Sanofi has offered a warranty on its drug, Cablivi (caplacizumab-yhdp), offering to pay the cost of six doses of the drug if the patient doesn’t respond, or 12 doses of the drug and the hospital stay if the patient’s condition worsens while on the drug.

Cablivi treats acquired thrombotic thrombocytopenic purpura (aTTP), a rare autoimmune disorder which causes blood clots to form in small blood vessels throughout the body and can be life threatening. Cablivi is used in combination with plasma exchange and immunosuppressive therapy.

The company will pay for six doses if treatment is discontinued because the patient still had low platelet counts after four days of combined treatment with Cablivi, plasma exchange and immunosuppressive therapy. The company will pay for the inpatient stay if the patient experienced a new drop in platelet count after initial platelet count normalization.