This is a randomized, double-blind, placebo-controlled, repeat-dose, multicenter trial. Participants will be screened within 4 weeks prior to the Baseline (Day 1) Visit. Approximately 300 participants who meet the trial eligibility criteria will be randomized on Day 1 in a 1:1:1 ratio to receive HZN-825 300 mg QD, HZN-825 300 mg BID or placebo for 52 weeks. The trial will include up to a 4-week Screening Period and a 52-week Double-blind Treatment Period. Participants will take their first dose of trial drug at the clinic and will return to the clinic for trial visits at Week 4 and every 6 weeks thereafter until Week 52. All participants who complete the Double-blind Treatment Period (Week 52) will be eligible to enter a 52-week extension trial (HZNP-HZN-825-302, NCT05626751). Participants not entering the extension will return to the clinic for a Safety Follow-up Visit 4 weeks after the last dose of trial drug.



Eligible Ages
Between 18 Years and 75 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  1. Written informed consent. 2. Male or female between the ages of 18 and 75 years, inclusive, at Screening. 3. Meets the 2013 American College of Rheumatology/European League Against Rheumatism classification criteria for SSc with a total score of ≥9 (Van den Hoogen et al., 2013). 4. Classified as having skin involvement proximal to the elbow and knee (diffuse cutaneous SSc subset by LeRoy and Medsger, 2001). 5. At the time of enrollment, less than 36 months since the onset of the first SSc manifestation, other than Raynaud's phenomenon. 6. Skin thickening from SSc in the forearm suitable for repeat biopsy. 7. mRSS units ≥15 at Screening. 8. FVC ≥45% predicted at Screening, as determined by spirometry. 9. Willing and able to comply with the prescribed treatment protocol and evaluations for the duration of the trial.

Exclusion Criteria

  1. Positive for anti-centromere antibodies. 2. Diagnosed with sine scleroderma or limited cutaneous SSc. 3. Diagnosed with other autoimmune connective tissue diseases, except for fibromyalgia, scleroderma-associated myopathy and secondary Sjogren's syndrome. 4. Scleroderma renal crisis diagnosed within 6 months of the Screening Visit. 5. Any of the following cardiovascular diseases: 1. uncontrolled, severe hypertension (≥160/100 mmHg) or persistent low blood pressure (systolic blood pressure <90 mmHg) within 6 months of Screening, 2. myocardial infarction within 6 months of Screening, 3. unstable cardiac angina within 6 months of Screening. 6. DLCO <40% predicted (corrected for hemoglobin). If severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure is of clinical concern for any subject, consider using a DLCO up to 6 months before the Screening Visit. 7. Pulmonary arterial hypertension (PAH) by right heart catheterization requiring treatment with more than 1 oral PAH-approved therapy or any parenteral therapy. Treatment is allowed for erectile dysfunction and/or Raynaud's phenomenon/digital ulcers. 8. Corticosteroid use for conditions other than SSc within 4 weeks prior to Screening (topical steroids for dermatological conditions and inhaled/intranasal/intra-articular steroids are allowed). 9. Use of any other non-steroid immunosuppressive agent, small biologic molecule, cytotoxic or anti-fibrotic drug within 4 weeks of Screening, including cyclophosphamide, azathioprine (Imuran®) or other immunosuppressive or cytotoxic medication. Exceptions include mycophenolate mofetil (CellCept®), mycophenolic acid (Myfortic®), methotrexate and low-dose prednisone, as follows: use of CellCept ≤3 g/day, Myfortic ≤2.14 g/day, methotrexate ≤15 mg/week and prednisone ≤10 mg/day (or equivalent dosing of glucocorticoids) is allowed. See Table 9.1 for full details. Subjects taking CellCept, Myfortic or methotrexate must have been doing so for ≥6 months and the dose must have been stable for ≥16 weeks prior to the Day 1 Visit. Prednisone must have been at a stable dose for ≥8 weeks prior to the Day 1 Visit. It is acceptable to be on background low-dose prednisone and anti-malarial drug along with CellCept, Myfortic or methotrexate. Rituximab must not have been used within 6 months of the Day 1 Visit. 10. Known active bacterial, viral, fungal, mycobacterial or other infection, including tuberculosis or atypical mycobacterial disease (fungal infections of nail beds are allowed). 11. Use of a United States Food and Drug Administration-approved agent for SSc or an investigational agent for any condition within 90 days or 5 half-lives, whichever is longer, prior to Screening or anticipated use during the course of the trial. 12. Malignant condition in the past 5 years (except successfully treated basal/squamous cell carcinoma of the skin or cervical cancer in situ). 13. Women of childbearing potential or male subjects not agreeing to use highly effective method(s) of birth control throughout the trial and for 1 month after last dose of trial drug. Male subjects must refrain from sperm donation and females from egg/ova donation for this same time period. 14. Pregnant or lactating women. 15. Current drug or alcohol abuse or history of either within the previous 2 years, in the opinion of the Investigator or as reported by the subject. 16. Previous enrollment in this trial or participation in a prior HZN-825 or SAR100842 clinical trial. 17. Known history of positive test for human immunodeficiency virus. 18. Active hepatitis (hepatitis B: positive hepatitis B surface antigen and positive anti-hepatitis B core antibody [anti-HBcAb] and negative hepatitis B surface antibody [HBsAb] or positive for HBcAb with a positive test for HBsAb and with presence of hepatitis B virus DNA at Screening; hepatitis C: positive anti-hepatitis C virus [anti-HCV] and positive RNA HCV). 19. Current alcoholic liver disease, primary biliary cirrhosis or primary sclerosing cholangitis. 20. Previous organ transplant (including allogeneic and autologous marrow transplant). 21. International normalized ratio >2, prolonged prothrombin time >1.5 × the upper limit of normal (ULN) or partial thromboplastin time >1.5 × ULN at Screening. 22. Alanine aminotransferase or aspartate aminotransferase >2 × ULN. 23. Estimated glomerular filtration rate <30 mL/min/1.73 m^2 at Screening. 24. Total bilirubin >2 × ULN. Subjects with documented diagnosis of Gilbert's syndrome may be enrolled if their total bilirubin is ≤3.0 mg/dL. 25. Any other condition that, in the opinion of the Investigator, would preclude enrollment in the trial.

Study Design

Phase 2
Study Type
Intervention Model
Parallel Assignment
Primary Purpose
Triple (Participant, Care Provider, Investigator)

Arm Groups

ArmDescriptionAssigned Intervention
HZN-825 300 mg once daily (QD)
300mg oral tablets given in the morning and placebo in the evening
  • Drug: HZN-825 QD
    300 mg oral tablets QD
HZN-825 300 mg twice daily (BID)
300mg oral tablets given in the morning and evening
  • Drug: HZN-825 BID
    300 mg oral tablets BID
Placebo Comparator
Placebo will be given orally in the morning and evening
  • Drug: Placebo
    Placebo BID

Recruiting Locations

Boston University School Of Medicine
Boston, Massachusetts 02118-2642
Kimberly Finch

More Details

Horizon Therapeutics Ireland DAC

Study Contact



Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.