Background: Trials examining the benefit of thrombectomy in anterior circulation proximal large vessel occlusion stroke have enrolled patients considered to have salvageable brain tissue, who were randomly assigned beyond 6 h and (depending on study protocol) up to 24 h from time last seen well. We aimed to estimate the benefit of thrombectomy overall and in prespecified subgroups through individual patient data meta-analysis., Methods: We did a systematic review and individual patient data meta-analysis between Jan 1, 2010, and March 1, 2021, of randomised controlled trials of endovascular stroke therapy. In the Analysis Of Pooled Data From Randomized Studies Of Thrombectomy More Than 6 Hours After Last Known Well (AURORA) collaboration, the primary outcome was disability on the modified Rankin Scale (mRS) at 90 days, analysed by ordinal logistic regression. Key safety outcomes were symptomatic intracerebral haemorrhage and mortality within 90 days., Findings: Patient level data from 505 individuals (n=266 intervention, n=239 control; mean age 68·6 years [SD 13·7], 259 [51·3%] women) were included from six trials that met inclusion criteria of 17 screened published randomised trials. Primary outcome analysis showed a benefit of thrombectomy with an unadjusted common odds ratio (OR) of 2·42 (95% CI 1·76-3·33; p<0·0001) and an adjusted common OR (for age, gender, baseline stroke severity, extent of infarction on baseline head CT, and time from onset to random assignment) of 2·54 (1·83-3·54; p<0·0001). Thrombectomy was associated with higher rates of independence in activities of daily living (mRS 0-2) than best medical therapy alone (122 [45·9%] of 266 vs 46 [19·3%] of 238; p<0·0001). No significant difference between intervention and control groups was found when analysing either 90-day mortality (44 [16·5%] of 266 vs 46 [19·3%] of 238) or symptomatic intracerebral haemorrhage (14 [5·3%] of 266 vs eight [3·3%] of 239). No heterogeneity of treatment effect was noted across subgroups defined by age, gender, baseline stroke severity, vessel occlusion site, baseline Alberta Stroke Program Early CT Score, and mode of presentation; treatment effect was stronger in patients randomly assigned within 12-24 h (common OR 5·86 [95% CI 3·14-10·94]) than those randomly assigned within 6-12 h (1·76 [1·18-2·62]; p interaction =0·0087)., Interpretation: These findings strengthen the evidence for benefit of endovascular thrombectomy in patients with evidence of reversible cerebral ischaemia across the 6-24 h time window and are relevant to clinical practice. Our findings suggest that in these patients, thrombectomy should not be withheld on the basis of mode of presentation or of the point in time of presentation within the 6-24 h time window., Funding: Stryker Neurovascular., Competing Interests: Declaration of interests TGJ is adviser and investor for Anaconda, Route92, Viz.ai, FreeOx, Blockade Medical and Methinks. He received personal fees in his role on the Data Safety Monitoring Board and steering committee from Cerenovus and on the screening committee for Contego Medical. He received stock as an advisory board member for Corindus. He received grant support for Medtronic and from Stryker Neurovascular in his capacity as principal investigator for DAWN and AURORA. RGN reports consulting fees for advisory roles with Anaconda, Biogen, Cerenovus, Genentech, Imperative Care, Medtronic, Phenox, Prolong Pharmaceuticals, and Stryker Neurovascular and stock options for advisory roles with Astrocyte, Brainomix, Cerebrotech, Ceretrieve, Corindus Vascular Robotics, Vesalio, Viz.ai, and Perfuze. AMD is a shareholder and patent holder in Circle NVI (imaging-based software). He has also received honoraria from Medtronic for consulting services. SOM is the recipient of a research grant by the Brazilian Ministry of Health (RESILIENT trial) and has received speaker fees from Boehringer Ingelheim, Medtronic, Penumbra, Bayer, Pfizer and advisory board fees from Boehringer Ingelheim. JM is a consultant for Endostream, Viseon, Imperative Care, RIST, Synchron, Viz.ai, Perflow, CVAid, and Cerebrotech, and a shareholder in Rebound, BlinkTBI, Endostream, Viseon, Imperative Care, Serenity, Cardinal Consulting, NTI, RIST, Synchron, Viz.ai, and Cerebrotech. MR is adviser and shareholder in Anaconda Biomed and Methinks and received grants and personal fees from Medtronic, personal fees from Stryker, Cerenovus, and Apta Targets. SO-G has received consultant fees from Medtronic, Stryker, and Siemens. MDH reports personal fees from Sun Pharma, grants from Boehringer Ingelheim, Stryker, NoNO, and Medtronic, outside the submitted work; he has a patent Systems and Methods for Assisting in Decision-Making and Triaging for Acute Stroke Patients issued to US Patent office Number: 62/086,077 and owns stock in Pure Web, a company that makes, among other products, medical imaging software; is a director of the Canadian Federation of Neurological Sciences, a not-for-profit group, is a director of the Canadian Stroke Consortium, a not-for-profit group, is a director of Circle NeuroVascular, and has received grant support from Alberta Innovates Health Solutions, CIHR, Heart and Stroke Foundation of Canada, and National Institutes of Neurological Disorders and Stroke. FOL has received lecture fees from Boehringer Ingelheim. DCH serves as a consultant for Stryker and Vesalio, and holds stock options in Viz.ai. SB's employer, Bright Research Partners, has received payments from the University of Pittsburgh for the statistical work related to the current study and from the University of Calgary and Medtronic outside the current project. MG reports grants or personal fees from Medtronic, Stryker, Microvention, Cerenovus, and has a patent Systems of Acute Stroke Diagnosis issued to GE Healthcare. AHS is the recipient of NIH grants and owns stock or stock options in Adona Medical, Amnis Therapeutics, BlinkTBI, Buffalo Technology Partners, Cardinal Consultants, Cerebrotech Medical Systems, Cognition Medical, Endostream Medical, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics, Q'Apel Medical, Radical Catheter Technologies, Rebound Therapeutics, Rist Neurovascular, Sense Diagnostics, Serenity Medical, Silk Road Medical, Spinnaker Medical, StimMed, Synchron, Three Rivers Medical, Vastrax, ICIS, and Viseon; consultant for Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA, Cerebrotech Medical Systems, Cerenovus, Corindus, Integra, Medtronic, MicroVention, Minnetronix Neuro, Northwest University – DSMB Chair for HEAT Trial, Penumbra, Rapid Medical, Rebound Therapeutics, Serenity Medical, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, VasSol, and W L Gore and Associates; principal investigator or on the Steering Committee for Cerenovus LARGE Trial and ARISE II Trial, Medtronic SWIFT PRIME and SWIFT DIRECT Trials, MicroVention FRED Trial and CONFIDENCE Study, POSITIVE Trial, Penumbra 3D Separator Trial, COMPASS Trial, and the INVEST Trial. JJH discloses consulting fees from Medtronic, Microvention, and iSchemaView. MPM owns stock in ThrombX Medica. DSL is consultant to Cerenovus, Genentech, Stryker, Medtronic as Imaging Core Lab. GWA is the principal investigator of the DEFUSE 3 study, which provided National Institutes of Health grant funding to Stanford University; he has equity interest in iSchemaView, and is a consultant for Genentech and iSchemaView. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)