Wayrilz (rilzabrutinib) for immune thrombocytopenia

Last updated Sept. 2, 2025, by Andrea Lobo,PhD
Fact-checked by Joana Carvalho, PhD

What is Wayrilz for immune thrombocytopenia?

Wayrilz (rilzabrutinib) is an oral medication approved to treat adults with persistent or chronic immune thrombocytopenia (ITP) who haven’t responded well to previous treatments. Taken as tablets, Wayrilz is the first Bruton’s tyrosine kinase (BTK) inhibitor to be approved for ITP.

ITP is an autoimmune disease wherein the immune system mistakenly attacks and destroys platelets, the cell fragments needed for blood clotting.

Wayrilz is intended to prevent platelet destruction by selectively inhibiting BTK, an enzyme that plays a key role in the development and function of the immune cells that drive these attacks. These include B-cells, which are responsible for producing antibodies, including the self-reactive ones that drive ITP, and macrophages that are involved in platelet destruction.

The therapy was developed and is marketed by Sanofi.

Therapy snapshot

Who can take Wayrilz?

Wayrilz is approved in the U.S. to treat adults with persistent or chronic ITP who have had an insufficient response to a previous treatment.

While its prescribing information lists no contraindications, Wayrilz should be avoided by people with moderate or severe liver impairment, as well as those with severe kidney impairment. Wayrilz is also generally not recommended for use alongside certain medications that strongly interfere with the activity of CYP3A, the enzyme that processes Wayrilz in the body. The medication should also not be used alongside stomach acid-reducing agents, which may lower its efficacy.

How is Wayrilz administered?

Wayrilz is supplied in 400 mg film-coated oral tablets. The recommended dosage is 400 mg, taken twice daily. Tablets should be swallowed whole with water and taken at approximately the same time each day, with or without food.

In patients taking stomach acid-reducing agents, Wayrilz should be administered at least two hours before.

Wayrilz in clinical trials

Wayrilz’s approval in the U.S. was based largely on data from the Phase 3 LUNA 3 (NCT04562766), which enrolled 202 adults with persistent or chronic ITP who had not responded adequately to standard treatments or could not tolerate them. Participants were randomly assigned to receive Wayrilz or a placebo for up to 24 weeks, or about six months.

• During the first 12 weeks of treatment, platelet levels increased to at least 50 billion platelets per liter, or at least 30 billion if doubled from the study’s start, in about two-thirds of the patients treated with Wayrilz compared with about a third of those on a placebo. This platelet response also lasted longer in patients treated with Wayrilz than in those given a placebo.
• The time to first platelet response was not reached for those on a placebo, and it took a median of 36 days for those on Wayrilz.
• 23% of patients treated with Wayrilz achieved a durable platelet response, meaning the threshold of at least 50 billion platelets per liter was met for at least two-thirds of at least eight non-missing weekly platelet measurements in the last 12 weeks of the initial 24-week blinded treatment period in the absence of rescue treatment. This was not seen in any of those on a placebo.
• Rescue medications were required by fewer patients receiving Wayrilz compared with placebo (33% vs. 58%).

Wayrilz’s safety and efficacy in people with ITP who do not respond to first-line treatments will be further assessed in the Phase 3 LUNA 4 trial (NCT07007962).

Common side effects of Wayrilz

The most common side effects of Wayrilz reported in clinical trials include:

• diarrhea
• nausea
• headache
• abdominal pain
• COVID-19

Wayrilz is associated with an increased risk of serious infections, including pneumonia, a type of lung infection, wound infection, and urinary tract infection. Patients should be monitored for signs of infection and treated appropriately.

Some patients treated with BTK inhibitors may experience liver toxicity, including severe, life-threatening drug-induced liver injury. Patients who have abnormal liver test results after treatment with Wayrilz should be monitored for symptoms of liver toxicity. If drug-induced liver injury is suspected, treatment should be withheld and, if confirmed, it should be discontinued.

Animal studies suggest Wayrilz may cause harm to a developing fetus if taken by pregnant women. Thus, women of childbearing potential should obtain a negative pregnancy test before starting Wayrilz and use effective contraception during treatment and for at least one week after the last dose. Also, due to the potential for adverse reactions in breastfed children, women should avoid breastfeeding while taking the medication and for at least one week after taking their last dose.

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