This is a first-in-human study of MR1817. This study will provide an initial assessment of the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of MR1817 after administration of ascending single oral doses to healthy adult subjects.

Inclusion criteria: 1- Men or women of non-childbearing potential (WONCBP) aged 18 to 55 years inclusive at screening.

2- Body mass index (BMI) in the range of 18 to 32 kg/m2 and body weight ≥50 kg. 3- Healthy as determined by the investigator on the basis of screening evaluations.

Exclusion criteria: 1- Presence or history of any disorder that may prevent the successful completion of the study. 2- Any significant cardiovascular, hepatic, renal, respiratory, gastrointestinal, endocrine, immunologic, dermatologic, hematologic, neurologic, or psychiatric disease. 3- History of drug abuse within 1 year before study day 1.