• The participant want treatment for active thyroid eye disease and is willing to be included in the study

• Clinical diagnosis of Graves' disease associated with active TED with a Clinical Activity Score (CAS) ≥ 4 (on the 7-item scale)

• Moderate-to-severe active TED (not sight-threatening but has an appreciable impact on daily life), usually associated with one or more of the following: lid retraction ≥ 2 mm, moderate or severe soft tissue involvement, exophthalmos ≥ 3 mm above normal for race and gender, and/or inconstant or constant diplopia

• Onset of active TED symptoms (as determined by participant records) within 9 months prior to inculsion

• Participants must be euthyroid with the Graves disease under control or have mild hypo- or hyperthyroidism (defined as free thyroxine and free triiodothyronine levels \< 50% above or below the normal limits).

• Does not require immediate surgical ophthalmological intervention and is not planning corrective surgery/irradiation during the course of the study

• Diabetic participants must have well-controlled stable disease (defined as HbA1C \< 9.0% with no new diabetic medication \[oral or insulin\] or more than a 10% change in the dose of a currently prescribed diabetic medication within 60 days prior to Screening)

• Women of childbearing potential (including those with an onset of menopause \<2 years prior to Screening, non-therapy-induced amenorrhea for \<12 months prior to Screening, or not surgically sterile \[absence of ovaries and/or uterus\]) must have a negative serum pregnancy test at Screening and negative urine pregnancy tests at all protocol-specified timepoints (i.e., prior to each dose and through Week 48 of the Follow-Up Period); participants who are sexually active with a non-vasectomized male partner must agree to use 2 reliable forms of contraception during the trial, one of which is recommended to be hormonal, such as an oral contraceptive. Hormonal contraception must be started at least one full cycle prior to Baseline and continue for 180 days after the last dose of study drug. Highly effective contraceptive methods (with a failure rate less than 1% per year) when used consistently and correctly, includes implants, injectables, combined oral contraceptives, intrauterine devices (IUDs), sexual abstinence or vasectomized partner

• Male participants must be surgically sterile or, if sexually active with a female partner of childbearing potential, must agree to use barrier contraceptive method from Screening through 180 days after the last dose of study drug

• Active Influenza and Pneumococcal vaccines