Inclusion Criteria:

• Participants must have completed the AG10-501 study (ACT-EARLY study) within the past 60 calendar days with a diagnosis of ATTR-CM (based on the AG10-501 protocol definition of ATTR-CM).

• Participant must be willing and able to give signed informed consent for participation in the study. Informed consent must be obtained prior to initiation of study procedures.

• Agree to the use of highly effective contraception:

  • FEMALE: WOCBP (defined as all women physiologically capable of becoming pregnant) who engage in heterosexual intercourse must agree to use a highly effective method of contraception from Day 1 and continuing for 30 calendar days after the last dose of study drug (see Section 8.3.6).

  • MALE: A male participant who has not had a vasectomy and is sexually active with a female of childbearing potential must agree to a double-barrier method of birth control during the study and continue for 30 calendar days after the last dose of study drug. Males must agree to refrain from sperm donation for a minimum of 30 calendar days post the last dose of the study drug.

Exclusion Criteria:

• Participants who completed the AG10-501 study with a diagnosis of ATTR-PN only, or who permanently discontinued study drug prior to diagnosis of ATTR-CM in AG10-501.

• History of AL or another non-TTR amyloid subtype (eg, ApoA-1, gelsolin).

• History of a monoclonal paraprotein or abnormal light chains in serum or urine (ie, MGUS) in which AL has not been ruled out.

• Stage IV or V chronic kidney disease (corresponding to an eGFR ≤ 29 mL/min/1.73 m2), or undergoing renal dialysis, or recipient of a kidney transplant.

• Active malignancy, except for basal or squamous cell carcinoma of the skin, carcinoma in situ of the cervix that has been successfully treated. In the event a participant developed a low-grade and treatable malignancy in the AG10-501 study (eg, low-grade, localized prostate cancer) and the decision by the Investigator at that time was to continue the participant in the AG10-501 study, that participant may still qualify for Study AG10504 after documentation with the Medical Monitor.

• History of any organ transplant (with the exception of corneal transplant).

• Known hypersensitivity to acoramidis or any of the excipients within the study drug.

• Treatment for ATTR-CM with any ATTR-oriented on- or off-label or OTC product.

• Female participants who are pregnant or breastfeeding. A negative urine pregnancy test on Day 1 prior to dosing is required for WOCBP. A positive urine dipstick pregnancy test will need to be confirmed with a serum test and participants cannot commence AG10-504 study unless the serum test results return negative.

• In the judgment of the Investigator or Medical Monitor, has any clinically relevant ongoing medical condition or laboratory abnormality or other condition that might jeopardize the participant’s safety, increase the participant’s risk from participation, interfere with the study, or confound study results.

• Participation in another investigational clinical trial. Participation in observational and/or registry studies must be discussed with the Medical Monitor.

• Major surgery planned during the next 6 months. For participants who may have required major surgery during their participation in the AG10-501 study and the decision by the Investigator at that time was to continue the participant in the AG10-501 study, that participant may still qualify for Study AG10-504 provided study participation does not interfere with the surgical care plan and vice versa.

Note: Other protocol defined Inclusion/Exclusion Criteria may apply.

Eligibility last updated 6/23/2025. Questions regarding updates should be directed to the study team contact.