Mps1-IN-1 dihydrochloride is a potent and ATP-competitive Mps1 kinase inhibitor with an IC50 of 367 nM. Mps1-IN-1 dihydrochloride inhibit Mps1 mitotic kinase activity and abrogates spindle assembly checkpoint (SAC) function. Mps1-IN-1 dihydrochloride decreases the viability of both cancer and ‘normal’ cells[1].