A Case of Liver Injury Immediately After Initiation of Triple Therapy in a Patient With BRAF V600E Mutation-Positive Colorectal Cancer

The combination therapy of binimetinib, encorafenib, and cetuximab ("triplet regimen") was approved in Japan in November 2020 for the second-line treatment of BRAF V600E mutation-positive colorectal cancer. In this study, we encountered a patient who developed a liver injury requiring drug withdrawal on day eight of the triplet regimen administration. The protocol for the international phase III study did not specify blood and biochemical tests on day eight. Hepatic failure occurred in 45.9% (222/484) of the patients within three months, but no specific timing of onset was reported. Since it is important to disseminate novel adverse events to the public, we report the results of this study based on a literature review.