Changes in serum interleukin-8 (IL-8) levels reflect and predict response to anti-PD-1 treatment in melanoma and non-small-cell lung cancer patients

ABSTRACT Background Surrogate biomarkers of efficacy are needed for anti-PD1/PD-L1 therapy, given the existence of delayed responses and pseudo-progressions. We evaluated changes in serum IL-8 levels as a biomarker of response to anti-PD-1 blockade in melanoma and non-small-cell lung cancer (NSCLC) patients. Patients and methods Metastatic melanoma and NSCLC patients treated with nivolumab or pembrolizumab alone or nivolumab plus ipilimumab were studied. Serum was collected at baseline; at 2–4 weeks after the first dose; and at the time-points of response evaluation. Serum IL-8 levels were determined by sandwich ELISA. Changes in serum IL-8 levels were compared with the Wilcoxon test and their strength of association with response was assessed with the Mann–Whitney test. Accuracy of changes in IL-8 levels to predict response was estimated using receiver operation characteristics curves. Results Twenty-nine melanoma patients treated with nivolumab or pembrolizumab were studied. In responding patients, serum IL-8 levels significantly decreased between baseline and best response (P Conclusions Changes in serum IL-8 levels could be used to monitor and predict clinical benefit from immune checkpoint blockade in melanoma and NSCLC patients.