ROCK2 inhibitor Pregnancy: Can cause fetal harm based on animal findings and mechanism of action; no human data. Advise pregnant women of the risk to the fetus, and females of reproductive potential and males with female partners of reproductive potential to use effective contraception during treatment and for one week after the last dose (US label 8.1, 5.1).

Belumosudil

Brand names: Rezurock

Belumosudil is an oral kinase inhibitor used to treat chronic graft-versus-host disease after failure of earlier lines of systemic therapy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 200 mg once daily

Route: Oral (swallow tablets whole with a meal; do not cut, crush or chew)

Frequency: Once daily, at approximately the same time each day, until progression of chronic GVHD requiring new systemic therapy

Indication: chronic graft-versus-host disease. Dose modifications for drug interactions: increase to 200 mg TWICE daily when co-administered with a strong CYP3A inducer or with a proton pump inhibitor. Toxicity modifications: hold for Grade 3 AST/ALT (5 to 20 x ULN) or Grade 2 bilirubin (1.5 to 3 x ULN) until recovery to Grade 0-1 then resume at the recommended dose; discontinue permanently for Grade 4 AST/ALT (more than 20 x ULN) or Grade 3 or higher bilirubin (more than 3 x ULN). Other adverse reactions: hold for Grade 3 until Grade 0-1 then resume; discontinue permanently for Grade 4. Monitor total bilirubin, AST and ALT at least monthly. Do not take extra doses to make up a missed dose. Hepatic impairment: avoid in moderate (Child-Pugh B) or severe (Child-Pugh C) impairment without liver GVHD; no adjustment in mild impairment. Paediatric: safety and effectiveness established in patients 12 years and older (the label states age and body weight had no clinically meaningful effect on pharmacokinetics, so the adult 200 mg once-daily dose applies); not established below 12 years. No UK SPC was retrieved for this bundle; the entry derives from US labelling (Rezurock, label date 2026-04-07) and must be verified against the UK SPC.

Dose adjustments

Renal

Not studied in patients with pre-existing severe renal impairment; consider the risks and potential benefits before initiating treatment in these patients

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

None stated - US label section 4 reads 'None'

Side effects

Infections
Asthenia and fatigue-type symptoms
Nausea and diarrhoea
Dyspnoea and cough
Oedema, haemorrhage, abdominal pain, musculoskeletal pain, headache and hypertension
Laboratory abnormalities: decreased phosphate, increased gamma-glutamyl transferase, decreased lymphocytes

Interactions

Strong CYP3A inducers: increase belumosudil dosage to 200 mg twice daily
Proton pump inhibitors: decrease belumosudil exposure (pH-dependent solubility) - increase dosage to 200 mg twice daily
BCRP substrates: avoid concomitant use where possible; if used together monitor more frequently and reduce the substrate dose
OATP1B1 substrates: if used together, monitor more frequently and reduce the substrate dose
Certain CYP1A2, CYP3A, P-gp or UGT1A1 substrates for which minimal concentration changes may cause serious toxicity: avoid concomitant use; if unavoidable, reduce the substrate dose

Clinical monograph

How it works

It inhibits Rho-associated coiled-coil kinase 2 (ROCK2), modulating the immune response and reducing the inflammatory and fibrotic processes that drive chronic graft-versus-host disease.

Prescribing in practice

It can raise liver enzymes, so liver function should be checked before and during treatment.
Strong CYP3A inducers reduce its exposure, so concomitant medicines should be reviewed for interactions.
Infection, nausea and fatigue are recognised effects in this immunosuppressed population.

Monitoring

Monitor liver function tests periodically and remain alert for signs of infection.

Counselling the patient

Take the medicine with food as advised.
Report signs of infection or yellowing of the skin or eyes.
Tell your team about all other medicines, as some can interact.

Evidence & guidelines

Belumosudil is supported by trial evidence showing meaningful response rates in chronic graft-versus-host disease after prior systemic therapy.

Reference: NICE TA evaluation; BSH; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways