AZALEA Trial results were presented at the American Heart Association Scientific Sessions 2023

AZALEA Trial: Potential of abelacimab for stroke protection without bleeding risk

November 27, 2023

  • Summary: Results of the late-breaking AZALEA Trial presented at AHA showed the potential of abelacimab for providing stroke protection without bleeding risk.
  • Reading time: 3–4 minutes

This month, the Afib Late-Breaking Clinical Trials session at the American Heart Association Scientific Sessions 2023 in Philadelphia featured the results from a critical trial of a new Factor XI inhibitor, abelacimab. Factor XIs are in trials to determine if they can avoid the bleeding risk found in currently available anticoagulants (blood thinners).

Dr. Christian T. Ruff, the trial’s global principal investigator, presented the results of the AZALEA-TIMI 71 Trial (A Multicenter, RandomiZed, Active-ControLled Study to Evaluate the Safety and Tolerability of Two Blinded Doses of Abelacimab Compared with Open Label Rivaroxaban in Patients with Atrial Fibrillation).

This trial was a phase 2b study of the safety and tolerability of abelacimab compared with rivaroxaban in afib patients. Abelacimab is a monoclonal antibody given just once a month by subcutaneous injection. It is not cleared by the kidneys, doesn’t require dose adjustments, and is not affected by other drugs. It achieves near-complete 99% inhibition of Factor XI over the entire month.   

In afib patients, the 150 mg dose showed a 67% reduction in relevant bleeding compared to rivaroxaban, a highly significant 74% reduction in major bleeding, and a 93% reduction in gastrointestinal (GI) bleeding. Because of these fantastic results, the Data Monitoring Committee (DMC) stopped the study early (back in September) due to such a substantial bleeding reduction. Since many people cannot take conventional anticoagulants, the hope is that abelacimab (and other Factor XI inhibitors) will address this pressing need for reducing stroke risk without causing bleeding.

The Food and Drug Administration (FDA) has granted abelacimab Fast Track Status for stroke prevention in those with afib due to this important unmet medical need.

The next step in the process is the LILAC-TIMI 76 study, an ongoing Phase 3 trial of abelacimab for those with afib who are unsuitable for currently available anticoagulants due to bleeding risks or fear. In the trial, 1900 people will be randomized to abelacimab 150 mg monthly or placebo monthly (both by subcutaneous injection).

Our CEO Mellanie True Hills said, “We are very optimistic about the potential future for afib patients after seeing the staggering bleeding reduction that abelacimab demonstrated in the AZALEA-TIMI 71 study. In our recent large patient survey, a considerable number of afib patients reported that bleeding and/or bruising problems since starting an anticoagulant had a significant impact on their quality of life. If approved, this could offer patients the protection they seek from strokes with minimal to no risk of bleeding.”

For more details about these results, see: