TRACE-5: Rethinking the 24-hour clock in Basilar Artery Occlusions

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Basilar artery occlusion (BAO) remains one of the most devastating strokes we face, and treatment decisions often stretch beyond the familiar anterior‑circulation playbook. This study, TRACE‑5, takes a bold step into that uncertainty, testing Tenecteplase in BAO patients presenting up to 24 hours from symptom onset. Join Dr. Onuzuruike as he unpacks the trial’s design, its surprising and practice‑shaping findings, and what this study might mean for the future of posterior circulation stroke care.

Xiong Y, Alemseged F, Cao Z, et al. Tenecteplase versus standard medical treatment for basilar artery occlusion within 24 h (TRACE-5): a multicentre, prospective, randomised, open-label, blinded-endpoint, superiority, phase 3 trial. Lancet. 2026;407(10530):763-772. doi:10.1016/S0140-6736(25)02633-9.

mETHODOLOGY

Multicenter, prospective, randomized, open-label, blinded-endpoint (PROBE), phase III superiority trial conducted across 66 stroke centers in China.

Patients with imaging-confirmed BAO presenting within 24 hours of symptom onset or last known well were randomized to receive:

  • Tenecteplase 0.25 mg/kg IV bolus (maximum 25 mg), or

  • Standard medical treatment

Study POPULATION

  • 452 total patients enrolled

  • 221 received Tenecteplase

  • 231 received standard treatment

  • Approximately 49% underwent endovascular thrombectomy

Primary outcome

Difference in functional independence at 90 days for two groups, defined as:

  • Modified Rankin Scale (mRS) 0–1, or

  • Return to baseline mRS for patients with pre-existing disability

RESULTS

  • Favorable functional outcome occurred in 38% of patients receiving Tenecteplase compared with 29% receiving standard treatment

  • Adjusted Relative Rate: 1.50 (95% CI 1.09–2.08)

  • Absolute Risk Reduction: 9%

  • Number Needed to Treat (NNT): ~11

Safety outcomes

  • Symptomatic intracranial hemorrhage: 2% vs 3%

  • 90-day mortality: 29% vs 31%

  • Severe disability or death (mRS 5–6): 37% vs 39%

Clinical Implications and other discussion points

  • TRACE-5 provides the largest randomized trial evidence supporting Tenecteplase for basilar artery occlusion.

  • Demonstrates potential benefit beyond the traditional 4.5-hour thrombolysis window.

  • Supports growing adoption of Tenecteplase as an alternative to Alteplase due to:

    • Single-bolus administration

    • Greater fibrin specificity

    • Favorable pharmacokinetics

  • Particularly relevant in settings where immediate thrombectomy is unavailable or delayed.

  • Reinforces the importance of rapid recognition of posterior circulation stroke in the emergency department.

  • May influence future stroke protocols and BAO-specific guideline recommendations.

Limiatations and Future directions

Limitations

  • Conducted exclusively in China, limiting generalizability to other populations.

  • Open-label treatment design introduces potential performance bias.

  • Nearly half of participants underwent thrombectomy, making it difficult to isolate the independent effect of Tenecteplase.

  • Standard medical therapy was heterogeneous and included alteplase in some patients.

  • Functional outcome definitions differed from prior stroke trials, limiting direct comparisons.

Future directions

  • Validation in multinational and more diverse patient populations.

  • Further investigation of Tenecteplase in combination with thrombectomy strategies.

  • Incorporation into future posterior circulation stroke guidelines.

  • Additional studies to better define optimal patient selection and treatment pathways.

Take home mESSAGE

Tenecteplase significantly improved functional outcomes in patients with acute basilar artery occlusion treated within 24 hours, with an absolute benefit of 9% and an NNT of approximately 11.

Importantly, this improvement occurred without increased rates of symptomatic intracranial hemorrhage or mortality.

For emergency physicians, TRACE-5 suggests that meaningful intervention for posterior circulation stroke may remain possible well beyond traditional thrombolytic windows and further strengthens the role of Tenecteplase in modern stroke care.

Tenecteplase should be viewed as an important tool in BAO reperfusion therapy, particularly when endovascular treatment is delayed or unavailable.

AUTHORSHIP

Written by: Anthony Onuzuruike, MD, PGY-3 University of Cincinnati Department of Emergency Medicine

Writing, Editing, Posting, and Audio Editing by Anita Goel, MD; Associate Professor, APD of UC EM Residency Program, and Co-editor of Tamingthesru.com

Cite as: Onuzuruike, a; Goel, A. TRACE-5: Rethinking the 24-hour clock in Basilar Artery Occlusions. TamingtheSRU.com. www.tamingthesru.com/blog/journal-club/tnk-for-basilar-artery-occlusion. 7/20/26.