Belumosudil is really a selective Rho-connected coiled-coil that contains protein kinase 2 (ROCK2) inhibitor. ROCK2 continues to be proven they are driving proinflammatory response and fibrosis occurring with chronic graft-versus-host disease therefore, inhibition of ROCK2 has become a therapeutic target for chronic graft-versus-host disease. Within this phase 1 two-part study, the pharmacokinetics, mass balance, and metabolic profile of belumosudil were evaluated after single doses of unlabeled belumosudil dental tablets (200 mg), radiolabeled belumosudil intravenous (IV) microtracer infusions (100 μg), and radiolabeled dental capsules (200 mg). Absolute bioavailability according to area underneath the plasma concentration-time curve from time to infinity for that dental dose/area underneath the plasma concentration-time curve from time to infinity for that IV dose was calculated as 63.7%. Radiolabeled IV microtracer dosing shown a minimal extraction ratio and distribution of belumosudil into tissues. Nearly all total radioactivity was retrieved in feces, with minimal amounts retrieved in urine, suggesting minimal kidney removal of belumosudil. Additionally to parent and primary metabolite KD025m2, metabolites identified in plasma incorporated the phase 2 metabolites O-dealkylated belumosudil sulfate and belumosudil glucuronide. These metabolites (except for the glucuronide) additionally to monohydroxy-belumosudil, and belumosudil diol were identified in feces. No metabolites in urine taken into account >10% from the radioactive dose.