Biogen Idec and Sobi See Progress in Pediatric Hemophilia B Study

This is an edited version of a press release from Biogen Idec. To read the full release, please click here.
Biogen Idec  and Swedish Orphan Biovitrum AB announced positive top-line results of the Kids B-LONG Phase 3 clinical study that evaluated the safety, efficacy and pharmacokinetics of ALPROLIX®Â [Coagulation Factor IX (Recombinant), Fc Fusion Protein] in children under age 12 with severe hemophilia B. ALPROLIX was generally well tolerated and no inhibitors (neutralizing antibodies that may interfere with the activity of the therapy) were detected during the study. In this study, once-weekly prophylactic dosing with ALPROLIX resulted in low bleeding rates. ALPROLIX is the only approved hemophilia B therapy with prolonged circulation in the body.
The successful completion of Kids B-LONG supports applications for pediatric indications in several geographies and is an important step in seeking marketing authorization for ALPROLIX in Europe. The European Medicines Agency requires the inclusion of pediatric study data in the initial marketing application for a new hemophilia therapy. Interim results of the Kids B-LONG study helped support the U.S. approval of ALPROLIX for use in children.
“According to published studies, prophylactic treatment for children with severe hemophilia is recommended because it is associated with proven clinical benefits. However, frequent administration schedules can be burdensome for children and their caregivers,” said Aoife Brennan, M.D, vice president of hematology clinical development at Biogen Idec. “These data will enable regulatory filings in Europe later this year as well as support pediatric indications in other countries, with the potential to help address a critical need among children with hemophilia B.”
Kids B-LONG investigated the safety, efficacy, and pharmacokinetics (measurement of the presence of the drug in a person’s body over time) of ALPROLIX in previously treated children under age 12 with severe hemophilia B. The study’s primary endpoint was to evaluate the occurrence of inhibitor development. Secondary endpoints included the overall and spontaneous annualized bleeding rates (ABR), which is the estimated number of yearly bleeding episodes, and the number of infusions used to treat bleeding episodes.
In the study, children treated prophylactically with ALPROLIX had an overall median ABR of 1.97. The median ABR for spontaneous joint bleeds was zero. Approximately 33 percent of participants in the study experienced zero bleeding episodes. Overall, 91.7 percent of bleeding episodes were controlled by one or two infusions of ALPROLIX. The terminal half-life of ALPROLIX in the study was 66.5 hours for children under six and 70.3 hours for children six to less than 12 years of age. Additional analyses of the Kids B-LONG study are ongoing, and detailed results will be presented at a future scientific meeting.
No inhibitors to ALPROLIX were detected during the study. ALPROLIX was generally well tolerated and no cases of serious allergic reactions or vascular thrombotic events were reported in any participants, all of whom had been previously treated with other commercially available factor IX products. No serious adverse events were determined by any investigator to be related to the drug. One adverse event, decreased appetite, was considered related to ALPROLIX treatment and was reported in one participant. No participant discontinued the study due to an adverse event after receiving ALPROLIX. The pattern of treatment-emergent adverse events reported was consistent with the population studied and generally consistent with results seen in adolescents and adults in the pivotal Phase 3 B-LONG study.
“Sobi and Biogen Idec are committed to advancing treatment options for adults and children with hemophilia,” said Birgitte Volck, M.D., Ph.D., senior vice president of development and chief medical officer at Sobi. “The completion of Kids B-LONG marks an important milestone in the ALPROLIX development program. We are excited to pursue the next stages of preparation for regulatory filing in Europe and to potentially advance treatment options for people with hemophilia B.”
About Kids B-LONG
Kids B-LONG was a global, open-label, multicenter Phase 3 study involving 30 boys with severe hemophilia B (factor IX activity equal to or less than 2 IU per dL, or 2 percent) with at least 50 prior exposure days to factor IX therapies. The study was conducted at 16 hemophilia treatment centers in six countries. Overall, 27 participants (90 percent) completed the study. The median time participants spent in the study was 49.4 weeks, and 24 participants received ALPROLIX infusions on at least 50 separate days (exposure days).

Biogen Idec Safe Harbor
This press release contains forward-looking statements, including statements about the potential and therapeutic impact of ALPROLIX. These forward-looking statements may be accompanied by such words as “anticipate,” “believe,” “could,” “estimate,” “expect,” “forecast,” “intend,” “may,” “plan,” “potential,” “project,” “target,” “will” and other words and terms of similar meaning. You should not place undue reliance on these statements. Drug development and commercialization involve a high degree of risk. Factors which could cause actual results to differ materially from our current expectations include the risk that unexpected concerns may arise from additional data or analysis, European regulatory authorities may require additional information or further studies, or may fail to approve, or refuse to approve, or may delay approval of our marketing authorization application for ALPROLIX, or we may encounter other unexpected hurdles. For more detailed information on the risks and uncertainties associated with our drug development and commercialization activities, please review the Risk Factors section of our most recent annual or quarterly report filed with the Securities and Exchange Commission. Any forward-looking statements speak only as of the date of this press release and we assume no obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise.