Abrocitinib

Abrocitinib is an orally active Janus kinase 1 (JAK1) inhibitor developed by Pfizer as PF-04965842 and marketed as Cibinqo for atopic dermatitis. The Abrocitinib molecular formula is C14H21N5O2S, and the Abrocitinib molecular weight is 323.42 g/mol. CAS 1622902-68-4 refers to a specific stereoisomer of Abrocitinib – the cis-cyclobutyl form, as reflected in the compound's IUPAC name.  The Abrocitinib IUPAC name is N-{cis-3-[methyl(7H-pyrrolo[2,3-d]pyrimidin-4-yl)amino]cyclobutyl}propane-1-sulfonamide. The Abrocitinib canonical SMILES is CCCS(=O)(=O)NC1CC(N(C)c2ncnc3[nH]ccc23)C1.

Application of Abrocitinib

Abrocitinib is used to examine JAK1-dependent cytokine signaling, including pathways activated by IL-4, IL-13, IL-31, and interferons. The PF 04965842 Abrocitinib research record supports comparisons between biochemical selectivity, STAT-phosphorylation assays, animal pharmacology, and clinical findings. This makes the compound useful as a reference when evaluating other JAK1-directed molecules without treating selectivity as absolute.

In Vitro

In enzymatic assays, Abrocitinib inhibited JAK1 with an IC50 of 29 nM, compared with 803 nM for JAK2, over 10,000 nM for JAK3, and 1,253 nM for TYK2. These values correspond to approximately 28-fold selectivity over JAK2, more than 340-fold over JAK3, and 43-fold over TYK2.

In human whole blood, the compound inhibited IFNα-stimulated STAT3 phosphorylation and IFN-stimulated STAT1 phosphorylation with IC50 values of 189 and 163 nM, respectively. Its IC50 against JAK2-dependent, EPO-stimulated STAT5 phosphorylation was 7.178 μM, providing a functional comparison under the reported assay conditions.

In Vivo

Oral Abrocitinib at 5, 15, and 50 mg/kg once daily for seven days reduced paw swelling in a rat adjuvant-induced arthritis model. In JADE COMPARE, both 100 and 200 mg once daily improved key outcomes versus placebo. The 200 mg dose, but not the 100 mg dose, was superior to dupilumab for itch response at week 2. Cibinqo is approved in the United States for patients aged 12 years and older with refractory moderate-to-severe atopic dermatitis under the conditions specified in its label.

Biochemical and Physiological Actions

The Abrocitinib chemical structure supports ATP-competitive binding to the JAK1 kinase domain. By limiting JAK1 activation, Abrocitinib reduces phosphorylation of receptor-associated STAT proteins and their subsequent transcriptional signaling. Because JAK1 partners with JAK2, JAK3, or TYK2 depending on the cytokine receptor, the measured Abrocitinib structure–activity profile must be interpreted for each assay system.

The formal Abrocitinib structure IUPAC name records the cis relationship of the cyclobutane substituents. It defines compound identity but does not, by itself, establish the bound conformation or guarantee assay selectivity.

Features and Benefits of Abrocitinib

• Low-nanomolar biochemical potency against JAK1.
• Selectivity evaluated across JAK-family and whole-blood assays.
• A verified Abrocitinib chemical formula and defined cis configuration.
• Preclinical, Phase 3, and regulatory data available for comparison.

The isomeric Abrocitinib SMILES shown on the product page preserves stereochemical information not present in the canonical string. Before an Abrocitinib buy, verify the Abrocitinib IUPAC name CAS pairing, purity, and stereochemical identity against the product-specific CoA rather than relying on a structure depiction alone.