Design Principles for Fragment Libraries: Maximizing the Value of Learnings from Pharma Fragment-Based Drug Discovery (FBDD) Programs for Use in Academia.

Fragment-based drug discovery (FBDD) is well suited for discovering both drug leads and chemical probes of protein function; it can cover broad swaths of chemical space and allows the use of creative chemistry. FBDD is widely implemented for lead discovery in industry but is sometimes used less systematically in academia. Design principles and implementation approaches for fragment libraries are continually evolving, and the lack of up-to-date guidance may prevent more effective application of FBDD in academia. This Perspective explores many of the theoretical, practical, and strategic considerations that occur within FBDD programs, including the optimal size, complexity, physicochemical profile, and shape profile of fragments in FBDD libraries, as well as compound storage, evaluation, and screening technologies. This compilation of industry experience in FBDD will hopefully be useful for those pursuing FBDD in academia.

[1]  M. Congreve,et al.  A 'rule of three' for fragment-based lead discovery? , 2003, Drug discovery today.

[2]  Shahul H. Nilar,et al.  The importance of molecular complexity in the design of screening libraries , 2013, Journal of Computer-Aided Molecular Design.

[3]  J. Irwin,et al.  An Aggregation Advisor for Ligand Discovery. , 2015, Journal of medicinal chemistry.

[4]  Rutger H A Folmer,et al.  Fragment screening to predict druggability (ligandability) and lead discovery success. , 2011, Drug discovery today.

[5]  G. McGaughey,et al.  Discovery and Optimization of a Series of Pyrimidine-Based Phosphodiesterase 10A (PDE10A) Inhibitors through Fragment Screening, Structure-Based Design, and Parallel Synthesis. , 2015, Journal of medicinal chemistry.

[6]  Yoshinori Matsuura,et al.  Multiple binding modes of a small molecule to human Keap1 revealed by X-ray crystallography and molecular dynamics simulation , 2015, FEBS open bio.

[7]  L. Lam,et al.  ABT-199, a potent and selective BCL-2 inhibitor, achieves antitumor activity while sparing platelets , 2013, Nature Medicine.

[8]  Doris Hafenbradl,et al.  A comparative study of fragment screening methods on the p38α kinase: new methods, new insights , 2011, J. Comput. Aided Mol. Des..

[9]  S. Runyon,et al.  Hydrolytic instability of the important orexin 1 receptor antagonist SB-334867: possible confounding effects on in vivo and in vitro studies. , 2012, Bioorganic & medicinal chemistry letters.

[10]  S. Barelier,et al.  Fragment-based deconstruction of Bcl-xL inhibitors. , 2010, Journal of medicinal chemistry.

[11]  P. Jansa,et al.  Compound instability in dimethyl sulphoxide, case studies with 5-aminopyrimidines and the implications for compound storage and screening. , 2012, Bioorganic & medicinal chemistry letters.

[12]  Peter W. Kenny,et al.  Inflation of correlation in the pursuit of drug-likeness , 2013, Journal of Computer-Aided Molecular Design.

[13]  Dima Kozakov,et al.  Ligand deconstruction: Why some fragment binding positions are conserved and others are not , 2015, Proceedings of the National Academy of Sciences.

[14]  E. Mandine,et al.  Requirements for specific binding of low affinity inhibitor fragments to the SH2 domain of (pp60)Src are identical to those for high affinity binding of full length inhibitors. , 2003, Journal of medicinal chemistry.

[15]  D. Fabbro,et al.  Optimization of a Dibenzodiazepine Hit to a Potent and Selective Allosteric PAK1 Inhibitor. , 2015, ACS medicinal chemistry letters.

[16]  Anthony M Giannetti,et al.  From experimental design to validated hits a comprehensive walk-through of fragment lead identification using surface plasmon resonance. , 2011, Methods in enzymology.

[17]  John P. Overington,et al.  Can we rationally design promiscuous drugs? , 2006, Current opinion in structural biology.

[18]  György G. Ferenczy,et al.  Thermodynamics of Fragment Binding , 2012, J. Chem. Inf. Model..

[19]  Kevan M. Shokat,et al.  K-Ras(G12C) inhibitors allosterically control GTP affinity and effector interactions , 2013, Nature.

[20]  P. Clemons,et al.  Route to three-dimensional fragments using diversity-oriented synthesis , 2011, Proceedings of the National Academy of Sciences.

[21]  M. Hann,et al.  Finding the sweet spot: the role of nature and nurture in medicinal chemistry , 2012, Nature Reviews Drug Discovery.

[22]  Joseph D. Bauman,et al.  Rapid experimental SAD phasing and hot-spot identification with halogenated fragments , 2016, IUCrJ.

[23]  Nir London,et al.  Covalent Docking of Large Libraries for the Discovery of Chemical Probes , 2014, Nature chemical biology.

[24]  Sandra L. Nelson,et al.  The Effect of Room-Temperature Storage on the Stability of Compounds in DMSO , 2003, Journal of biomolecular screening.

[25]  Nathan Brown,et al.  Fragment-based hit identification: thinking in 3D. , 2013, Drug discovery today.

[26]  Kerim Babaoglu,et al.  Deconstructing fragment-based inhibitor discovery , 2006, Nature chemical biology.

[27]  Andrew J. Woodhead,et al.  Discovery of an allosteric mechanism for the regulation of HCV NS3 protein function , 2012, Nature chemical biology.

[28]  Binh Vu,et al.  Deconstruction of a nutlin: dissecting the binding determinants of a potent protein-protein interaction inhibitor. , 2013, ACS medicinal chemistry letters.

[29]  Lionel Colliandre,et al.  e-Drug3D: 3D structure collections dedicated to drug repurposing and fragment-based drug design , 2012, Bioinform..

[30]  Kam Y. J. Zhang,et al.  Discovery of a selective inhibitor of oncogenic B-Raf kinase with potent antimelanoma activity , 2008, Proceedings of the National Academy of Sciences.

[31]  B. Davis,et al.  Fragment screening by weak affinity chromatography: comparison with established techniques for screening against HSP90. , 2013, Analytical chemistry.

[32]  T. Magee Progress in discovery of small-molecule modulators of protein-protein interactions via fragment screening. , 2015, Bioorganic & medicinal chemistry letters.

[33]  Brian Dymock,et al.  Design and Characterization of Libraries of Molecular Fragments for Use in NMR Screening against Protein Targets , 2004, J. Chem. Inf. Model..

[34]  A. Joerger,et al.  Principles and applications of halogen bonding in medicinal chemistry and chemical biology. , 2013, Journal of medicinal chemistry.

[35]  B. Shoichet,et al.  Molecular docking and ligand specificity in fragment-based inhibitor discovery. , 2009, Nature chemical biology.

[36]  A. Leach,et al.  Molecular complexity and fragment-based drug discovery: ten years on. , 2011, Current opinion in chemical biology.

[37]  Richard Morphy,et al.  The influence of target family and functional activity on the physicochemical properties of pre-clinical compounds. , 2006, Journal of medicinal chemistry.

[38]  G. Chessari,et al.  Fragment-Based Drug Discovery Targeting Inhibitor of Apoptosis Proteins: Discovery of a Non-Alanine Lead Series with Dual Activity Against cIAP1 and XIAP. , 2015, Journal of medicinal chemistry.

[39]  Ian M. Eggleston,et al.  Structure-Based Dissection of the Natural Product Cyclopentapeptide Chitinase Inhibitor Argifin , 2008, Chemistry & biology.

[40]  M. Congreve,et al.  Fragment-based lead discovery , 2004, Nature Reviews Drug Discovery.

[41]  Ian Collins,et al.  Fragment growing to retain or alter the selectivity of anchored kinase hinge-binding fragments , 2014 .

[42]  Andrew R. Leach,et al.  CHAPTER 4:Current Status and Future Direction of Fragment-Based Drug Discovery: A Computational Chemistry Perspective , 2015 .

[43]  Marcel L Verdonk,et al.  Detection of secondary binding sites in proteins using fragment screening , 2015, Proceedings of the National Academy of Sciences.

[44]  Steven F. Baker,et al.  Crystallographic fragment screening and structure-based optimization yields a new class of influenza endonuclease inhibitors. , 2013, ACS chemical biology.

[45]  Alan E Mark,et al.  Missing fragments: detecting cooperative binding in fragment-based drug design. , 2012, ACS medicinal chemistry letters.

[46]  Anne Mai Wassermann,et al.  Large Scale Meta-Analysis of Fragment-Based Screening Campaigns , 2015, Journal of biomolecular screening.

[47]  G. Klebe,et al.  Enhancement of hydrophobic interactions and hydrogen bond strength by cooperativity: synthesis, modeling, and molecular dynamics simulations of a congeneric series of thrombin inhibitors. , 2010, Journal of medicinal chemistry.

[48]  Dima Kozakov,et al.  New Frontiers in Druggability. , 2015, Journal of medicinal chemistry.

[49]  Ariel Fernández,et al.  Dehydron analysis: quantifying the effect of hydrophobic groups on the strength and stability of hydrogen bonds. , 2010, Advances in experimental medicine and biology.

[50]  Irini Akritopoulou-Zanze,et al.  Kinase-targeted libraries: the design and synthesis of novel, potent, and selective kinase inhibitors. , 2009, Drug discovery today.

[51]  Daniel A Erlanson,et al.  Tethering: fragment-based drug discovery. , 2004, Annual review of biophysics and biomolecular structure.

[52]  Edgar Jacoby,et al.  Library design for fragment based screening. , 2005, Current topics in medicinal chemistry.

[53]  T. Blundell,et al.  Optimization of Inhibitors of Mycobacterium tuberculosis Pantothenate Synthetase Based on Group Efficiency Analysis , 2015, ChemMedChem.

[54]  Stefan Wetzel,et al.  Natural-product-derived fragments for fragment-based ligand discovery , 2012, Nature Chemistry.

[55]  Isabelle Krimm,et al.  Ligand specificity, privileged substructures and protein druggability from fragment-based screening. , 2011, Current opinion in chemical biology.

[56]  Dima Kozakov,et al.  Analysis of protein binding sites by computational solvent mapping. , 2012, Methods in molecular biology.

[57]  Tudor I. Oprea,et al.  Pursuing the leadlikeness concept in pharmaceutical research. , 2004, Current opinion in chemical biology.

[58]  Xianrui Zhao,et al.  Tailoring Small Molecules for an Allosteric Site on Procaspase‐6 , 2013, ChemMedChem.

[59]  Brian Pease,et al.  Discovery of Leukotriene A4 Hydrolase Inhibitors Using Metabolomics Biased Fragment Crystallography† , 2009, Journal of medicinal chemistry.

[60]  R. Stroud,et al.  Site-directed ligand discovery. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[61]  T. Ritchie,et al.  The impact of aromatic ring count on compound developability--are too many aromatic rings a liability in drug design? , 2009, Drug discovery today.

[62]  Jonathan W. Essex,et al.  Water Network Perturbation in Ligand Binding: Adenosine A2A Antagonists as a Case Study , 2013, J. Chem. Inf. Model..

[63]  C. Murray,et al.  The rise of fragment-based drug discovery. , 2009, Nature chemistry.

[64]  Christopher W. Murray,et al.  Assessing the lipophilicity of fragments and early hits , 2011, J. Comput. Aided Mol. Des..

[65]  Andrew R Leach,et al.  Fragment screening: an introduction. , 2006, Molecular bioSystems.

[66]  Peter Ertl,et al.  Natural Product‐Likeness Score and Its Application for Prioritization of Compound Libraries. , 2008 .

[67]  I. Mellman,et al.  Small-molecule ligands bind to a distinct pocket in Ras and inhibit SOS-mediated nucleotide exchange activity , 2012, Proceedings of the National Academy of Sciences.

[68]  Marcel L. Verdonk,et al.  The consequences of translational and rotational entropy lost by small molecules on binding to proteins , 2002, J. Comput. Aided Mol. Des..

[69]  Kurt Scudder,et al.  High throughput sonication: evaluation for compound solubilization. , 2005, Combinatorial chemistry & high throughput screening.

[70]  Daniel S. Hitchcock,et al.  Substrate Deconstruction and the Nonadditivity of Enzyme Recognition , 2014, Journal of the American Chemical Society.

[71]  Daniel A Erlanson,et al.  Learning from our mistakes: the 'unknown knowns' in fragment screening. , 2013, Bioorganic & medicinal chemistry letters.

[72]  Márton Vass,et al.  Multiple fragment docking and linking in primary and secondary pockets of dopamine receptors. , 2014, ACS medicinal chemistry letters.

[73]  P. Bonnet,et al.  The Azaindole Framework in the Design of Kinase Inhibitors , 2014, Molecules.

[74]  C. Humblet,et al.  Escape from flatland: increasing saturation as an approach to improving clinical success. , 2009, Journal of medicinal chemistry.

[75]  Roderick E. Hubbard,et al.  Lessons for fragment library design: analysis of output from multiple screening campaigns , 2009, J. Comput. Aided Mol. Des..

[76]  Qi Sun,et al.  Discovery of small molecules that bind to K-Ras and inhibit Sos-mediated activation. , 2012, Angewandte Chemie.

[77]  Saul H Rosenberg,et al.  Discovery of an orally bioavailable small molecule inhibitor of prosurvival B-cell lymphoma 2 proteins. , 2008, Journal of medicinal chemistry.

[78]  Daniel A Erlanson,et al.  Learning from PAINful lessons. , 2015, Journal of medicinal chemistry.

[79]  T. Blundell,et al.  Small-Molecule Inhibitors That Target Protein–Protein Interactions in the RAD51 Family of Recombinases , 2014, ChemMedChem.

[80]  Miklos Feher,et al.  Property Distributions: Differences between Drugs, Natural Products, and Molecules from Combinatorial Chemistry , 2003, J. Chem. Inf. Comput. Sci..

[81]  Andrew R. Leach,et al.  Molecular Complexity and Its Impact on the Probability of Finding Leads for Drug Discovery , 2001, J. Chem. Inf. Comput. Sci..

[82]  Ronald J. Quinn,et al.  Capturing Nature's Diversity , 2015, PloS one.

[83]  P. Hajduk,et al.  Druggability indices for protein targets derived from NMR-based screening data. , 2005, Journal of medicinal chemistry.

[84]  Marcel L Verdonk,et al.  Group Efficiency: A Guideline for Hits‐to‐Leads Chemistry , 2008, ChemMedChem.

[85]  Robert Abel,et al.  Motifs for molecular recognition exploiting hydrophobic enclosure in protein–ligand binding , 2007, Proceedings of the National Academy of Sciences.

[86]  J Willem M Nissink,et al.  Promiscuous 2-aminothiazoles (PrATs): a frequent hitting scaffold. , 2015, Journal of medicinal chemistry.

[87]  Jack Taunton,et al.  Electrophilic fragment-based design of reversible covalent kinase inhibitors. , 2013, Journal of the American Chemical Society.

[88]  Gregory J. Crowther,et al.  Plasmodium gametocyte inhibition identified from a natural-product-based fragment library. , 2013, ACS chemical biology.

[89]  Peter Brandt,et al.  Deconstruction of non-nucleoside reverse transcriptase inhibitors of human immunodeficiency virus type 1 for exploration of the optimization landscape of fragments. , 2011, Journal of medicinal chemistry.

[90]  Andreas Thomann,et al.  Dissecting fragment-based lead discovery at the von Hippel-Lindau protein:hypoxia inducible factor 1α protein-protein interface. , 2012, Chemistry & biology.

[91]  Anders Friberg,et al.  Discovery of tricyclic indoles that potently inhibit Mcl-1 using fragment-based methods and structure-based design. , 2015, Journal of medicinal chemistry.

[92]  M. Hann Molecular obesity, potency and other addictions in drug discovery , 2011 .

[93]  Jan Schultz,et al.  Integration of fragment screening and library design. , 2007, Drug discovery today.

[94]  Michael M. Hann,et al.  RECAP — Retrosynthetic Combinatorial Analysis Procedure: A Powerful New Technique for Identifying Privileged Molecular Fragments with Useful Applications in Combinatorial Chemistry. , 1998 .

[95]  J. Baell,et al.  New substructure filters for removal of pan assay interference compounds (PAINS) from screening libraries and for their exclusion in bioassays. , 2010, Journal of medicinal chemistry.

[96]  Harren Jhoti,et al.  The 'rule of three' for fragment-based drug discovery: where are we now? , 2013, Nature Reviews Drug Discovery.

[97]  A. Bogan,et al.  Anatomy of hot spots in protein interfaces. , 1998, Journal of molecular biology.

[98]  Tjelvar S. G. Olsson,et al.  The thermodynamics of protein-ligand interaction and solvation: insights for ligand design. , 2008, Journal of molecular biology.

[99]  Christopher L. McClendon,et al.  Reaching for high-hanging fruit in drug discovery at protein–protein interfaces , 2007, Nature.

[100]  Pascal Rigollier,et al.  Fragment-Based Screening by Biochemical Assays , 2010, Journal of biomolecular screening.

[101]  György G Ferenczy,et al.  How are fragments optimized? A retrospective analysis of 145 fragment optimizations. , 2013, Journal of medicinal chemistry.

[102]  Kam Y. J. Zhang,et al.  Clinical efficacy of a RAF inhibitor needs broad target blockade in BRAF-mutant melanoma , 2010, Nature.

[103]  Masaya Orita,et al.  Lead generation and examples opinion regarding how to follow up hits. , 2011, Methods in enzymology.

[104]  Eddy Arnold,et al.  Detecting allosteric sites of HIV-1 reverse transcriptase by X-ray crystallographic fragment screening. , 2013, Journal of medicinal chemistry.

[105]  Nick Palmer,et al.  Design and synthesis of dihydroisoquinolones for fragment-based drug discovery (FBDD). , 2016, Organic & biomolecular chemistry.

[106]  James E. J. Mills,et al.  Design of a multi-purpose fragment screening library using molecular complexity and orthogonal diversity metrics , 2011, J. Comput. Aided Mol. Des..

[107]  Channa K. Hattotuwagama,et al.  Lead-oriented synthesis: a new opportunity for synthetic chemistry. , 2012, Angewandte Chemie.

[108]  Ali Jazayeri,et al.  Fragment and Structure-Based Drug Discovery for a Class C GPCR: Discovery of the mGlu5 Negative Allosteric Modulator HTL14242 (3-Chloro-5-[6-(5-fluoropyridin-2-yl)pyrimidin-4-yl]benzonitrile). , 2015, Journal of medicinal chemistry.

[109]  Stefan G. Kathman,et al.  A Fragment-Based Method to Discover Irreversible Covalent Inhibitors of Cysteine Proteases , 2014, Journal of medicinal chemistry.

[110]  G. Keserű,et al.  On the enthalpic preference of fragment binding , 2016 .

[111]  G. Petsko,et al.  Multiple solvent crystal structures: probing binding sites, plasticity and hydration. , 2006, Journal of molecular biology.

[112]  Christopher W Murray,et al.  Opportunity Knocks: Organic Chemistry for Fragment-Based Drug Discovery (FBDD). , 2016, Angewandte Chemie.

[113]  Hans Matter,et al.  Fragment deconstruction of small, potent factor Xa inhibitors: exploring the superadditivity energetics of fragment linking in protein-ligand complexes. , 2012, Angewandte Chemie.

[114]  Ian Collins,et al.  Fragment-Based Screening Maps Inhibitor Interactions in the ATP-Binding Site of Checkpoint Kinase 2 , 2013, PloS one.

[115]  G. Rastelli,et al.  αC helix displacement as a general approach for allosteric modulation of protein kinases. , 2013, Drug discovery today.

[116]  Claudio Luchinat,et al.  Entropic contribution to the linking coefficient in fragment based drug design: a case study. , 2010, Journal of medicinal chemistry.

[117]  Christopher W Murray,et al.  Efficient exploration of chemical space by fragment-based screening. , 2014, Progress in biophysics and molecular biology.

[118]  Ajay,et al.  The SHAPES strategy: an NMR-based approach for lead generation in drug discovery. , 1999, Chemistry & biology.

[119]  Rob Leurs,et al.  Fragment growing induces conformational changes in acetylcholine-binding protein: a structural and thermodynamic analysis. , 2011, Journal of the American Chemical Society.

[120]  Niklas Blomberg,et al.  Design of compound libraries for fragment screening , 2009, J. Comput. Aided Mol. Des..

[121]  Timo Krotzky,et al.  One Question, Multiple Answers: Biochemical and Biophysical Screening Methods Retrieve Deviating Fragment Hit Lists , 2015, ChemMedChem.

[122]  A. Hopkins,et al.  The role of ligand efficiency metrics in drug discovery , 2014, Nature Reviews Drug Discovery.

[123]  Chang Park,et al.  Fragment-based discovery of potent inhibitors of the anti-apoptotic MCL-1 protein. , 2014, Bioorganic & medicinal chemistry letters.

[124]  Dima Kozakov,et al.  The FTMap family of web servers for determining and characterizing ligand-binding hot spots of proteins , 2015, Nature Protocols.

[125]  Martin J. Scanlon,et al.  Design and Evaluation of the Performance of an NMR Screening Fragment Library , 2013 .

[126]  J. Baell,et al.  Chemistry: Chemical con artists foil drug discovery , 2014, Nature.

[127]  Tim Cernak,et al.  The medicinal chemist's toolbox for late stage functionalization of drug-like molecules. , 2016, Chemical Society reviews.

[128]  Frank von Delft,et al.  A poised fragment library enables rapid synthetic expansion yielding the first reported inhibitors of PHIP(2), an atypical bromodomain† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc03115j , 2015, Chemical science.

[129]  Paul Bamborough,et al.  Selectivity of kinase inhibitor fragments. , 2011, Journal of medicinal chemistry.

[130]  S. P. Andrews,et al.  Structure‐Based and Fragment‐Based GPCR Drug Discovery , 2014, ChemMedChem.

[131]  Peter Ballard,et al.  Discovery of 4-amino-N-[(1S)-1-(4-chlorophenyl)-3-hydroxypropyl]-1-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperidine-4-carboxamide (AZD5363), an orally bioavailable, potent inhibitor of Akt kinases. , 2013, Journal of medicinal chemistry.

[132]  Olan Dolezal,et al.  Parallel Screening of Low Molecular Weight Fragment Libraries , 2013, Journal of biomolecular screening.