Phase 3 study of recombinant factor IX Fc fusion protein in hemophilia B.

BACKGROUND: Prophylactic factor replacement in patients with hemophilia B improves outcomes but requires frequent injections. A recombinant factor IX Fc fusion protein (rFIXFc) with a prolonged half-life was developed to reduce the frequency of injections required. METHODS: We conducted a phase 3, nonrandomized, open-label study of the safety, efficacy, and pharmacokinetics of rFIXFc for prophylaxis, treatment of bleeding, and perioperative hemostasis in 123 previously treated male patients. All participants were 12 years of age or older and had severe hemophilia B (endogenous factor IX level of ≤2 IU per deciliter, or ≤2% of normal levels). The study included four treatment groups: group 1 received weekly dose-adjusted prophylaxis (50 IU of rFIXFc per kilogram of body weight to start), group 2 received interval-adjusted prophylaxis (100 IU per kilogram every 10 days to start), group 3 received treatment as needed for bleeding episodes (20 to 100 IU per kilogram), and group 4 received treatment in the perioperative period. A subgroup of group 1 underwent comparative sequential pharmacokinetic assessments of recombinant factor IX and rFIXFc. The primary efficacy end point was the annualized bleeding rate, and safety end points included the development of inhibitors and adverse events. RESULTS: As compared with recombinant factor IX, rFIXFc exhibited a prolonged terminal half-life (82.1 hours) (P<0.001). The median annualized bleeding rates in groups 1, 2, and 3 were 3.0, 1.4, and 17.7, respectively. In group 2, 53.8% of participants had dosing intervals of 14 days or more during the last 3 months of the study. In groups 1, 2 and 3, 90.4% of bleeding episodes resolved after one injection. Hemostasis was rated as excellent or good during all major surgeries. No inhibitors were detected in any participants receiving rFIXFc; in groups 1, 2, and 3, 73.9% of participants had at least one adverse event, and serious adverse events occurred in 10.9% of participants. These events were mostly consistent with those expected in the general population of patients with hemophilia. CONCLUSIONS: Prophylactic rFIXFc, administered every 1 to 2 weeks, resulted in low annualized bleeding rates in patients with hemophilia B. (Funded by Biogen Idec; ClinicalTrials.gov number, NCT01027364.).

Major and Minor Classifications for Surgery in People With Hemophilia: A Literature Review.

Agents that control bleeding and the usage of bypassing agents have made surgery an option to consider in people with hemophilia. However, the lack of consistent definitions for major or minor surgery may lead to inconsistencies in patient management. This literature review has evaluated how surgical procedures in people with hemophilia were categorized as major or minor surgery and assessed the consistency across publications. After screening 926 potentially relevant articles, 547 were excluded and 379 full-text articles were reviewed. Ninety-five articles categorized major or minor surgical procedures; of these, 35 publications categorized three or more major or minor surgical procedures and were included for analysis. Seven (20%) publications provided varying criteria for defining major or minor surgery, five of which defined surgery according to the level of surgical invasiveness. Across all 35 publications, there was considerable variance in the categorization of major and minor surgical procedures and some overlap in surgical nomenclature (eg, type of synovectomy, arthroscopy, and central venous access device insertion/removals). The lack of consistent guidance when referring to major or minor surgery in people with hemophilia needs to be addressed. Clear and consistent definitions, achieved by consensus and promoted by relevant international hemophilia committees, are desirable, to provide guidance on appropriate treatment, to increase the accuracy of trial data and may confound the interpretation of surgical outcomes.