GNE-4997 is a potent and selective inhibitor of the interleukin-2-inducible T-cell kinase (Ki: 0.09 nM). The correlation between the basicity of solubilizing elements in GNE-4997 and off-target antiproliferative effects decreases cytotoxicity.
(3S, 4S)-PF-06459988 is the less active S enantiomer of PF-06459988, which is a potent irreversible inhibitor of T790M mutant epidermal growth factor receptor (EGFR). PF-06459988 exhibits excellent selectivity against EGFR wild-type due to its minimally reactive electrophile, which reduces the likelihood of off-target labeling.