Open-Label Rollover Study of AMG 732 in Thyroid Eye Disease Nonresponders and Relapsed Participants

The primary objective is to assess the efficacy of AMG 732 in participants with thyroid eye disease who are primary nonresponders or who relapsed during safety follow-up in the parent study. This is clinically relevant for determining whether treatment benefit can be achieved or regained in patients with inadequate initial response or subsequent disease recurrence. The secondary objectives are to characterize the pharmacokinetics of AMG 732 and to investigate its safety and tolerability. Additional efficacy assessments include participants with relapse after a prior proptosis response and participants defined as primary nonresponders in the parent study.

The trial population consisted of 25 participants with thyroid eye disease, including both female and male patients. Participants were adults aged 18 years or older at the time of informed consent in the parent study. The population was selected from individuals who had completed an Amgen-sponsored clinical trial of AMG 732 and who were defined as primary nonresponders or had relapsed during the safety follow-up in the parent study. Participants had moderate-to-severe disease at enrollment in the parent study, did not require immediate surgical ophthalmological intervention, and were not planning corrective surgery or irradiation during the rollover trial. Thyroid status was required to remain euthyroid throughout the study, and protocol-specified contraception was required during treatment and for 6 months after the last dose of trial intervention.

This thyroid eye disease rollover study is an open-label, phase 2 clinical trial in participants previously enrolled in Amgen-sponsored AMG 732 studies who are primary proptosis non-responders or who relapsed during safety follow-up. The trial evaluates the efficacy and safety of AMG 732 and includes pharmacokinetic assessments. Study participation begins with a screening visit to confirm eligibility, including review of prior study participation, disease status, and protocol requirements. Eligible participants then enter the treatment and assessment period, with follow-up visits performed to evaluate efficacy, safety, and pharmacokinetic outcomes. An end-of-study visit is performed at study completion to document final assessments. The overall trial is planned from 2026-05-04 to 2028-07-14. Participant involvement is expected to continue for the duration of the rollover study, including treatment, follow-up, and the final visit. Early termination may occur if consent is withdrawn, eligibility criteria are no longer met, protocol-specified contraception or euthyroid status requirements are not maintained, planned corrective surgery or irradiation becomes necessary, or if adverse events or other medical circumstances require discontinuation.

AMG 732 was administered as a solution for injection at a dose of 9999 mg by subcutaneous route. The study was open-label and rollover in design. Administration was intended for participants previously enrolled in AMG 732 studies with thyroid eye disease who were primary proptosis non-responders or who relapsed during safety follow-up. No comparator, placebo, or other non-experimental treatment was specified in the source data. Information on dosing frequency, detailed dosing schedule, and compliance monitoring was not provided.

The efficacy of AMG 732 will be assessed in participants with thyroid eye disease using proptosis response status in the study eye at week 9999. Responders are defined as participants with a ≥ 2 mm reduction from baseline in the study eye without deterioration, defined as a ≥ 2 mm increase, of proptosis in the fellow eye. Change from baseline at week 9999 in proptosis measurement by an exophthalmometer in the study eye will also be evaluated.