PF-06463922 abrogates ALK phosphorylation more effectively than crizotinib in vivo. Mice harboring NB-1643 xenografts (n = 3 per arm) were treated for 3 days with vehicle, crizotinib (100 mg/kg QD), or PF-06463922 (5 mg/kg BID, 10 mg/kg/day). Tumors were harvested 1 hour after the final drug treatment, and subjected to immunoblotting as described in Methods using antibodies against pY1278 in the activation loop of the kinase (A) or pY1604 in the C-terminal regulatory tail (B), alongside control blots for total ALK and β-actin (lower panels).