Abstract 3593: Challenges to Recruiting Stroke Patients Into Cell Therapy Clinical Trials

Objective: Stringent selection criteria pose challenges to recruiting patients into clinical trials testing potential novel therapies for stroke. We conducted a pilot study, Safety of Intravenous Mononuclear Cells for Acute Stroke (SIMVAS) trial involving autologous bone marrow cell administration in patients with middle cerebral artery (MCA) territory stroke within 72 hours of symptom onset. Given the stringent selection criteria for initial cell therapy clinical trials in stroke, we analyzed reasons for patient ineligibility into the SIVMAS trial to assess feasibility of recruitment. Methods: We retrospectively collected ischemic stroke patients from our stroke registry admitted from March 2009 to June 2010, the recruitment period of SIVMAS, and identified which of the selection criteria the patients did not meet. Results: Of a total of 534 MCA territory stroke patients, 25 met all the selection criteria. Ten patients were enrolled as planned over the 15 month period, 3 declined enrollment, 2 were excluded due to pending DSMB review on previously enrolled patients, and the rest did not have an adequate time window between bone marrow aspiration and dosing. A total of 1,943 exclusions were recorded; major reasons were NIHSS (15.3%) and infarct sizes above or below the selection criteria (12.4%). The table summarizes the patient exclusion frequency based on selection criteria. Among ineligible patients (n=509), 47 (9.2%) had a single exclusion, 81 (15.9%) had two exclusions and 108 (21.2%) had three exclusions. The figure presents a CONSORT flow diagram of the entire recruitment. Conclusion: This is the first study to assess recruitment of patients with acute ischemic stroke into a pilot cell therapy clinical trial. Among eligible patients, there was a low refusal rate. Among excluded patients, stroke severity and infarct size were major reasons for exclusion from SIVMAS. It is hoped that the data from this study may help facilitate the design of future clinical trials testing new cell-based therapies for ischemic stroke. We encourage investigators to choose selection criteria that will provide scientifically meaningful data but are not overly rigid in selecting potential research candidates.