Sponsor terminated open-label extension

This is a Phase 3 multicenter, double-blind, randomized, placebo-controlled study assessing the efficacy and safety of lenabasum for the treatment of diffuse cutaneous systemic sclerosis (SSc). Approximately 354 subjects will be enrolled in this study at about 60 sites in North America, Europe, Australia, and Asia. The planned duration of treatment with study drug is 52 weeks.

Key Inclusion Criteria:

1. ≥ 18 years of age at the time Informed Consent is signed.
2. Diffuse cutaneous SSc (skin thickening on upper arms, upper legs, or trunk).
3. Disease duration ≤ 6 years from the first non-Raynaud's symptom.
4. No new or increased doses of immunosuppressive medications within 8 weeks prior to Screening.

Key Exclusion Criteria:

1. Unstable SSc or SSc with end-stage organ involvement at Screening or Visit 1.

2. Any of the following values for laboratory tests at Screening:

   1. A positive pregnancy test in women of childbearing potential;
   2. Hemoglobin < 9 g/dL for males and < 8 g/dL for females;
   3. Neutrophils < 1.0 ×10^9/L;
   4. Platelets < 75 ×10^9/L;
   5. Creatinine clearance < 50 mL/min according to the Modification of Diet in Renal Disease (MDRD) Study equation;
   6. Aspartate aminotransferase or alanine aminotransferase > 2.0 × upper limit of normal.

3. Any medical condition or concurrent medical therapies at Screening or Visit 1, including a history of non-compliance with medical treatments, that may put the subject at greater safety risk, influence response to study product, or interfere with study assessments.