Factor VIII, recombinant

Production of recombinant factor VIII (Table 12.2) has ended dependence on blood as the only source of this product, and eliminated the possibility of transmitting blood-borne diseases specifically derived from infected blood. In the past, over 60 per cent of haemophiliacs were likely to be accidentally infected via contaminated products at some stage of their life. 

Several companies have expressed the cDNA coding for human factor VIII C in a variety of eukaryotic production systems (human VIII C contains 25 potential glycosylation sites). CHO cells and BHK cell lines have been most commonly used, in addition to other cell lines, such as various mouse carcinoma cell lines. The recombinant factor VIII product generally contains only VIII C (i.e. is devoid of vWF). However, both clinical and preclinical studies have shown that administration of this product to patients suffering from haemophilia A is equally as effective as administering blood-derived factor VIII complex. The recombinant VIII C product appears to bind plasma... 

Owing to the frequency of product administration, the purification procedure for recombinant factor VIII C must be particularly stringent. Unlike the situation pertaining when the product is purified from human blood, any contaminant present in the final product will be non-human and, hence, immunogenic. Sources of such contaminants would include ... 

Recombinant factor VIII is gaining an increasing market share of the factor VIII market. Researchers are also attempting to develop modified forms of VIII C (by site-directed mutagenesis) that display additional desirable characteristics. Particularly attractive in this regard would be the development of a product exhibiting an extended circulatory half-life. This could reduce... 

Natural source may carry risk of infection. Recombinant Factor VIII used to treat hemophilia A has helped reduce the incidence of HIV infection in hemophiliacs. Recombinant HbsAg is now used to immunize against hepatitis B, eliminating the risk of introducing a viral infection during vaccination. 

Palsson, E., Smeds, A.L., Petersson, A., and Larsson, P.-O., Faster isolation of recombinant factor VIII SQ, with a superporous agarose matrix, J. Chromatogr. A, 840, 39-50, 1999. 

Clinical trials have demonstrated excellent efficacy with recombinant human factor VIII concentrates available as Recombinate and Kogenate. These recombinant factor VIII products are purified from the cell culture of plasmids, not viral DNA-transfected hamster cells and therefore do not express viral sequences. The addition of human serum albumin for stabilization, constitutes the sole possible source for human viral contamination. More recently recombinant factor IX has been genetically engineered by insertion of the human factor IX gene into a Chinese hamster ovary cell line. It has been proved to be safe and effective in the treatment of patients with hemophilia B. 

E Role in therapy Antihemophilic factor is indicated for the treatment of bleeding episodes or perioperative treatment in patients with hemophilia A. Prophylactic use has also been advocated for the prevention and/or reduction of bleeding episodes. The largest issue in treatment with antihemophilic factor is the choice of formulations because of the relative risk of viral transmission. Recombinant factor VIII has the lowest risk of transmission of blood-borne viruses, but its use may be limited due to cost and availability. 

Antihemophilic factor, human recombinant factor VIII produced in BHK cells... 

VIII Hemophilia A 30-50% 100% for major bleeding or trauma 12 hours Recombinant factor VIII products Plasma-derived high purity concentrates Cryoprecipitate1 Some patients with mild deficiency will respond to DDAVP... 

Osterberg, T., Fatouros, A., Neidhardt, E., Warne, N., and Mikaelsson, M. (2001), B-domain-deleted recombinant factor VIII formulation and stability, Semin. Hematol., 38,40 13. 

Fatouros A, Osterberg T, Mikaelsson M. Recombinant factor VIII SQ—influence of oxygen, metal ions, pH and ionic strength on its stability in aqueous solution. Int J Pharm 1997 155 121-131. 

Yoshioka, A., Fukutake, K., Takamatsu, J., and Shirahata, A. (2006). Clinical evaluation of recombinant factor VIII preparation (Kogenate) in previously treated patients with hemophiliaA descriptive meta-analysis of post-marketing study dateit. J. Hematol., 84, 158-165. 

Bodeker BDG (1994), Production of recombinant factor VIII from perfusion cultures I Large-scale fermentation, In Spier RE, Griffiths JB, Berthold W (Eds), Animal Cell Technology Products of Today, Prospects of Tomorrow, Butterworth-Fleinemann, London, pp. 580-583. 

Blood factor VIII (FVIII) is a glycoprotein with 2351 amino acids and 330 kDa. Its deficiency causes hemophilia A. The first products based on recombinant factor VIII to reach the market were Recombinate and Kogenate, expressed in CHO and BHK cells, respectively. Over the last decade, other rFVIII products were approved, with modifications to the molecule (e.g. deletion of the B-domain), in the formulation or in the production processes. 

Bhattacharyya MS, Singh J, Soni P, Banerjee UC (2003), Recombinant factor VIII for haemophilia an overview of production technologies, CRIPS 4 2-8. 

Boedeker BGD (1992), The manufacturing of the recombinant factor VIII Kogenate , Transf. Med. Rev. 6 256-260. 

Homologous recombinant proteins have had to undergo a more extensive evaluation preclinically. For example, a recombinant factor VIII product was evaluated in acute and subacute studies in mice, rats, rabbits, dogs, and nonhuman primates over a range of concentrations and dose frequency [12],... 

In one second-generation recombinant factor VIII product, ReFacto , hemophilic dogs were used to demonstrate utility for bleeding time correction, association with von Willebrand s factor, and evaluating pharmacokinetics... 

Giles AR,Tinlin S, Hoogendoorn H, Fournel MA, Ng P, Pancham N. In vivo characterization of recombinant factor VIII in a canine model of hemophilia a (factor VIII deficiency). Blood 1988 72 335-9. 

Brinkhous K, Sandberg H, Widlund L, Read M, Nichols T, Sigman J, et al. Preclini-cal pharmacology of albumin-free b-domain deleted recombinant factor VIII. Sem Thromb Hemostasis 2002 28 269-72. 

Lusher JM, Arkin S, Abildgaard CF, et al. Recombinant factor VIII for the treatment of previously untreated patients with hemophilia A safety, efficacy, and development of inhibitors. N Engl J Med 1993 328(7) 453—9. 

In the past, hemophiliacs were treated with transfusions of a concentrated plasma fraction containing factor VIII. This therapy carried the risk of infection. Indeed, many hemophiliacs contracted hepatitis and AIDS. A safer preparation of factor VIII was urgently needed. With the use of biochemical purification and recombinant DNA techniques, the gene for factor VIII was isolated and expressed in cells grown in culture. Recombinant factor VIII purified from these cells has largely replaced plasma concentrates in treating hemophilia. 

Recombinant factor VIII or IX concentrates are recommended for all previously untreated patients, those who have been previously treated but remain hepatitis C virus or HIV seronegative, and for mild to moderate severity disease when desmopressin is not sufficient. 

Fatouros, A. Sjostrom, B. Recombinant factor VIII SQ—The influence of formulation parameters on structure and surface adsorption. Int. J. Pharm. 2000, 194, 69-79. 

Osterberg, T. Fatouros, A. Mikaelsson, M. Development of a freeze-dried albumin-free formulation of recombinant factor VIII SQ. Pharm. Res. 1997, 14 (7), 892-898. 

Bray GL, Gomperts ED, Courier S, Gmppo R, Gorden EM, Manco-Johnson M, Shapiro A, Scheibel E, White G, 3rd, Lee M. A multicenter study of recombinant factor VIII (Recombinate) safety, efficacy and inhibitor risk in previously untreated patients with hemophiha A. The Recombinate Study Group. Blood 1994 83(9) 2428-35. 

Lyophilized factor VIII has been used as substitution therapy in patients with hemophilia A. Most, but not all, recombinant factor VIII (recFVIII) is structurally and immunologically similar to plasma-derived factor VIII, and it has been well tolerated by patients in clinical trials. A major concern about recombinant factor VIII has been the occurrence inhibitors (1). However, there is evidence that there is no difference in the occurrence of inhibitors between recombinant factor VIII and plasma-derived factor VIII (2). 

In 58 previously treated patients with hemophiha treated with a recombinant factor VIII product for more than 5 years, there were neither allergic reactions to murine or hamster proteins nor any de novo formation of inhibitors of factor VIII (20). 

---