Recombinant Factor IX for Clinical and Research Use
ABSTRACT The last significant advance in the therapy of hemophilia B was the introduction of recombinant factor IX (FIX), ensuring an advanced level of safety from potential infectious contaminants of plasma-derived clotting factors. Since that time, recombinant DNA techniques have been applied in research to elucidate the role of FIX and its functional domains within coagulation. At the same time, recombinant DNA technology has been applied to engineer an expanding spectrum of novel FIX therapies that are now being translating into clinical trials. The experience with the existing recombinant FIX product is reviewed with a focus on the novel products and the potential to improve the quality of life for individuals with hemophilia B.
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ABSTRACT: Hemophilia B is a rare hereditary hemorrhagic disorder characterized by deficiency of the clotting factor IX (FIX). Hemophilia B patients experience mild-to-severe bleeding complications according to the degree of FIX defect. The mainstay of treatment of hemophilia B consists of replacement therapy and nowadays several plasma-derived and recombinant FIX products are commercially available. This article reviews the current management of hemophilia B patients analyzing the results of the most important clinical trials. In addition, it will focus on the more recent advances in the production of new FIX molecules aimed at the improvement of the clinical management of such patients.Expert Review of Hematology 08/2014; 7(5). DOI:10.1586/17474086.2014.947955 · 2.14 Impact Factor
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ABSTRACT: Human glycoproteins, expressed in hamster cell lines, show similar glycosylation patterns to naturally occurring human molecules except for a minute difference in the linkage of terminal sialic acid: both cell types lack α2,6-galactosyl-sialyltransferase, abundantly expressed in human hepatocytes and responsible for the α2,6-sialylation of circulating glycoproteins. This minute difference, which is currently not known to have any physiological relevance, was the basis for the selective measurement of recombinant glycoproteins in the presence of their endogenous counterparts. The assay is based on using the lectin Sambucus nigra agglutinin (SNA), selectively binding to α2,6-sialylated N-glycans. Using von Willebrand factor (VWF), factor IX (FIX), and factor VIIa (FVIIa), it was demonstrated that (i) the plasma-derived proteins, but not the corresponding recombinant proteins, specifically bind to SNA and (ii) this binding can be used to deplete the plasma-derived proteins. The feasibility of this approach was confirmed in spike-recovery studies for all three recombinant coagulation proteins in human plasma and for recombinant VWF (rVWF) in macaque plasma. Analysis of plasma samples from macaques after administration of recombinant and a plasma-derived VWF demonstrated the suitability and robustness of this approach. Data showed that rVWF could be selectively measured without changing the ELISAs and furthermore revealed the limitations of baseline adjustment using a single measurement of the predose concentration only. The SNA gel-based depletion procedure can easily be integrated in existing procedures as a specific sample pre-treatment step. While ELISA-based methods were used to measure the recombinant coagulation proteins in the supernatants obtained by depletion, this procedure is applicable for all biochemical analyses. Copyright © 2015. Published by Elsevier B.V.Journal of Pharmaceutical and Biomedical Analysis 02/2015; 108C:21-28. DOI:10.1016/j.jpba.2015.01.047 · 2.83 Impact Factor
Article: Emerging drugs for hemophilia B[Show abstract] [Hide abstract]
ABSTRACT: Introduction: Hemophilia B is a rare congenital bleeding disorder characterized by a deficiency of coagulation factor IX (FIX). Hemophilia B patients experience mild-to-severe bleeding complications according to the degree of FIX defect. Prophylaxis, with regular infusion of FIX concentrates, is nowadays, the mainstay of hemophilia care. However, because the relatively short half-life of such products necessitates frequent infusions and thus makes patients’ adherence difficult, a number of strategies have been implemented to improve the pharmacokinetics of FIX clotting factors.Areas covered: This review summarizes the main results of Phase I/II and III studies on new FIX molecules engineered to have a longer half-life. Several technologies are being applied to extend FIX half-life, including Fc fusion, recombinant (r) albumin fusion and the addition of PEG polymers.Expert opinion: By prolonging the FIX half-life up to 5 times, long-acting FIX products are expected to substantially improve the management of hemophilia B patients, allowing less frequent infusions and improving patients’ adherence to prophylactic regimens and individualized treatments. Some of them are at an advanced stage of development, such as the rFIX-Fc which has been launched in March 2014. Along with the ongoing Phase III trials, long-term post-marketing surveillance studies are needed to assess their safety and effectiveness and their impact on patients’ quality of life.Expert Opinion on Emerging Drugs 08/2014; DOI:10.1517/14728214.2014.946010 · 2.48 Impact Factor