This Phase 1 study aims to determine the oral bioavailability of a single dose of a new vapendavir tablet formulation and compare it to that of the previous vapendavir capsule formulation. The safety of both drug products will also be assessed.

Inclusion Criteria:

• Must be male or female between 18 and 55 years of age (inclusive) with BMI between 18 and 30 kg/m2 (inclusive), and weight ≥50 kg at the time of screening
• Capable of giving written informed consent
• Subject is able to understand and comply with the protocol requirements, instructions and restrictions
• Healthy on the basis of physical examination, medical history, medication usage, VS, ECGs, and clinical laboratory tests
• Female subjects must be of non-childbearing potential
• Male subjects must agree to use a double barrier method of birth control

Exclusion Criteria:

• Positive results for Hepatitis B, Hepatitis C, or HIV
• Frequent use of tobacco products, including cigarettes, cigars, chewing tobacco
• A medical history of significant hematological, gastrointestinal, respiratory, renal, hepatic, cerebrovascular, immunologic, psychiatric or cardiovascular disease or event; Current or recent respiratory infection
• Presence or history of significant allergy
• Clinically significant abnormalities noted on ECG
• Screening vital signs representing sustained elevated blood pressure
• Presence of significant gastrointestinal abnormalities
• Safety laboratory abnormalities noted at screening which are clinically significant
• Current or defined history of abuse of alcohol or illicit drugs
• A positive pregnancy test at screening
• Poor vein access or fear of venipuncture or sight of blood