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

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 (15 U/kg) was administered 15 hours before surgery; subsequently, 3 doses (10 U/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.