PF-06463922 is a potent, selective, brain-penetrant, and high affinity ALK (Anaplastic lymphoma kinase) and ROS1 (c-Ros oncogene 1) inhibitor displaying >100-fold selectivity for ROS1 over panel of 204 other kinases. It has strong activity against all known ALK and ROS1 mutants identified in patients, including the EML4-L1196M mutant of ALK (Ki = < 0.02 nM). It inhibits proliferation of BaF3 cells containing Crizotinib resistant ROS1 mutation in vitro. MW: 406.41. Purity ≥98% by HPLC