The safety profile for E6201 in this study contrasts with that of the oral MEK1/MEK2 inhibitor trametinib, which was associated with retinal pigment epithelial detachment, retinal vein occlusion, interstitial lung disease, skin toxicity, and cardiomyopathy in clinical trials (Mekinist (trametinib) tablets, for oral use [package insert]. This evidence concerns the gene MAP2K2 and cardiomyopathy.