MR WITNESS: Intravenous Thrombolysis with Alteplase in MRI-Selected Patients

Sponsor: NIH & Genetech
Principal investigator: Carlos Kase MD
Sub-investigators: Viken Babikian MD, Thanh Nguyen MD, Jose Romero MD, Hesham Masoud MD, Hugo Aparicio MD


This is a multi-center, open-label, single-arm, Phase IIa safety study to determine if it is safe to extend intravenous thrombolytic treatment to subjects who are evaluated within 24 hours from last known well and eligible to receive thrombolytic treatment within 4.5 hours from symptom discovery with the assistance of an MRI-based "witness" when no human witness of stroke onset is available. The study is designed to investigate the safety in using standard diagnostic MRI in selecting patients for thrombolytic therapy when the last known well time places the patient beyond the current IV thrombolytic time-window.


Determine the safety of IV rt-PA in subjects with unwitnessed stroke onset, last known well less than 24 hours before, and MRI evidence of early stroke.

Inclusion Criteria (highlights only):

  • Age, 18 to 85 years inclusive
  • Brain MRI findings consistent with early stroke onset
  • Clinical diagnosis of acute ischemic stroke with disabling neurological deficit
  • Stroke symptoms present for at least 30 minutes with no significant improvement before treatment
  • Be last known well (without stroke symptoms) within 24 hours of triage
  • Be able to receive IV rt-PA within 4.5 hours from the time the symptoms were discovered.
  • MRI diagnostic of acute ischemic stroke and consistent with clinical syndrome
  • Time between completion of qualifying MRI studies to treatment initiation ≤ 1 hour

Status: Actively enrolling patients