Extension Study to Assess Batoclimab in Participants With Thyroid Eye Disease

This is a 2-cohort (observational and treatment cohort) extension study for participants completing feeder studies (IMVT-1401-3201 or IMVT-1401-3202). The observational cohort will assess the durability of proptosis response of feeder studies off treatment. The treatment cohort will evaluate the efficacy of batoclimab as assessed by proptosis responder rate.

Inclusion criteria: For all participants: 1\. Have completed the Week 24 visit of the feeder study. For participants assigned to the Open-label Treatment Cohort: 1. Do not require immediate surgical intervention and is not planning corrective surgery/irradiation or medical therapy for TED during the course of the study. 2. Did not permanently discontinue batoclimab Additional inclusion criteria are defined in the protocol. Exclusion criteria: For all participants: 1\. In the Investigator's judgement, the benefits of entry in the study do not outweigh the risk.