The present invention relates to a combination therapy of propane-1-sulfonic acid {3-[5-(4-chlorophenyl)-1H-pyrrolo[2,3-b]pyridine-3-carbonyl]-2,4-difluoro-phenyl}-amide, or a pharmaceutically acceptable salt thereof, and an topoisomerase inhibitor for treating a patient suffering from a proliferative disorder, in particular a solid tumor, for example, colorectal cancer, melanoma, and thyroid cancer. In particular, the present invention relates to such a therapy wherein the topoisomerase inhibitor is irinotecan, or a pharmaceutically acceptable salt thereof, and the disorder is colorectal cancer involving a tumor comprising b-Raf having the V600E mutation.