Patient description: The patient is a 35-year-old woman with myasthenia gravis, class IIa. She complains of diplopia and fatigue and weakness that affects mainly her upper limbs. She had a positive anti-AChR antibody test, and her single fiber electromyography (SFEMG) was positive. She takes pyridostigmine 60 mg three times a day. But she still has some symptoms that interfere with her job. She is a research coordinator and has 3 children. Her 70-year-old father has hypertension. She does not smoke or use illicit drugs. She drinks alcohol occasionally at social events. Her physical exam and lab studies were not remarkable for any other abnormalities. BP: 110/75 Hgb: 11 g/dl WBC: 8000 /mm3 Plt: 300000 /ml Creatinine: 0.5 mg/dl BUN: 10 mg/dl Beta hcg: negative for pregnancy

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  Thyroid Eye Disease Graves Orbitopathy Signed informed consent must be obtained prior to participation in the study Male or non-pregnant, non-lactating female patients ≥ 18 years of age Clinical diagnosis of active, moderate-to-severe TED (not sight threatening) at Baseline associated with 2 or more of the following: Lid retraction ≥ 2 mm; Moderate or severe soft tissue involvement; Exophthalmos ≥ 3 mm above normal for race and gender; Inconstant or constant diplopia Onset of TED symptoms fewer than 12 months prior to Baseline CAS ≥ 4 (on a 7-point scale, with a score of ≥ 3 indicating active TED) in the more severely affected (study) eye at Screening and Baseline. . Note: Proptosis is the primary qualifier for selection of the study eye. In case both eyes show a similar degree of proptosis, other inflammatory signs and symptoms (CAS) should be taken into account by the investigator for the selection of the study eye Peripheral euthyroidism or mild hypo-/hyperthyroidism defined as free T3 (fT3) and free T4 (fT4) < 30% above/below normal limits. Every effort should be made to correct the mild hypo-/hyperthyroidism promptly and to maintain the euthyroid state until the end of this study Orbital MRI assessment available confirming the diagnosis of TED for patients initially presenting with hypo or euthyroidism (without treatment for hyperthyroidism) before or at the time of TED diagnosis (to rule out other potential causes of orbital signs and symptoms  Improvement in CAS of ≥ 2 points and/or improvement in proptosis of ≥ 2 mm in the study eye between Screening and Baseline Signs of sight-threatening TED defined by optic neuropathy or corneal decompensation Decreased best corrected visual acuity (BCVA) as defined by a decrease in vision of 2 lines on the Snellen chart, new visual field defect or color defect within the last 6 months Any other ophthalmic and/or orbital disease or condition that might interfere with the assessment of TED Previous orbital radiotherapy Previous ophthalmological/orbital surgery for TED (e.g. orbital decompression) Requires immediate surgical ophthalmological intervention or is planning corrective surgery/irradiation during the course of the study Previous use of biological agents for the treatment of TED Previous use of systemic, non-biologic, immunomodulatory agents for the treatment of TED (e.g. mycophenolate or cyclosporine) Previous exposure to secukinumab or other biologic drugs directly targeting IL-17A or the IL 17 receptor (e.g. ixekizumab, brodalumab)