Drug-drug Interaction Study of TPOXX When Co-administered With Phosphate Binders

Inclusion Criteria

• Each subject must meet all of the following criteria to be enrolled in this study:
• Subject is male or female 18 to 50 years of age, inclusive.
• Phosphorus levels within normal laboratory reference range.
• Women of childbearing potential have a negative human chorionic gonadotropin pregnancy test (serum) at the screening visit and a confirmatory negative serum pregnancy test on Day -1 of each period before receipt of study drug, and meet one of the following criteria:
• The subject or their partner has undergone surgical sterilization
• The subject is postmenopausal, defined as 12 consecutive months with no menses without an alternative medical cause and has a documented plasma follicle-stimulating hormone level >40 IU/mL

Exclusion Criteria

Subjects meeting any of the following criteria will be excluded from the study:

• Subject is a female who is pregnant or breastfeeding or planning to become pregnant within 3 months after the last dose of study drug.
• Subject has a history of any clinically significant conditions including:
• Asthma treated with oral systemic steroids within the past 6 months
• Diabetes mellitus (type 1 or 2), with the exception of gestational diabetes
• Hypertension that is poorly controlled (repeat readings >140 mm Hg systolic and/or >90 mm Hg diastolic)
• Thyroidectomy or thyroid disease that required medication within the past 12 months
• Serious angioedema episodes within the previous 3 years or requiring medication in the previous 2 years
• Head trauma resulting in a diagnosis of traumatic brain injury other than concussion
• Frequent episodes of headache.
• Subject has received treatment in another clinical study of an investigational drug (or medical device) within 30 days or 5 half-lives (whichever is longer) before the first dose of study drug.
• Subject has a history of relevant drug and/or food allergies (ie, allergy to TPOXX or excipients, or any significant food allergy that could preclude a standard diet in the study site).
• Subject has any condition possibly affecting drug absorption (eg, previous surgery on the gastrointestinal tract, including removal of parts of the stomach, bowel, liver, gallbladder, or pancreas, with the exception of appendectomy).
• Subject has evidence or history of clinically significant allergic (except for untreated, asymptomatic, seasonal allergies at time of the first dose of study drug), hematological, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, or neurological disease. Exceptions to these criteria (eg, stable, mild joint disease unassociated with collagen vascular disease) may be made following discussions with the medical monitor.
• Subject has a history of cardiac disease, symptomatic or asymptomatic arrhythmias, syncopal episodes, or risk factors for torsades de pointes (eg, heart failure, hypokalemia).
• Subject has a family history of sudden cardiac death not clearly due to acute myocardial infarction.
• Subject has a seizure disorder or history of seizures (does not include childhood febrile seizures) or a past history that increases seizure risks such as significant head injury that caused loss of consciousness or other changes in the subject's daily function, concussion, stroke, central nervous system infection or disease, or alcohol or drug abuse or family history of idiopathic seizures.
• Subject has a history of a peptic ulcer or significant gastrointestinal bleeding.
• Subject has a bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with blood draws.
• Subject has a malignancy that is active, or treated malignancy for which there is not reasonable assurance of sustained cure, or malignancy that is likely to recur during the period of the study (subject should be in complete remission for at least 5 years).
• Subject has neutropenia or