Two randomised controlled trials have been published which compare endovascular stroke treatments with intravenous tPA. Both the American Interventional Management of Stroke (IMS) III trial (1) and the Italian SYNTHESIS Expansion trial (2) had Modified Rankin Scores as their primary endpoint. No significant differences in this outcome or in mortality or intracranial haemorrhage rates were found in either trial, and IMS III was terminated early due to futility.
A third trial, from North America, called MR RESCUE, randomised patients within 8 hours after the onset of large vessel, anterior-circulation strokes to undergo mechanical embolectomy or receive standard care(3). No clinical outcome differences were demonstrated.
An accompanying editorial (4) draws the following conclusion:

“The IMS III and SYNTHESIS Expansion studies show that intravenous thrombolysis should continue to be the first-line treatment for patients with acute ischemic stroke within 4.5 hours after stroke onset, even if imaging shows an occluded major intracranial artery. Beyond 4.5 hours, the MR RESCUE trial does not provide data supporting the use of endovascular treatment in patients with an ischemic penumbra of any size.”

Many might argue that showing endovascular treatment is equivalent to thrombolysis just means endovascular treatment doesn’t work, because a significant proportion of the emergency medicine community views this as the correct interpretation of a thorough analysis of the stroke thrombolysis literature.
1. Endovascular Therapy after Intravenous t-PA versus t-PA Alone for Stroke
NEJM Feb 8, 2013 Full Text Link
2. Endovascular Treatment for Acute Ischemic Stroke
NEJM Feb 8, 2013 Full Text Link
3. A Trial of Imaging Selection and Endovascular Treatment for Ischemic Stroke
NEJM Feb 8, 2013 Full Text Link
4.Endovascular Treatment for Acute Ischemic Stroke — Still Unproven
NEJM Feb 8, 2013 Full Text Link