Prion-removal capacity of chromatographic and ethanol precipitation steps used in the production of albumin and immunoglobulins

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.

Global immunoglobulin supply: steaming towards the iceberg?

PURPOSE OF REVIEW

This review describes how plasma is sourced for fractionation into plasma-derived medicinal products (PDMPs), such as immunoglobulin (Ig) together with differences between plasma from whole blood (recovered plasma) and from plasmapheresis (source plasma) in terms of global plasma supply. Specific areas of growth in immunoglobulin use are identified alongside novel therapies, which may reduce demand for some immunoglobulin indications.

RECENT FINDINGS

There has been a 6--8% annual growth in immunoglobulin use. Secondary immunodeficiency alongside improved recognition and diagnosis primary immunodeficiency disorders are drivers whereas the novel neonatal Fc receptor inhibitors (FcRni) may reduce demand for some immunomodulatory indications.

SUMMARY

There is a significant geographical imbalance in global supply of plasma with 65% collected in the United States. This results in a dependency of other countries on United States supply and argues for both more plasma supply and greater regionally balanced plasma collection. In addition, progress towards a transparent, regulated and well tolerated framework for the coexistence of unpaid and compensated plasma donations is needed as unpaid donation will not be sufficient. These discussions should be informed by the needs of patients for this life-saving therapy, the care of donors and the safety of plasma and PDMPs.

Potential BSE risk posed by the use of ruminant collagen and gelatine in feed for non-ruminant farmed animals

EFSA was requested to estimate the cattle bovine spongiform encephalopathy (BSE) risk (C-, L- and H-BSE) posed by ruminant collagen and gelatine produced from raw material fit for human consumption, or from material classified as Category 3 animal by-products (ABP), to be used in feed intended for non-ruminant animals, including aquaculture animals. Three risk pathways (RP) were identified by which cattle could be exposed to ruminant feed cross-contaminated with ruminant collagen or gelatine: 1) recycled former foodstuffs produced in accordance with Regulation (EC) No 853/2004 (RP1), 2) technological or nutritional additives or 3) compound feed, produced either in accordance with Regulation (EC) No 853/2004 (RP2a) or Regulation (EU) No 142/2011 (RP2b). A probabilistic model was developed to estimate the BSE infectivity load measured in cattle oral ID 50 (CoID 50)/kg, in the gelatine produced from the bones and hide of one infected animal older than 30 months with clinical BSE (worst-case scenario). The amount of BSE infectivity (50th percentile estimate) in a member state (MS) with negligible risk status was 7.6 × 10-2 CoID 50/kg, and 3.1 × 10-4 CoID 50/kg in a MS with controlled risk status. The assessment considered the potential contamination pathways and the model results (including uncertainties) regarding the current epidemiological situation in the EU and current statutory controls. Given the estimated amount of BSE infectivity to which cattle would be exposed in a single year, and even if all the estimated undetected BSE cases in the EU were used for the production of collagen or gelatine (either using raw materials fit for human consumption or Category 3 ABP raw materials), it was concluded that the probability that no new case of BSE in the cattle population would be generated through any of the three RP is 99-100% (almost certain).

Biological Safety of a Highly Purified 10% Liquid Intravenous Immunoglobulin Preparation from Human Plasma

Background

A highly purified 10% liquid intravenous immunoglobulin, IQYMUNE^®, has been developed using an innovative manufacturing process including an affinity chromatography step for the removal of anti-A and anti-B hemagglutinins.

Objectives

The pathogen (viruses and prions) clearance efficacy of the manufacturing process and its robustness for critical steps were investigated.

Methods

The manufacturing process of IQYMUNE^® includes two dedicated complementary virus reduction steps: solvent/detergent (S/D) treatment and 20 nm nanofiltration as well as two contributing steps, namely caprylic acid fractionation and anion-exchange chromatography. The clearance capacity and robustness of these steps were evaluated with a wide range of viruses (enveloped and non-enveloped) and with a model of human transmissible spongiform encephalopathies (TSEs).

Results

The IQYMUNE^® manufacturing process demonstrated a high and robust virus removal capacity with global reduction factors (RFs) of relevant and model viruses: ≥14.8 log₁₀ for human immunodeficiency virus type 1 (HIV-1), ≥16.9 log₁₀ for bovine viral diarrhoea virus (BVDV)/Sindbis virus, ≥15.7 log₁₀ for pseudorabies virus (PRV), ≥12.8 log₁₀ for encephalomyocarditis virus (EMCV) and 11.0 log₁₀ for porcine parvovirus (PPV). The process also exhibited a high removal capacity for the TSE agent with an overall RF of ≥12.9 log₁₀ due to the complementary actions of the caprylic acid fractionation, anion-exchange chromatography and nanofiltration steps.

Conclusion

Data from virus and prion clearance studies fully support the high safety profile of IQYMUNE^®, with a minimal reduction of 11 log₁₀ for the smallest and most resistant non-enveloped virus, PPV, and more than 12 log₁₀ for the TSE agent.

The Perioperative Use of Albumin

Human serum albumin (HSA) is the predominant product of hepatic protein synthesis and one of the more abundant plasma proteins. HSA is a monomeric multidomain macromolecule, representing the main determinant of plasma oncotic pressure and the main modulator of fluid distribution between body compartments. HSA displays an essential role in maintaining the integrity of the vascular barrier. HSA is the most important antioxidant capacity of human plasma, in addition to its ability to protect the body from the harmful effects of heavy metals such as iron and copper and reduce their ability to produce reactive oxygen radicals. HSA is the main depot for nitric oxide (NO) transport in the blood. HSA represents the main carrier for fatty acids, affects pharmacokinetics of many drugs, and provides the metabolic modification of some drugs and displays pseudo-enzymatic properties. HSA has been widely used successfully for more than 50 years in many settings of perioperative medicine including hypovolemia, shock, burns, surgical blood loss, sepsis, and acute respiratory distress syndrome (ARDS). Recently, the use of HSA has shown a promising neuroprotective effect in patients with subarachnoid hemorrhage. The most recent evidence-based functions and uses of HSA in the perioperative period are reviewed in this chapter.

Immunoglobulin replacement therapy for primary immunodeficiencies

Exogenous antibody therapy to protect patients against infections and toxins is over 100 years old, yet progress continues to be made in the manufacture, administration and application of this type of immunotherapy, known as therapeutic human immunoglobulin. For the majority of patients with primary immunodeficiencies, immunoglobulin replacement is the only life-saving therapy and treatment is life-long, since the vast majority of primary immunodeficiency patients have primary antibody failure. Successful treatment depends on multiple factors: the availability of products, the type of immunodeficiency and any comorbidities of the individual patient. Essential components include long-term follow-up, regular monitoring and a close relationship between the patient and the multidisciplinary clinical immunology team. In this article, we describe the current immunoglobulin products and the types of adverse reactions. We provide evidence for clinical decision-making regarding dosing, route of administration and location of therapy, highlighting current ‘best practice’ recommendations.

Albumin—Beyond Fluid Replacement in Cardiopulmonary Bypass Surgery

Maintaining vascular barrier competence, preventing interstitial edema, and keeping microcirculation intact is crucial to achieve an optimal outcome in cardiopulmonary bypass surgery (CPB). Blood contact with roller pumps and foreign surfaces during CPB induces shear stress and a pressure drop across the pump boot that leads to transient systemic activation of the inflammatory and hemostatic systems. Moreover, patients after CPB often need volume resuscitation using the smallest possible amount of colloid solution because of fluid overload. For this purpose, human-derived albumin may be preferred over synthetic colloids because CPB priming with albumin preserves oncotic pressure, prevents platelet adhesion, and likely induces less consumption of coagulation factors. In patients with increased bleeding or renal failure, albumin is a safe alternative because of its minimal side effects. Large, randomized clinical trials comparing the benefit of albumin versus other fluids are warranted in the future to define albumin’s distinct role in select high-risk surgical populations.

A review of the use of human albumin in burn patients

This review article examines the use of human albumin (HA) in burn treatment. Generally, there are two scenarios where HA may be administered: acutely as a volume expander during burn shock resuscitation and chronically following resuscitation to correct hypoalbuminemia. Although colloids were the cornerstone of the earliest burn resuscitation formulas, HA was in fact rarely used. More recently however, with the recognition of fluid creep, HA usage during resuscitation has increased. Animal studies demonstrate that during acute fluid resuscitation, administration of colloids, including albumin (ALB), have no ability to arrest the formation of burn wound edema, but they do reduce edema formation in the nonburn soft tissues and help preserve intravascular volume and reduce resuscitation fluid requirements with no apparent increase in extravascular water accumulation in the lung. Human studies suggest that immediate use of ALB during acute resuscitation achieves adequate resuscitation using a lower total overall volume requirement, transiently provides better maintenance of intravascular volume and cardiac output, produces less overall edema gain than crystalloid resuscitation alone but may be associated with increased extravascular lung water accumulation during the first postburn week. However, many questions remain unanswered, and modern, large-scale prospective studies are desperately needed. Maintenance of normal serum ALB levels through continuous supplementation of HA following burn resuscitation is even less well understood. Although this approach makes physiologic sense, the limited amount of available data from human burn studies reveal that chronic ALB supplementation is expensive and may not result in any major clinical benefits. Again, modernized prospective studies are greatly needed in this area.

Human Albumin Solution Resuscitation in Severe Sepsis and Septic Shock

There has been a recent resurgence of interest in the use of human albumin solution (HAS) for the resuscitation of critically ill patients. In particular, it may be beneficial for patients with severe sepsis and septic shock. We outline the evidence for the biological plausibility of this effect, perform a meta-analysis of randomised controlled trials comparing the effect of HAS with other fluid resuscitation on mortality in this group of patients and discuss the likely contribution of recently completed trials in this area. We included nine trials of 1,435 patients in the meta-analysis. Although HAS resuscitation was associated with a trend to lower mortality (relative risk 0.90, 95% confidence interval 0.79–1.02), we found that most trials reported to date are small and of variable methodological quality. The questions of a potential differential effect of dose on outcome and the pharmacological variability of HAS products have not been adequately addressed to date. We conclude that the routine administration of HAS to patients with severe sepsis and septic shock is difficult to justify on the basis of current knowledge.

Removal of TSE agent from plasma products manufactured in the United Kingdom

BACKGROUND AND OBJECTIVES

The outbreak of vCJD in the UK leads to concern regarding the potential for human-to-human transmission of this agent. Plasma-derived products such as albumin, immunoglobulin and coagulation factors were manufactured by BPL from UK plasma up until 1999 when a switch to US plasma was made. In the current study, the capacity of various manufacturing processes that were in use both prior to and after this time to remove the TSE agent was tested.

MATERIALS AND METHODS

Small-scale models of the various product manufacturing steps were developed. Intermediates were spiked with scrapie brain extract and then further processed. Samples were assayed for the abnormal form of prion protein (PrP(SC) ) by Western blotting, and the reduction in the amount of scrapie agent determined.

RESULTS

Many of the manufacturing process steps produced significant reduction in the scrapie agent. Particularly effective were steps such as ethanol fractionation, depth filtration, ion-exchange and copper chelate affinity chromatography. Virus retentive filters, of nominal pore size 15 or 20 nm, removed >3 log. The total cumulative reduction capacity for individual products was estimated to range from 7 to 14 log. In the case of factor VIII (8Y), the total removal was limited to 3 log.

CONCLUSION

All the processes showed a substantial capacity to remove the TSE agent. However, this was more limited for the intermediate purity factor VIII 8Y which included fewer manufacturing steps.

Information for healthcare providers on general features of IGIV with emphasis on differences between commercially available products

OBJECTIVE

Intravenous immunoglobulin (IGIV) has provided an essential replacement therapy for primary and secondary immunodeficiencies patients and prophylaxis of infectious diseases in them. It is also used in several autoimmune and chronic inflammatory disorders. An overview of IGIV with information on several commercially available IGIV products is discussed.

DATA SOURCES

Medline databases and literature provided by the manufacturer for each product presented in the manuscript.

STUDY SELECTION

From the vast body of information on IGIV, only those studies were selected that were pertinent to general features of IGIV (as presented below) or information provided by the manufacturer that facilitated comparing one product to the other.

DATA EXTRACTION

Data was extracted on production, and purification procedures, removal of infectious agents, physical and biochemical properties and issues of safety. Data was extracted only for products available in the US.

DATA SYNTHESIS

IGIV is prepared using pooled plasma. The purification of IGIV is a complex and multi-step process. There is a reciprocal relationship between the purity of IgG in the product and the recovery rate from the total plasma. It is quite possible that some of the biological mediators of the inflammatory and immune systems may be present in trace amounts. Screening and removal of blood borne pathogens is necessary and there are several different techniques available. The specifics of the administration are often variable and no consistent pattern or protocol has been used. When limited dosages are required IGIV may be administered subcutaneously. The side effects associated with IGIV are usually mild and self-limiting.

CONCLUSION

There are differences in products produced by different manufacturers. The current data does not provide sufficient detail or information to be able to make specific recommendations for the use of a given commercial preparation in a specific disease state. The use of IGIV is associated with certain common and uncommon side effects. The identification of risk factors that might predispose a patient to developing them have been studied and reported. In choosing a IGIV preparation the user may avoid features that may predispose to certain side effects. Equally important is monitoring of patients during and after the IGIV therapy.

Susceptibility of cell substrates to PrPSc infection and safety control measures related to biological and biotherapeutical products

Concerns over the potential for infectious prion proteins to contaminate human biologics and biotherapeutics have been raised from time to time. Transmission of the pathogenic form of prion protein (PrP(Sc)) through veterinary vaccines has been observed, yet no human case through the use of vaccine products has been reported. However, iatrogenic transmissions of PrP(Sc) in humans through blood components, tissues and growth hormone have been reported. These findings underscore the importance of reliable detection or diagnostic methods to prevent the transmission of prion diseases, given that the number of asymptomatic infected individuals remains unknown, the perceived incubation time for human prion diseases could be decades, and no cure of the diseases has been found yet. A variety of biochemical and molecular methods can selectively concentrate PrP(Sc) to facilitate its detection in tissues and cells. Furthermore, some methods routinely used in the manufacturing process of biological products have been found to be effective in reducing PrP(Sc) from the products. Questions remain unanswered as to the validation criteria of these methods, the minimal infectious dose of the PrP(Sc) required to cause infection and the susceptibility of cells used in gene therapy or the manufacturing process of biological products to PrP(Sc) infections. Here, we discuss some of these challenging issues.

Manufacture of plasma-derived products in France and measures to prevent the risk of vCJD transmission: Precautionary measures and efficacy of manufacturing processes in prion removal

The emergence of the variant Creutzfeldt-Jakob disease in the mid 1990s soon raised concerns about its possible transmission through the use of blood and plasma-derived medicinal products. A risk analysis approach was initiated by health authorities, based on updated scientific knowledge and precautionary measures were implemented in France and other countries for the management of this new possible risk. Assessment of the vCJD risk is based on epidemiology and estimates of the number of potential cases in the future, on blood infectivity data from models of transmissible spongiform encephalopathies and on data from studies of the capacity of manufacturing processes to remove the agent, should it be present in the plasma of infected donors. The transmission of vCJD by non leukocyte-depleted labile blood components has recently been confirmed. There have been no reports of cases associated with the use of plasma-derived products and the scientific data, and risk analyses for those plasma products, which are of the greatest therapeutic interest, support their safety with respect to this transmission risk. The precautionary measures applied in France and the data contributing to the risk assessment of plasma products are reviewed and updated in the present paper. The uncertainties, which remain, are also addressed and discussed, as well as the ongoing research and developments in this area.

Investigation of prion removal/inactivation from chromatographic gel

BACKGROUND AND OBJECTIVES

Concerns about the potential for prions to be retained on chromatography gels during the manufacture of plasma products prompted development of an investigational strategy for detecting infectious prions bound to gels. The objective was to firstly examine methods of implanting gels intracerebrally (IC) in mice, then to examine prion cleaning from a scaled-down version of the DEAE Sepharose column used in a production process to fractionate immunoglobulins and albumin from human plasma.

MATERIALS AND METHODS

The study consisted of two parts: (i) the pathophysiological impact by IC inoculation of ground gel beads was compared to whole gel beads; (ii) the feedstreams to two DEAE Sepharose columns were spiked with scrapie ME7. One column was subjected to the protein loading and elution portions of the chromatography cycle. The other column was subjected to the full cycle of protein loading and elution, followed by regeneration with 0.5 m NaCl, 1 m NaOH and solvent/detergent washes. The gels were unpacked and bioassayed by IC implantation in mice to quantify infectivity.

RESULTS

IC inoculation of ground gel beads resulted in unacceptably high pathological impact in the mice whereas whole gel bead inoculation resulted in a reduced affect. Accordingly, the whole bead model system was used to assess prion removal/inactivation from chromatography gels at the pre- and postcleaning stage of the chromatography cycle. Infectious prions were detected on the DEAE Sepharose prior to the cleaning step; however, the gel cleaning cycle reduced infectivity by a log reduction factor (LRF) of > or = 2.75, thus reducing infectivity by bioassay to below detectable limits.

CONCLUSIONS

A model system for assessment of prion inactivation/removal from chromatography gels has been established. Spiked prion infectivity does bind to DEAE Sepharose gel; however, the cleaning cycle removed infectivity to levels below that detectable by bioassay.