The Effects of the Proton Pump Inhibitor Esomeprazole on the Bioavailability of Regorafenib

Patients will start with regorafenib in a loading phase of 21 days and will be admitted for 24 hours to the hospital for pharmacokinetic blood sampling on day 21, 49 and 77 (± 1-2 days). Patients will be randomized into 2 sequence groups (respectively sequences phase A-B-C or phase C-B-A). The patient will use regorafenib alone (phase A) or with esomeprazole for five days (phases B and C). To (completely) rule out a pH-dependent DDI between regorafenib and esomeprazole, during phase B of the study regorafenib is given concomitantly for five days, while during phase C regorafenib is given 3 hours after esomeprazole intake for five days (when the intragastric pH is maximally elevated by esomeprazole).