[CAS NO. 1628838-42-5]  RAF709

RAF709 appears to have very slow dissociation kinetics (T > 6.5 h) using the rapid dilution method to measure its dissociation rate constant. In cellular assays, the dose−response of pMEK and pERK are measured in Calu-6 cells with EC50 of 0.02 and 0.1 μM with minimal paradoxical activation and inhibition of proliferation with EC50 of 0.95 μM. RAF709 stabilizes BRAF−CRAF dimers with an EC50 of 0.8 μM. Of the 456 kinases tested, RAF709 shows a high level of selectivity, demonstrating greater than 99% on-target binding to BRAF, BRAFV600E, and CRAF at 1 μM and very few off-targets with DDR1 (>99%), DDR2 (86%), FRK (92%), and PDGFRb (96%), the only kinases with binding >80% at 1 μM. RAF709 shows equal activity against both RAF monomers and dimers. In in vitro biochemical assays, RAF709 exhibits potent inhibitory activity targeting BRAF, BRAFV600E, and CRAF with IC50 values ranging between 0.3 to 1.5 nmol/L. RAF709 treatment leads to a dose-dependent induction of B/CRAF heterodimerization in HCT116, but inhibits MEK and ERK phosphorylation, in line with the ability of RAF709 to effectively inhibit the RAF dimers. RAF709 selectively inhibits oncogenic signaling and proliferation in tumor cells with BRAF, NRAS, or KRAS mutations with minimal paradoxical activation.