Regorafenib therapy in metastatic colorectal cancer patients: markers and outcome in an actual clinical setting.

Matthias Unseld, Michaela Filip, Siegfried Seirl, Andreas Gleiss, Daniela Bianconi, Markus Kieler, Svitlana Demyanets, Werner Scheithauer, Christoph Zielinski,  Gerald Prager

Abstract:

The oral multikinase inhibitor regorafenib had beneficial effects in randomized clinical phase III trials compared to the placebo in patients with metastatic colorectal cancer (mCRC) who progressed on standard therapies. The factors which influence regorafenib response and therapy sequence during treatment history are still highly discussed, and herein we analyzed the therapy algorithm, outcome and clinical markers following regorafenib application in a single center register study. Clinical data for 48 metastatic colorectal cancer patients were collected from 01.01.2013 to 31.12.2016. Treatment effects according to various patient and tumor characteristics were evaluated using univariate and multivariate Cox proportional hazard regression models. The 48 patients comprised 14 (29%) females and 34 (71%) males, with mean age 64.2±9 and ECOG 0-1. Progression free survival under regorafenib therapy was 2.9 months (quartiles 2.2; 4.4) and the overall response rate was 2 (4%) and disease control rate was 19 (40%). Overall survival (OS) and progression free survival (PFS) were investigated under regorafenib in the chemotherapy regimen given immediately before and afterthis treatment. Variables including tumor localization, Ras status, CEA and CA 19-9 plasma levels were analyzed for their impact on PFS, and the regorafenib-related adverse events were also observed. Our study confirms the efficacy of regorafenib in a real-life setting. We established that response rate and PFS in regorafenib treatment are independent of tumor localization, Ras status or biomarkers such as CEA and CA 19-9. Trifluridin/tripacil application or re-induction of chemotherapy +/- target therapy was effective following regorafenib therapy.