A Medical Research Study to Evaluate the Effects of ACT-246475 in Adults With Heart Attack

This study is planned in patients presenting with Acute Myocardial Infarction (AMI) scheduled for an invasive strategy. Platelet activation and thrombus formation play a pivotal role in the pathophysiology of acute coronary syndrome. Early platelet inhibition has been shown to reduce the risk of recurrent events after a myocardial infarction.

The screening period starts when the participant provides informed consent and ends with participant's randomization. Eligible participants had an acute myocardial infarction (AMI; ST-segment elevation myocardial infarction [STEMI] or non-ST-elevation myocardial infarction [NSTEMI]), a life-threatening condition, and will therefore fulfill the ICH-GCP definition of vulnerable subjects ("persons in emergency situations"). Accordingly, a specific process for obtaining consent in compliance with local regulations and approved by the independent ethics committee will be implemented.

The study will be performed during a participant's hospital stay related to the qualifying AMI.

Standard treatment of AMI is allowed including anticoagulants. Ticagrelor will be the only oral P2Y12 receptor antagonist allowed to be initiated during the study and its administration will be possible only after selatogrel administration. Use of fibrinolytics or GPIIb/IIIa inhibitors will be prohibited unless required for bail-out. All other standard-of-care treatments for AMI will be allowed without restriction.

The treatment period starts with the participant's randomization and ends after the end-of-study assessments, approximately 48 hours after the administration of a single study treatment dose.

Main Inclusion Criteria:

• Informed consent obtained prior to any study-mandated procedure,
• Males aged from 18 to 85 and postmenopausal females aged up to 85 years,
• Onset of symptoms of AMI of more than 30 min and less than 6 hours prior to randomization,
• Subjects presenting a type I AMI including STEMI or NSTEMI.

Main Exclusion Criteria:

• Cardiogenic shock or severe hemodynamic instability,
• Cardiopulmonary resuscitation,
• Loading dose of any oral P2Y12 receptor antagonist prior to randomization,
• Planned fibrinolytic therapy or any fibrinolytic therapy administered within 24 h prior to randomization,
• Known platelet disorders (e.g., thromboasthenia, thrombocytopenia, von Willebrand disease).
• Active internal bleeding, or bleeding diathesis or conditions associated with high risk of bleeding.
• Known clinically important anemia.
• Oral anticoagulation therapy within 7 days prior to randomization