BTK inhibitor rilzabrutinib (WAYRILZ™) is approved by the Food and Drug Administration (FDA) for adults with persistent or chronic immune thrombocytopenia (ITP) who have received a prior treatment that did not work well enough.

Rilzabrutinib (WAYRILZ™)

Rilzabrutinib (WAYRILZ™) is the first Bruton’s Tyrosine Kinase (BTK) inhibitor approved by the FDA for the treatment of persistent and chronic ITP in adults when a prior treatment has not worked well enough. Rilzabrutinib comes in tablet form and is taken twice daily with or without food.

Bruton’s Tyrosine Kinase (BTK) is part of a network of proteins (found in certain cells of the immune system) which trigger platelet autoantibody production and platelet destruction. When the back end of the antibodies attached to platelets contact their receptors on immune cells, an important way that they trigger platelet destruction is to signal the immune cells into action. When platelets are coated with antibodies, they attach to cells and start the signaling pathway for destruction. This signal goes through BTK so blocking BTK blocks the signal. The immune cells then no longer react to the antibodies on the platelets and no longer destroy the platelets.

Rilzabrutinib works differently than other treatments by specifically targeting BTK. The drug limits platelet destruction by the immune system by blocking the action of the scavenger cells (macrophages), which in turn raises platelet counts in the body helping to reduce the risk of severe bleeding. The drug also inhibits the signal to produce autoantibodies (B-cell) which bind to platelets, reducing the potential for future platelet destruction. Rilzabrutinib does not suppress the immune system; it modulates the over-active immune system responses in ITP.
Dosage

Rilzabrutinib is taken as 400mg (one tablet) twice daily. There are no dosage adjustments for safety or effectiveness. Rilzabrutinib can be taken with or without food. If you experience diarrhea, nausea, or stomach area (abdominal) pain during treatment with WAYRILZ, taking it with food may reduce these side effects.

Taking Rilzabrutinib (WAYRILZ)

Before taking WAYRILZ, tell your healthcare provider about all of your medical conditions, including if you:

  • have liver problems
  • have kidney problems
  • are pregnant or plan to become pregnant. WAYRILZ may harm your unborn baby. If you are able to have a baby, your healthcare provider will do a pregnancy test before starting treatment with WAYRILZ.
    • Females who are able to become pregnant should use effective birth control (contraception) during treatment with WAYRILZ and for 1 week after the last dose.
  • are breastfeeding or plan to breastfeed. It is not known if WAYRILZ passes into your breast milk. Do not breastfeed during treatment with WAYRILZ and for at least 1 week after the last dose.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Taking WAYRILZ with certain other medicines may affect how WAYRILZ works and can cause side effects. WAYRILZ may also affect how other medicines work. Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.

Side Effects

WAYRILZ may cause serious side effects, including:

  • Serious infections. WAYRILZ can increase the risk of infections, including serious infections that can lead to death. Your healthcare provider will check you for signs and symptoms of infection during your treatment with WAYRILZ. Tell your healthcare provider right away if you get any signs or symptoms of infection, including fever, chills, or flu-like symptoms.
  • Liver problems including Drug-Induced Liver Injury (DILI). Liver problems, which may be severe, life-threatening, or lead to death have happened in people treated with Bruton’s tyrosine kinase (BTK) inhibitors. Your healthcare provider will do blood tests to check your liver before and as necessary during treatment with WAYRILZ. Tell your healthcare provider right away if you have any signs or symptoms of liver problems, including stomach-area (abdominal) pain or discomfort, dark or “tea-colored” urine, or yellowing of the skin or the white part of your eyes.

The most common side effects of WAYRILZ include:

  • diarrhea
  • nausea
  • headache
  • stomach area (abdominal) pain
  • COVID-19

Patient Support

Sanofi has established HemAssist for patient support. Learn more online or by calling 1-833-723-5463 Monday through Friday 8am to 7pm ET.

Clinical Trial Data

In a study of 202 adults with persistent or chronic ITP, rilzabrutinib was compared to placebo (an inactive tablet that looked like the real medication) to see how effective it was in raising platelet counts with subjects taking it for up to 6 months of treatment. At the beginning of the study, the median platelet counts for people enrolled were equal to or less than 15,000 per microliter. On average, the people in the trial had had long-standing chronic ITP for 7.69 years. All individuals in the study had had at least one prior treatment, which was either corticosteroids, IVIg, TPO-RA, rituximab, or fostamatinib. The patients who benefited from rilzabrutinib did so regardless of whether they had had a specific prior treatment and whether they had responded temporarily to that treatment.

As part of the clinical trial design, patient's platelet counts were checked halfway through the trial, at month 3, to be eligible to complete the initial, double blind period of the trial. At month 3, 64% of rilzabrutinib patients and 32% of placebo patients had a platelet count response (≥50 x 109/L or between 30 x 109/L and <50 x 109/L and doubled from baseline) without rescue medication. At 6 months, 23% of rilzabrutinib patients and 0% of placebo patients had a durable platelet response (a weekly platelet count ≥50 x 109/L for ≥ two-thirds of at least 8 non-missing weekly scheduled platelet measurements during the last 12 weeks of the 24-week DB period in the absence of rescue therapy). Of those who responded to rilzabrutinib, most patients responded within 15 days of starting treatment.

One of the endpoints in the clinical trial was examining patient reported quality of life. Prior to the start of the study, patients completed a survey called the ITP-Patient Assessment Questionnaire that looked at how ITP affected different parts of their lives. At month 6, patients took the ITP-PAQ survey again. People taking WAYRILZ reported a 10.6 point increase vs 2.3 point increase in placebo in overall health related quality of life. The results of these analyses are descriptive and not statistically tested to determine a difference between treatment groups.

Select a treatment table to view or download below.

Wayrilz™ Treatment Table
Adult Table

References:

  1. David J. Kuter, et. al.; Safety and efficacy of rilzabrutinib vs placebo in adults with immune thrombocytopenia: the phase 3 LUNA3 study. Blood 2025; 145 (24): 2914–2926. doi: https://doi.org/10.1182/blood.2024027336
  2. Kuter, D. J., & Ghanima, W. (2025). Evaluating rilzabrutinib in the treatment of immune thrombocytopenia. Immunotherapy, 1–16. https://doi.org/10.1080/1750743X.2025.2545170
  3. Wayrilz package insert: https://products.sanofi.us/wayrilz/wayrilz.pdf
  4. Wayrilz website: wayrilz.comwayrilz.com