Abstract A092: The SPAN Score as the Primary Outcome for Multicenter Preclinical Randomized Controlled Stroke Trials

Background: Selecting a robust, generalizable primary outcome is critical for multicenter preclinical stroke trials. The Stroke Preclinical Assessment Network is a randomized, placebo-controlled, blinded, multi-laboratory trial using a multi-arm, multi-stage design to evaluate interventions with high translational potential. During a SPAN 2. 0 pilot study, we developed the SPAN score to capture functional deficits after middle cerebral artery occlusion (MCAO). Reliability and validity analyses led to a 6-item weighted version. This study evaluated (1) the performance of the weighted score in the SPAN 2. 0 pilot dataset and (2) its external validation in independent SPAN 2. 1 and 2. 2 cohorts to determine suitability as the standardized primary outcome for multicenter preclinical stroke research. Methods: Data from SPAN 2. 0, 2. 1, and 2. 2 were analyzed. In the pilot, mice underwent 30- or 60-minute MCAO to produce mild to severe injuries. Outcomes included behavioral assessments, MRI, and survival. Probabilistic Index modeling estimated the probability that a randomly selected 30-minute outperformed a 60-minute MCAO animal (0. 5 = no difference, >0. 5 favors 30-minute). Kaplan–Meier curves and Cox models assessed mortality. Receiver Operating Characteristic (ROC) analysis tested the SPAN score’s ability to distinguish stroke from non-stroke and detect lesion volumes > 5 mm3 and > 10 mm3. Worst-score imputation was applied for deaths before data collection. Results: In SPAN 2. 0, survival was higher after 30-minute MCAO (chi² = 4. 17, p = 0. 04). The weighted SPAN score was worse in the 60-minute group (p = 0. 036). Differentiating measures included day-2 Bederson score, day-30 Novel Object Recognition, day-2 MRI infarct volume with midline shift, and day-30 CSF volume; several behavioral tests did not significantly separate groups. In SPAN 2. 1 and 2. 2, with worst-score imputation, the SPAN score showed greater impairment in aged vs. diabetes-induced (p = 0. 022) and young healthy mice (p 10 mm3 vs. none, AUC = 0. 774 (p < 0. 001). Conclusion: The 6-item weighted SPAN score was the most suitable primary outcome in the SPAN 2. 0 pilot. External validation in SPAN 2. 1 and 2. 2 confirmed its consistent ability to differentiate stroke severity across models and sites, supporting its adoption as the standardized primary outcome for future multicenter preclinical stroke trials.