BIIB's rFIXFc meets Phase III endpoints

Biogen Idec Inc. (NASDAQ:BIIB) and partner Swedish Orphan Biovitrum AB (SSE:SOBI) said rFIXFc as prophylaxis met the primary efficacy and safety endpoints in the Phase III B-LONG trial to treat hemophilia B patients. To meet the efficacy endpoint, the partners said rFIXFc as prophylaxis needed to reduce annualized bleeding rates by at least 50% compared to as needed treatment with rFIXFc for bleeding episodes. Biogen Idec did not disclose the reduction in bleeding rates, but did report that rFIXFc led to overall median annualized bleeding rates, including spontaneous and traumatic bleeds, of 2.95 in the weekly prophylaxis arm and 1.38 in the individualized interval prophylaxis arm vs. 17.69 in the as needed treatment arm. rFIXFc was generally well tolerated with no inhibitors to rFIXFc detected and no cases of anaphylaxis reported. According to the study design, the trial would have been stopped if two inhibitors to rFIXFc were detected.

There was one serious adverse event of obstructive uropathy in the setting of hematuria, which was possibly related to rFIXFc. The patient continued treatment and the event resolved with medical management. The product is a recombinant fusion protein consisting of human coagulation Factor IX attached to the Fc domain of human IgG1. The trial enrolled123 evaluable previously treated patients aged 12 and older. ...