The investigational drug, veligrotug (VRDN-001), is a monoclonal antibody that inhibits the activity of a cell surface receptor called insulin-like growth factor-1 receptor (IGF-1R). Inhibition of IGF-1R may help to reduce the inflammation and associated tissue swelling that occurs in patients with thyroid eye disease (TED). The primary objective of this clinical trial is to establish the safety, tolerability, and efficacy of veligrotug, and the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of veligrotug in active TED patients who received 10 mg/kg.

Key Inclusion Criteria for Active TED Participants (THRIVE):

• Must have moderate to severe active TED with documented evidence of ocular symptoms or signs that began within 15 months prior to screening
• Must have Clinical Activity Score (CAS) of ≥ 3 on the 7-item scale for the study eye
• Must agree to use highly effective contraception as specified in the protocol
• Female TED participants must have a negative serum pregnancy test at screening

Key Exclusion Criteria for Active TED Participants (THRIVE):

• Must not have received prior treatment with another anti-IGF-1R therapy or any investigational agent for TED
• Must not have used systemic corticosteroids or selenium within 2 weeks prior to Day 1
• Must not have received rituximab, tocilizumab or other immunosuppressive agents or any other therapy for TED within 8 weeks prior to Day 1
• Must not have received an investigational agent for any condition with 8 weeks prior to Day 1
• Must not have a pre-existing ophthalmic condition in the study eye that in the opinion of the Investigator would confound interpretation of the study results
• Must not have had previous orbital irradiation or surgery for TED in the study eye
• Must not have a history of inflammatory bowel disease
• Must not have a history of or screening audiometry assessment of clinically significant (as determined by investigator) ear pathology, relevant ear surgery, or hearing loss
• Female TED participants must not be pregnant or lactating

Note: Prior thyroidectomy, radioactive iodine (RAI) treatment, or orbital decompression surgery limited to bone only are NOT exclusions.