AZ304 shows potent inhibitory activities to the kinase domains of wild type BRAF, V600E mutant BRAF and wild type CRAF in vitro, with IC50 values of 79 nM, 38 nM and 68 nM, respectively. AZ304 potently reduces ERK phosphorylation (p-ERK), with a mean EC50 of 65 nM in the V600E mutant BRAF containing melanoma cell line A375 and an EC50 of 60 nM in the wild type BRAF containing melanoma cell line SK-MEL-31. AZ304 markedly inhibits cell proliferation in mutant BRAF cancer cell lines, and effectively reduces cell growth in selected cell lines harbouring wild type BRAF/RAS or mutant RAS. The GI50 values ranged from 0.08-7.72 μM in mutant BRAF cell lines, 0.43-11.7 μM in wild type BRAF/RAS cell lines, and 0.9-16.66 μM in mutant RAS cell lines. AZ304 exhibits anti-proliferative effects on multiple cancer types, including melanoma, colorectal cancer, leukaemia, ovarian cancer, lung cancer, and pancreatic cancer, independently of BRAF genetic status. AZ304 retains inhibitory activity against both V600E mutant and wild type BRAF CRC cell lines in the presence of the EGFR ligand EGF^[1].

AZ304 monotherapy and its combination with Cetuximab have anti-tumour effects on RKO and Caco-2 tumour xenografts without obvious toxicity, independently of BRAF mutation status^[1].