.
Dr. Bryan Iorgulescu, a post doctoral fellow in the department of pathology at Brigham and Women’s Hospital, Harvard Medical School and Dana-Farber Cancer Center, and his colleagues attempted to address that gap in research with the current study. He and his team found that in 2015—four years since the first immune-based therapy, called checkpoint inhibitors, were approved—34% of people with melanoma that had spread to the brain were treated with them, compared to 11% in 2011. Median survival for these people increased in that time from five months to nearly 12.5 months.
“This is one of the first studies saying that yes, we can rest assured that the same survival benefits we saw in early melanoma patients are also being observed in patients with brain metastases,” says Iorgulescu of the immune-based therapies, also called checkpoint inhibitor drugs. The medications work in various ways by essentially releasing the immune system to target the cancer; normally immune cells leave tumors alone, since they originate from normal tissue and immune defenses are designed to recognize and destroy only foreign invaders. The checkpoint inhibitors allow powerful immune cells to recognize and hone in on cancer cells and co-opt killer cells to destroy them.
The data did not distinguish whether the people with melanoma that had spread to the brain were taking steroids or not, but Iorgulescu says it’s encouraging that among the entire group, some of whom might have been taking steroids, the checkpoint inhibitors seems to show some benefit. The findings should launch additional studies that look in more detail at which conditions and which doses of checkpoint inhibitor treatment are most effective for these people. “Checkpoint blockade treatments have had phenomenal success and made revolutionary advances in treating melanoma,” he says. “We now show that the same benefit we found in early trials of advanced patients also transfers to patients with brain metastases. This sets the groundwork for more trials and studies to better understand how to treat advanced disease.”