Circulating cytokines and outcome in metastatic colorectal cancer patients treated with regorafenib

BACKGROUND: Regorafenib is an oral small-molecule multikinase inhibitor approved in third or later line of treatment for patients with metastatic colorectal cancer (mCRC). Regorafenib has shown significant benefits in overall survival and progression free survival in two phase III trials compared to placebo in patients with mCRC who had progressed on previous therapy. AIM: To identify an immune profile that might specifically correlate with the outcome in patients treated with regorafenib. METHODS: Blood samples were collected from 17 patients before treatment with regorafenib and from 6 healthy volunteers. The proteins evaluated (TNF-α, TGF-β, VEGF, CCL-2, CCL-4, and CCL-5) were selected on the basis of their roles in angiogenesis and colorectal cancer pathogenesis. RESULTS: We found that TNF-α basal level was significantly higher in mCRC patients compared to healthy individuals. Non Responder (NR) patients showing progression of disease (n = 12) had higher basal level of TGF-β, TNF-α, VEGF, CCL-2 and CCL-5 compared to Responder (R) patients (complete response CR, n = 1; partial response PR, n = 1; Stable Disease SD, n = 3). On the contrary, plasma basal level of CCL-4 was higher in R compared to NR patients. High values of TGF-β and TNF-α negatively correlated with progression free survival. CONCLUSION: These results suggest a cytokine signature potentially able to discriminate between R and NR patients to treatment with regorafenib.