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Computational Toxicology and Virtual Development in Drug Design. Dale E. Johnson, Pharm.D., Ph.D. Chief Scientific Officer ddplatform LLC. The “Problem” in pharmaceutical R&D. The “Solution” for R&D . ~ $700 MM and over 10 years to develop novel drug
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Computational Toxicology and Virtual Development in Drug Design Dale E. Johnson, Pharm.D., Ph.D. Chief Scientific Officer ddplatform LLC
The “Problem” in pharmaceutical R&D The “Solution” for R&D • ~ $700 MM and over 10 years to develop novel drug • Approximately 75% of overall R&D cost attributed to failures • Identify/eliminate problematic drugs early • Design desirable properties into drugs
Drug Discovery: the hunting process where is toxicology today? From: Rosamond and Allsop, Science 287, 1973 (2000)
Early toxicology at the Lead Optimization Step: still a high failure rate – high cost to R&D ADME, PK, TOX Lead optimization Secondary in vitro screening In vivo and mechanistic screens Lead selection Primary & secondary efficacy screening Chemical Libraries Chemical Libraries Development Candidate 65% Drop Out IND enabling studies Phase I, II
The toxicology solution • Incorporate predictive toxicology concept throughout discovery & development • Design reduced toxicity into chemical libraries • Create expert systems to accelerate and increase success rate • Expert systems must be multi-disciplinary for real impact
Major needs in Predictive Toxicology: Recent industry surveys • Predictive software with updated databases • Improved data mining capabilities • Enhanced in vitro mechanistic screens • Ready access to human hepatocytes and other cells • Relevant application of new technologies ie. toxicogenomics
Major needs in Predictive Toxicology: Recent industry surveys • Predictive software with updated databases • Improved data mining capabilities • Enhanced in vitro mechanistic screens • Ready access to human hepatocytes and other cells • Relevant application of new technologies ie. toxicogenomics
Missing elements in the toolbox • Quality data from controlled sources • Newly created database(s) using “pharmaceutical” chemical space • Multi-disciplinary chem-tox Information / decision tools • Data mining via “med chem building blocks” • Flexibilityto incorporate all data from internal and external sources • Web-based, platform independent
LeadScopeTM Technology • Structural analysis based on familiar structural features • Powerful graphical representations and dynamic querying • Refine structure alerts to reflect new assay results • Statistically test structural hypotheses
RTECS database & liver toxicity • ~7000 compounds with liver toxicity codes • Expert conversion to grades (risk) • Ordinal ranks using severity of findings, dose, regimen, species • Create 1o liver tox – chemical space • Data mining with ToxScopeTM: correlations between chemical structure and liver toxicity
Feature Hierarchy Graphic Panel Filter Panel Information Windows
Portion of the Heterocycles hierarchy showing 3 levels of the pyridine subhierarchy Selected subset of compounds containing a pyridine substructure with an acyclic alkenyl group in the 2-position Subset contains 2 compounds
Each structure feature in the hierarchy is defined as a substructure search query Structural definition atom and bond restrictions
Compounds containing a pyridine, 2-(alkenyl, acyc) substructure
Uncovering bias in chemical space within data sets • Detect + and – coverage within a desired chemical space • Understand decision errors that can be introduced with biased space
Structural alerts • Can rapidly find structural alerts • Can view new libraries in relation to structural alerts • Can evaluate impact of alert on optimization scheme
ToxScopeTM Components • LeadScopeTM Enterprise Technology • Several public or commercial databases • New databases using “pharmaceutical" chemical space • New specific organ toxicity database • Structural alerts • Continual updates on target organs
Conclusion “… an in silico revolution is emerging that will alter the conduct of early drug development in the future.” “Preclinical safety must transition from an experimental-based process into a knowledge-based, predictive process, where experimentation is used primarily to confirm existing knowledge”
Acknowledgements Grushenka Wolfgang, Co-author Julie Roberts Kevin Cross Bill Snyder Michael Crump Chris Freeman Jeff Miller Don Swartz Michael Murray Ilya Utkin Mark Balbes Wayne Johnson Zhicheng Li Allen Richon Yan Wang Paul Blower Limin Yu Glenn Myatt Sighle Brackman Emily Johnson Lisa Balbes