Publications by authors named "Rigsby P"

A candidate preparation of the fully human anti-tumour necrosis factor (TNF) monoclonal antibody golimumab was formulated and lyophilised at the Medicines and Healthcare products Regulatory Agency (MHRA) prior to evaluation in a collaborative study for its suitability to serve as a World Health Organization (WHO) International Standard (IS)/European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for the potency assay of golimumab.

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Previously established World Health Organization (WHO) International Standards (IS) for anti-HPV16 and HPV18 antibodies are used to harmonize results across human papillomavirus (HPV) serology assays. Here, we present an international collaborative study to establish ISs for antibodies against HPV6 (NIBSC code 19/298), HPV11 (20/174), HPV31 (20/176), HPV33 (19/290), HPV45 (20/178), HPV52 (19/296) and HPV58 (19/300). The candidate standards were prepared using sera from naturally infected individuals.

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Antigen identity, quantity and integrity are key factors to be evaluated as part of consistency testing of tetanus vaccines. Here we have developed a monoclonal antibody sandwich ELISA to measure the relative amount and quality of tetanus toxoid (TTxd) in human and animal tetanus vaccines. The ELISA is highly specific, has good dilutional linearity, and is suitable for detecting TTxd in a range of different products.

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An international collaborative study was jointly organised by the World Health Organization (WHO) and the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish the WHO 3 International Standard (IS) for Prekallikrein activator (PKA) and European Pharmacopoeia (Ph. Eur.) PKA in albumin Biological Reference Preparation (BRP) batch 7.

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Two candidate International Standards for meningococcal capsular group W and Y (MenW and MenY, respectively) polysaccharides were assessed for their suitability as quantitative standards in various physicochemical assays. The study was designed to evaluate the intended purpose of these standards, namely, to standardize the quantification of the respective polysaccharide content in meningococcal polysaccharide and conjugate vaccines and their intermediate components. Twelve laboratories from eleven different countries participated in the collaborative study of candidate preparations for International Standards for MenW and MenY polysaccharide (coded 16/152 and 16/206, respectively).

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This publication describes the outcome of a project to develop a replacement European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for Human tetanus immunoglobulin (TIg) as well as for the World Health Organization (WHO) International Standard (IS) for Tetanus Immunoglobulin, Human.

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An international hybrid meeting held 21-22 June 2023 in Ottawa, Canada brought together regulators, scientists, and industry experts to discuss a set of principles and best practices in the development and implementation of standards. Although the use of international standards (ISs) and international units (IUs) has been an essential part of ensuring human and animal vaccine quality in the past decades, the types and uses of standards have expanded with technological advances in manufacture and testing of vaccines. The needs of stakeholders are evolving in response to the ever-increasing complexity, diversity, and number of vaccine products as well as increasing efforts to replace animal-based potency tests with in vitro assays that measure relevant quality attributes.

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This publication describes the outcome of a project to develop a replacement European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for Human tetanus immunoglobulin (TIg) as well as for the World Health Organization (WHO) International Standard (IS) for Tetanus Immunoglobulin, Human.

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Metrology - the science of measure - is a subject few biological scientists are taught about in their training to their detriment; the application of simple standardization processes to everyday working practices provides confidence in data and reproducibility over distance and time. This method demonstrates how to standardize a core laboratory experiment used widely in hemostasis research and clinical practice, specifically, measuring responses to the platelet collagen receptor (glycoprotein [GP]VI) agonist collagen-related peptide, cross-linked (CRP-XL) by light transmission aggregometry (LTA). Using this approach will ensure intra-lab reproducibility and inter-lab harmonization, regardless of agonist stock or supplier.

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At present, quality control of diphtheria vaccines by both manufacturers and national control laboratories relies heavily on in vivo assays to confirm potency. As part of the VAC2VAC project we have developed a monoclonal antibody (mAb) enzyme-linked immunosorbent assay (ELISA) to measure the relative amount and quality of diphtheria toxoid (DTxd) in diphtheria-tetanus based vaccines and believe this test has the potential to play a key role in a control strategy no longer including an in vivo potency test. The mAb ELISA is highly specific, has good dilutional linearity, and is suitable for detecting DTxd in a range of different human vaccine products.

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For the batch release of vaccines, potency release assays are required. Non-animal in vitro tests have numerous advantages and are preferred; however, several vaccines are still released using in vivo assays. Their major drawback is the inherent variability with its practical implications.

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Determination of the potency of a vaccine is critical to ensuring that an appropriate dose is delivered, lot-to-lot consistency is maintained, and that the formulation is stable over the life of the vaccine. The potency of inactivated influenza vaccines is determined routinely by the Single Radial Immunodiffusion (SRID) assay. A number of alternative potency assays have been proposed and have been under evaluation in recent years.

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Chromogenic assay discrepancies were reported at General European Official Medicines Control Laboratories Network (GEON) meetings by laboratories testing FVIII-products. The objectives of the present investigation were to carry out a controlled collaborative study to examine these reports and to delineate the reasons for these discrepancies by assessing affected and unaffected FVIII products. The laboratories followed a strict study protocol, which included assessing their own individual observed factor X (FX) activation times, i.

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The International Standard for Diphtheria Antitoxin Equine is essential for the standardisation of assays used to determine the potency of therapeutic diphtheria antitoxin products produced from equine serum. This paper describes the production and characterization of the 2nd International Standard for Diphtheria Antitoxin Equine and its calibration in International Units. Calibration was performed by toxin neutralization test in vivo and in vitro (Vero cell assay), and potency was expressed relative to the 1st International Standard to ensure continuity of the International Unit.

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Reliable and accurate quantification of cell-associated HIV DNA (CA HIV DNA) is critical for early infant diagnosis, clinical management of patients under therapy, and to inform new therapeutics efficacy. The present study assessed the variability of CA HIV DNA quantification obtained from various assays and the value of using reference materials to help harmonize the measurements. Using a common set of reagents, our multicenter collaborative study highlights significant variability of CA HIV DNA quantification and lower limit of quantification across assays.

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Objectives: To evaluate and calibrate two candidate preparations for the 4th International Standard for Ferritin (Human, Recombinant) (codes: 19/118 and 19/162) against the 3rd International Standard for Ferritin (Human, Recombinant) (code: 94/572), and three serum commutability samples in an international collaborative study involving 12 laboratories in nine countries.

Methods: Eleven of the 12 participating laboratories performed Ferritin quantitation using automated assay platforms and one laboratory used a manual ELISA kit.

Results: There was better overall agreement between all laboratories and between assay methods for the potency of preparation 19/118 than for preparation 19/162.

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Several Bevacizumab products are approved for clinical use, with many others in late-stage clinical development worldwide. To aid the harmonization of potency assessment across different Bevacizumab products, the first World Health Organization (WHO) International Standard (IS) for Bevacizumab has been developed. Two preparations of a Bevacizumab candidate and comparator were assessed for their ability to neutralize and bind vascular endothelial growth factor (VEGF) using different bioassays and binding assays in an international collaborative study.

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Background: Factor XIII (FXIII)-B subunit measurements are required for the diagnosis and characterization of the type of FXIII deficiency. Furthermore, therapy for FXIII-A deficiency with recombinant FXIII (rFXIII-A) relies on available FXIII-B.

Objective: To carry out a collaborative study to calibrate and assign value to the current WHO 1st International Standard (IS) FXIII Plasma for Total FXIII-B subunit, relative to locally collected normal plasma pools.

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Measurement of Thrombin-activatable fibrinolysis inhibitor (TAFI) in human plasma is dependent on reproducible assays. To date, standards for measuring TAFI are frequently calibrated relative to pooled normal human plasma and arbitrarily assigned a potency of 100% TAFI, despite variation in TAFI concentrations between plasma pools. Alternatively, TAFI calibrators can be assigned a value in SI units but the approach used for value assignment is not consistent and furthermore, if purified TAFI is used to determine TAFI concentration in plasma, may be adversely affected by matrix effects.

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Article Synopsis
  • * The WHO established an International Standard (IS) for Adalimumab to ensure consistent quality, safety, and efficacy across products, which is key for their long-term success.
  • * A collaborative international study demonstrated that using the IS reduced variability in bioassays, enhancing the precision of potency estimates and supporting the use of the IS for bioassay validation and global harmonization of adalimumab products.
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A joint World Health Organization (WHO) - European Directorate for the Quality of Medicines & HealthCare (EDQM) study was run to calibrate the WHO 5th International Standard (IS) for Blood Coagulation Factor IX (FIX), Concentrate, and European Pharmacopoeia (Ph. Eur.) Human Coagulation Factor IX concentrate Biological Reference Preparation (BRP) Batch 3.

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The calibration of thrombin products relies on the World Health Organization (WHO) 2nd International Standard (IS) for Thrombin (01/580) which defines the international unit (IU) for thrombin potency. With stocks of the 2nd IS (01/580) running low, an international collaborative study was organized to calibrate a replacement. Twenty laboratories from 13 countries took part in the study and measured the potency of two candidate replacement standards (coded 01/578 and 19/188) relative to the 2nd IS.

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Potency of meningococcal polysaccharide-protein conjugate vaccines relies on the polysaccharide content to prevent meningitis. NIBSC, as the official national control laboratory in UK, analysed ten different mono- and multi-meningococcal conjugate vaccines, using established International Standards for meningococcal serogroups A, C, W, Y and X, by resorcinol or HPAEC-PAD assay. Most saccharide contents were within ±20% of their claimed content for licensure with taking different O-acetylation levels into consideration, with only MenC content in two vaccines below (by 60% and 54%) the labelled value, however, previous study showed different dosage was not necessarily correlated to the immunogenicity of those vaccines.

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Immunomodulatory therapeutics such as monoclonal antibodies (mAb) carry an inherent risk of undesired immune reactions. One such risk is cytokine release syndrome (CRS), a rapid systemic inflammatory response characterized by the secretion of pro-inflammatory cytokines from immune cells. It is crucial for patient safety to correctly identify potential risk of CRS prior to first-in-human dose administration.

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Clostridioides difficile (C. difficile) is the most common cause of nosocomial antibiotic associated diarrhoea. The incidence of C.

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