Successful hip arthroplasty in an adult male with severe factor XI deficiency using Hemoleven®, a factor XI concentrate

Summary. Severe factor XI (sFXI) deficiency is a rare bleeding disorder (RBD). FXI replacement is most often required for surgical hemostasis. Plasma, the sole US treatment option, is often complicated by life‐threatening allergic reactions. In such circumstances, the FDA offers a mechanism for institution‐industry collaboration to facilitate limited use of replacement products licensed abroad. A 58 years old man with sFXI deficiency, required hip replacement. In the past, he received prophylactic plasma for thyroidectomy and experienced a severe allergic reaction. A single use institutional IND FDA application was initiated in collaboration with LFB (Les Ulis, France) to access Hemoleven^®, a plasma‐derived FXI concentrate. The application required an investigator‐initiated IRB‐approved protocol for treatment and safety/efficacy monitoring that included: preoperative thrombophilia, FXI inhibitor and pharmacokinetic (PK) evaluations; peri‐ postoperative administration of ≤ 4 doses of 10‐15 U/kg Hemoleven^®; DIC monitoring; postoperative thromboprophylaxis; observation for product efficacy and potential complications. PK study demonstrated the expected 1.8% FXI recovery per U/kg with half‐life of 62 hours. Mild D‐Dimer elevation was noted 6‐9 hours post‐infusion. The initial dose (15U/kg) was administered 15 hours before surgery; subsequently, 3 doses (10U/kg) were infused every 72 hours. Hemostasis was excellent. No complications were observed. Collaboration allowed for successful patient access to Hemoleven^® with excellent PK, safety, and efficacy. This case underscores the need for additional efforts to ensure safe and effective licensed replacement therapies for RBD patients.