Human Absorption, Distribution and Metabolism Study (hAME) [14C]-KD025

Inclusion Criteria

• Healthy males
• Good state of health (mentally and physically) as indicated by a comprehensive clinical assessment (detailed medical history and a complete physical examination), electrocardiogram (ECG) and laboratory investigations (hematology, clinical chemistry and urinalysis)
• Body weight ≥ 50 kg
• Body mass index (BMI) of 18.0 to 35.0 kg/m^2
• Must be willing and able to communicate and participate in the whole study
• Must have regular bowel movements (i.e., average stool production of ≥ 1 and ≤ 3 stools per day)
• Subjects must have participated in Part 1 in order to be eligible for Part 2
• Must provide written informed consent
• Must agree to adhere to the contraception requirements of the study

In addition to the above criteria, subjects must agree to the following restrictions:

• No alcohol during the 24 hours prior to screening and the 24-hour prior to each admission until discharge from each part of the study.
• No food or drinks containing grapefruit, cranberry, caffeine or other xanthines from 24 hours prior to each admission until discharge from each part of the study.
• No food containing poppy seeds for 48 hours prior to screening and for 48 hours prior to each admission until discharge from each part of the study.
• No unaccustomed strenuous exercise from the 72-hour period before the screening visit and then from 72 hours prior to each admission until discharge from each part of the study.

Exclusion Criteria

• Subjects who previously participated in any other investigational study drug trial in which receipt of an investigational study drug occurred within 90 days prior to dosing
• Subjects who have previously participated in a study where subjects were dosed with belumosudil
• Subjects who are study site employees or immediate family members of a study site or sponsor employee
• Subjects with pregnant partners
• History of any drug or alcohol abuse in the past 2 years
• Regular alcohol consumption in males > 21 units per week (1 unit = ½ pint beer, or a 25 mL shot of 40% spirit, 1.5 to 2 Units = 125 mL glass of wine, depending on type)
• Current smokers and those who have smoked within the last 12 months. A breath carbon monoxide reading of greater than 10 ppm at screening and admission
• Current users of e-cigarettes and nicotine replacement products and those who have used these products within the last 12 months
• Radiation exposure, including that from the present study, excluding background radiation but including diagnostic x-rays and other medical exposures, exceeding 5 mSv in the last 12 months or 10 mSv in the last 5 years. No occupationally exposed worker, as defined in the Ionizing Radiation Regulations 2017.
• Subjects who have been enrolled in an ADME/IV microtracer study in the last 12 months
• Subjects who do not have suitable veins for multiple venepunctures/cannulation
• Clinically significant abnormal biochemistry, hematology or urinalysis. Subjects with blood platelet count, hemoglobin and red blood cells lower than the reference range
• Confirmed positive drugs of abuse test result
• Positive hepatitis B surface antigen (HBsAg), hepatitis C virus antibody (HCV Ab), or human immunodeficiency virus (HIV) results
• Evidence of renal impairment at screening as indicated by an estimated creatinine clearance of upper limit of normal (ULN)
• Renal disease and/or serum creatinine > upper limit of normal (ULN)
• Other condition known to interfere with the absorption, distribution, metabolism or excretion of drugs
• Subject has QT interval corrected using Fridericia's formula (QTcF) intervals > 450 msec at screening or admission
• Serious adverse reaction or serious hypersensitivity to any drug or the formulation excipients
• Presence or history of clinically significant allergy requiring treatment
• Donation or loss of greater than 400 mL of blood within the previous 3 months
• Subjects who are taking, or have taken, any prescr