Critzotinib is a Type-1 kinase inhibitor and was first approved by the FDA in 2011. It inhibits ALK, cMET and ROS1 receptor tyrosine kinases. Critzotinib is a chiral molecule that exploits the three-dimensional space of the ATP pocket to achieve optimal potency and selectivity [6
]. The R
-enantiomer as shown here exhibits better potency than the either the racemate or S
-isomer and the approved drug should contain only the R
Pfizer developed the 3rd generation ALK inhibitor lorlatinib
as a follow-up to critzotinib, and this new drug has been reported to outperfom its predecessor in lung cancer.