Inclusion Criteria

To be eligible to participate in the study, a patient must meet all of the following criteria:

• Completed participation in study AG10-201.
• Willing and able to comply with the study medication regimen and all study requirements.
• The ability to understand and provide informed consent, which must be obtained prior to initiation of study participation.
• Male patients and female patients of childbearing potential who engage in heterosexual intercourse must agree to use effective method(s) of contraception.

Exclusion Criteria:

To be eligible to participate in the study, a patient must meet none of the following criteria:

• Hemodynamic instability that would pose too great a risk to the subject.
• Estimated glomerular filtration rate (GFR) <30 mL/min/1.73 m2.
• Abnormalities in clinical laboratory tests that would pose too great a risk to the subject.
• Any clinically significant ongoing medical condition or any laboratory abnormality or condition that could adversely affect the safety of the patient.
• Known hypersensitivity to study drug (AG10), its metabolites, or formulation excipients.
• Likely to undergo heart transplantation or placement of a mechanical circulatory device within the next year.
• Receiving current treatment with diflunisal, tafamidis, green tea, doxycycline, TUDCA/ursodiol, patisiran, inotersen or any other investigational ATTR agent within 14 days or 5 half-lives of the prior investigational agent (whichever is longer) prior to dosing with study drug.
• Females who are pregnant or breastfeeding. Lactating females must agree to discontinue nursing before the study drug is administered. Negative urine pregnancy test at each visit is required for female patients of childbearing potential.