Biogen Idec and Swedish Orphan Biovitrum have presented promising late-stage data on an investigational drug for haemophilia B, which will be filed in the USA by the biotech major next year.

Top-line results from B-LONG, a Phase III 123-patient study of the companies’ long-lasting recombinant Factor IX Fc fusion protein (rFIXFc), showed that the treatment was effective in the control and prevention of bleeding, routine prophylaxis and perioperative management. Indeed, one injection of rFIXFc controlled 90.4% of bleeding episodes and the treatment was well-tolerated.

Biogen and SOBI also noted that a pharmacokinetic analysis of rFIXFc revealed its half-life to be 82 hours compared to 34 hours for the current haemophilia B market leader, Pfizer's BeneFix (recombinant coagulation factor IX). The results of the B-LONG study "offer the potential for longer-lasting protection from bleeding”, said Glenn Pierce, chief medical officer of Biogen’s haemophilia therapeutic area.

He noted that currently, treatment requires intravenous injections up to three times a week, "which makes the prospect of a longer-lasting Factor IX therapy very exciting.” Haemophilia B, a rare, inherited clotting disorder, occurs in about one in 25,000 male births annually.

Biogen plans to submit a Biologics License Application to the US Food and Drug Administration in the first half of 2013. Noting that the European Medicines Agency requires a study in children less than 12 years of age prior to filing, the partners will submit the therapy upon completion of the ongoing Kids B-LONG study.

Biogen and SOBI are also investigating a long-lasting recombinant Factor VIII Fc fusion protein (rFVIIIFc) for haemophilia A and top-line results from a Phase III trial,  A-LONG, are expected later this year. The latter is about four times the size of the haemophilia B market.

Investors in SOBI were particularly pleased and its shares shot up 44.2% to close at 37.50 kroner.