Nerandomilast is being developed to help people with systemic sclerosis by potentially improving symptoms and slowing disease progression. This study is open to adults who are at least 18 years old and have systemic sclerosis (SSc). People can join the study if they have limited or diffuse cutaneous SSc with disease onset within 7 years of the first non-Raynaud's symptom. The purpose of this study is to find out whether a medicine called nerandomilast helps people with systemic sclerosis. This study also aims to find out how well nerandomilast is tolerated in people with systemic sclerosis.

Participants are put into 2 groups randomly, which means by chance. One group takes nerandomilast tablets and the other group takes placebo tablets. Placebo tablets look like nerandomilast tablets but do not contain any medicine. Participants take the tablets twice a day.

Participants are in the study for 1 to about 4 years. During this time, they visit the study site regularly and get phone calls from the site staff. During study visits participants regularly have blood samples taken and doctors check changes in skin thickening, lung function, and internal organs, overall health and the safety and tolerability of study treatment in people with SSc. The results are compared between the groups to see whether the treatment works. The doctors also regularly check participants' health and take note of any unwanted effects.

Inclusion criteria:

1. Signed and dated written informed consent in accordance with ICH-GCP and local legislation prior to admission to the trial.
2. Patients must be at least 18 years of age and fulfil the 2013 American College of Rheumatology/European Alliance of Associations for Rheumatology (ACR/EULAR) criteria for SSc.
3. Patients must be diagnosed with limited cutaneous SSc (lcSSc) or diffuse cutaneous SSc (dcSSc), as defined by LeRoy et al. (1988).
4. Disease onset (defined by first non-RP [Raynaud's phenomenon] symptom) must be within 7 years of Visit 1.
5. Trial participants with dcSSc must have evidence of active disease during screening.
6. Trial participants with lcSSc must have evidence of active disease during screening. LcSSc patients must be anti-centromere antibody (ACA) negative.
7. FVC % predicted ≥45% at Visit 1.
8. Diffusing Capacity of the Lungs for Carbon Monoxide (DLCO) % predicted ≥25% corrected for haemoglobin (Hb) at Visit 1.
9. Women of childbearing potential (WOCBP) must be ready and able to use highly effective methods of birth control.
10. Patients may be either untreated or on stable treatment with permitted immunosuppressive/immunomodulatory agents and/or nintedanib. All treatments must remain stable prior to Visit 2 and during the screening period

Exclusion criteria:

1. Active, unstable, or uncontrolled vasculitis within 8 weeks prior to Visit 1 or during the screening period.
2. Any suicidal behaviour in the past 2 years.
3. Any suicidal ideation of type 4 or 5 on the C-SSRS in the past 3 months. Further exclusion criteria apply.

Once the criteria in section 'time frame' are fulfilled, researchers can use the following link https:// www.mystudywindow.com/msw/datasharing to request access to the clinical study documents regarding this study, and upon a signed "Document Sharing Agreement". Furthermore, researchers can request access to the clinical study data, for this and other listed studies, after the submission of a research proposal and according to the terms outlined in the website.

One year after the approval has been granted by major Regulatory Authorities and after the primary manuscript has been accepted for publication, or after termination of the development program.

For study documents -upon signing of a 'Document Sharing Agreement'.For study data -1. after the submission and approval of the research proposal (checks will be performed by the sponsor and/or the independent review panel, including checking that the planned analysis does not compete with sponsor'spublication plan); 2. and upon signing of a legal agreement.