Expert: Recombinant Factor IX Fc fusion protein (rFIXFc). The Fc domain binds neonatal Fc receptor (FcRn) in endothelial cells, diverting FIX from lysosomal degradation into FcRn-mediated recycling. Results in ~3x longer terminal half-life vs native FIX (~82 hrs vs ~34 hrs). Allows extended dosing intervals (Q1-2W vs Q2-3 days).

Everyday: A lab-made version of the clotting factor (Factor IX) that people with hemophilia B are missing, engineered to last longer in the body. Normal Factor IX replacement gets used up quickly, requiring injections every few days. By fusing it with another protein (Fc fragment of antibody), it "tricks" the body into recycling it instead of breaking it down — roughly doubling how long it works.

Targets: []

Primary EP: [{"id":"blong-ep1","name":"ABR on individualized interval prophylaxis","type":"PRIMARY","unit":"bleeds/year","results":[{"arm":"blong-ind","label":"Median ABR 1.38 (Q10-14 day dosing)","value":1.38},{

Safety: 0 inhibitors across all clinical studies. No serious treatment-related AEs. Excellent/good hemostasis in all 12 surgical patients. Very clean safety profile.

Extended half-life rFIX-Fc for hemophilia B. ~3x longer half-life than standard FIX. Allows weekly or biweekly dosing. Mature product with stable patient base. Hemophilia B is ~5x rarer than Hem A, so market is smaller.