(R)-2-Phenylpyrrolidine Substitute Imidazopyridazines: a New Class of Potent and Selective Pan-TRK Inhibitors

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 

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Ligand Structure Quality Assessment 

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(R)-2-Phenylpyrrolidine Substituted Imidazopyridazines: A New Class of Potent and Selective Pan-TRK Inhibitors.

Choi, H.S.Rucker, P.V.Wang, Z.Fan, Y.Albaugh, P.Chopiuk, G.Gessier, F.Sun, F.Adrian, F.Liu, G.Hood, T.Li, N.Jia, Y.Che, J.McCormack, S.Li, A.Li, J.Steffy, A.Culazzo, A.Tompkins, C.Phung, V.Kreusch, A.Lu, M.Hu, B.Chaudhary, A.Prashad, M.Tuntland, T.Liu, B.Harris, J.Seidel, H.M.Loren, J.Molteni, V.

(2015) ACS Med Chem Lett 6: 562-567

  • DOI: https://doi.org/10.1021/acsmedchemlett.5b00050
  • Primary Citation of Related Structures:  
    4YMJ, 4YNE, 4YPS

  • PubMed Abstract: 

    Deregulated kinase activities of tropomyosin receptor kinase (TRK) family members have been shown to be associated with tumorigenesis and poor prognosis in a variety of cancer types. In particular, several chromosomal rearrangements involving TRKA have been reported in colorectal, papillary thyroid, glioblastoma, melanoma, and lung tissue that are believed to be the key oncogenic driver in these tumors. By screening the Novartis compound collection, a novel imidazopyridazine TRK inhibitor was identified that served as a launching point for drug optimization. Structure guided drug design led to the identification of (R)-2-phenylpyrrolidine substituted imidazopyridazines as a series of potent, selective, orally bioavailable pan-TRK inhibitors achieving tumor regression in rats bearing KM12 xenografts. From this work the (R)-2-phenylpyrrolidine has emerged as an ideal moiety to incorporate in bicyclic TRK inhibitors by virtue of its shape complementarity to the hydrophobic pocket of TRKs.

  • Organizational Affiliation

    Genomics Institute of the Novartis Research Foundation , 10675 John Jay Hopkins Drive, San Diego, California 92121, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
High affinity nerve growth factor receptor303Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P04629 (Homo sapiens)
Explore P04629 
Go to UniProtKB:  P04629
PHAROS:  P04629
GTEx:  ENSG00000198400 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP04629
Sequence Annotations
  • Reference Sequence
Small Molecules
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.257 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.203 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.481α = 90
b = 106.481β = 90
c = 204.511γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report

Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-06-03
    Type: Initial release
  • Version 1.1: 2023-09-27
    Changes: Data collection, Database references, Derived calculations, Refinement description, Source and taxonomy