- Guide to PHARMACOLOGY
Synonyms: compound 11 [PMID: 28139931] | example 5 [WO2015083028] | Litfulo® | PF-06651600 | PF06651600
ritlecitinib is an approved drug (FDA (2023))
Compound class: Synthetic organic
Comment: Ritlecitinib (PF-06651600) is a potent, orally active, molecule with dual inhibitor activities. It acts as a covalent and selective inhibitor of Janus kinase 3 (JAK3)  (a type I inhibitor, that binds to the kinase in its ATP pocket), and it also inhibits TEC family kinases (BTK, ITK, TEC, Etk, TXK) that are involved in immune cell regulation. It has demonstrated anti-inflammatory activities in in vivo models . Ritlecitinib is example 5 in a Pfizer patent that provides SAR for 343 analogues . There are three crystal structures available for compounds reported in  with JAK3, but not for compound 11 (the PDB identifiers are 5TTV, 5TTU and 5TTS).
Ligand Activity Visualisation Charts
These are box plot that provide a unique visualisation, summarising all the activity data for a ligand taken from ChEMBL and GtoPdb across multiple targets and species. Click on a plot to see the median, interquartile range, low and high data points. A value of zero indicates that no data are available. A separate chart is created for each target, and where possible the algorithm tries to merge ChEMBL and GtoPdb targets by matching them on name and UniProt accession, for each available species. However, please note that inconsistency in naming of targets may lead to data for the same target being reported across multiple charts.✖
|PF-06651600 exhibits favourable selectivity against a screening panel of 305 kinases in vitro, and shows measurable inhibition of 7 of the 10 other kinases which share a cysteine residue analogous to Cys-909 in the JAK3 ATP binding site (these were BMX, ITK, TXK, TEC, BTK, BLK and HER4) .
ATP concentration for JAK3 is 4 μM at Km and for JAK1 is 40 μM at Km, but some assays reported in  were carried out at 1 mM ATP .
|Selectivity at enzymes|
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