title: Assessment of the Embryonic Stem Cell Test and application and use in the pharmaceutical industry.
abstract: BACKGROUND
  The European Centre for the Validation of Alternative Methods (ECVAM) designed the Embryonic Stem Cell Test (EST) as a tool for classifying developmentally toxic compounds. An in vitro tool to assess developmental toxicity would be of great value to the pharmaceutical industry to help with toxicity-associated attrition.
  
  
  METHODS
  ECVAM's EST protocol was used, but employing a different mouse embryonic stem cell (ESC) line and an alternative differentiation medium. A subset of the compounds used to validate the EST assay along with a number of in-house pharmaceutical compounds plus marketed pharmaceutical compounds were used to assess the EST performance with receptor-mediated compounds.
  
  
  RESULTS
  Our results with ECVAM compounds mirrored ECVAM's. Compounds that were developmentally toxic in vivo were classified by the EST as moderate risk. Overall, the accuracy was 75% with the current set of data and the predictivity of low-, moderate-, and high-risk compounds was 90, 71, and 60% while the precision was 59, 86, and 100%, respectively. Interestingly, a number of the non-developmentally toxic compounds had values for the 3T3 IC(50) values, which were lower than the ESC IC(50) and ID(50), a situation not taken into account by ECVAM when designing the EST algorithm.
  
  
  CONCLUSIONS
  The assay as currently constructed has a significant false-positive rate (approximately 40%), but a very low false-negative rate (approximately 7%). Additional moderate- and high-risk compounds need to be assessed to increase confidence, accuracy, and understanding in the EST's predictivity.
authors: Pfizer Global Research & Development, Global DART, Groton/New London Laboratories, Pfizer Inc., Groton, CT 06340, USA. jennifer.a.paquette@pfizer.com
authors: Jennifer A
authors: JA
authors: Paquette
authors: Steven W
authors: SW
authors: Kumpf
authors: Randal D
authors: RD
authors: Streck
authors: Jason J
authors: JJ
authors: Thomson
authors: Robert E
authors: RE
authors: Chapin
authors: Donald B
authors: DB
authors: Stedman
mesh_terms: D000826:Animal Testing Alternatives / Q000379:methods; D000818:Animals; D041702:BALB 3T3 Cells; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004345:Drug Industry / Q000379:methods*; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000502:physiology; D051379:Mice; D008811:Mice, Inbred DBA; D018675:Toxicity Tests / Q000379:methods*