Lung cancer spreads to the brain in about one-quarter of patients with an advanced form of the disease.
To date, radiation has been the only treatment option, but it comes with toxic side effects.
In a new study, researchers have found that the use of the checkpoint inhibitor pembrolizumab in place of radiation can extend life with very few side effects in patients.
The findings showed that patient response depended on the level of the biomarker (PD-L1) expressed in their tumors.
Of those that did respond, overall survival at one year was 40% and 34% at two years.
The research was conducted by a team at Yale Cancer Center (YCC)
This is the first study to specifically test the benefit of the treatment in a clinical trial of lung cancer patients who had not yet been treated for brain metastasis or whose tumors recurred after radiation.
Before this, most clinical trials of a checkpoint immunotherapy drug did not include patients with brain metastasis, but the few that did provide hints of benefit when retrospectively analyzed.
The researchers clearly showed, for the first time, that brain metastasis responds to targeted immunotherapy treatment for lung cancer.
In general, they found that the benefit offered by pembrolizumab to the lungs in patients with advanced lung cancer was mirrored in control of their brain tumors. The brain and body responses were the same.
This study enrolled 42 patients with small brain tumors (5-20 mm) that had not been previously treated or that progressed after radiation treatment.
Patients did not have neurologic symptoms. They were divided into two groups: patients in cohort 1 had some PD-L1 activity; those in cohort 2 had none. Researchers found that none of the six patients in cohort 2 responded to pembrolizumab.
With further study and biomarker analysis, the team says it might make sense for some patients to try a checkpoint inhibitor first to treat both their lung cancer and brain metastasis. Radiation could follow, if necessary
The lead author of the study is Sarah B. Goldberg, M.D., M.P.H., associate professor of medicine (medical oncology) at YCC.
The study is published in The Lancet Oncology.
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