The objectives for this 2 Part study are to assess the safety, tolerability, and pharmacokinetics following single ascending oral doses of nacresertib in healthy adult participants (Part 1) and to assess the safety, tolerability, and pharmacokinetics following multiple ascending oral doses in healthy adult participants (Part 2).

Inclusion Criteria:

-- A condition of general good health, based upon the results of a medical history, physical examination, vital signs, laboratory profile, and a 12-lead ECG.

Exclusion Criteria:

• History of epilepsy, any clinically significant cardiac, respiratory (except mild asthma as a child), renal, hepatic, gastrointestinal, hematologic or psychiatric disease or disorder, or any uncontrolled medical illness.
• History of any clinically significant sensitivity or allergy to any medication or food.
• History of or active medical condition(s) or surgical procedure(s) that might affect gastrointestinal motility, pH, or absorption [e.g., Crohn's disease, celiac disease, gastroparesis, short bowel syndrome, gastric surgery (except pyloromyotomy for pyloric stenosis during infancy), cholecystectomy, vagotomy, bowel resection, etc.]