Identification of M4205 a highly selective inhibitor of cKIT mutations for unresectable metastatic or recurrent GIST

Experimental Data Snapshot

  • Resolution: 3.09 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.226 

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This is version 1.2 of the entry. See complete history


Identification of M4205─A Highly Selective Inhibitor of KIT Mutations for Treatment of Unresectable Metastatic or Recurrent Gastrointestinal Stromal Tumors.

Blum, A.Dorsch, D.Linde, N.Brandstetter, S.Buchstaller, H.P.Busch, M.Glaser, N.Gradler, U.Ruff, A.Petersson, C.Schieferstein, H.Sherbetjian, E.Esdar, C.

(2023) J Med Chem 66: 2386-2395

  • DOI: https://doi.org/10.1021/acs.jmedchem.2c00851
  • Primary Citation of Related Structures:  
    7ZW8, 7ZY6

  • PubMed Abstract: 

    The treatment of gastrointestinal stromal tumors (GISTs) driven by activating mutations in the KIT gene is a prime example of targeted therapy for treatment of cancer. The approval of the tyrosine kinase inhibitor imatinib has significantly improved patient survival, but emerging resistance under treatment and relapse is observed. Several additional KIT inhibitors have been approved; still, there is a high unmet need for KIT inhibitors with high selectivity and broad coverage of all clinically relevant KIT mutants. An imidazopyridine hit featuring excellent kinase selectivity was identified in a high-throughput screen (HTS) and optimized to the clinical candidate M4205 (IDRX-42). This molecule has a superior profile compared to approved drugs, suggesting a best-in-class potential for recurrent and metastatic GISTs driven by KIT mutations.

  • Organizational Affiliation

    Merck Healthcare KGaA, Frankfurter Str. 250, 64293Darmstadt, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
HUMAN PROTO-ONCOGENE C-KIT327Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P10721 (Homo sapiens)
Explore P10721 
Go to UniProtKB:  P10721
PHAROS:  P10721
GTEx:  ENSG00000157404 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP10721
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
KCI (Subject of Investigation/LOI)
Query on KCI

Download Ideal Coordinates CCD File 
B [auth A]5-imidazo[1,2-a]pyridin-3-yl-~{N}-[(1~{R})-1-(6-pyrrolidin-1-ylpyridin-3-yl)ethyl]pyridin-3-amine
C23 H24 N6
Experimental Data & Validation

Experimental Data

  • Resolution: 3.09 Å
  • R-Value Free: 0.298 
  • R-Value Work: 0.220 
  • R-Value Observed: 0.226 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.944α = 90
b = 78.806β = 90
c = 97.039γ = 90
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2023-02-22
    Type: Initial release
  • Version 1.1: 2023-03-08
    Changes: Database references
  • Version 1.2: 2024-02-07
    Changes: Data collection, Refinement description