Sanofi's Wayrilz

With FDA nod, Sanofi's Wayrilz becomes 1st US BTK drug approved for immune thrombocytopenia

Sanofi has hailed rilzabrutinib's potential as a “multi-indication blockbuster” that could deliver more than 10 billion euros ($11.6 billion) in sales. While Sanofi originally had its eye on tolebrutinib when it purchased its partner Principia Biopharma for $3.7 billion five years ago, another one of the BTK inhibitors inherited from the biotech has made it across the FDA finish line first.

The drug rilzabrutinib, which is now approved as Wayrilz in immune thrombocytopenia (ITP), has been hailed (PDF) by Sanofi as a potential “multi-indication blockbuster” that could deliver 2 billion to 5 billion euros at its sales peak. The FDA’s approval on Friday specifically clears Wayrilz for use in adults with persistent or chronic ITP who haven't responded to prior therapy.

The regulatory endorsement marks the first approval for a Bruton tyrosine kinase (BTK) inhibitor to treat ITP in the U.S., where the condition is estimated to affect around 100,000 people, Mike Quigley, Ph.D., Sanofi’s CSO and global head of research, said in an interview with Fierce.

According to a Friday approval announcement, Sanofi believes there are around 25,000 patients who could specifically benefit from the new medication in the U.S.

ITP is an autoimmune disorder in which low levels of platelets—the cells that allow blood to clot—can lead patients to bruise easily, start bleeding without cause and bleed more than those without ITP.

To holistically treat ITP, a drug must attack the disease on three fronts, Quigley said, singling out autoantibody production by B cells, FC gamma receptor biology implicated in the body’s immune responses and inflammation.

Sanofi believes that BTK proteins form a “key node that sort of permeates all three components of that pathophysiology,” Quigley explained. By targeting BTK with Wayrilz, the French pharma believes it can address ITP across all three of those axes.