The Study: After all, colorectal cancer comprises one of the largest global oncology market shares. The Chinese phase 3 TAILOR trail (no “x”) was designed to assess the benefit of adding cetuximab to standard FOLFOX chemo in patients with RAS-wildtype (wt) metastatic colorectal cancer. Here’s an important distinction: RAS-wt encompass more genes than specifically KRAS, all of which encode GTPases. Among almost 400 patients enrolled, the addition of cetuximab significantly improved the primary endpoint of progression-free survival (PFS) from 7 to 9 months as well as overall survival from 18 to 21 months. On pre-planned subgroup analysis, those with either right- or left-sided primaries benefited from the addition of cetuximab, and those who were BRAF-wt benefitted the most.
Bottom Line: Counterintuitively, rather than EGFR-status, RAS- and BRAF-wt (i.e., the best-acting) status appear to predict which metastatic colorectal cancers benefit from the addition of cetuximab to standard FOLFOX. | Qin, J Clin Oncol 2018