title: Multicentre, randomized, open-label study of on-demand treatment with two prophylaxis regimens of recombinant coagulation factor IX in haemophilia B subjects.
abstract: Few randomized studies have reported on the use of factor IX (FIX) for secondary prophylaxis in haemophilia B patients. This study aimed to evaluate the efficacy and safety of two secondary prophylaxis regimens of recombinant coagulation FIX, nonacog alfa, compared with on-demand therapy. Male subjects aged 6-65 years with severe or moderately severe haemophilia B (FIX:C ≤ 2, n = 50) and ≥12 bleeding episodes (including ≥6 haemarthroses episodes) within 12 months of study participation were enrolled in this multicentre, randomized, open-label, four-period crossover trial. The primary measure was the annualized bleeding rate (ABR) of two prophylactic regimens vs. on-demand therapy. In the intent-to-treat group, mean ABR values were 35.1, 2.6 and 4.6 for the first on-demand period, the 50 IU kg(-1) twice-weekly period, and the 100 IU kg(-1) once-weekly period respectively. Differences in ABR between the first on-demand period and both prophylaxis regimens were significant (P < 0.0001); no significant differences were observed between prophylaxis regimens (P = 0.22). Seven serious adverse events occurred in five subjects, none related to study drug. Results demonstrated that secondary prophylaxis therapy with nonacog alfa 50 IU kg(-1) twice weekly or 100 IU kg(-1) once weekly reduced ABR by 89.4% relative to on-demand treatment. Both prophylaxis regimens demonstrated favourable safety profiles in subjects with haemophilia B.
authors.affiliation: Rush University Medical Center, Chicago, IL, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: Valentino
authors.forename: L
authors.initials: L
authors.lastname: Rusen
authors.forename: I
authors.initials: I
authors.lastname: Elezovic
authors.forename: L M
authors.initials: LM
authors.lastname: Smith
authors.forename: J M
authors.initials: JM
authors.lastname: Korth-Bradley
authors.forename: P
authors.initials: P
authors.lastname: Rendo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D018592:Cross-Over Studies; D005164:Factor IX / Q000627:therapeutic use*; D002836:Hemophilia B / Q000188:drug therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D011994:Recombinant Proteins; D005164:Factor IX
keywords: factor IX; haemophilia B; prophylaxis; recombinant factor IX