Rationale for the ASSAIL-MI-trial: a randomised controlled trial designed to assess the effect of tocilizumab on myocardial salvage in patients with acute ST-elevation myocardial infarction (STEMI)

Introduction Interleukin-6 (IL-6) may be involved in ischaemia-reperfusion injury and myocardial remodelling after myocardial infarction (MI). We have recently shown that IL-6 inhibition by tocilizumab attenuates systemic inflammation and troponin T-release in patients with acute non-ST elevation MI (NSTEMI). Experimental studies suggest that IL-6 inhibition can limit infarct size through anti-inflammatory mechanisms, but this has not been tested in clinical studies. With the ASSessing the effect of Anti-IL-6 treatment in MI (ASSAIL-MI) trial, we aim to examine whether a single administration of the IL-6 receptor antagonist tocilizumab can increase myocardial salvage in patients with acute ST-elevation MI (STEMI). Methods and analysis The ASSAIL-MI trial is a randomised, double blind, placebo-controlled trial, conducted at three high-volume percutaneous coronary intervention (PCI) centres in Norway. 200 patients with first-time STEMI presenting within 6 hours of the onset of chest pain will be randomised to receive tocilizumab or matching placebo prior to PCI. The patients are followed-up for 6 months. The primary endpoint is the myocardial salvage index measured by cardiac MRI (CMR) 3-7 days after the intervention. Secondary endpoints include final infarct size measured by CMR and plasma markers of myocardial necrosis. Efficacy and safety assessments during follow-up include blood sampling, echocardiography and CMR. Ethics and dissemination Based on previous experience the study is considered feasible and safe. If tocilizumab increases myocardial salvage, further endpoint-driven multicentre trials may be initiated. The ASSAIL-MI trial has the potential to change clinical practice in patients with STEMI.