Efficiency and Safety of Regorafenib in Metastatic Colorectal Cancer (mcrc): Real Life Experience from Turkey.

e15551 Background: In this study, we aimed to investigate the efficiency and safety of initiation of regorafenib at different doses in mCRC Methods: Between January 2013 and January 2018, this study retrospectively reviewed mCRC patients (pts) who treated with regorafenib after failure of fluoropyrimidine, irinotecan and oxaliplatin +/- biologic agent from 7 centers in Turkey Results: The median age of 112 pts was 54.85 years (range, 28-78) and 63 (56.3%) pts was male. At the time of diagnosis; there were 12 pts (10.7%) with ECOG PS 0, 68 pts (60.7%) with ECOG PS 1, and 32 pts (28.6%) with ECOG PS 2. The disease was localized to the right colon in 20.5% of the pts. RAS mutation was detected in 56.8% of the pts. All of the pts had a history of using one or two biological agents. Median 3 lines (range, 2-7) of treatment was given before regorafenib. The median regorafenib cycle was 3 (1-24). Regorafenib was continued in 14 (12.5%) pts during the analysis. Regorafenib was started with 80 mg in 14 pts (14.3%), 120 mg in 17 pts (15.2%) and 160 mg in 79 pts (70.5%). Regorafenib dose was increased in 21 pts (%18.8) after initial dose. The maintenance dosage was 160 mg in 71 pts, 120 mg in 29 pts, and 80 mg in 12 pts. In the follow-up, dose reduction was performed in 32 pts (28.6%). Median progression-free survival (PFS) and median overall survival (OS) were 12 weeks (11.6-17.3w) and 72 weeks (64.9-77.3w) respectively. PFS was longer (15 weeks versus 12 weeks) in the low-dose started group (p < 0.05). OS was longer in the groups that started with standard dose treatment and dose reduction performed in the follow up (p < 0.05). The clinical benefit rate was 31.8% (partial response 11.8%). The reason for discontinuation of treatment was toxicity in 33 pts (29.5%) and progression in 64 pts (57.1%). 75.9% of the patients had any degree of toxicity. The most frequent serious (grade 3-4, 41.9%) adverse events complaints were fatigue (n = 26), hypertension (n = 5), rash (n = 5), diarrhea (n = 4) and hand foot syndrome (n = 7). Conclusions: Initiation of regorafenib at the standard 160 mg dose and appropriate dose reduction according to toxicity should be the standard approach.