Previous Radiotherapy Improves Response to Immunotherapy in NSCLC

Submitted by admin5 on Tue, 05/30/2017 - 17:58

Patients with advanced non-small cell lung cancer (NSCLC) who receive previous radiotherapy are more likely to benefit from immunotherapy than those patients without previous radiotherapy, according to research published in The Lancet (published online May 24, 2017; doi:10.1016/S1470-2045(17)30380-7).

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An estimated less than 20% of patients with NSCLC respond to anti-PD1 therapies. Pre-clinical studies have recently shown that radiation therapy in combination with immunotherapy can improve the body’s immune response to tumors. However, more research is needed is needed to validate this association.

Percy Lee, MD, associate professor, department of radiation oncology, David Geffen School of Medicine, University of California Los Angeles, and colleagues conducted a study to assess response and toxicity in patients who previously received radiotherapy for NSCLC before receiving the anti-PD1 therapy pembrolizumab. The secondary analysis included 97 patients who were treated with pembrolizumab as part of a previous phase I clinical trial. Researchers separated the patients into subgroups to compare patients who had received previous radiation therapy (n = 42) with those who had not (n = 55).

Results of the study showed that patients who received previous extracranial radiotherapy had a significantly longer median progression-free survival (PFS) compared with those did not (6.3 months vs 2.0 months, respectively). Additionally, patients who received radiation therapy had a longer median overall survival (OS) compared with those who did not (11.6 months vs 5.3 months, respectively).

Authors of the study acknowledged that patients who had received prior thoracic radiation therapy exhibited more treatment related pulmonary toxicity following pembrolizumab treatment compared with those who received any other type of radiotherapy or no radiation at all (13% vs 1%, respectively).

Authors reported that these findings represent the largest clinical data analysis to date on the impact of prior radiation therapy in enhancing the activity of anti-PD1 therapies in patients with NSCLC. “Further clinical trials investigating this combination are needed to determine the optimal treatment strategy for patients with advanced NSCLC,” the authors wrote.—Zachary Bessette