1. Structural and functional outcomes in animal models of stroke: What do they measure? Malcolm Macleod University of Edinburgh

2. The problem … The failure of successful translation from animal studies to clinical trials Primary endpoint in animal studies is usually a structural outcome Primary endpoint in clinical trials is usually a functional outcome Is there a relationship, in animals, between structural and functional outcome?

3. 1026 1026 interventions in experimental stroke

4. 1026 603 1026 interventions in experimental stroke Tested in focal ischaemia

5. 1026 883 374 1026 interventions in experimental stroke Effective in focal ischaemia

6. 1026 883 550 9718 1026 interventions in experimental stroke Tested in clinical trial

7. 1026 883 550 9717 13 1026 interventions in experimental stroke Effective in clinical trial

8. Progress to date: Better understanding of the limited internal validity of animal studies Better understanding of publication bias Better understanding of the limited external validity of animal studies

9. Methodological approach Written review protocol – hypothesis, inclusion and exclusion criteria, analyses prespecified Standardised search strategy – 3 online databases, conference abstracts, dual screening Data extraction to bespoke database/analysis tool Random effects weighted mean difference stratified meta-analysis or meta-regression Publication bias by Funnel plot, Egger regression, Trim and Fill

10. CAMARADES Disease modelInterventionsPublicationsExperimentsAnimals Focal cerebral ischaemia 17556143920690 Intracerebral Haemorrhage 62974073647 Experimental Allergic Encephalomyelitis 36 (1717)123 (1152)4387224 Transgenic models of AD 207612179422000 Parkinsons Disease 28573032245 Spinal Cord Injury34693313596 Total2543471259402

11. Internal validity 9 publications, 29 experiments, 408 animals 44% (35-53%) improvement in outcome

12. Publication Bias

13. External validity NXY-059 Normal BP Efficacy tPA Normal BP Efficacy

14. External validity – good practice

15. Surrogate outcomes and biomarkers

16. Surrogate outcome Functional outcome

17. Can animal models help? In animal studies –Does structural outcome predict functional outcome? –Does this relationship hold across interventions? Inclusion criteria: –Reports of the efficacy of a candidate stroke drug in an animal model of focal cerebral ischaemia –Structural and functional outcome reported from the same cohort of animals –Simultaneous measurement of structural and functional outcome

18. Data 1047 257 16 71 131 71 21 25 110 13 110 12 24 18 26 9 Experiments reporting any outcome 299TOTAL 58Stem Cells 11Other Thrombolytics 20Nicotinamide 54Thrombolytics 16NOS Inhibitors 8FK506 0NOS Donors 42Hypothermia 4Melatonin 51Growth Factors 3NXY-059 7Enriched Environment 16Tirilazad 8Minocycline 1IL1-RA Experiments reporting structural and functional outcomes Drug Group

19. Raw correlation Raw correlation coefficient = 0.439 adjusted r 2 =0.301 Functional outcome Structural outcome Better Worse

20. Structural Outcome Coefficient95% CI Constant (tPA)23.917.1-30.7 Other lytics19.32.93-35.7 FK50619.91.62-38.1 Tirilazad21.47.91-34.9 Nicotinamide23.46.75-40.2 Hypothermia26.115.9-36.4 NXY 05929.10.43-57.8 Delay to assessment (days)-0.01-0.02-0.00 % improvement (SO) = 23.9 + f(drug) -0.01*(days to assessment) Adjusted r 2 = 0.24

21. Functional Outcome Coefficient95% CI Structural outcome (Infarct Volume)0.470.37 to 0.56 Stem cells10.01.9 to 18.1 Hypothermia11.22.4 to 19.9 FK50618.44.2 to 32.6 Minocycline18.55.1 to 31.9 Nicotinamide19.910.1 to 29.7 NOS Inhibitors20.710.4 to 30.9 Tirilazad22.98.1 to 37.9 Delay to assessment (days)0.580.36 to 0.82 Delay to treatment (hours)-0.96-1.44 to -0.48 % improvement (FO) = 0.47*SO + f(drug) + 0.58*(days to assessment) – 0.96*(hours to drug administration) Adjusted r 2 = 0.56

22. Summary Structural OutcomeFunctional OutcomeIndependent effects on both tPAStem cellsFK506 Other lyticsMinocyclineTirilazad NXY 059NOS InhibitionNicotinamide Hypothermia Delay to treatment (-ve) Delay to assessment (-ve SO, +ve FO) Lesion Structural Outcome Functional Outcome

23. Summary Structural OutcomeFunctional OutcomeIndependent effects on both tPAStem cellsFK506 Other lyticsMinocyclineTirilazad NXY 059NOS InhibitionNicotinamide Hypothermia Delay to treatment (-ve) Delay to assessment (-ve SO, +ve FO) Lesion Structural Outcome Functional Outcome

24. Summary Structural OutcomeFunctional OutcomeIndependent effects on both tPAStem cellsFK506 Other lyticsMinocyclineTirilazad NXY 059NOS InhibitionNicotinamide Hypothermia Delay to treatment (-ve) Delay to assessment (-ve SO, +ve FO) Lesion Structural Outcome Functional Outcome

25. Summary Structural OutcomeFunctional OutcomeIndependent effects on both tPAStem cellsFK506 Other lyticsMinocyclineTirilazad NXY 059NOS InhibitionNicotinamide Hypothermia Delay to treatment (-ve) Delay to assessment (-ve SO, +ve FO) Lesion Structural Outcome Functional Outcome

26. DISCUSSION Structural outcome explains around 30% of the variation in functional outcome Crucially, this relationship is different for different interventions Surrogate outcome measures in Phase II are likely to be intervention specific rather than disease specific Nonetheless, this approach might help with rational selection of combination therapies

27. Acknowledgements CAMARADES collaborators –Bart van der Worp (Hypothermia) –Philip Bath (NOS Inhibitors) –Jen Lees/ David Howells/ Simon Koblar (Stem cells) NHS Lothian R&D Infrastructure Funding Edinburgh MRC Trials Methodology Hub