Research Update: Hemophilia B Study Shows Benefit of Secondary Prophylaxis

A study published in January in the journal Haemophilia is notable for its focus on the use of factor IX (FIX) therapy for secondary prophylaxis in hemophilia B patients. No such study has been done in 30 years. Secondary prophylaxis involves infusing factor product on a regular schedule, but only after a patient has had multiple bleeds into the same joint, such as the knee, ankle or elbow. The study, “Multicentre, Randomized, Open-Label Study of On-Demand Treatment with Two Prophylaxis Regimens of Recombinant Coagulation Factor IX in Haemophilia B Subjects,” was published online January 13, 2014. The lead author was Leonard A. Valentino, MD, Professor, Director, Section of Pediatric Hematology/Oncology, Director, Rush Hemophilia and Thrombophilia Center in Chicago.

Investigators measured the efficacy and safety of two secondary prophylaxis regimens of recombinant FIX (rFIX), compared with on-demand therapy. The product used in the study was BeneFIX®, manufactured by Pfizer, which also funded the study. The study included 47 males (ages 6-65) with moderate to severe hemophilia B; of those, 41 completed the trial. All patients received 16 weeks of on-demand therapy at the beginning of the trial and then were randomly assigned to receive BeneFIX® either once weekly or twice weekly for 16 weeks. All patients then switched back to on-demand dosing for eight weeks, followed by 16 weeks of prophylaxis with the dose they had not received during the first 16-week prophylaxis period. On-demand therapy was allowed during prophylaxis periods if needed.

Annual bleeding rate (ABR) was used to measure bleeding rates. The ABR for the on-demand group was 35.1 vs. 4.6 and 2.6 for the prophylaxis regimens. Results demonstrated that secondary prophylactic therapy with BeneFIX® once or twice weekly reduced ABR by 89.4% compared to on-demand treatment.

The majority of joint and soft-tissue bleeding events were resolved with a single infusion of BeneFIX®; however, five joint bleeds required more than four infusions to resolve. Although seven serious adverse events occurred in five subjects, none were related to the product used in the study.

“Both prophylaxis regimens demonstrated favorable safety profiles in subjects with hemophilia B,” concluded the authors.

 Source: Medscape Medical News, January 31, 2014