Study to Assess Linsitinib in Participants With Moderate to Severe Active Thyroid Eye Disease (TED)

Participants must be ≥ 18 years of age at Screening

Clinical diagnosis of Graves' Disease and/or autoimmune Hashimoto's thyroiditis associated with active moderate to severe TED with a CAS ≥ 3 (on the 7-item scale) for the most severely affected eye (primary study eye) at Screening and Baseline.

Moderate to severe active TED (not sight-threatening but has an appreciable impact on daily life), with diagnosis of TED within 15 months prior to the Screening visit and usually associated with 1 or more of the following: lid retraction ≥ 2 mm, moderate or severe soft tissue involvement, proptosis ≥ 3 mm above normal for race and gender, and/or inconstant or constant diplopia.

Participants must be euthyroid with the participant's baseline disease under control or have mild hypo- or hyperthyroidism (defined as free thyroxine [FT4] and free triiodothyronine levels [FT3] < 50% above or below the normal limits of the central laboratory) at Screening.