ASTRO 2019: Adding SBRT to Pembrolizumab in Metastatic Lung Cancer
Posted: Tuesday, October 1, 2019
Patients with metastatic non–small cell lung cancer (NSCLC) who have experienced disease progression on immunotherapy may benefit from stereotactic body radiotherapy (SBRT) in terms of progression-free survival. Allison M. Campbell, MD, PhD, of the Yale School of Medicine in Connecticut, presented the results of a phase II trial conducted with colleagues at the 2019 Annual Meeting of the American Society for Radiation Oncology (ASTRO) in Chicago (Abstract 74).
“This study provides one more important piece of data that indicates that, for some patients, the immune system can be a really powerful tool to combat metastatic lung cancer,” said Dr. Campbell in an ASTRO press release. “It points us in the direction of places to look for biomarkers that might predict which patients would best respond to this type of therapy.”
The study enrolled 56 patients with NSCLC who had two or more measurable lesions. Patients who had previously experienced disease progression on anti–PD-1 immunotherapy at the time of enrollment received SBRT followed by pembrolizumab. For patients who had not been treated before, they first received pembrolizumab until disease progression, followed by SBRT and continued pembrolizumab treatment.
Of the 56 enrolled patients, 50 were immunotherapy-naive, and 16 of these patients experienced disease progression during the trial. In total, 22 patients received SBRT (6 up front and 16 after pembrolizumab), and 21 completed treatment. Adding SBRT to pembrolizumab led to a mean of 150.67 days before further disease progression, and the disease control rate was 57.14%. Two patients achieved a partial response for over 1 year, and 10 patients achieved stable disease after SBRT.
Patients with higher tumor-infiltrating lymphocyte scores (2–3) saw improved progression-free survival compared with patients who had low tumor-infiltrating lymphocyte scores (0–1; 215 days vs. 59 days). In addition, patients who had an immune-relate adverse event had a longer mean survival than patients who did not have such an event (208 days vs. 88 days).
Disclosure: The study authors’ disclosure information may be found at redjournal.org.