Belumosudil with or without FAM Regimen and Corticosteroid for the Treatment of New Onset or Incipient Bronchiolitis Obliterans Syndrome in Patients Who Have Undergone Allogeneic Hematopoietic Cell Transplantation, The BEBOP Trial

Inclusion Criteria

• COHORT A: Diagnosis of BOS after hematopoietic cell transplantation (HCT) using pulmonary function testing, per the National Institute of Health (NIH) diagnostic criteria OR the Atypical BOS criteria
• COHORT A: NIH Diagnostic Criteria for BOS. All of the following must be met: * FEV1/VC < 0.7 or < 5th percentile of predicted (FEV1 = Forced Expiratory Volume in 1 second; VC = Vital Capacity) (either FVC, forced vital capacity, or SVC, slow vital capacity, whichever is greater) * FEV1 < 75% of predicted with ≥ 10% absolute decline over less than 2 years. FEV1 should not correct to > 75% of predicted with albuterol, and the absolute decline for the corrected values should still remain ≥ 10% over 2 years * Absence of active infection in the respiratory tract, documented with investigations directed by clinical symptoms, such as chest radiographs or computed tomographic scans or microbiologic cultures (sinus aspiration, upper respiratory tract viral screen, sputum culture, bronchoalveolar lavage) * One of the two supporting features of BOS: ** Evidence of air trapping by expiratory CT or small airway thickening or bronchiectasis by high-resolution chest CT OR ** Evidence of air trapping by pulmonary function tests (PFTs): RV (Residual Volume) > 120% of predicted or RV/total lung capacity (TLC) elevated outside the 90% confidence interval (RV/Total Lung Capacity)
• COHORT A: Atypical Criteria for BOS. All of the following must be met: * FEV1 < 80% of predicted with ≥ 10% absolute decline over the last 2 years or since transplant. The remote comparator can be an evaluation of PFTs done within 2 years of the PFTs assessment being evaluated to determine eligibility or the PFT assessment done prior to transplant * VC < 80% of predicted * FEV1/VC > 0.7 * Absence of active infection in the respiratory tract, documented with investigations directed by clinical symptoms, such as chest radiographs or computed tomographic scans or microbiologic cultures (sinus aspiration, upper respiratory tract viral screen, sputum culture, bronchoalveolar lavage) or active non-infectious lung disease (such as interstitial lung disease) that explain spirometric changes or chest CT findings
• COHRT B: Diagnosis of BOS-0p * Decline in FEV1 of 10% - 19% of predicted compared with pretransplant testing OR * Decline in predicted FEF 25-75% (Forced Expiratory Flow between 25% and 75% of vital capacity) > 25%
• COHORT A AND B: Age ≥ 18 years. Belumosudil is currently being tested in pediatric populations and the safety and efficacy in pediatric patients have not yet been established. A protocol amendment to include pediatric patients will be considered once safety in pediatric patients is established
• COHORT A AND B: Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 60%)
• COHORT A AND B: White blood cells (WBC) ≥ 3,000/μL
• COHORT A AND B: Absolute neutrophil count ≥ 1,500/ μL
• COHORT A AND B: Platelets ≥ 50,000/mcL
• COHORT A AND B: Aspartate aminotransferase (AST)(serum glutamic oxaloacetic transaminase [SGOT])/ Alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase [SGPT]) ≤ 5 × institutional upper limit of normal (ULN)
• COHORT A AND B: No evidence of relapsed malignancy at the time of enrollment. Formal re-staging is not required for trial entry
• COHORT A AND B: All females of childbearing potential must have a negative serum or urine pregnancy test < 7 days before study drug administration
• COHORT A AND B: The ability to understand and willingness to sign a written consent document

Exclusion Criteria

• Participants who have received prior therapy specifically for BOS. Therapy for cGVHD in the absence of BOS is permissible
• Prior exposure to belumosudil
• Participants who are receiving any other investigational immunosuppressive agents for cGVHD
• Presence of an active uncontrolled infection. An active uncontrolled infection is defined as hemodynamic instability attributable to sepsis or new symptoms, worsening physical signs, or radiographic findings attributable to infection. Persistent fever without signs or symptoms will not be interpreted as an active uncontrolled infection
• Known human immunodeficiency virus infection. Interactions between belumosudil and antiretroviral agents have not been established
• Active hepatitis B virus (HBV) or hepatitis C virus infection that requires treatment or at risk for HBV reactivation. At risk for HBV reactivation is defined as hepatitis B surface antigen positive or anti–hepatitis B core antibody positive. Subjects with previous positive serology results must have negative polymerase chain reaction results. Subjects whose immune status is unknown or uncertain must have results confirming immune status before enrollment