Study to Assess Batoclimab in Participants With Active Thyroid Eye Disease

Inclusion criteria:

1. Are ≥18 years of age at screening.

2. Have a clinical diagnosis of TED associated with active, moderate to severe TED withthe following at screening and Visit 0:

• A CAS ≥ 4 in either eye, and

• Clinical evidence of worsened proptosis with:

• Proptosis ≥ 18 mm and/or

• Proptosis ≥ 3 mm increase from participant's baseline (prior to diagnosisof TED), as estimated by the Investigator/assessor

3. Have moderate to severe active TED, as defined by European Group on Graves'Orbitopathy (EUGOGO) guidelines.

4. Have onset of active TED within 12 months prior to screening.

5. Have documented evidence of detectable anti-TSHR-Ab at screening.

6. Are not expected to require immediate surgical intervention and are not planningcorrective surgery/irradiation or medical therapy for TED during the course of thestudy.

7. Are euthyroid with the Baseline disease under control or have mild hypo- orhyperthyroidism.

Additional inclusion criteria are defined in the protocol.

Exclusion criteria:

1. Have decreased best corrected visual acuity due to optic neuropathy.

2. Have at least a 2-point decrease in CAS or ≥2 mm decrease in proptosis betweenscreening and Baseline assessments in either eye.

3. Have used any steroid (intravenous or oral) for the treatment of TED or otherconditions within 4 weeks prior to screening.

4. Have used any steroid (Intravenous or oral) with a cumulative dose equivalent to ≥ 1g of methylprednisolone for the treatment of TED.

5. Have known autoimmune disease other than TED, that, in the opinion of theInvestigator, would interfere with the course and conduct of the study.

6. Had previous orbital irradiation or surgery for TED.

Additional exclusion criteria are defined in the protocol.