9NWX | pdb_00009nwx

Discovery of a Small Molecule ITK and Pan-TRK Kinase Inhibitor (PF-07245303) for the Potential Topical Treatment of Atopic Dermatitis

• PDB DOI: https://doi.org/10.2210/pdb9NWX/pdb

• Classification: SIGNALING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Linospadix microcaryus
• Mutation(s): No 


• Deposited: 2025-03-24 Released: 2025-11-19 
• Deposition Author(s): Liu, S.
• Funding Organization(s): Not funded

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.35 Å
• R-Value Free: 
  0.227 (Depositor), 0.219 (DCC) 
• R-Value Work: 
  0.182 (Depositor), 0.182 (DCC) 
• R-Value Observed: 
  0.184 (Depositor) 

Starting Model: experimental

Literature

Discovery of an ITK and TRK kinase inhibitor for the potential topical treatment of atopic dermatitis.

Duffen, J.L., Crouse, K.K., Ji, L., Brault, A.L., Ford, K., Brooks, J., Jelinsky, S.A., Li, Y., Shin, J.H., Zhao, Y., Andreyeva, T., Hammerman, K., Arnold, C., Sheldon, R.T., Garren, J., LaBarge, W., Resek, A., Volmer, J., Bagley, S.W., Casimiro-Garcia, A., Chinigo, G.M., Davoren, J.E., Denny, R.A., Drozda, S., Foley, T.L., Hicklin, R.W., Liu, S., Lovering, F.E., Nedoma, N.L., Parikh, M.D., Strohbach, J.W., Trujillo, J.I., Steyn, S.J., Nocka, K., Hegen, M., Vincent, F., Lee, K.L., Gerstenberger, B.S., Primiano, M.J.

(2026) Nat Commun 17

• PubMed: 41803126 
• DOI: https://doi.org/10.1038/s41467-026-70000-6
• Primary Citation Related Structures: 
  9NWX


• PubMed Abstract: 
  

  Interleukin-2-inducible T cell kinase is expressed by T cells and amplifies T cell receptor-dependent signals. Interleukin-2-inducible T cell kinase deletion or inhibition reduces production of interleukin-4 and interleukin-13, key drivers of atopic dermatitis. Nerve growth factor signals via the receptor tropomyosin-related kinase A and may promote pruritus in atopic dermatitis lesions. Here we describe PF-07245303, a compound which potently inhibits interleukin-2-inducible T cell kinase and tropomyosin-related kinase family kinases capable of inhibiting T cell receptor-mediated cytokine production from CD4 and CD8 T cells and suppressing nerve growth factor-induced human basophil activation. In human skin explants, PF-07245303 demonstrates inhibition of tropomyosin-related kinase A phosphorylation, suppresses cytokine expression from T cell receptor-activated resident T cells and reverses the expression of atopic dermatitis associated genes. Topical application of PF-07245303 reduces proinflammatory and epidermal changes in a dermatitis model using female mice. By inhibiting both pathogenic inflammatory mechanisms, PF-07245303 may have therapeutic value for patients with atopic dermatitis.

---

Organizational Affiliation: 
• Inflammation and Immunology, Pfizer Inc, Cambridge, MA, USA. [e-mail].
Inflammation and Immunology, Pfizer Inc, Cambridge, MA, USA.
Medicine Design, Pfizer Inc, Groton, CT, USA.
Drug Safety Research and Development, Pfizer Inc, Cambridge, MA, USA.
Data Sciences and Analytics, Pfizer Inc, Cambridge, MA, USA.
MedPharm Ltd, Durham, NC, USA.
Medicine Design, Pfizer Inc, Cambridge, MA, USA.
Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc, Cambridge, MA, USA.
Medicine Design, Pfizer Inc, Cambridge, MA, USA. [e-mail].

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Biological Assembly Evidence: gel filtration

Macromolecule Content 

• Total Structure Weight: 31.1 kDa 
• Atom Count: 2,538 
• Modeled Residue Count: 264 
• Deposited Residue Count: 269 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Tyrosine-protein kinase ITK/TSK	A	269	Homo sapiens	Mutation(s): 0  Gene Names: ITK, EMT, LYK EC: 2.7.10.2
UniProt & NIH Common Fund Data Resources
Find proteins for Q08881 (Homo sapiens) Explore Q08881  Go to UniProtKB:  Q08881
PHAROS:  Q08881 GTEx:  ENSG00000113263

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
A1B66 (Subject of Investigation/LOI)	B [auth A]	(2S)-N-methyl-N-{6-methyl-2-[(4aS,5aR)-5a-methyl-1,4,4a,5,5a,6-hexahydrocyclopropa[f]indazol-3-yl]-1H-1,3-benzimidazol-5-yl}-2-(morpholin-4-yl)propanamide C25 H32 N6 O2 DVXKDRBZBOJVGG-JAUXOLPYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.35 Å
• R-Value Free:  0.227 (Depositor), 0.219 (DCC) 
• R-Value Work:  0.182 (Depositor), 0.182 (DCC) 
• R-Value Observed: 0.184 (Depositor) 

Space Group: P 1 2₁ 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 40.23	α = 90
b = 68.67	β = 106.94
c = 49.51	γ = 90

Software Package:

Software Name	Purpose
BUSTER	refinement
XDS	data reduction
autoPROC	data scaling
PHASER	phasing

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2025-11-19 
Deposition Author(s): Liu, S.

---

Funding Organization	Location	Grant Number
Not funded		--

Revision History  

• Version 1.0: 2025-11-19
  Type: Initial release
  
• Version 1.1: 2026-08-05
  Changes: Database references