Innovative approach for improved rFVIII concentrate.

The development of a new recombinant factor VIII was designed and implemented to answer a number of unmet needs of patients affected by hemophilia A. Turoctocog alfa is bioengineered in a specific Chinese hamster ovary clone to present translational and posttranslational characteristics (sulphation, glycosylation) biosimilar to natural circulating forms of FVIII, with the aim to devoid any minimal change which may impact immunogenicity and antigenicity of recombinant protein. Both producer cell line and media are maintained free of any animal or human plasma derivative. Downstream processes of purification are performed by five steps (immunoaffinity chromatography, ion-exchange chromatography, virus inactivation by means of solvent-detergent treatment and nanofiltration, and to end with gel filtration), to provide the best possible margin of safety from known and unknown infectious agents. Large clinical trials seem to confirm the expectations placed in Turoctocog alfa in terms of high quality and safety of recombinant FVIII toward the goal of overcoming actual and future challenges of hemophilia therapy.

Expression, purification, and partial in vitro characterization of biologically active human coagulation factor VIII light chain (A3-C1-C2) in Pichia pastoris.

Recombinant coagulation factor VIII (FVIII) expressed in mammalian expression systems is used extensively in the treatment of hemophilia A. It is reported that the heavy (A1-A2) and light chains (A3-C1-C2) of factor VIII purified from plasma regained the coagulation activity by dimerization in vitro. In this work, cDNA coding for the light chain of human coagulation factor VIII (FVIII-LC) was cloned into pPICZα-A expression vector downstream of alcohol oxidase promoter and α-mating signal sequence from Saccharomyces cerevisiae in order to express the protein with a native N-terminus. The methylotrophic yeast, Pichia pastoris X-33, was transformed with this cassette, and transformants were selected for production of human factor VIII light chain into culture media. SDS-PAGE and Western blot analysis confirmed the expression of factor VIII light chain protein. The expressed protein was purified to near homogeneity using histidine ligand affinity chromatography (2.342 mg/L). The biological activity of FVIII-LC was confirmed by analyzing the interaction between FVIII-LC and phospholipid vesicles. The data presented here indicate the possibilities of exploring cost-effective systems to express complex proteins of therapeutic value.

How we choose factor VIII to treat hemophilia.

In high-income countries, the large availability of coagulation factors for replacement therapy of patients with hemophilia A has raised the life expectancy of these lifelong bleeders to that of males from the general population. The practicing clinician is offered a multitude of choices among several commercial brands of factor VIII extracted from human plasma or engineered from mammalian cell cultures by means of recombinant DNA technology. This article has the goal to offer our opinions on how to choose among the different products, that we consider interchangeable relevant to their clinical efficacy in the control of bleeding and safety from pathogen transmission. Hence, the main determinants of our choices are price and the risk of occurrence of factor VIII inhibitory alloantibodies. With this as background, we present the rationale underlying the choices for different categories of patients with severe hemophilia A: previously untreated patients, multiply treated patients, and patients undergoing immune tolerance induction with large doses of factor VIII to eradicate inhibitors. Mention is also made to the possible strategies that should be implemented to make available coagulation factors for replacement therapy in developing countries.

Economical impact of plasma fractionation project in Iran on affordability of plasma-derived medicines.

In Iran all transfusion services are concentrated under authority of one public and centralized transfusion organization which has created the opportunity of using plasma produced in its blood centers for fractionation. In 2008 voluntary and non remunerated Iranian donors donated 1.8 million units of blood. This indicates a 25/1000 donation index. After responding to the needs for fresh plasma and cryoprecipitate each year about 150000 L of recovered plasma are reserved for fractionation. In an attempt to improve both blood safety profile and availability and affordability of plasma derived medicines, Iran's national transfusion service has entered into a contract fractionation agreement for surplus of plasma produced from donated blood by voluntary non remunerated donors. In order to ensure safety of product produced, Iran has chosen to collaborate with international fractionators based in highly regulated countries. The main objective of this study was to evaluate the impact of contract plasma fractionation on the affordability of the plasma derived medicines in Iran. During 2006-2008, Iran's contract fractionation project was able to produce 46%, 18% and 6% of IVIG, Albumin and FVIII consumed in Iran's market, respectively. In contrary to IVIG and Albumin, due to fairly high consumption of FVIII in Iran, the role of fractionation project in meeting the needs to FVIII was not substantial. However, Iran's experience has shown that contract plasma fractionation, through direct and indirect effects on price of plasma derived medicines, could substantially improve availability and affordability of such products in national health care system.

Dry-heat treatment process for enhancing viral safety of an antihemophilic factor VIII concentrate prepared from human plasma.

Viral safety is a prerequisite for manufacturing clinical antihemophilic factor VIII concentrates from human plasma. With particular regard to the hepatitis A virus (HAV), a terminal dry-heat treatment (100 degrees for 30 min) process, following lyophilization, was developed to improve the virus safety of a solvent/detergent-treated antihemophilic factor VIII concentrate. The loss of factor VIII activity during dry-heat treatment was of about 5%. No substantial changes were observed in the physical and biochemical characteristics of the dry-heat-treated factor VIII compared with those of the factor VIII before dry-heat treatment. The dry-heat-treated factor VIII was stable for up to 24 months at 4oC. The dry-heat treatment after lyophilization was an effective process for inactivating viruses. The HAV, murine encephalomyocarditis virus (EMCV), and human immunodeficiency virus (HIV) were completely inactivated to below detectable levels within 10 min of the dry-heat treatment. Bovine herpes virus (BHV) and bovine viral diarrhea virus (BVDV) were potentially sensitive to the treatment. However porcine parvovirus (PPV) was slightly resistant to the treatment. The log reduction factors achieved during lyophilization and dry-heat treatment were > or =5.55 for HAV, > or =5.87 for EMCV, > or =5.15 for HIV, 6.13 for BHV, 4.46 for BVDV, and 1.90 for PPV. These results indicate that dry-heat treatment improves the virus safety of factor VIII concentrates, without destroying the activity. Moreover, the treatment represents an effective measure for the inactivation of non-lipid-enveloped viruses, in particular HAV, which is resistant to solvent/detergent treatment.

Progress in large-scale purification of factor VIII/von Willebrand factor concentrates using ion-exchange chromatography.

BACKGROUND AND OBJECTIVES: We investigated and optimized the parameters of a chromatographic process suitable for industrial scale to obtain a highly purified factor VIII (FVIII)/von Willebrand factor (VWF) concentrate. MATERIALS AND METHODS: Several chromatographic runs were performed on the same production intermediate using different anion-exchange supports. The best matrix was selected and the final product was characterized. Once the chromatographic medium was chosen, the other parameters were evaluated to obtain the highest purified product and to modulate the VWF content in the FVIII/VWF complex. RESULTS: Fractogel EMD TMAE was the best support among those tested. It was the only one maintaining good results either with standard or double loading and flow rate conditions with respect to a typical industrial process. The chromatographic recovery of FVIII co-purified with VWF was at least 86% with a specific activity not lower than 140 IU/mg. The FVIII/VWF complex obtained is highly pure and, with the exception of immunoglobulin M (IgM), all investigated contaminant proteins are under the detection limit. Different concentrates characterized by variable FVIII/VWF ratios were purified by varying the chromatographic conditions. CONCLUSIONS: Several highly purified products, suitable for haemophilia A and von Willebrand disease management, can be obtained, through the same chromatographic process, on an industrial scale.

The new albumin-free recombinant factor VIII concentrates for treatment of hemophilia: do they represent an actual incremental improvement?

The goal of eliminating the low levels of infectious disease risk from hemophilia treatment has resulted in the development of multiple generations of recombinant factor VIII (rFVIII) products. The ideal product should be devoid of human and animal proteins, which may transmit infectious agents. These products should also maintain molecular integrity, hemostatic efficacy, similar immunogenicity, and acceptable side effect profiles as compared to plasma-derived factor VIII. Currently available first-, second-, and third-generation rFVIII products include Recombinate; Kogenate FS/Helixate FS and ReFacto; and Advate, respectively. During the evolution of rFVIII products, either full-length or B-domain-deleted factor VIII were transfected into immortalized cell lines. The B-domain-deleted product, ReFacto, has resulted in an additional method to monitor factor VIII levels. The third-generation products offer the theoretical advantage of being produced without human and/or animal proteins. Upon initial introduction into the marketplace, the newer products have a higher cost. However, when analyzing historical trends, the prices of these products are almost equivalent to first-generation products within 3 years of licensure. Thus, the initial cost of the product may be a minimal issue in the medical decision process when selecting rFVIII replacement therapy.

Removal and inactivation of hepatitis B virus from contaminated pooled plasma in a large-scale manufacturing process for factor VIII and human serum albumin.

BACKGROUND AND OBJECTIVES: The Japanese Red Cross Society recalled one lot of monoclonal-antibody-purified factor VIII (F VIII) and two lots of human serum albumin (HSA) 5 months after preparation of the final products, because of a procedural error that led to contamination by a unit of plasma positive for hepatitis B surface antigen (HBsAg). We evaluated the effectiveness of virus inactivation/removal in a large-scale process for manufacturing F VIII and HSA. MATERIALS AND METHODS: HBV DNA in the retained samples in process was measured by the polymerase chain reaction (PCR). The kinetics of virus inactivation by solvent-detergent (S/D) treatment was examined using model viruses. We also did a look-back survey of the patients who received corresponding products. RESULTS: Contaminated hepatitis B virus (HBV) DNA became undetectable beyond fraction S IV-I in the albumin process and immunoaffinity chromatography in the F VIII process, respectively. The model viruses were inactivated within 5 s by S/D treatment. There is no evidence that patients were infected by HBV after transfusion of these products. CONCLUSION: We conclude that virus inactivation/removal was effectively achieved in a large-scale manufacturing process for F VIII and HSA.

Influence of phospholipids on the assessment of factor VIII activity.

In view of reported discrepancies between different factor VIII assays, the influence of phospholipids on the performance of one-stage clotting (OS) and chromogenic substrate (CS) assays was evaluated. The B domain deleted recombinant factor VIII, rVIII SQ, two full-length recombinant products and a plasma derived factor VIII concentrate were each diluted into severe haemophilia A plasma and assayed against a plasma standard. The one-stage activity was 50, 80, 75 and 106%, respectively, of the chromogenic result. Variations in the phospholipid concentration did not affect the chromogenic assay, except at very low levels where the apparent activity increased. In contrast, dilution of the phospholipid reagent had a substantial influence on the activity measured by OS assays, especially in the case of rVIII SQ. At low levels of phospholipid, the one-stage activity of rVIII SQ exceeded the chromogenic result. When mixtures of phosphatidylserine (PS) and phosphatidyl-choline (PC) were used as a source of phospholipid, the OS results for rVIII SQ agreed well with the CS activity as long as the content of PS was below 10%, i.e., closer to the physiological level. At higher levels of PS, as in most commercial APTT reagents, the OS activity decreased. When the APTT reagent was replaced by platelets in the OS assay, the results compared well with those obtained by the CS assay for both t-VIII SQ and full-length factor VIII products.

Why prescribe highly purified factor VIII and IX concentrates?

The aftermath of the HIV catastrophe and hepatitis virus transmission to hemophiliacs has been characterized by continuous efforts to improve the purity of factor VIII and factor IX concentrates, increasing sophistication of the virucidal methods used, and the introduction of recombinant factor VIII. The cost of hemophilia care is substantial and there is a large price difference between products depending on their purity; generally, the purer the concentrate, the higher the price. The use of expensive highly purified concentrates may be questioned if these products are not superior in terms of safety, efficacy or convenience. The properties of concentrates used in hemophilia care are discussed in this review, as are their safety and side effects. The available data do not clearly reveal any clinical difference between factor VIII concentrates, although the highly purified products may be of theoretical benefit. With regard to factor IX, purified products do not seem to carry any risk of the well-known thromboembolic complications which occur in certain situations after treatment with prothrombin complex concentrates.

Should clinical freedom be constrained in the name of self-sufficiency?

Clinical freedom should enable a physician to decide in a free and unbiased manner which is the most appropriate therapy to use for a particular patient. In order to implement the four aims of the German Haemophilia Society an average of 4-4.5 units of Factor VIII per capita of the general population per year is needed. At present European countries do not produce this amount, but to reduce the consumption of F VIII in therapy lowers treatment levels. Until plasma collection services in Europe can be expanded it is necessary that the additional, imported, sources of plasma are available, otherwise clinical freedom will be curtailed.

The effects of type of factor VIII concentrate used in haemophilia on T-helper cell number and inhibitor incidence.

This review surveys the available published data on the impact of the type of factor VIII concentrate infused on T-helper lymphocyte count and factor VIII inhibitor induction in haemophiliacs. While concern has been expressed that certain products may have adverse effects on these parameters, only one trial published to date shows a significant benefit of a high purity product in reducing the rate of CD4 lymphocyte decline in HIV seropositive haemophiliacs. A number of other studies show no such significant benefit although the design of many of these might be criticized and few of them consider the potential impact of viral infection other than HIV, such as hepatitis C. More recent data on the incidence and prevalence of inhibitors in the haemophiliac population suggest that the reported high frequency of inhibitor formation for some products may lie within the expected normal range. This raises interest in why some products appear not to induce inhibitor formation, even in the group of patients at greater risk: multitransfused, severely deficient patients. The occasional reports of late onset high titre inhibitors in multitransfused haemophilia patients associated with the introduction of newer products are a matter of concern.

Simultaneous collection of platelets and cryoprecipitate by plasma-exchange donation.

To increase cost efficiency, the simultaneous collection of platelets during plasma-exchange donation of cryoprecipitate was investigated. Sixteen desmopressin (DDAVP)-stimulated donors underwent 90 simultaneous donations. Permanent donor plasma loss for each donation averaged 150 ml in cryoprecipitate and 151 ml in platelet concentrates. Mean factor VIII (FVIII) yield was 4699 +/- 2754 IU per donation. The mean yield in the platelet products was 4.63 X 10(11) platelets; aggregation properties and posttransfusion increments were satisfactory. White cell contamination averaged 4.05 X 10(9) but could be lowered by a secondary centrifugation. The direct cost for a single-donor platelet transfusion produced in this way is estimated at $102.19 and that for FVIII at $0.055 per IU. Simultaneous donation is technically feasible and safe for donors, and it provides functional products that are more cost-effective than apheresis platelets or cryoprecipitate donated separately.

Assessment of multimeric structure and ristocetin-induced binding to platelets of von Willebrand factor present in cryoprecipitate and different factor VIII concentrates.

The multimeric structure of von Willebrand factor (vWF) and its ristocetin-induced binding to platelets, using a simple and very sensitive radiomonoclonal antibody-labeled vWF method, was compared in normal plasma, single-donor cryoprecipitate (CP) and five different antihemophilic factor (AHF) concentrates. All the AHF showed a lack of larger vWF multimers, an abnormal 'triplet' pattern, and much lower vWF binding to platelets than that of plasma or CP, vWF being the lowest for those with a lesser proportion of larger vWF multimers. These results suggest that the combination of vWF multimeric analysis and the radiomonoclonal-labeled vWF method may be very useful in the assessment of AHF preparations.

Starting a plasmapheresis program with hollow-fiber filtration.

In a routine donor center, a program of hollow-fiber filtration can be instituted. With the Organon Teknika PLASMAPUR system the collection of 600 ml plasma was completed within 50 min in 76% of the procedures. Changing the tubing set took 12-15 min. From the plasma a frozen cryoprecipitate is made with a recovery of 59%. After pooling, lyophilization and heat treatment, the recovery is 42%.