Sponsor decision.

The purpose of this study is to measure safety and efficacy of oral belumosudil in Black or African American, American Indian or Alaska Native, and Native Hawaiian or Other Pacific Islander male and female participants with cGVHD who have previously been treated with at least 2 prior lines of systemic therapy aged 12 years and above.

The duration of participants participation will be up to 4 weeks for screening, treatment until clinically significant progression of disease, and 4 weeks of safety follow-up, and then long-term follow-up every 12 weeks.1 Cycle = 28 days.

Up to 4 weeks for screening, treatment until clinically significant progression of disease, 4 weeks of safety follow-up and then long-term follow-up every 12 weeks.

Inclusion Criteria:

• Participants are included in the study if any of the following criteria apply:
• Participant is Black or African American, or American Indian or Alaska Native, or Native Hawaiian or Other Pacific Islander by self-identification.
• Previously received at least 2 and not more than 5 lines of systemic therapy for cGVHD.
• Receiving glucocorticoid therapy with a stable dose over the 2 weeks prior to screening.
• Have persistent cGVHD manifestations and systemic therapy is indicated.
• Karnofsky (if aged ≥ 16 years) / Lansky (if aged < 16 years) Performance Score of ≥ 60.
• At least 12 years of age; weight ≥ 40 kilograms (kg).
• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 3 x upper limit of normal (ULN).
• Total bilirubin ≤ 1.5 x ULN.
• Contraception (with double contraception methods) for male and female participants; not pregnant or breastfeeding for female participants
• Capable of giving signed informed consent.

Exclusion Criteria:

• Participants are excluded from the study if any of the following criteria apply:
• Participant has not been on a stable dose/regimen of systemic cGVHD treatment(s) for at least 2 weeks prior to screening. (Note: Concomitant corticosteroids, calcineurin inhibitors, sirolimus, MMF, methotrexate, rituximab, and ECP are acceptable. Systemic investigational GVHD treatments are not permitted).
• Histological relapse of the underlying cancer or post-transplant lymphoproliferative disease at the time of screening.
• Current treatment with ibrutinib or ruxolitinib. Prior treatment with ibrutinib or ruxolitinib is allowed with a washout of at least 28 days prior to enrollment.
• History or other evidence of severe illness or any other conditions that would make the participant, in the opinion of the Investigator, unsuitable for the study (such as malabsorption syndromes, poorly controlled psychiatric disease, or coronary artery disease).
• Corrected QT interval using Fridericia's formula (QTc[F]) > 480 ms.
• Forced expiratory volume (in the first second; FEV1) ≤ 39% The above information is not intended to contain all considerations relevant to the potential participation in a clinical trial.

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org