The aim of this first-in-human study is to assess the safety, tolerability, PK and exploratory pharmacodynamics (PD) of single and multiple oral ascending doses of OMT-28 in healthy male subjects to support further clinical development of OMT-28 in the indication of atrial fibrillation (AF) and to obtain data on food and gender effects of OMT-28 to guide dosing for Phase II trials.

This first-in-human study will be carried out in one study center involving multiple steps. Up to 100 healthy male and female subjects will be enrolled. The study consists of 4 parts:

1. a single ascending dose (SAD) part
2. a multiple ascending dose (MAD) part
3. a single dose, double cross-over food effect (FE) part.
4. a single dose gender effect part (female subjects group) The safety and PK data will be evaluated by the DSMC after each cohort to decide on further dose escalation.

Inclusion Criteria:

1. In general good physical health as determined by medical and surgical history, physical examination, 12 lead ECG, vital signs, and clinical laboratory tests
2. Normal blood pressure (Systolic Blood Pressure (SBP) between 100 to 140 mmHg (both inclusive); Diastolic Blood Pressure (DBP) ≥55, ≤89 mmHg) measured after 5 min rest in supine position.
3. SAD, MAD, and FE part: male of 18 to 45 years (inclusive) of age.
4. Gender effect part: female of 18 to 45 years (inclusive) of age.

Exclusion Criteria:

1. More than moderate smoker (> 10 cigarettes/day).
2. More than moderate alcohol consumption (> 35 g of ethanol regularly per day or > 245 g regularly per week).
3. Use of any medication
4. One or more key safety laboratory parameters out of normal range Gender effect part Pregnant or breastfeeding women and of childbearing potential Previous assignment to treatment during this study.

SAD, MAD and Gender parts: double blind randomized. Food Effect part: open label, crossover design