Analysis of 52 240 source plasma donors of convalescent COVID-19 plasma: Sex, ethnicity, and age association with initial antibody levels and rate of dissipation.

Background: COVID-19 convalescent plasma (CCP) was approved under emergency authorization to treat critically ill patients with COVID-19 in the United States in 2020. We explored the demographics of donors contributing plasma for a hyperimmune, plasma-derived therapy to evaluate factors that may be associated with anti-SARS-CoV-2 antibody response variability and, subsequently, antibody titers.

Study Design: An electronic search of CCP donors was performed across 282 US plasma donation centers.

Modelling the concentration of anti-SARS-CoV-2 immunoglobulin G in intravenous immunoglobulin product batches.

Background: Plasma-derived intravenous immunoglobulin (IVIg) products contain a dynamic spectrum of immunoglobulin (Ig) G reactivities reflective of the donor population from which they are derived. We sought to model the concentration of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG which could be expected in future plasma pool and final-product batches of CSL Behring's immunoglobulin product Privigen.

Study Design And Methods: Data was extracted from accessible databases, including the incidence of coronavirus disease 2019 and SARS-CoV-2 vaccination status, antibody titre in convalescent and vaccinated groups and antibody half-life.

Hepatitis A Virus Incidence Rates and Biomarker Dynamics for Plasma Donors, United States.

The United States is currently affected by widespread hepatitis A virus (HAV) outbreaks. We investigated HAV incidence rates among source plasma donors in the United States since 2016. Serial donations from HAV-positive frequent donors were analyzed for common biologic markers to obtain a detailed picture of the course of infection.

Determination of neutralising anti-SARS-CoV-2 antibody half-life in COVID-19 convalescent donors.

Despite the burgeoning field of coronavirus disease-19 (COVID-19) research, the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralising antibodies remains unclear. This study validated two high-throughput immunological methods for use as surrogate live virus neutralisation assays and employed them to examine the half-life of SARS-CoV-2 neutralising antibodies in convalescent plasma donations made by 42 repeat donors between April and September 2020. SARS-CoV-2 neutralising antibody titres decreased over time but typically remained above the methods' diagnostic cut-offs.

Hepatitis E virus: Efficacy of pasteurization of plasma-derived VWF/FVIII concentrate determined by pig bioassay.

Background: Hepatitis E virus (HEV) is the leading cause of acute hepatitis throughout the world. Increasing blood component transfusion-associated HEV infections highlight the need for reliable virus inactivation procedures for plasma derivatives from pooled plasma donations.

Study Design And Methods: An animal infection study was conducted to evaluate the efficiency of HEV inactivation by pasteurization during the manufacturing process of the von Willebrand Factor/Factor VIII (VWF/FVIII) concentrate Haemate P/Humate-P (CSL Behring, Marburg, Germany).

Impact of the isoelectric point of model parvoviruses on viral retention in anion-exchange chromatography.

Anion-exchange chromatography (AEX) is used in the downstream purification of monoclonal antibodies to remove impurities and potential viral contamination based on electrostatic interactions. Although the isoelectric point (pI) of viruses is considered a key factor predicting the virus adsorption to the resin, the precise molecular mechanisms involved remain unclear. To address this question, we compared structurally homologous parvoviruses that only differ in their surface charge distribution.

Nanofiltration as a robust method contributing to viral safety of plasma-derived therapeutics: 20 years' experience of the plasma protein manufacturers.

Background: Nanofiltration entails the filtering of protein solutions through membranes with pores of nanometric sizes that have the capability to effectively retain a wide range of viruses.

Study Design And Methods: Data were collected from 754 virus validation studies (individual data points) by Plasma Protein Therapeutics Association member companies and analyzed for the capacity of a range of nanofilters to remove viruses with different physicochemical properties and sizes. Different plasma product intermediates were spiked with viruses and filtered through nanofilters with different pore sizes using either tangential or dead-end mode under constant pressure or constant flow.

Viral contamination in biologic manufacture and implications for emerging therapies.

Recombinant protein therapeutics, vaccines, and plasma products have a long record of safety. However, the use of cell culture to produce recombinant proteins is still susceptible to contamination with viruses. These contaminations cost millions of dollars to recover from, can lead to patients not receiving therapies, and are very rare, which makes learning from past events difficult.

Manufacturing of plasma-derived C1-inhibitor concentrate for treatment of patients with hereditary angioedema.

Replacement therapy with plasma-derived C1-inhibitor (C1-INH) has been used for decades to treat patients with hereditary angioedema (HAE) with C1-INH deficiency. This article reviewed the rationale for using C1-INH replacement therapy in patients with HAE and the process of manufacturing plasma-derived C1-INH. The manufacture of C1-INH is an involved and carefully monitored process that includes screening and selection of prospective donors, the collection of source plasma, and purification with dedicated pathogen reduction steps.

Choice of parvovirus model for validation studies influences the interpretation of the effectiveness of a virus filtration step.

Different parvoviruses are used interchangeably as models in validation studies to demonstrate effective clearance of small viruses by filtration in the manufacturing of biotherapeutics. The aim of these experiments was to determine if filtration of different parvoviruses (canine parvovirus [CPV], minute virus of mice [MVM], and porcine parvovirus [PPV]) results in similar virus retention. While filtration with a Planova™ 20 N filter (mean pore size: 19 ± 2 nm) completely removed PPV and MVM from the filtrate (mean log reduction factors [LRFs] ≥5.

Characterization of a quasi-enveloped, fast replicating hepevirus from fish and its use as hepatitis E virus surrogate.

Hepatitis E virus (HEV) is an emerging concern for the safety of plasma-derived medicinal products. The lack of an efficient cell culture system hampers the studies on HEV biology as well as validation studies to test the capacity of virus reduction steps to clear HEV. Hence, a surrogate hepevirus that can efficiently replicate in cell culture is needed.

Effective inactivation of a wide range of viruses by pasteurization.

Background: Careful selection and testing of plasma reduces the risk of blood-borne viruses in the starting material for plasma-derived products. Furthermore, effective measures such as pasteurization at 60°C for 10 hours have been implemented in the manufacturing process of therapeutic plasma proteins such as human albumin, coagulation factors, immunoglobulins, and enzyme inhibitors to inactivate blood-borne viruses of concern. A comprehensive compilation of the virus reduction capacity of pasteurization is presented including the effect of stabilizers used to protect the therapeutic protein from modifications during heat treatment.

Low hepatitis E virus RNA prevalence in a large-scale survey of United States source plasma donors.

Background: Hepatitis E virus (HEV) is a small, nonenveloped, single-stranded, RNA virus of emerging concern in industrialized countries. HEV transmission through transfusion of blood components has been reported, but not via plasma-derived medicinal products (PDMPs) manufactured with virus inactivation and/or removal steps. This study aimed to determine the prevalence of HEV among US source plasma donors.

Pathogen safety and characterisation of a highly purified human alpha-proteinase inhibitor preparation.

Alpha-proteinase inhibitor (API) deficiency is a genetic condition predisposing to emphysema. Respreeza/Zemaira, a therapeutic preparation of API, is prepared from human plasma. This article describes the purity and stability of Respreeza/Zemaira and the capacity of virus and prion reduction steps incorporated into its manufacturing process.

Pathogen safety of a pasteurized four-factor human prothrombin complex concentrate preparation using serial 20N virus filtration.

Background: Beriplex P/N/Kcentra/Coaplex/Confidex is a four-factor human prothrombin complex concentrate (PCC). Here, we describe the pathogen safety profile and biochemical characteristics of an improved manufacturing process that further enhances the virus safety of Beriplex P/N.

Study Design And Methods: Samples of product intermediates were spiked with test viruses, and prions were evaluated under routine production and robustness conditions of the scale-down version of the commercial manufacturing process for their capacity to inactivate or remove pathogens.

Robustness of nanofiltration for increasing the viral safety margin of biological products.

In this study, the virus-removal capacity of nanofiltration was assessed using validated laboratory scale models on a wide range of viruses (pseudorabies virus; human immunodeficiency virus; bovine viral diarrhea virus; West Nile virus; hepatitis A virus; murine encephalomyocarditis virus; and porcine parvovirus) with sizes from 18 nm to 200 nm and applying the different process conditions existing in a number of Grifols' plasma-derived manufacturing processes (thrombin, α1-proteinase inhibitor, Factor IX, antithrombin, plasmin, intravenous immunoglobulin, and fibrinogen). Spiking experiments (n = 133) were performed in process intermediate products, and removal was subsequently determined by infectivity titration. Reduction Factor (RF) was calculated by comparing the virus load before and after nanofiltration under each product purification condition.

Characterization of Thrombate III®, a pasteurized and nanofiltered therapeutic human antithrombin concentrate.

Thrombate III(®) is a highly purified antithrombin concentrate that has been used by clinicians worldwide for more than two decades for the treatment of hereditary antithrombin deficiency. The manufacturing process is based on heparin-affinity chromatography and pasteurization. To modernize the process and to further enhance the pathogen safety profile of the final product, despite the absence of infectious disease transmission, a nanofiltration step was added.

Prion removal capacity of plasma protein manufacturing processes: a data collection from PPTA member companies.

Background: The variant Creutzfeldt-Jakob disease incidence peaked a decade ago and has since declined. Based on epidemiologic evidence, the causative agent, pathogenic prion, has not constituted a tangible contamination threat to large-scale manufacturing of human plasma-derived proteins. Nonetheless, manufacturers have studied the prion removal capabilities of various manufacturing steps to better understand product safety.

Pathogen safety profile of a 10% IgG preparation manufactured using a depth filtration-modified process.

Gamunex®-C is a highly purified liquid 10% IgG preparation manufactured by a process that includes caprylate precipitation and incubation, and chromatography steps. In the original process, caprylate precipitation was followed by cloth filtration to remove impurities. The highly porous cloth filter has since been replaced with a tight depth filter.

Inactivation and neutralization of parvovirus B19 Genotype 3.

Background: Parvovirus B19 (B19V) is a common contaminant of human plasma donations. Three B19V genotypes have been defined based on their DNA sequence. Reliable detection of Genotype 3 DNA has proved problematic because of unexpected sequence variability.

Contribution to safety of immunoglobulin and albumin from virus partitioning and inactivation by cold ethanol fractionation: a data collection from Plasma Protein Therapeutics Association member companies.

Background: Virus removal by partitioning into different fractions during cold ethanol fractionation has been described by several authors, demonstrating that cold ethanol fractionation can provide significant contribution to virus removal, even in those cases where virus removal is limited and must be supported by additional measures for virus inactivation during further processing.

Study Design And Methods: Plasma Protein Therapeutics Association (PPTA) member companies collected and evaluated 615 studies on virus removal by the steps of the cold ethanol fractionation process. The studies describe the precipitation and separation of Fraction (F)III or FI/III in the immunoglobulin fractionation process and precipitation and separation of FII/III, FI/II/III, and FIV/IV in the albumin fractionation process.

Studies of Glu-416 variants of beta-galactosidase (E. coli) show that the active site Mg(2+) is not important for structure and indicate that the main role of Mg (2+) is to mediate optimization of active site chemistry.

Variants of beta-galactosidase with Valine and with Glutamine replacing Glutamate-416 did not have a Mg(2+) bound at the active site even at high Mg(2+) concentrations (200 mM). They had low catalytic activity and the pH profiles were very different from those of the native enzyme. In addition, substrates, substrate analogs, transition state analogs and galactose bound very poorly.