RAF dimer inhibition enhances the antitumor activity of MEK inhibitors in K-RAS mutant tumors. (PubMed, Mol Oncol)
Here, we report that the RAF dimer inhibitors, lifirafenib (BGB-283) and Compound C, show a strong synergistic effect with MEK inhibitors (MEKi), including mirdametinib (PD-0325901) and selumetinib, in suppressing the proliferation of K-RAS-mutated non-small cell lung cancer (NSCLC) and colorectal cancer (CRC) cell lines. This synergistic effect was not observed with the B-RAF selective inhibitor, vemurafenib...A pharmacodynamic analysis supported a role for the synergistic phospho-ERK blockade in enhancing the antitumor activity observed in the K-RAS mutant models. These findings support a vertical inhibition strategy in which RAF dimer and MEK inhibitors are combined to target K-RAS-mutated cancers, and has led to a Phase 1b/2 combination therapy study of lifirafenib and mirdametinib in solid tumor patients with K-RAS mutations and other MAPK pathway aberrations.