Randomized Trial of Interleukin-6 Receptor Inhibition in Patients With Acute ST-Segment Elevation Myocardial Infarction

J Am Coll Cardiol. 2021 Apr 20;77(15):1845-1855. doi: 10.1016/j.jacc.2021.02.049.


Background: Prompt myocardial revascularization with percutaneous coronary intervention (PCI) reduces infarct size and improves outcomes in patients with ST-segment elevation myocardial infarction (STEMI). However, as much as 50% of the loss of viable myocardium may be attributed to the reperfusion injury and the associated inflammatory response.

Objectives: This study sought to evaluate the effect of the interleukin-6 receptor inhibitor tocilizumab on myocardial salvage in acute STEMI.

Methods: The ASSAIL-MI trial was a randomized, double-blind, placebo-controlled trial conducted at 3 high-volume PCI centers in Norway. Patients admitted with STEMI within 6 h of symptom onset were eligible. Consenting patients were randomized in a 1:1 fashion to promptly receive a single infusion of 280 mg tocilizumab or placebo. The primary endpoint was the myocardial salvage index as measured by magnetic resonance imaging after 3 to 7 days.

Results: We randomized 101 patients to tocilizumab and 98 patients to placebo. The myocardial salvage index was larger in the tocilizumab group than in the placebo group (adjusted between-group difference 5.6 [95% confidence interval: 0.2 to 11.3] percentage points, p = 0.04). Microvascular obstruction was less extensive in the tocilizumab arm, but there was no significant difference in the final infarct size between the tocilizumab arm and the placebo arm (7.2% vs. 9.1% of myocardial volume, p = 0.08). Adverse events were evenly distributed across the treatment groups.

Conclusions: Tocilizumab increased myocardial salvage in patients with acute STEMI. (ASSessing the effect of Anti-IL-6 treatment in Myocardial Infarction [ASSAIL-MI]; NCT03004703).

Keywords: ST-segment elevation myocardial infarction; infarct size; inflammation; myocardial salvage; randomized controlled trial; reperfusion injury.

Publication types

  • Clinical Trial, Phase II
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Antibodies, Monoclonal, Humanized / administration & dosage
  • Antibodies, Monoclonal, Humanized / therapeutic use*
  • Cardiac Imaging Techniques
  • Cardiovascular Agents / administration & dosage
  • Cardiovascular Agents / therapeutic use*
  • Coronary Occlusion / complications
  • Coronary Occlusion / diagnostic imaging
  • Coronary Occlusion / pathology
  • Coronary Vessels
  • Double-Blind Method
  • Female
  • Heart* / diagnostic imaging
  • Heart* / drug effects
  • Humans
  • Infusions, Intravenous
  • Magnetic Resonance Imaging
  • Male
  • Middle Aged
  • Myocardial Ischemia / diagnostic imaging
  • Myocardium / pathology
  • Necrosis / diagnostic imaging
  • Percutaneous Coronary Intervention
  • Receptors, Interleukin-6 / antagonists & inhibitors*
  • ST Elevation Myocardial Infarction / diagnostic imaging
  • ST Elevation Myocardial Infarction / drug therapy*
  • ST Elevation Myocardial Infarction / pathology
  • ST Elevation Myocardial Infarction / therapy
  • Time-to-Treatment


  • Antibodies, Monoclonal, Humanized
  • Cardiovascular Agents
  • Receptors, Interleukin-6
  • tocilizumab

Associated data

  • ClinicalTrials.gov/NCT03004703