The study was terminated for business reasons; there were no safety concerns.

The purpose of this clinical trial is to compare the amount of tafamidis in the blood of healthy adult participants after taking two different forms of tafamidis by mouth under fed conditions.

This study will be a Phase 1, open-label, randomized, two-treatment, two-period, crossover, single dose bioequivalence study to compare 61 mg tafamidis free acid tablet (Test) to 61 mg tafamidis free acid capsule (Reference) administered under fed conditions in healthy adult participants.

Inclusion Criteria

Age and Sex:

1. 18 years of age or older (or the minimum age of consent in accordance with local regulations) at screening who are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and cardiac monitoring.

   Other Inclusion Criteria:

2. BMI of 16-32 kg/m2; and a total body weight >45 kg (99 lb).

3. Evidence of a personally signed and dated informed consent document indicating that the subject has been informed of all pertinent aspects of the study.

Exclusion Criteria

Medical Conditions:

1. Evidence or history of clinically significant hematological, renal, endocrine, pulmonary, gastrointestinal, cardiovascular, hepatic, psychiatric, neurological, or allergic disease (including drug allergies, but excluding untreated, asymptomatic, seasonal allergies at the time of dosing).

   • Any condition possibly affecting drug absorption (eg, gastrectomy, cholecystectomy).
   • History of HIV infection, hepatitis B, or hepatitis C; positive testing for HIV, HBsAg, HBcAb or HCVAb. Hepatitis B vaccination is allowed.
   • Hypersensitivity to any component of the formulations.

2. Any medical or psychiatric condition including any active suicidal ideation in the past year or suicidal behavior in the past 5 years or laboratory abnormality or other conditions that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.

   Prior/Concomitant Therapy:

3. Use of prescription or nonprescription drugs and dietary and herbal supplements within 7 days or 5 half-lives (whichever is longer) prior to the first dose of study intervention.

4. Use of any prohibited concomitant medication(s) or unwillingness or inability to use a required concomitant medication(s).

   Prior/Concurrent Clinical Study Experience:

5. Previous administration of an investigational product (drug or vaccine) within 30 days or 5 half-lives preceding the first dose of study intervention used in this study (whichever is longer). Participation in studies of other investigational products (drug or vaccine) at any time during participation in this study.

   Diagnostic Assessments:

6. A positive urine drug test. A single repeat for positive drug screen may be allowed.

7. Screening supine BP ≥140 mm Hg (systolic) or ≥90 mm Hg (diastolic) for participants <60 years; and ≥150/90 mm/Hg for participants ≥60 years old, following at least 5 minutes of supine rest. If systolic BP is ≥ 140 or 150 mm Hg (based on age) or diastolic ≥90 mm Hg, the BP should be repeated 2 more times and the average of the 3 BP values should be used to determine the participant's eligibility.

8. Renal impairment as defined by eGFR <60 mL/min/1.73 m², which may be confirmed by a single repeat test, if necessary.

9. Standard 12-lead ECG that demonstrates clinically relevant abnormalities that may affect participant safety or interpretation of study results (including, but not limited to, QTcF >450 ms, complete LBBB, signs of an acute or indeterminate- age myocardial infarction, ST segment and/or T wave changes suggestive of myocardial ischemia, second- or third- degree AV block, or serious bradyarrhythmias or tachyarrhythmias). If QTcF exceeds 450 ms, or QRS exceeds 120 ms, the ECG should be repeated twice and the average of the 3 QTcF or QRS values used to determine the participant's eligibility. Computer-interpreted ECGs should be overread by an investigator experienced in reading ECGs before excluding a participant.

10. Participants with ANY of the following abnormalities in clinical laboratory tests at screening, as assessed by the study-specific laboratory and confirmed by a single repeat test, if deemed necessary:

    • ALT, AST, Bilirubin ≥1.5× ULN. Participants with a history of Gilbert's syndrome may have direct bilirubin measured and would be eligible for this study provided the direct bilirubin level is ≤ ULN.

    Other Exclusion Criteria:

11. History of alcohol abuse or repeated binge drinking and/or any other illicit drug use or dependence within 6 months of screening. Binge drinking is defined as a pattern of 5 (male) and 4 (female) or more alcoholic drinks in about 2 hours. As a general rule, alcohol intake should not exceed 14 units per week (1 unit = 8 ounces (240 mL) beer, 1 ounce (30 mL) of 40% spirit, or 3 ounces (90 mL) of wine).

12. Unwilling or unable to comply with the criteria in the Lifestyle Considerations section of this protocol.

13. Investigator site staff directly involved in the conduct of the study and their family members, site staff otherwise supervised by the investigator, and sponsor and sponsor delegate employees directly involved in the conduct of the study and their family members.

14. Use of tobacco/nicotine containing products in excess of the equivalent of 5 cigarettes/day or 2 chews of tobacco/day.

Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.