This is a randomized, double-blind, placebo-controlled, repeat-dose, multicenter study. Participants will be screened for the study within 4 weeks prior to the Baseline (Day 1) Visit. Approximately 25 participants who meet the study eligibility criteria will be randomized on Day 1 in a 3:2 ratio to receive 8 infusions of TEPEZZA or placebo q3W. During the 24-week double-blind Treatment Period, study drug will be infused on Day 1 (Baseline) and Weeks 3, 6, 9, 12, 15, 18 and 21 with a comprehensive visit at Week 24 (end of treatment). On each dosing day, scheduled assessments (except for Adverse Events [AE] and concomitant medication use monitoring, which will be monitored throughout the clinic visit) will be completed prior to study drug infusions.~At the end of the Treatment Period (Week 24), participants will enter a 24-week Follow-up Period, during which study drug will not be administered and a clinic visit will be scheduled for Weeks 28, 36 and 48. A phone call or email at Weeks 32 and 42 will occur to inquire how the participant is doing.
The overall objective is to investigate the safety, tolerability and effect on insulin-like growth factor-1 (IGF-1), inflammatory and fibrotic biomarkers of TEPEZZA (teprotumumab-trbw, HZN-001), a fully human monoclonal antibody (mAb) inhibitor of the IGF-1 receptor (IGF-1R), administered once every 3 weeks (q3W) for 24 weeks in the treatment of participants with diffuse cutaneous systemic sclerosis (dcSSc).