A Multicenter, Open-label Extension Trial to Evaluate the Efficacy, Safety and Tolerability of HZN-825 in Patients With Diffuse Cutaneous Systemic Sclerosis

Primary Objectives: 1. The primary efficacy objective is to assess the efficacy of 52 weeks of open-label treatment with HZN-825 in participants with diffuse cutaneous systemic sclerosis, as measured by change from both baselines in forced vital capacity percent (FVC %) predicted. 2. The primary safety objective is to examine the safety and tolerability of 52 weeks of open-label treatment with HZN-825, inclusive of, but not limited to, adverse events (AEs), serious AEs (SAEs) and the adverse event of special interest (AESI), from Day 1 to 4 weeks after last dose.