Summary:

• **What is Rilzabrutinib?** Rilzabrutinib is a new medicine being developed by a company called Sanofi to treat a rare blood disease called warm autoimmune hemolytic anemia, where the body's immune system accidentally attacks and destroys its own red blood cells. The U.S. government has given this medicine special "breakthrough therapy" status because it could help patients much faster than usual medicines.

• **Why is this important?** This disease makes people very tired and weak because they don't have enough healthy red blood cells to carry oxygen through their body. Rilzabrutinib works differently than old treatments by stopping certain cells in the immune system from attacking red blood cells, which could help patients feel better and healthier.