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WAYRILZ™ (rilzabrutinib) Mechanism of Action


As a next-generation BTKi, WAYRILZ offers a novel approach by targeting key sources of ITP1-4

WAYRILZ is a selective, reversible BTK inhibitor specifically designed to treat autoimmune dysregulation in ITP. It uses BTK inhibition to modulate multiple immune pathways1,2:

Illustration of Wayrilz (rilzabrutinib) inhibiting BTK to stop B cell activation.
Illustration of Wayrilz (rilzabrutinib) inhibiting BTK to interrupt macrophage phagocytosis by FcγR.

WAYRILZ selectively and reversibly inhibits BTK1-4

Infographic showing the covalent and non-covalent binding of Wayrilz (rilzabrutinib) to selectively inhibit BTK.
Infographic showing the reversible binding of Wayrilz (rilzabrutinib) with BTK.

The LUNA-3 study included a wide range of patients1,2*

See the established safety profile of WAYRILZ1

BCR, B-cell receptor; BTK, Bruton's tyrosine kinase;  BTKi, Bruton's tyrosine kinase inhibitor; FcγR, Fc gamma receptor; ITP, immune thrombocytopenia; MOA, mechanism of action. 

*Including those with insufficient response to corticosteroids and/or multiple other treatments.1,2

INDICATION

WAYRILZ™ (rilzabrutinib) is indicated for the treatment of adult patients with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment.

IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS
Serious Infections: An increased risk of serious infections (including bacterial, viral, or fungal) can occur in patients treated with Bruton’s tyrosine kinase (BTK) inhibitors, including WAYRILZ. Fatal pneumonia occurred in one participant treated with WAYRILZ in the LUNA-3 trial. Other serious infections [one each (0.8%)] included COVID-19 infection, wound infection, urinary tract infection and kidney abscess. Monitor patients for signs and symptoms of infection and treat appropriately.

Hepatotoxicity, Including Drug-Induced Liver Injury (DILI): Hepatotoxicity, including severe, life-threatening, and potentially fatal cases of DILI, can occur in patients treated with BTK inhibitors. Elevations of liver transaminases occurred with WAYRILZ in the ITP clinical trials and were generally mild to moderate in severity. Evaluate bilirubin and transaminases at baseline and as clinically indicated during treatment with WAYRILZ. For patients who develop abnormal liver tests after WAYRILZ, monitor more frequently. If DILI is suspected, withhold WAYRILZ. Upon confirmation of DILI, discontinue WAYRILZ.

Embryo-Fetal Toxicity: Based on findings from preliminary animal reproduction studies, WAYRILZ may cause fetal harm when administered to a pregnant woman. Verify pregnancy status of females of reproductive potential prior to initiating WAYRILZ treatment. Advise females of reproductive potential to use effective contraception while taking WAYRILZ and for 1 week after the final dose.

ADVERSE REACTIONS

Most common adverse reactions reported (incidence ≥10%) were diarrhea, nausea, headache, abdominal pain, and COVID-19.

DRUG INTERACTIONS

  • Avoid concomitant use of WAYRILZ with strong or moderate CYP3A inhibitors, which increases the risk of WAYRILZ adverse reactions. If short term use of these inhibitors cannot be avoided, interrupt treatment with WAYRILZ. Avoid concomitant use of grapefruit, starfruit and products containing these fruits, and Seville oranges with WAYRILZ.
  • Avoid concomitant use with a strong or moderate CYP3A inducer, which may reduce WAYRILZ efficacy.
  • Administer the dose of WAYRILZ at least 2 hours before administration of an antacid or histamine H2 receptor antagonist. Avoid concomitant use of proton pump inhibitors with WAYRILZ. Concomitant use of acid reducing agents may reduce WAYRILZ efficacy.
  • Rilzabrutinib is a moderate inhibitor of CYP3A and increases exposure of these substrates. Monitor for adverse reactions and consider dosage adjustment of the CYP3A substrate.
  • Rilzabrutinib is an inhibitor of P-gp, BCRP and OATP1B in vitro. The effect of concomitant use of WAYRILZ with OATP1B and BCRP substrates has not been established in clinical studies. Monitor for adverse reactions of the concurrently administered P-gp, BCRP, or OATP1B substrate more frequently where minimal substrate concentration changes may lead to serious adverse reactions.

USE IN SPECIFIC POPULATIONS

  • Lactation: Due to the potential for adverse reactions in a breastfed child from WAYRILZ, advise lactating women not to breastfeed while taking WAYRILZ and for at least 1 week after the final dose
  • Hepatic Impairment: Avoid administration of WAYRILZ in patients with moderate or severe hepatic impairment (Child-Pugh class B-C)
  • Renal Impairment: Avoid use in patients with severe renal impairment

Please see full Prescribing Information.

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INDICATION

IMPORTANT SAFETY INFORMATION

References: 1. WAYRILZ. Prescribing information. Sanofi, Inc. 2. Kuter DJ, Ghanima W, Cooper N, et al; LUNA3 Trial Group. Safety and efficacy of rilzabrutinib vs placebo in adults with immune thrombocytopenia: the phase 3 LUNA3 study. Blood. 2025;145(24):2914-2926. 3. Langrish CL, Bradshaw JM, Francesco MR, et al. Preclinical efficacy and anti-inflammatory mechanisms of action of the Bruton tyrosine kinase inhibitor rilzabrutinib for immune-mediated disease. J Immunol. 2021;206(7):1454-1468. 4. Kuter DJ, Bussel JB, Ghanima W, et al. Rilzabrutinib versus placebo in adults and adolescents with persistent or chronic immune thrombocytopenia: LUNA 3 phase III study. Ther Adv Hematol. 2023;14:20406207231205431.

© 2025 Sanofi. All rights reserved. WAYRILZ, HemAssist, and Sanofi are trademarks of Sanofi or an affiliate. All other trademarks above are the property of their respective owners, who have no affiliation or relationship with Sanofi. MAT-US-2508446-v1.0-08/2025