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Reduce & Repeat Non-Clinical Statistics Conference 2014, Brugge October 2014 More Precise XC50s Using Fewer Wells (in vitro) and Fewer Animals (in vivo)
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Raw Conc-Response Data 2 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Only Half of the Concs 3 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Only Half of the Replicates 4 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Only Half of the Concs and Half of the Replicates 5 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Only Half of the Concs and Half of the Replicates and Half of the Controls 6 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 and 95% Confidence Interval 7 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Findings #1 For a “well-behaved” assay, the resource (wells) may be dramatically reduced with little impact on either the estimate of the XC50 or its confidence interval “Well-behaved” -Max and min controls that safely position the curve top and bottom -Conc-response data that have the right sort of sigmoid shape -Acceptable to overlook details such as biphasic and partial inhibition May be exploited -Throughput -Cost -Compound use 8 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Second Set of Raw Conc-Response Data 9 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 and 95% Confidence Interval 10 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 and 95% Confidence Interval 11 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Findings #2 Run-to-run differences in XC50 are massive compared to the small changes in XC50 that occur as a result of reducing the resource (wells) on any given run Put in terms of components of variation -Between run variation dominates within-run variation -Within-run variation changes hardly at all as the number of concs and number of replicates changes May be exploited -Reduce the resource per run -Repeat -Average 12 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 13 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 14 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 15 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 16 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 17 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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IC50 vs Run 18 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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In Vivo A situation similar to the in vitro case has been observed, whereby study-to-study differences are the main component of variation -Was it a “good day” or a “bad day” for compound X 2 Start Strategy (Brian Middleton) -Start half the planned animals (reduce) -Independently run the second half (repeat) -Average Gives a superior estimate of the e.g. XC50 or XD50 Provides in some cases a chance to change doses for the second start 19 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Summary In both in vitro and in vivo settings there are large run-to-run or study-to-study differences when a compound is retested -Root cause analysis Exploit by -reducing the resource (wells or animals) on a given occasion -repeating the experiment -averaging across the experiments Reduce -Throughput, cost and compound benefits Reduce and Repeat -Precision benefit + 20 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Acknowledgement and Reference Siller H, Taylor JD, Middleton B. Two-start design within a Sephadex inflammatory model – A means to generate reliable ED 50 data whilst significantly reducing the number of animals used. Pulm Pharmacol Ther 2012; 25:223-227. 21 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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Extra Slide 22 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences
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23 Jonathan Bright | September 2014Innovative Medicines | Discovery Sciences Confidentiality Notice This file is private and may contain confidential and proprietary information. If you have received this file in error, please notify us and remove it from your system and note that you must not copy, distribute or take any action in reliance on it. Any unauthorized use or disclosure of the contents of this file is not permitted and may be unlawful. AstraZeneca PLC, 2 Kingdom Street, London, W2 6BD, UK, T: +44(0)20 7604 8000, F: +44 (0)20 7604 8151, www.astrazeneca.com
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