Half-life extension through albumin fusion technologies

Area of Science:

• Biochemistry
• Hematology
• Protein Engineering

Background:

• Hemophilia B results from factor IX deficiency, impacting hemostasis and causing severe bleeding.
• Current factor IX (FIX) replacement therapies require frequent infusions due to short circulation half-life.
• Managing hemophilia B aims to prevent hemorrhage, reduce joint damage, and improve patient quality of life.

Purpose of the Study:

• To develop an improved recombinant factor IX (rFIX) variant with enhanced pharmacokinetic properties.
• To assess the efficacy and safety of a novel rFIX-albumin fusion protein (rIX-FP) in preclinical models.

Main Methods:

• Genetic fusion of recombinant FIX (rFIX) to albumin via a cleavable peptide linker to create rIX-FP.
• Expression and purification of the rIX-FP construct in mammalian cells.
• In vitro activation studies, pharmacokinetic analysis in rats, rabbits, and mice, and bleeding time assessment in a murine hemophilia B model.

Main Results:

• Cleavage of the linker was observed concurrently with FIX activation in vitro.
• The cleavable fusion protein (rIX-FP) exhibited 10- to 30-fold higher molar specific clotting activity than non-cleavable fusion proteins.
• rIX-FP demonstrated significantly improved pharmacokinetics compared to rFIX in multiple animal models.
• rIX-FP effectively corrected bleeding time and reduced blood loss in a murine hemophilia B model.

Conclusions:

• The rIX-FP fusion protein exhibits enhanced biological characteristics and superior efficacy in preclinical models.
• rIX-FP represents a potentially promising therapeutic candidate for managing hemophilia B.
• This novel approach may overcome limitations of current factor IX replacement therapies.