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

A Multi-center, Open-label, Randomized, Study to Assess the Onset of Platelet Aggregation Inhibition After a Single Subcutaneous Injection of ACT-246475 in Adults With Acute Myocardial Infarction

The goal of this study is to find out how fast a drug called selatogrel (ACT-246475) can prevent platelets from binding together. This study will also help to find out more about the safety of this new drug. The drug selatogrel (ACT-246475) will be used in 2 different doses (8 mg or 16 mg) and will be administered in the thigh.

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.

Selatogrel (ACT-246475) is given as a single subcutaneous dose of 8 mg administered in a volume of 0.8 mL. Administration will be performed at the investigational site by qualified personnel.

Selatogrel (ACT-246475) is given as a single subcutaneous dose of 16 mg administered in a volume of 0.8 mL. Administration will be performed at the investigational site by qualified personnel.

Selatogrel is a reversible P2Y12 receptor antagonist for subcutaneous administration. It is supplied in sealed glass vials at a strength of 20 mg. The vials with ACT-246475A (hydrochloride salt of ACT-246475) will be reconstituted with 1 mL of water and further diluted with 1 mL sodium chloride (NaCl) 0.9%.

Selatogrel is a reversible P2Y12 receptor antagonist for subcutaneous administration. It is supplied in sealed glass vials at a strength of 20 mg. The vials with ACT-246475A (hydrochloride salt of ACT-246475) will be reconstituted with 1 mL of water for injection.

Number of Participants With a Pharmacodynamic Response as Assessed by the Inhibition of Platelet Aggregation

The pharmacodynamic response was determined by measuring the inhibition of platelet aggregation, using the VerifyNow® assay. The VerifyNow® is a point-of-care test measuring platelet reactivity. The results are expressed as P2Y12 reaction units (PRU).The target of 100 PRU corresponds to 80% inhibition of ADP-induced platelet aggregation. A participant with a PRU less than 100 at 30 minutes post-dose was counted as a participant that had a pharmacodynamic response.

Number of Participants (Per-protocol Subgroup) With a Pharmacodynamic Response as Assessed by the Inhibition of Platelet Aggregation

The pharmacodynamic response was determined by measuring the inhibition of platelet aggregation, using VerifyNow®. The VerifyNow® is a point-of-care test measuring platelet reactivity. The results are expressed as P2Y12 reaction units (PRU). The target of 100 PRU corresponds to 80% inhibition of ADP-induced platelet aggregation. A participant with a PRU of less than 100 starting at 30 minutes post-dose was counted as a participant that had a pharmacodynamic response.

Number of Participants With a Pharmacodynamic Response Within the First Hour as Assessed by the Inhibition of Platelet Aggregation

The purpose of this supportive analysis was to assess the effect when relaxing the time of a PRU < 100, i.e., considering as a response a PRU < 100 at 15, 30 or 60 min. post injection. The pharmacodynamic response was determined by measuring the inhibition of platelet aggregation, using the VerifyNow® assay. The VerifyNow® is a point-of-care test measuring platelet reactivity. The results are expressed as P2Y12 reaction units (PRU).The target of 100 PRU corresponds to 80% inhibition of ADP-induced platelet aggregation. A participant with a PRU less than 100 post-dose was counted as a participant that had a pharmacodynamic response.

The pharmacodynamic response assessed by the inhibition of adenosine diphosphate (ADP)-mediated platelet aggregation was determined by measuring the inhibition of platelet aggregation, using VerifyNow®. The VerifyNow® is a point-of-care test. The results are expressed as P2Y12 reaction units (PRU).

The Cmax is the peak concentration of selatogrel in the plasma after subcutaneous injection. The pharmacokinetic parameters of selatogrel (ACT-246475) were derived by non-compartmental analyses of the plasma concentration-time profiles.

Time after subcutaneous injection to reach the maximum observed selatogrel plasma concentration (Cmax).

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

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