CREGS-2 - A multinational, high-quality comparative effectiveness study of Cerebrolysin in moderate acute ischemic stroke

Background: The main objective of the Cerebrolysin REGistry Study in Stroke 2 (C-REGS2) was to systematically record the routine clinical use of Cerebrolysin in patients with moderate ischemic stroke (IS) following the principles of a prospective controlled effectiveness study (CES) to compare its effectiveness in terms of functional recovery to patients treated with standard therapy alone. Methods: C-REGS2 used an open label, prospective controlled comparative effectiveness design aligning with the Target Trial Emulation Framework (TTEF) and the GRACE principles for high-quality observational studies based on the principles of high-quality comparative effectiveness research (HQCER) to capture treatment effects in clinical practice. The study was conducted in 16 countries worldwide between April 2018 and April 2024. Moderate IS was defined as baseline NIH Stroke Scale (NIHSS) score 8-15. Treatment modalities and concomitant medications were according to local standards. The methodology included rigorous pre-specified analysis and tight risk-based centralized monitoring, to ensure minimal enrollment bias, maximize data quality and overall reliability of trial results. The compared patient groups were standardised using a restricted cohort design and non-parametric multilevel stratification following the Good Research for Comparative Effectiveness (GRACE) principles. The primary endpoint was ordinal analysis of the modified Rankin Scale (mRS) at 90 days after stroke onset. Secondary endpoints were the ordinal NIH Stroke Scale (NIHSS) at day 21 and 90 after stroke onset, the ordinal mRS at 21 days after IS, the proportion of patients with excellent recovery (mRS 0-1) as well as the proportion of patients with functional independence (mRS 0-2) at 90 days after stroke onset and the ordinal analysis of Montreal Cognitive Assessment (MoCA) scale at 90 days after IS. Results: Out of 1865 enrolled patients, the target population (TP) comprised 1769 patients (1021 Cerebrolysin-treated and 748 controls). The median NIHSS at baseline was 10.0. Median Cerebrolysin dose was 30 ml, median treatment duration was 10 days. Cerebrolysin was superior to standard therapy in the primary endpoint independently to prior thrombolysis (MW 0.6157; CI 0.5910 to 0.6404; P<0.0001) as well as in all secondary endpoints: mRS at day 21 (MW 0.6065, 95% CI 0.5811-0.6319, P<0.0001), NIHSS at day 21 (MW 0.5792; 95% CI 0.5576-0.6008; P<0.0001) and NIHSS at day 90 (MW 0.5781; CI 0.5561-0.6002; P<0.0001). Additional pre-specified secondary endpoints (proportion of patients with excellent recovery and functional independence) showed moderate superiority for Cerebrolysin. The ordinal MoCA showed superiority for Cerebrolysin in the TP (MW 0.5530; CI 0.5282-0.5778; P<0.0001) with more pronounced effects in the subgroup with cognitive impairments at baseline (Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) ≥3.3). No differences in safety measures were recorded. The study is notable for its robust data integrity, with valid entries of 90.9% for the primary 90-day mRS assessment with multilevel case mix standardisation and an overall dropout rate to the final visit of only 5.7%. Conclusion The results of the CREGS-2 study showed the effectiveness and safety of Cerebrolysin treatment for moderate acute IS in real world clinical practice.