Adults 18 to 65 years of age, inclusive, at the time of signing the ICF
Documented GD diagnosis,
Receiving stable dose of ATD (Antithyroid drug)
Body weight at least 50 kg (110 lb) and body mass index (BMI) 18.0-35.0 kg/m2, inclusive
Women of childbearing potential must agree to use highly effective contraceptive methods
Men with partners of childbearing potential or who are pregnant must agree to use a condom or strict abstinence
Signed informed consent to participate in the study
Willingness and ability, in the opinion of the investigator, to comply with protocol requirements and restrictions (eg, dosing, schedule of assessments).
History of:
total thyroidectomy.
History of hyperthyroidism not caused by GD (eg, toxic adenoma, toxic multinodular goiter).
History of thyroid storm.
History of agranulocytosis, anemia, leukopenia, thrombocytopenia, vasculitis, or liver toxicity due to prior ATD therapy Treatment with RAI therapy within 12 months prior to Screening
Likely to require definitive treatment for GD (RAI therapy or thyroidectomy) during the study, based on GD history and anticipated prognosis.
Use of levothyroxine, desiccated thyroid extract, or T3 at any dose within 6 weeks prior to Screening.
Current active or chronic moderate-to-severe TED per EUropean Group On Graves' Orbitopathy (EUGOGO) criteria as judged by the investigator at Screening
History of TED-directed medical treatment (including IV/oral steroids, immunosuppressants, or teprotumumab), surgical treatment, and/or orbital radiation within 3 months prior to Screening, or per required prohibited concomitant therapy washout criteria in the protocol (whichever is longer)
Major surgery or use of iodinated contrast within 3 months prior to planned IMP dosing.
Active systemic autoimmune disease requiring treatment that causes undue risk in the opinion of the investigator.
History of cardiovascular, respiratory, renal, gastrointestinal, endocrinological (other than GD), hematological, immunodeficiency, or neurological disorders that may constitute a risk when taking the IMP or interfere with data interpretation.
History of liver disease
Pregnant, breastfeeding, or planning to become pregnant during the study
Treatment with prohibited medications prior to planned IMP dosing or likely to require prohibited concomitant therapy during the study
Live vaccine(s) or mRNA vaccine(s) within 1 month prior to IMP dosing, or plans to receive such vaccines during the study
Treatment with any investigational drug within within 3 months or 5 half-lives (whichever is longer) prior to enrollment
Total IgG level <700 mg/dL at Screening
Any of the following at Screening (confirmed by single repeat measurement, if deemed necessary):
Estimated glomerular filtration rate (eGFR) <75 mL/min/1.73 m2 using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) creatinine equation
Positive result for HIV antibody, HBsAg, or hepatitis C antibody with detectable viral RNA levels at Screening
Positive drug screen or positive test for alcohol
12-lead ECG demonstrating any of the following at Screening:
QTcF interval >450 ms
QRS interval >120 ms
PR interval >220 ms
Blood pressure measurements demonstrating any of the following at Screening:
Heart rate <45 bpm or >100 bpm
Donated more than 500 mL of blood in the 2 months prior to signing the ICF
Current enrollment or past participation within 3 months or 5 half-lives (whichever is longer) prior to signing the ICF in any other clinical trial involving an IMP
Refusal to adhere to lifestyle considerations as defined in the protocol
Employee of the investigator, clinic, or sponsor with direct involvement in the proposed study or other studies under the direction of the investigator or clinic, as well as family members of the employee or investigator
Any other conditions that, in the opinion of the investigator or the sponsor, could interfere with participation in or completion of the study