Immune Checkpoint Inhibitor Nivolumab and Radiotherapy in Pretreated Lung Cancer Patients: Efficacy and Safety of Combination.

Background: In the last decade, the discovery of immune checkpoint inhibitors such as the PD-1 inhibitor, nivolumab, has revolutionized the treatment of advanced non-small cell lung cancer (NSCLC). Concurrent radiotherapy (RT) is of particular interest in showing the potential role of the combination.

Objective: The purpose of this study was to retrospectively evaluate the addition of RT to an immune checkpoint inhibitor, nivolumab, with regard to activity and feasibility in pretreated, advanced, or metastatic lung cancer patients at our center.

Patients And Methods: We retrospectively identified 35 consecutive patients (30 men and 5 women), who received nivolumab for pretreated NSCLC, between March 2015 to December 2016. Fifteen received hypofractionated RT as a palliative measure, and, in these patients, nivolumab was administered at an interval of at least 1 week from the end of RT.

Results: The median age was 69 years, and 23 patients (65.7%) had an Eastern Cooperative Oncology Group (ECOG) score of 0 to 1. All patients had previously received at least 1 systemic regimen, and, for only 3 (8.6%), nivolumab was a third-line treatment. The 2 treatment arms, RT-nivolumab and only-nivolumab, were well matched for baseline characteristics. At a median follow-up of 7.4 months, the 1-year overall survival rates were 57.8% for patients treated with RT-nivolumab and 27.4% for patients treated with only-nivolumab (P=0.043). The 1-year progression-free survival in the RT-nivolumab group was 57.8% and 20.6% in the only-nivolumab group (P=0.040). No difference in adverse events was detected.

Conclusions: In conclusion, RT and nivolumab can be combined, obtaining a benefit in overall survival and progression-free survival, without an increase in acute toxicities in pretreated advanced NSCLC patients. Prospective studies are needed to confirm these results.