Rezurock (belumosudil)
An approved treatment for Chronic Graft-versus-Host Disease.
The same compound appears under different names depending on the context. Here is how to identify Belumosudil wherever you encounter it, plus the key facts at a glance.
- Generic name
- Belumosudil
- Brand name
- Rezurock
- Development codes
- KD025, SLx-2119
- Drug class
- ROCK2 inhibitor
- Manufacturer
- Kadmon / Sanofi
- How it's taken
- Taken as an oral tablet, 200 mg once daily with food.
The first ROCK2 inhibitor approved for chronic GVHD, for adults and children 12 years and older after failure of at least 2 prior lines of systemic therapy. Belumosudil uniquely addresses both the immune dysfunction and the tissue fibrosis (scarring) that characterize late-stage cGVHD.
Where Belumosudil fits
Third-line agent approved after two or more prior therapy lines. The anti-fibrotic properties make belumosudil particularly valuable for patients with sclerotic skin disease, bronchiolitis obliterans, or other fibrotic manifestations of cGVHD. Positioned alongside ruxolitinib (Jakafi, second-line), ibrutinib (Imbruvica, second-line), and axatilimab (Niktimvo, third-line) in a growing cGVHD treatment landscape. Durable responses even in heavily pretreated populations distinguish it from other options.
How Belumosudil works
In chronic GVHD, the immune system becomes imbalanced: there are too many inflammatory Th17 cells and too few protective regulatory T cells (Tregs). A protein called ROCK2 controls this balance by regulating which direction immune cells develop. Belumosudil selectively blocks ROCK2, shifting the immune system back toward balance.
When ROCK2 is inhibited, inflammatory Th17 cells decrease, protective Treg cells expand, and the production of pro-inflammatory cytokines like IL-17 and IL-21 drops. This addresses the root immune dysfunction driving cGVHD rather than broadly suppressing the immune system.
What sets belumosudil apart is its anti-fibrotic activity. ROCK2 also controls fibrotic (scarring) pathways in tissues. Many late-stage cGVHD patients develop chronic scarring in the skin, lungs, and other organs. By blocking ROCK2, belumosudil reduces both the inflammatory attack and the progressive fibrosis, making it particularly valuable for patients with sclerotic or fibrotic disease manifestations.
Mechanism: Selective ROCK2 inhibitor that rebalances immune cells by reducing pro-inflammatory Th17 cells and expanding protective regulatory T cells, while also reducing tissue fibrosis
Side effects and safety
Common side effects include infections (viral and bacterial), fatigue and weakness, nausea, diarrhea, shortness of breath, cough, swelling (edema), bleeding, abdominal pain, musculoskeletal pain, headache, and elevated blood pressure. Lab abnormalities can include decreased phosphate levels, elevated liver enzymes (GGT), and decreased lymphocyte counts. About 18% of patients stopped treatment because of side effects. Rezurock can harm an unborn baby, so people who can become pregnant should use effective birth control during treatment and for at least 1 week after the last dose, and men with partners who can become pregnant should also use birth control.
This is not a complete list of side effects. Talk to your doctor or pharmacist about what to expect and when to seek medical attention.
Taking Belumosudil
Taken as an oral tablet, 200 mg once daily with food. If taking a proton pump inhibitor (acid reflux medication) or a strong CYP3A inducer (such as rifampin), the dose is increased to 200 mg twice daily. Treatment continues until disease progression requiring new therapy.
Availability and cost
Only available as the brand-name product.
Help paying for Rezurock
Pick your insurance to see which help fits. Drugmaker copay cards can't be used with Medicare, Medicaid or TRICARE; charity funds are the usual route there.
- Copay help
Commercially or privately insured patients may pay as little as $0 per month; yearly maximum. Medicare, Medicaid, TRICARE and cash-paying patients are not eligible.
For: private insurance · source - Free medicine program
Uninsured or underinsured patients meeting income criteria may get free REZUROCK for up to 12 months through Sanofi Cares North America.
For: no insurance, underinsured · source - Bridge or quick-start supply
Quick Start: free 30-day supply for new patients with drug coverage facing coverage delays over 5 business days. Bridge: 30-day supply for commercially insured patients with coverage interruptions.
The official page does not say who qualifies. Ask the program. · source - Insurance and case manager help
Case Managers verify benefits, help with prior authorizations and appeals, coordinate specialty pharmacy delivery, and refer to independent foundations.
The official page does not say who qualifies. Ask the program. · source
Good to know: Mon-Fri 8 AM-8 PM ET.
- From a charity · TotalAssist (formerly PAN Foundation)Graft-vs-Host Disease (GVHD) fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $9,500 per year. Requires health insurance (any kind).
- From a charity · NMDP (formerly Be The Match / National Marrow Donor Program)NMDP Patient Financial Assistance Grants fundApply directly
Pays for: Out-of-pocket costs before and after blood or marrow transplant, ongoing GVHD treatment costs, clinical-trial travel and financial-crisis grants.
The foundation says: “Status not shown on page”
Clinical trial results
The Phase 2 ROCKstar trial enrolled patients with active cGVHD after two or more prior systemic therapy lines. The overall response rate was 75% at the 200 mg once-daily dose. Among people who responded, 62% were alive without needing a new treatment for at least 12 months after their response.
Development history
Originally developed by Surface Logix as SLx-2119, the compound was licensed to Kadmon Corporation and became the first specific ROCK2 inhibitor described in scientific literature. Kadmon received orphan drug designation in 2017 and completed the ROCKstar Phase 2 trial. FDA approved belumosudil in July 2021. Sanofi subsequently acquired Kadmon and now markets the drug.
Explore Chronic Graft-versus-Host Disease trials
Other Chronic Graft-versus-Host Disease treatments
Common questions about Belumosudil
▸What is Belumosudil (Rezurock)?
The first ROCK2 inhibitor approved for chronic GVHD, for adults and children 12 years and older after failure of at least 2 prior lines of systemic therapy. Belumosudil uniquely addresses both the immune dysfunction and the tissue fibrosis (scarring) that characterize late-stage cGVHD.
▸How does Belumosudil work?
In chronic GVHD, the immune system becomes imbalanced: there are too many inflammatory Th17 cells and too few protective regulatory T cells (Tregs). A protein called ROCK2 controls this balance by regulating which direction immune cells develop. Belumosudil selectively blocks ROCK2, shifting the immune system back toward balance.
When ROCK2 is inhibited, inflammatory Th17 cells decrease, protective Treg cells expand, and the production of pro-inflammatory cytokines like IL-17 and IL-21 drops. This addresses the root immune dysfunction driving cGVHD rather than broadly suppressing the immune system.
What sets belumosudil apart is its anti-fibrotic activity. ROCK2 also controls fibrotic (scarring) pathways in tissues. Many late-stage cGVHD patients develop chronic scarring in the skin, lungs, and other organs. By blocking ROCK2, belumosudil reduces both the inflammatory attack and the progressive fibrosis, making it particularly valuable for patients with sclerotic or fibrotic disease manifestations.
▸What are the side effects of Belumosudil?
Common side effects include infections (viral and bacterial), fatigue and weakness, nausea, diarrhea, shortness of breath, cough, swelling (edema), bleeding, abdominal pain, musculoskeletal pain, headache, and elevated blood pressure. Lab abnormalities can include decreased phosphate levels, elevated liver enzymes (GGT), and decreased lymphocyte counts. About 18% of patients stopped treatment because of side effects. Rezurock can harm an unborn baby, so people who can become pregnant should use effective birth control during treatment and for at least 1 week after the last dose, and men with partners who can become pregnant should also use birth control.
▸How is Belumosudil taken?
Taken as an oral tablet, 200 mg once daily with food. If taking a proton pump inhibitor (acid reflux medication) or a strong CYP3A inducer (such as rifampin), the dose is increased to 200 mg twice daily. Treatment continues until disease progression requiring new therapy.
▸Is Belumosudil FDA approved?
Yes, Belumosudil (Rezurock) is FDA approved (2021) for the treatment of Chronic Graft-versus-Host Disease.
▸What is Rezurock used for?
Rezurock (belumosudil) is an FDA-approved ROCK2 inhibitor for adults and children 12 years and older with chronic graft-versus-host disease after failure of at least 2 prior lines of systemic therapy. It uniquely addresses both immune dysfunction and tissue fibrosis.
▸How does belumosudil help with fibrosis in GVHD?
Belumosudil blocks ROCK2, a protein that controls both immune cell balance and fibrotic (scarring) pathways. This makes it particularly effective for patients with sclerotic skin disease, lung scarring (bronchiolitis obliterans), or other fibrotic cGVHD manifestations.
Sources and references
Every factual claim on this page is drawn from the public sources listed below. Click any reference to open the original document.
- U.S. Food and Drug Administration · July 2021. FDA approves belumosudil for chronic graft-versus-host disease. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-disco-burst-edition-fda-approval-rezurok-belumosudil-adult-and-pediatric-patients-12-years-and
- Transplantation and Cellular Therapy. Belumosudil for Chronic Graft-versus-Host Disease After 2 or More Prior Lines of Therapy. https://pmc.ncbi.nlm.nih.gov/articles/PMC9197942/
- Sanofi / Kadmon. MyROCK ASSIST Program. https://www.rezurock.com/myrock-assist