A Study to Evaluate the Efficacy and Safety of LASN01 in Patients With Thyroid Eye Disease

Inclusion Criteria: 1. Male or female patients ≥18 years of age at the time of Screening 2. Clinical diagnosis of Graves' disease associated with active TED 3. Moderate-to-severe active TED 4. Female patients must be nonpregnant, nonlactating, surgically sterile for ≥6 months, or agree to use a highly effective method of contraception. Males must be surgically sterile or agree to use a highly effective method of contraception. 5. No previous: 1. Medical treatment for TED, with the exception of: * Local supportive measures; * Mycophenolate, and oral or injectable steroids; * Immunomodulating therapies * For the open-label treatment arm only: Previous treatment with teprotumumab is required. 2. Orbital surgery 3. Orbital radiation 6. Patients * Without prior anti-IGF-1R treatment: less than 15 months from onset of TED symptoms * With prior teprotumumab treatment: depending on time of diagnosis or reactivation of disease Exclusion Criteria: 1. Patients with 2 mm proptosis decrease between Screening and Day 1, or a 1-point decrease on the CAS 7-point scale between Screening and Day 1 2. Patients with a known decreased best corrected visual acuity due to optic neuropathy as defined by a decrease in vision of 3 lines on the Snellen chart, new visual field defect, or color defect secondary to optic nerve involvement within the last 6 months before Screening; or any known optic neuropathy or compression or any neurologic or neuro-ophthalmologic condition that may result in visual field loss. 3. Previous or any planned orbital irradiation/radiotherapy or orbital surgery for TED during the study period (ie, treatment and FU) 4. Use of oral and/or IV corticosteroid for conditions other than TED in the 6 weeks before Day 1 (topical steroids for conditions other than TED are allowed) 5. Active autoimmune disorder(s) requiring or likely to require treatment (other than Grave's disease and TED) that would interfere with study assessments, as determined by the PI or designee 6. Any previous use of anti-IGF-1R monoclonal antibody (eg, teprotumumab) at any time, with exception to the open-label post-teprotumumab treatment arm where prior use of teprotumumab is required 7. Use of selenium within 3 weeks before Day 1 or expected use during the clinical trial (multivitamins that include selenium are allowed in usual doses) 8. Use or expected use of biotin (including multivitamins that include biotin) within 2 days before any laboratory collection