Efficacy and Safety of Lonigutamab in Subjects With Thyroid Eye Disease (TED)

Key Inclusion Criteria:

• Male or female, ≥18 and ≤75 years of age.

• Proptosis defined in the study eye as ≥3 mm above normal.

• Clinical Activity Score (CAS) ≥4 (using a 7-item scale) for the most severelyaffected eye

• Onset of active TED symptoms prior to baseline

• Must agree to use highly effective contraception as specified in the protocol

Key Exclusion Criteria:

• Pathology related to inflammatory bowel disease or irritable bowel syndrome.

• Clinically significant pathology related to hearing or history of hearing impairment

• Optic neuropathy

• Corneal decompensation unresponsive to medical management.

• Previous orbital irradiation (for any cause) or any previous surgical treatment forTED.

• Subjects with diabetes or hemoglobin A1c >6.0% at screening

• Any steroid use (intravenous [IV] or oral) with a cumulative dose equivalent to >3 g of methylprednisolone for the treatment of TED within the last year.

• Previous steroid use (IV or oral) specifically for the treatment of TED not toexceed 1 g total dose in the 8 weeks prior to Screening.

• Previous use of teprotumumab or any other IGF-1 receptor (IGF-1R) inhibitor.

• Any previous treatment with a biologic drug for the treatment of TED (eg, rituximaband tocilizumab)

• Any other immunosuppressive agent within 1 month of screening.

• Cohort 4 only: Prior history of craniofacial surgery or medical conditions thatcould alter orbital or facial features.