The use of chromatography to manufacture purer and safer plasma products

PlasmaCap EBA: An innovative method of isolating plasma proteins from human plasma

BACKGROUND AND OBJECTIVES

The growing demand for immunoglobulin (IG) requires development of improved plasma fractionation methods to provide higher yields in a cost effective, scalable manner without compromising product purity and efficacy. A novel protein extraction method, utilizing expanded bed adsorption (EBA) chromatography, has been developed. PlasmaCap IG (10% liquid formulation intravenous IG [IVIG]) is the first plasma-derived product manufactured using PlasmaCap EBA technology.

MATERIALS AND METHODS

The PlasmaCap EBA platform consists of a series of consecutive columns which bind a target protein, or group of proteins, in their native state directly from cryo-poor plasma. EBA chromatography includes five key steps: (1) expand, (2) sanitize and equilibrate, (3) load, (4) wash and (5) elute. These steps are made possible using high-density tungsten-carbide agarose beads, suspended by upward flow. The PlasmaCap EBA process was evaluated during Evolve's clinical campaign for scalability, product quality and yield.

RESULTS

PlasmaCap EBA technology can be predictably scaled by maintaining the minimum residence time and residence time distribution for EBA columns of different diameters. Scalability of the manufacturing process was demonstrated by the 50-fold volumetric increase from laboratory-scale lots to clinical-scale lots. The process is also associated with enhanced product purity, such as lower aggregates. The PlasmaCap EBA process is expected to have the same or better yield and purity at commercial scale production compared to the clinical campaign.

CONCLUSION

The PlasmaCap EBA platform was used to successfully develop PlasmaCap IG (10% liquid formulation IVIG) with proven scalability, product quality and yield.

Functionalizing DNA origami to investigate and interact with biological systems

DNA origami has emerged as a powerful method to generate DNA nanostructures with dynamic properties and nanoscale control. These nanostructures enable complex biophysical studies and the fabrication of next-generation therapeutic devices. For these applications, DNA origami typically needs to be functionalized with bioactive ligands and biomacromolecular cargos. Here, we review methods developed to functionalize, purify, and characterize DNA origami nanostructures. We identify remaining challenges, such as limitations in functionalization efficiency and characterization. We then discuss where researchers can contribute to further advance the fabrication of functionalized DNA origami.

Therapeutic solutions of human albumin - The possible effect of process-induced molecular alterations on clinical efficacy and safety

Human albumin solutions were developed as therapeutic during the Second World War to address blood loss due to battlefield injury. This indication was based on the recognition that albumin provided most of the oncotic capacity of human plasma. For the succeeding sixty years, this formed the basis for the use of albumin in traumatology and emergency medicine. In more recent times, the pharmacological properties arising from albumin's complex structure have become a focus of attention by clinical researchers. In particular, albumin, through anti-inflammatory and anti-oxidant properties, has been proposed as an agent for the treatment of sepsis, cirrhosis and other inflammatory states. Some evidence for these indications has accrued from a number of small clinical trials and observational studies. These studies have not been confirmed in other large trials. Together with other investigators, we have shown that the process of plasma fractionation results in alterations in the structure of albumin, including those parts of the molecule involved in anti-oxidant and anti-inflammatory effects. Albumin products from diverse manufacturers show heterogeneity in their ability to address these effects. In this article, we review the historical development of albumin solutions, pointing out the variations in fractionation chemistries which different manufacturers have adopted. We suggest ways by which the manufacturing processes have contributed to variations in the physico-chemical properties of molecule. We review the outcomes of clinical studies assessing the role of albumin in ameliorating conditions such as sepsis and cirrhosis, and we speculate as to the extent which heterogeneity in the products may have contributed to variable clinical outcomes. Finally, we argue for a change in the perception of the plasma product industry and its regulatory overseers. Historically, albumin has been viewed as a generic commodity, with different preparations being interchangeable in their clinical application. We suggest that this implied biosimilarity is not necessarily applicable for different albumin solutions. The use of albumin, in indications other than its historical role as a plasma expander, can only be validated by clinical investigation of each separate albumin product.

Separation of Albumin from Bovine Serum Applying Ionic-Liquid-Based Aqueous Biphasic Systems

In this work, the extraction and separation of bovine serum albumin (BSA) from its original matrix, i.e., bovine serum, was performed using a novel ionic-liquid-based aqueous biphasic system (IL-based ABS). To this end, imidazolium-, phosphonium-, and ammonium-based ILs, combined with the anions’ acetate, arginate and derived from Good Buffers, were synthesized, characterized, and applied in the development of ABS with K2HPO4/KH2PO4 buffer aqueous solutions at pH 7. Initial studies with commercial BSA revealed a preferential migration of the protein to the IL-rich phase, with extraction efficiencies of 100% obtained in a single-step. BSA recovery yields ranging between 64.0% and 84.9% were achieved, with the system comprising the IL tetrabutylammonium acetate leading to the maximum recovery yield. With this IL, BSA was directly extracted and separated from bovine serum using the respective ABS. Different serum dilutions were further investigated to improve the separation performance. Under the best identified conditions, BSA can be extracted from bovine serum with a recovery yield of 85.6% and a purity of 61.2%. Moreover, it is shown that the BSA secondary structure is maintained in the extraction process, i.e., after being extracted to the IL-rich phase. Overall, the new ABS herein proposed may be used as an alternative platform for the purification of BSA from serum samples and can be applied to other added-value proteins.

Immunoglobulin G in Platelet-Derived Wound Healing Factors

We intended to reformulate an existing platelet-derived wound healing formula to target each phase of the healing wound with the appropriate phase-specific molecules. A decreased perfusion of the skin, often associated with conditions such as thalassemia, sickle cell disease, diabetes mellitus, and chronic vascular disease, is the most common etiology of cutaneous ulcers and chronic wounds. We had previously shown that a PDWHF topically applied to a chronic nonhealing ulcer of a β-thalassemia homozygote stimulated and accelerated closure of the wound. The PDWHF was prepared from a pooled platelet concentrate of a matching blood group, consisting of a combination of platelet α-granule-derived factors. Processing of the apheresis-pooled platelets yielded various amounts of proteins (3.36 g/mL ± 0.25 (SD) (N = 10)) by the better lysis buffer method. Immunoglobulin G was found to be the most abundant α-granule-secreted protein. Equally broad quantities of the IgG (10.76 ± 12.66% (SD) (N = 10)) and IgG/albumin ratios (0.6 ± 0.4 (SD) (N = 10)) were quantified. We have developed a method using a reformulated lysis buffer followed by size exclusion chromatography and affinity chromatography to extract, identify, quantify, and purify IgG from activated platelets. IgG purification was confirmed by Western blot and flow cytometry. It was thought unlikely that the platelet IgG could be accounted for by adsorption of plasma protein, though the variable quantities could account for diversity in wound healing rates. The IgG could protect the wound even from subclinical infections and functionally advance healing. It may be useful in the management of skin ulcers in the early phase of wound healing.

Polysaccharide-based chromatographic adsorbents for virus purification and viral clearance

Viruses still pose a significant threat to human and animal health worldwide. In the fight against viral infections, high-purity viral stocks are needed for manufacture of safer vaccines. It is also a priority to ensure the viral safety of biopharmaceuticals such as blood products. Chromatography techniques are widely implemented at both academic and industrial levels in the purification of viral particles, whole viruses and virus-like particles to remove viral contaminants from biopharmaceutical products. This paper focuses on polysaccharide adsorbents, particulate resins and membrane adsorbers, used in virus purification/removal chromatography processes. Different chromatographic modes are surveyed, with particular attention to ion exchange and affinity/pseudo-affinity adsorbents among which commercially available agarose-based resins (Sepharose®) and cellulose-based membrane adsorbers (Sartobind®) occupy a dominant position. Mainly built on the development of new ligands coupled to conventional agarose/cellulose matrices, the development perspectives of polysaccharide-based chromatography media in this antiviral area are stressed in the conclusive part.

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Chromatography has been and is still extensively implemented in virus purification/removal downstream processes.

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Typical application fields are the manufacturing of purified viral vaccines and virus-free biopharmaceuticals.

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Agarose and cellulose remain the primary polysaccharide bases for chromatography adsorbents in such virus-related applications.

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Present R&D studies mainly focus on multimodal chromatography and affinity ligands.

Overview of Albumin and Its Purification Methods

As the most frequent plasma protein, albumin constitutes more than 50% of the serum proteins in healthy individuals. It has a key role in oncotic pressure maintenance and it is known as a versatile protein carrier for transportation of various endogenous and exogenous ligands. Reduced amounts of albumin in the body will lead to different kinds of diseases such as hypovolemia and hypoproteinemia. It also has various indications in shocks, burns, cardiopulmonary bypass, acute liver failure and etc. Further applications in research consist of cell culture supplement, drug delivery carrier and protein/drug stabilizer. So, the demand for albumin increased annually worldwide. Due to different applications of albumin, many efforts have been accomplished to achieve albumin during a long period of time. In this review, an overview of serum albumin and different purification methods are summarized.

Pathogen inactivation and removal methods for plasma-derived clotting factor concentrates

Pathogen safety is crucial for plasma-derived clotting factor concentrates used in the treatment of bleeding disorders. Plasma, the starting material for these products, is collected by plasmapheresis (source plasma) or derived from whole blood donations (recovered plasma). The primary measures regarding pathogen safety are selection of healthy donors donating in centers with appropriate epidemiologic data for the main blood-transmissible viruses, screening donations for the absence of relevant infectious blood-borne viruses, and release of plasma pools for further processing only if they are nonreactive for serologic markers and nucleic acids for these viruses. Despite this testing, pathogen inactivation and/or removal during the manufacturing process of plasma-derived clotting factor concentrates is required to ensure prevention of transmission of infectious agents. Historically, hepatitis viruses and human immunodeficiency virus have posed the greatest threat to patients receiving plasma-derived therapy for treatment of hemophilia or von Willebrand disease. Over the past 30 years, dedicated virus inactivation and removal steps have been integrated into factor concentrate production processes, essentially eliminating transmission of these viruses. Manufacturing steps used in the purification of factor concentrates have also proved to be successful in reducing potential prion infectivity. In this review, current techniques for inactivation and removal of pathogens from factor concentrates are discussed. Ideally, production processes should involve a combination of complementary steps for pathogen inactivation and/or removal to ensure product safety. Finally, potential batch-to-batch contamination is avoided by stringent cleaning and sanitization methods as part of the manufacturing process.

Efficacy, safety and pharmacokinetics of a novel subcutaneous immunoglobulin, Evogam®, in primary immunodeficiency

This phase III, open-label, multi-centre study investigated the efficacy, safety, pharmacokinetics and quality of life impact of Evogam(®), a new chromatographically fractionated 16% subcutaneous immunoglobulin, utilising a 1:1 dose transition ratio from previous immunoglobulin therapy. Thirty-five previously treated patients with primary immunodeficiency received weekly Evogam over 36 weeks. Primary endpoints were rate of serious bacterial infections (SBIs) and steady-state serum immunoglobulin G (IgG) trough concentrations. No SBIs were reported during the study. Evogam produced significantly higher mean trough IgG concentrations with 1:1 dose conversion compared to previous immunoglobulin treatment (8.94 versus 8.27 g/L, p = 0.0063). Evogam was efficacious in the prevention of infections and maintenance of trough levels using a 1:1 dose conversion. It was well tolerated with no withdrawals due to adverse events and was preferred to IVIg by the majority of patients.

A non-chromatographic method for the purification of a bivalently active monoclonal IgG antibody from biological fluids

This paper describes a method for the purification of monoclonal antibodies (rat anti-2,4-dinitrophenyl IgG: IgG(DNP); and mouse antidigoxin IgG: IgG(Dgn)) from ascites fluid. This procedure (for IgG(DNP)) has three steps: (i) precipitation of proteins heavier than immunoglobulins with ammonium sulfate; (ii) formation of cyclic complexes of IgG(DNP) by causing it to bind to synthetic multivalent haptens containing multiple DNP groups; (iii) selective precipitation of these dimers, trimers, and higher oligomers of the target antibody, followed by regeneration of the free antibody. This procedure separates the targeted antibody from a mixture of antibodies, as well as from other proteins and globulins in a biological fluid. This method is applicable to antibodies with a wide range of monovalent binding constants (0.1 microM to 0.1 nM). The multivalent ligands we used (derivatives of DNP and digoxin) isolated IgG(DNP) and IgG(Dgn) from ascites fluid in yields of >80% and with >95% purity. This technique has two advantages over conventional chromatographic methods for purifying antibodies: (i) it is selective for antibodies with two active Fab binding sites (both sites are required to form the cyclic complexes) over antibodies with one or zero active Fab binding sites; (ii) it does not require chromatographic separation. It has the disadvantage that the structure of the hapten must be compatible with the synthesis of bi- and/or trivalent analogues.

Entropic interaction chromatography: Separating proteins on the basis of size using end-grafted polymer brushes

Partitioning of a macromolecule into the interfacial volume occupied by a grafted polymer brush decreases the configurational entropy (DeltaSbrush(c)) of the terminally attached linear polymer chains due to a loss of free volume. Self-consistent field theory (SCF) calculations are used to show that DeltaSbrush(c) is a strong function of both the size (MWp) of the partitioning macromolecule and the depth of penetration into the brush volume. We further demonstrate that the strong dependence of DeltaSbrush(c) on MWp provides a novel and powerful platform, which we call entropic interaction chromatography (EIC), for efficiently separating mixtures of proteins on the basis of size. Two EIC columns, differing primarily in polymer grafting density, were prepared by growing a brush of poly(methoxyethyl acrylamide) chains on the surface of a wide-pore (1,000-A pores, 64-microm diameter rigid beads) resin (Toyopearl AF-650M) bearing surface aldehyde groups. Semipreparative 0.1-L columns packed with either EIC resin provide reduced-plate heights of 2 or less for efficient separation of globular protein mixtures over at least three molecular-weight decades. Protein partitioning within these wide-pore EIC columns is shown to be effectively modeled as a thermodynamically controlled process, allowing partition coefficients (K(P)) and elution chromatograms to be accurately predicted using a column model that combines SCF calculation of K(P) values with an equilibrium-dispersion type model of solute transport through the column. This model is used to explore the dependence of column separation efficiency on brush properties, predicting that optimal separation of proteins over a broad MWp range is achieved at low to moderate grafting densities and intermediate chain lengths.

Clinical efficacy of highly purified, doubly virus-inactivated factor VIII/von Willebrand factor concentrate (Fanhdi) in the treatment of von Willebrand disease: a retrospective clinical study

The goal of therapy in patients with von Willebrand disease (vWD) is to correct the dual defect of primary haemostasis and intrinsic coagulation reflected by low levels of von Willebrand factor (vWF) and factor VIII coagulant activity (FVIII:C). Factor VIII/von Willebrand factor (FVIII/vWF) concentrates are currently the treatment of choice in vWD patients unresponsive to desmopressin (DDAVP). However, only few studies on their clinical use are available so far. The main objective of this study was to retrospectively evaluate the clinical efficacy of a highly purified, doubly virus-inactivated FVIII/vWF concentrate with a high content of FVIII/vWF (Fanhdi). Twenty-two patients with congenital vWD have been treated from 1999 to 2001 at eight specialized centres belonging to the Italian Association of Hemophilia Centers (AICE). Ten males and 12 females, median age 28.5 years, range 5-70 years) had type 3 vWD (six cases), DDAVP-unresponsive type 1 (nine cases) and type 2B (seven cases). The study drug was given to stop or prevent 12 bleeding episodes or to prevent excessive bleeding during 14 surgical or invasive procedures. Overall, replacement therapy with the concentrate showed an excellent to good clinical efficacy in 92% of bleeding episodes and in 93% of surgical procedures. No adverse events occurred during 1,601 infusions, accounting for a total of 304,500 IU of FVIII:C administered. These results confirm the efficacy and safety of this concentrate in the management of bleeding episodes and in the prevention of excessive bleeding during major and minor surgery.