Establishment of the 1st Chinese national standard for CA6 neutralizing antibody

Coxsackievirus A6 (CA6) is one of the major causative agents of herpangina and hand-foot-mouth disease (HFMD). Since 2008, CA6 has circulated widely around the world. Especially in Asia-Pacific region CA6 had even replaced enterovirus A71 (EV71) and coxsackievirus A16 (CA16) as the main prevalent strain of HFMD. In the recent 10 years, monovalent and multivalent vaccines against CA6 have been researched and developed by manufacturers from China, Korea, and the USA. The neutralizing antibody titer is a key indicator for accurately evaluating immunogenicity of vaccine. However, so far, the World Health Organization international standard for CA6 neutralizing antibody has not been available. In order to meet the needs of evaluating the immunogenicity of vaccines against CA6, the first Chinese national standard for CA6 neutralizing antibody was established, which was conducted to ensure that methods used to measure the neutralizing antibody titers against CA6 are accurate, reliable, and comparable. Three lyophilized candidate standards (29#, 39# and 44#) were produced with 0.40 ml/vial from plasma samples donated by healthy individuals. The collaborative study showed that the 29# candidate standard could effectively minimize the variability in neutralization titers between labs and across challenging viruses of different genotypes (A, D1, and D3). Therefore, the 29# candidate sample was established as the first Chinese national standard for CA6 neutralizing antibody test. This standard has good long-term stability and was assigned a potency of 150 units per milliliter (U/ml) of CA6 neutralizing antibody. It will contribute to ensure uniformity of potency or activity of vaccines and potentially therapeutic antibody preparations.

Establishment and Characterization of the First Chinese National Standard for Nucleic Acid Amplification Technology Assays for Hepatitis E Virus Nucleic Acid Detection

The detection of hepatitis E virus (HEV) RNA is the gold standard for HEV infection diagnosis. In order to address the quality control requirements for HEV RNA detection kits within China, we aimed to establish the first Chinese national standard for HEV RNA detection through a collaborative study. The candidate standard was quantified using digital PCR (dPCR). A total of five laboratories were invited to determine the estimated mean value of this national standard relative to the World Health Organization International Standard (WHO IS). Additionally, four commercial kits were used to assess the applicability of the candidate standard. The stability was determined by freeze-thaw cycles and storage at 37 °C, 25 °C and 4 °C. The estimated mean value of this national standard relative to the WHO IS was 5.67 log10 IU/mL. Two out of the four commercial kits can detect as low as the estimated limit of detection (LOD). The degradation rates of samples in the stability study ranged from 4% to 19%. In conclusion, we have established the first Chinese national standard for HEV nucleic acid detection against WHO IS, which can be employed to evaluate the quality of HEV RNA detection kits.

Validation of a qPCR method for determination of viral genome titres of AAV2-based vector preparations

The viral genome titre is universally used for the dosing of adeno-associated virus (AAV)-based vectors used for gene therapy. To standardise this determination, the development of a common method would be valuable to facilitate comparison of viral doses used in the clinic and in the subsequent quality control of the products. A collaborative study was initiated by the Gene Therapy Working Group of the General European Official Medicines Control Laboratories Network in order to validate a qPCR-based method targeting the ITR2 sequence common to a broad variety of AAV vectors, independently from the serotype of the capsid or from the specific transgene. Five preparations of AAV vectors from various serotypes, including the AAV2/2 (RSS2) and AAV2/8 (RSS8) Reference Standard Stocks (American Type Culture Collection, USA) were used in the study. A plasmid carrying the ITR2 sequence was used to prepare standard curves. Its digestion outside the ITR regions facilitated melting of the hairpin ITR sequence during PCR, allowing better accessibility to the DNA polymerase. The results show that this qPCR method is satisfactory in terms of accuracy and precision. The reproducibility is also acceptable when compared with other similar studies, as it was shown previously that titres obtained by qPCR generally show higher inter-laboratory variability. The use of RSS2 or RSS8 as normalisation control in each assay demonstrated a promising help to identify potential sources of variation in a given laboratory or to smooth out inter-laboratory variations, thus improving reproducibility.

Assessing the Variability of Cell-Associated HIV DNA Quantification through a Multicenter Collaborative Study

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. The quantification of CA HIV DNA from a panel of infected PBMCs can be harmonized through cross-subtype normalization but assay calibration with the commonly used 8E5 cell line failed to reduce quantification variability between assays, demonstrating the requirement to thoroughly evaluate reference material candidates to help improve the comparability of CA HIV DNA diagnostic assay performance. IMPORTANCE Despite a global effort, HIV remains a major public health burden with an estimated 1.5 million new infections occurring in 2020. HIV DNA is an important viral marker, and its monitoring plays a critical role in the fight against HIV: supporting diagnosis in infants and underpinning clinical management of patients under therapy. Our study demonstrates that HIV DNA measurement of the same samples can vary significantly from one laboratory to another, due to heterogeneity in the assay, protocol, and reagents used. We show that when carefully selected, reference materials can reduce measurement variability and harmonize HIV DNA quantification across laboratories, which will help contribute to improved diagnosis and clinical management of patients living with HIV.

Research Trends in Individuals at High Risk for Psychosis: A Bibliometric Analysis

The study of clinical high risk for psychosis (CHR-P) has progressed rapidly over the last decades and has developed into a significant branch of schizophrenia research. Organizing the information about this rapidly growing subject through bibliometric analysis enables us to gain a better understanding of current research trends and future directions to be pursued. Electronic searches from January 1991 to December 2020 yielded 5,601 studies, and included 1,637 original articles. After processing the data, we were able to determine that this field has grown significantly in a short period of time. It has been confirmed that researchers, institutions, and countries are collaborating closely to conduct research; moreover, these networks are becoming increasingly complex over time. Additionally, there was a shift over time in the focus of the research subject from the prodrome, recognition, prevention, diagnosis to cognition, neuroimaging, neurotransmitters, cannabis, and stigma. We should aim for collaborative studies in which various countries participate, thus covering a wider range of races and cultures than would be covered by only a few countries.

Collaborative study for the establishment of Human immunoglobulin for anticomplementary activity BRP replacement batches 3, 4, 5 and 6

Human immunoglobulin products are used for the treatment of a number of diseases, such as primary or secondary immunodeficiencies and autoimmune conditions due to the complete absence of antibodies or the production of defective immunoglobulins. Quality control of human immunoglobulin products is essential to ensure therapeutic functionality and safety. This includes testing for Fc function and anticomplementary activity (ACA), as well as verification of appropriate molecular size distribution using size-exclusion chromatography as prescribed in the European Pharmacopoeia (Ph. Eur.) monographs 0338, 0918, 2788 and 1928. To this end, specific biological reference preparations (BRPs) must be used. Stocks of the Ph. Eur. Human immunoglobulin for anticomplementary activity BRP were running low and therefore a collaborative study was run by the European Directorate for the Quality of Medicines & HealthCare (EDQM), under the aegis of the Biological Standardisation Programme, to calibrate replacement batches. Six laboratories, including manufacturers and one Official Medicines Control Laboratory, took part in the study. Several batches of candidate BRPs were calibrated against Ph. Eur. Human immunoglobulin for anticomplementary activity BRP batch 2 to ensure continuity. Based on the study results, the candidate BRPs were adopted by the Ph. Eur. Commission as Ph. Eur. human immunoglobulin for anticomplementary activity BRP batch 3, 4, 5 and 6.

[Collaborative Study of an LC-MS/MS Method for Determination of Chlorpropham in Feeds]

A collaborative study for validating the determination method of chlorpropham in feeds by LC-MS/MS was conducted in 13 laboratories using 2 kinds of formula feeds, oats, barley, wheat, and corn. The resulting trueness ranged from 75.3 to 87.0%, repeatability and reproducibility in terms of relative standard deviation (RSD_r and RSD_R) were within 7.3% and 33% respectively, and the HorRat values ranged from 0.39 to 1.5. The limit of detection and limit of quantitation of chlorpropham in feed ware 0.008 mg/kg and 0.003 mg/kg, respectively. This method was thus validated as useful for inspections of chlorpropham in feed.

[Determination of Inorganic Arsenic for Pet Food by LC-ICP-MS]

We have developed a quantitative determination method of the concentration of inorganic arsenic in pet foods using a liquid chromatograph-inductively coupled plasma-mass spectrometer (LC-ICP-MS). After adding 2 w/v% TMAH solution to a sample, inorganic arsenic was extracted by heating and the extract was collected by water. The pH of the solution was adjusted, and injected into a LC-ICP-MS to determine the concentration of inorganic arsenic. LC separation was carried out on an ODS column with 10 mmol/L sodium 1-butanesulfonate, 4 mmol/L malonic acid, 4 mmol/L TMAH and 0.05% methanol solution as a mobile phase. A collaborative study was conducted by nine laboratories using dry and wet-type pet foods, formed jerky, dried jerky and biscuit. Dry-type pet food and dried jerky was added with 2 mg/kg of As (III). Wet-type pet food was added with 0.5 mg/kg of As (III). Formed jerky was added with 1 mg/kg of As (III). Biscuit was added with 0.2 mg/kg of As (III). The mean recoveries, repeatabilities and reproducibilities in the form of relative standard deviation (RSD_r and RSD_R), and HorRat, were 95.4% to 98.3%, less than 2.9%, less than 9.1%, and 0.22 to 0.51, respectively.

Collaborative Studies for the Detection of Taenia spp. Infections in Humans within CYSTINET, the European Network on Taeniosis/Cysticercosis

Laboratory tools for diagnosing taeniosis/cysticercosis in non-endemic countries are available; however, there is little data on their performance. To provide information on the sensitivity, specificity, and reproducibility of these tools, inter-laboratory studies were organized within the EU COST-Action CYSTINET (TD1302). Two serological and one coprological Ring Trials (RTs) were organized to test a panel of human-derived sera and stool samples using assays routinely conducted by the participating laboratories to detect Taenia spp. infections. Four Western blots (WBs) and five ELISAs were used by nine laboratories for cysticercosis diagnosis. In the first serological RT, the overall sensitivity was 67.6% (95% CI, 59.1–75.4), whereas specificity was 97% (95% CI, 89.8–99.6). WBs recorded the best accuracy. A second serological RT was organized, to assess the three tests most frequently used during the first RT. Two out of six laboratories performed all the three tests. The overall sensitivity and specificity were 52.8% (95% CI, 42.8–62.7) and 98.1% (95% CI, 93.2–99.7), respectively. Laboratory performance strongly affected test results. Twelve laboratories participated in the coprological RT using conventional microscopy and six laboratories used molecular assays. Traditional diagnosis by microscopy yielded better results than molecular diagnosis. This may have been influenced by the lack of standardization of molecular tests across participating laboratories.

Iodine determination in animal feed by inductively coupled plasma mass spectrometry - results of a collaborative study

A collaborative study was conducted in order to fully validate the performance characteristics and to evaluate the suitability of a method for determination of iodine in animal feed. The method consists of an alkaline extraction in tetramethylammonium hydroxide (TMAH) solution followed by the determination of iodine by inductively coupled plasma-mass spectrometry (ICP-MS). The method was validated for different types of feed and feed materials with a broad concentration range of 0.65-622 mg I/kg. Good agreement was found between the overall mean mass fraction values from the collaborative trial (13.8 ± 1.3 mg I/kg and 0.657 ± 0.228 mg I/kg) and the values previously determined in proficiency tests for two of the test materials (12.65 ± 2.47 mg I/kg and 0.72 ± 0.22 mg I/kg) indicating satisfactory accuracy of the method. Reproducibility standard deviations were between 7.85% and 34.65% and the HorRat values were under the acceptable limit of 2 so the between-laboratory precision was considered acceptable. Based on the statistical evaluation of the results it was concluded that the method is suitable for its intended purpose; it has been accepted as European Standard EN17050:2017 by the European Committee for Standardisation (CEN).

Calibration of the Ph. Eur. human coagulation Factor VIII Concentrate BRP batch 6

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for human coagulation Factor VIII (FVIII) Concentrate is used as working standard for potency determination of human coagulation FVIII preparations by chromogenic assay. BRP batch 5 was established in 2015 and its stocks were running low. Therefore, the European Directorate for the Quality of Medicines & HealthCare (EDQM) initiated a project (BSP156) for the calibration of a replacement batch. The potency of BRP batch 6 was assigned during an international collaborative study involving 16 laboratories worldwide, with reference to the WHO 8th International Standard (IS) and BRP batch 5. Participants were instructed to perform 3 independent FVIII potency assays following their own routine validated methods for the chromogenic assay, which is the assay prescribed by the Ph. Eur. As an outcome of the study, Ph. Eur. human coagulation FVIII Concentrate BRP batch 6 was assigned a consensus potency of 9.9 IU/ampoule for the chromogenic assay. The Ph. Eur. BRP batch 6 is a freeze-dried, plasma-derived concentrate. Based on accelerated degradation studies, the stability of the material is suitable for a reference preparation. The Ph. Eur. BRP batch 6 was adopted at the 167th session of the Ph. Eur. Commission in June 2020 and is available from the EDQM under product code H0920000.

Establishment of Pertussis toxin BRP batch 2 for CHO clustering assay

Recently, the Chinese hamster ovary (CHO) cell-based clustering assay replaced the in vivo Histamine Sensitisation Test (HIST) in mice in European Pharmacopoeia (Ph. Eur.) general chapter 2.6.33. ‘Residual pertussis toxin’ as the recommended method to test for residual pertussis toxin in acellular pertussis vaccine intermediates. To support the standardised CHO clustering assay, availability of a reference standard is critical. Ph. Eur. pertussis toxin Biological Reference Preparation (BRP) batch 1 was first calibrated in International Units in 2008 for the HIST and subsequently also calibrated for the CHO clustering assay in 2017. However, its stocks were dwindling and needed to be replaced. In an effort to maintain adequate supply, a project (BSP141) was initiated by the European Directorate for the Quality of Medicines & HealthCare (EDQM), under the aegis of the Biological Standardisation Programme, to establish a second pertussis toxin BRP (BRP2). Candidate material was manufactured ad hoc by an acellular pertussis vaccine manufacturer and an optimal formulation for long-term stability was defined. Exhaustive in-process and post-production controls demonstrated that the material was fit for its intended purpose and therefore a collaborative study for calibration and stability assessment of the candidate material was organised, which included 10 laboratories worldwide. As a result of the study, the candidate material was established as Ph. Eur. Pertussis toxin BRP batch 2 with a potency of 130 IU/vial for the CHO clustering assay. Unopened vials must be stored at −20°C. The BRP may be used for up to two weeks after reconstitution if appropriately handled and stored at 2–8°C.

Human albumin (molecular size) Biological Reference Preparation batches 1, 2 and 3

To comply with European Pharmacopoeia (Ph. Eur.) monograph Human albumin solution (0255), albumin solutions have to be tested for molecular-size distribution by size-exclusion chromatography (SEC). However, differences in interpretation of the test results continue to be observed among albumin manufacturers in Europe. A collaborative study was run by the European Directorate for the Quality of Medicines & HealthCare (EDQM), under the aegis of the Biological Standardisation Programme (BSP), to support the revision of Ph. Eur. monograph 0255 and to establish a Biological Reference Preparation (BRP) for use in the molecular-size distribution test. In 2019, Ph. Eur. Expert Group 6B proposed to include an analytical improvement of the SEC procedure in the monograph, which was then submitted for public enquiry. This publication describes the evaluation of three candidate BRPs to serve as a tool for both the system suitability test (SST) and albumin monomer and dimer peak identification according to the proposed revised methodology. Three Official Medicines Control Laboratories (OMCLs) involved in the official batch release of human albumin solution took part in the study. Based on the study results, the candidate BRPs were found suitable for purpose and were adopted by the Ph. Eur. Commission as Ph. Eur. Human albumin (molecular size) BRP batches 1, 2 and 3 concomitantly with the revised monograph Human albumin solution (0255) in November 2020.

Determination of Zearalenone and Trichothecenes, Including Deoxynivalenol and Its Acetylated Derivatives, Nivalenol, T-2 and HT-2 Toxins, in Wheat and Wheat Products by LC-MS/MS: A Collaborative Study

An analytical method for the simultaneous determination of trichothecenes-namely, nivalenol (NIV), deoxynivalenol (DON) and its acetylated derivatives (3- and 15-acetyl-DON), T-2 and HT-2 toxins-and zearalenone (ZEN) in wheat, wheat flour, and wheat crackers was validated through a collaborative study involving 15 participants from 10 countries. The validation study, performed within the M/520 standardization mandate of the European Commission, was carried out according to the IUPAC (International Union of Pure and Applied Chemistry) International Harmonized Protocol. The method was based on mycotoxin extraction from the homogenized sample material with a mixture of acetonitrile-water followed by purification and concentration on a solid phase extraction column. High-performance liquid chromatography coupled with tandem mass spectrometry was used for mycotoxin detection, using isotopically labelled mycotoxins as internal standards. The tested contamination ranges were from 27.7 to 378 μg/kg for NIV, from 234 to 2420 μg/kg for DON, from 18.5 to 137 μg/kg for 3-acetyl-DON, from 11.4 to 142 μg/kg for 15-acetyl-DON, from 2.1 to 37.6 μg/kg for T-2 toxin, from 6.6 to 134 μg/kg for HT-2 toxin, and from 31.6 to 230 μg/kg for ZEN. Recoveries were in the range 71-97% with the lowest values for NIV, the most polar mycotoxin. The relative standard deviation for repeatability (RSD_r) was in the range of 2.2-34%, while the relative standard deviation for reproducibility (RSD_R) was between 6.4% and 45%. The HorRat values ranged from 0.4 to 2.0. The results of the collaborative study showed that the candidate method is fit for the purpose of enforcing the legislative limits of the major Fusarium toxins in wheat and wheat-based products.

Determination of Zearalenone and Trichothecenes, Including Deoxynivalenol and Its Acetylated Derivatives, Nivalenol, T-2 and HT-2 Toxins, in Wheat and Wheat Products by LC-MS/MS: A Collaborative Study

An analytical method for the simultaneous determination of trichothecenes-namely, nivalenol (NIV), deoxynivalenol (DON) and its acetylated derivatives (3- and 15-acetyl-DON), T-2 and HT-2 toxins-and zearalenone (ZEN) in wheat, wheat flour, and wheat crackers was validated through a collaborative study involving 15 participants from 10 countries. The validation study, performed within the M/520 standardization mandate of the European Commission, was carried out according to the IUPAC (International Union of Pure and Applied Chemistry) International Harmonized Protocol. The method was based on mycotoxin extraction from the homogenized sample material with a mixture of acetonitrile-water followed by purification and concentration on a solid phase extraction column. High-performance liquid chromatography coupled with tandem mass spectrometry was used for mycotoxin detection, using isotopically labelled mycotoxins as internal standards. The tested contamination ranges were from 27.7 to 378 μg/kg for NIV, from 234 to 2420 μg/kg for DON, from 18.5 to 137 μg/kg for 3-acetyl-DON, from 11.4 to 142 μg/kg for 15-acetyl-DON, from 2.1 to 37.6 μg/kg for T-2 toxin, from 6.6 to 134 μg/kg for HT-2 toxin, and from 31.6 to 230 μg/kg for ZEN. Recoveries were in the range 71-97% with the lowest values for NIV, the most polar mycotoxin. The relative standard deviation for repeatability (RSD_r) was in the range of 2.2-34%, while the relative standard deviation for reproducibility (RSD_R) was between 6.4% and 45%. The HorRat values ranged from 0.4 to 2.0. The results of the collaborative study showed that the candidate method is fit for the purpose of enforcing the legislative limits of the major Fusarium toxins in wheat and wheat-based products.

Collaborative Study to Validate Purity Determination by 1H Quantitative NMR Spectroscopy by Using Internal Calibration Methodology

NMR spectroscopy has recently been utilized to determine the absolute amounts of organic molecules with metrological traceability since signal intensity is directly proportional to the number of each nucleus in a molecule. The NMR methodology that uses hydrogen nucleus (¹H) to quantify chemicals is called quantitative ¹H-NMR (¹H qNMR). The quantitative method using ¹H qNMR for determining the purity or content of chemicals has been adopted into some compendial guidelines and official standards. However, there are still few reports in the literature regarding validation of ¹H qNMR methodology. Here, we coordinated an international collaborative study to validate a ¹H qNMR based on the use of an internal calibration methodology. Thirteen laboratories participated in this study, and the purities of three samples were individually measured using ¹H qNMR method. The three samples were all certified via conventional primary methods of measurement, such as butyl p-hydroxybenzoate Japanese Pharmacopeia (JP) reference standard certified by mass balance; benzoic acid certified reference material (CRM) certified by coulometric titration; fludioxonil CRM certified by a combination of freezing point depression method and ¹H qNMR. For each sample, ¹H qNMR experiments were optimized before quantitative analysis. The results showed that the measured values of each sample were equivalent to the corresponding reference labeled value. Furthermore, assessment of these ¹H qNMR data using the normalized error, E_n-value, concluded that statistically ¹H qNMR has the competence to obtain the same quantification performance and accuracy as the conventional primary methods of measurement.

Establishment of Ph. Eur. Bordetella pertussis mouse antiserum Biological Reference Preparation batches 2, 3 and 4

A project aimed at establishing replacement batches for the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) Bordetella (B.) pertussis mouse antiserum was started in 2013 under the aegis of the Biological Standardisation Programme (BSP) of the European Directorate for the Quality of Medicines & HealthCare (EDQM). This BRP is used for the immunogenicity assay in mice to assess the potency of acellular pertussis (aP) vaccines as described in Ph. Eur. general method 2.7.16. Assay of pertussis vaccine (acellular). In a preliminary phase of the project (referred to herein as BSP129 phase 1) a hyper-immune serum pool was produced in mice using a combined aP vaccine as immunogen. This pool was used to generate 3 freeze-dried candidate (c) B. pertussis anti-mouse serum BRP batches (cBRP2, cBRP3 and cBRP4). After the pre-qualification that showed their suitability as candidate batches, an international collaborative study (BSP129 phase 2) was carried out in order to standardise these 3 batches against the current BRP1 in terms of anti-PT, -FHA, -PRN and -FIM2/3 antibody contents. For the sake of continuity with the standardisation of BRP1, the corresponding WHO standard (1RR 97/642) was introduced as a second reference for the calibration of the 3 candidate BRPs. Eleven laboratories took part in phase 2. Ten of them performed the ELISA method they use routinely for aP vaccine batch release and one laboratory performed the Multiplex Immunoassay (MIA) as an alternative test. Four participants titrated the antibodies against all 5 pertussis antigens, 5 participants determined the antibody content against 3 antigens (PT, FHA, PRN), one participant titrated the antibodies against PT and FHA antigens and one laboratory determined the antibody content for the PT antigen only. Details of all ELISA methods used were analysed to evaluate their impact on the calibration of the cBRPs. The variability of the results in relation to the nature and methodology of the tests appeared rather limited. Discrepant titres of cBRPs were measured depending on the reference used: the use of the 1RR induced an overestimation (in 8 out of 11 laboratories) and a large inter-laboratory variation in the calculated titres. Regardless of the reference used, equivalency between the calculated titres of cBRP2 and cBRP3 was observed, whilst cBRP4 had systematically lower titres for all antibodies against the 5 acellular pertussis vaccine components. Based on these observations, it was decided to establish the candidate BRP batches against BRP1 and to assign the following potencies based on the mean values determined through centrally calculated results of the calibration assays performed by ELISA in BSP129 phase 2: For cBRP2 and cBRP3 Anti-pertussis toxin: 37 ELISA Units (ELU) per vial Anti-filamentous haemagglutinin: 114 ELU per vial Anti-pertactin: 44 ELU per vial Anti-fimbrial agglutinogens (FIM2/3): 25 ELU per vial For cBRP4 Anti-pertussis toxin: 32 ELU per vial Anti-filamentous haemagglutinin: 98 ELU per vial Anti-pertactin 38 ELU per vial Anti-fimbrial agglutinogens (FIM2/3):23 ELU per vial In February 2018, BRP2, BRP3 and BRP4 were adopted by correspondence by the Ph. Eur. Commission.

Collaborative study for the establishment of the 3rd international standard for amphotericin B

An international collaborative study was organised to establish the 3rd World Health Organization (WHO) International Standard (IS) for amphotericin B. Sixteen laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 2nd IS for amphotericin B was used as a reference. Based on the results of the study, the 3rd IS for amphotericin B was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2019 with an assigned potency of 953 International Units (IU) per mg. The 3rd IS for amphotericin B is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Production and characterisation of a candidate hyper-immune serum for the replacement of the Bordetella pertussis mouse antiserum Biological Reference Preparation

For acellular pertussis (aP) vaccines, the current European Pharmacopoeia (Ph. Eur.) monograph Pertussis vaccine (acellular, component, adsorbed) (1356) requires an immunogenicity assay in mice or guinea pigs to assess the potency of each lot of vaccine (Ph. Eur. general method 2.7.16. Assay of pertussis vaccine (acellular)). This biological assay, carried out on the final bulk of the vaccine lot, is based on the measurement of the specific antibody response to the 5 antigenic components (pertussis toxin (PT), Fimbrial haemagglutinin (FHA), pertactin (PRN) and Fimbriae 2 and 3 (FIM2/3)) that are present in the combined aP vaccines. In the mouse assay, serum antibody levels are measured by ELISA. The immunogenicity of a vaccine under test is estimated versus a homologous reference vaccine and a reference antiserum e.g. the first Ph. Eur. Biological Reference Preparation for Bordetella (B.) pertussis mouse anti-serum (BRP1), established in 1998, is used to normalise the titre of antibodies (expressed in ELISA Units (ELU)/mL). In anticipation of the depletion of BRP1 stocks, a project was launched in 2013 by the Biological Standardisation Programme (BSP) of the European Directorate for the Quality of Medicines & HealthCare (EDQM) in order to establish a new standardised reference serum. The project, referred to herein as BSP129, was conducted in 2 phases: 1) the production and characterisation of a mouse serum pool (using a multicomponent aP vaccine marketed in Canada similar to the vaccine used in the BRP1 production as immunogen) and of candidate BRP batches (cBRPs) and 2) an international collaborative study aimed at calibrating the cBRPs in terms of antibody levels against PT, FHA, PRN and FIM2/3. This article presents the design and results of the first phase of the collaborative study to establish the optimal conditions for immunisation and bleeding of mice in order to produce a large pool of hyper-immune serum against the 5 antigens. After the characterisation of this pool, cBRP pilot lots were manufactured by freeze-drying diluted solutions of the hyper-immune serum pool. The pilot lots were then characterised in two Official Medicines Control Laboratories (OMCLs) for their antibody contents against aP vaccine antigens using in-house ELISA (based on methods developed by 2 European vaccine manufacturers) and Multiplex Immunoassay (MIA) methods. The antibody titres recovered demonstrated that a dilution factor of 1/40 could be considered for the scaled-up manufacture of candidate reference preparations (cBRPs). Three batches (15 000 vials) of cBRP were manufactured and fully characterised. In light of the data obtained, and although titration results between the ELISA methods were sometimes discrepant, it was agreed that the establishment study (phase 2) could be launched. Real-time and accelerated stability studies were also included in the first study phase to document the stability of the cBRPs in freeze-dried form and after reconstitution and storage at -20°C±5°C. The results showed that the stability of the freeze-dried cBRPs at usual storage and shipment temperatures is acceptable and that reconstituted cBRP solutions are stable for 12 months at -20°C±5°C. It could therefore be recommended to freeze small aliquots of the 1 mL solution obtained by the reconstitution of one BRP vial in order to store them for use in separate assays. With the application of this strategy, the stocks of the BRP1 replacement batches should cover the needs of OMCLs and manufacturers for at least the next decade.

Collaborative study for the establishment of the 3rd international standard for erythromycin

An international collaborative study was organised to establish the 3rd World Health Organization (WHO) International Standard (IS) for Erythromycin. Fifteen laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 2nd IS for Erythromycin was used as a reference. Based on the results of the study, the 3rd IS for Erythromycin was adopted at the meeting of the WHO Expert Committee on Biological Standardization (ECBS) in 2018 with an assigned potency of 925 International Units (IU) per mg. The 3rd IS for Erythromycin is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Multiple Mycotoxins Determination in Food by LC-MS/MS: An International Collaborative Study

An intercollaborative study was organized to evaluate the performance characteristics of a liquid chromatography tandem mass spectrometry procedure for the simultaneous determination of 12 mycotoxins in food, which were ochratoxin A, aflatoxins B1, B2, G1, G2, and M1, deoxynivalenol, zearalenone, fumonisins B1 and B2, and T-2 and HT-2 toxins. The method combined the simplicity of the QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) approach with the efficiency of immunoaffinity column cleanup (the step used to enhance sensitivity and sample cleanup for some matrices only). Twenty-three entities were enrolled and were European reference laboratories for mycotoxin analysis, U.S. and European service laboratories, and Nestlé laboratories. Each participant analyzed 28 incurred and/or spiked blind samples composed of spices, nuts, milk powder, dried fruits, cereals, and baby food using the protocol given. Method performances were assessed according to ISO 5725-2. Relative standard deviations of repeatability and reproducibility and trueness values for each of the 115 mycotoxin/sample combinations ranged from 5% to 23%, 7% to 26%, and 85% to 129%, respectively, in line with requirements defined in EC 401/2006. The overall set of data gathered demonstrated that the method offered a unique platform to ensure compliance with EC 1881/2006 and EC 165/2013 regulations setting maximum limits for mycotoxins in food samples, even at low regulated levels for foods intended for infants and young children. The method was applicable regardless of the food, the regulated mycotoxin, and the concentration level, and thus is an excellent candidate for future standardization.

Establishment of detection antibodies BRRs batch 5 for in vitro potency assay of hepatitis A vaccines by ELISA

The European Pharmacopoeia (Ph. Eur.) standard ELISA method for determination of antigen content of hepatitis A vaccines (HAV) requires specific coating and detection Biological Reference Reagents (BRRs). The 4th batch of detection antibodies BRRs was established in 2017 for use in conjunction with the Ph. Eur. General Chapter 2.7.14 Assay of hepatitis A vaccine. Stocks of these BRRs were running low and therefore the European Directorate for the Quality of Medicines and HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies batch 5 were prepared under appropriate conditions from starting materials similar to previous batches to ensure continuity. Prior to the study, a low level of detection was obtained with new batches of the HRPO-GAM provided by the established supplier, supposedly due to a manufacturing issue in the conjugation step. Several other batches procured from the same supplier were tested without any success. Consequently HRPO-GAM batches from 3 other suppliers were tested and one batch was chosen to be included as a BRR based on its suitable characteristics. During the collaborative study, the new batches of antibodies were compared to previous batches of BRRs. Results confirmed that they were suitable to be used for the intended purpose, and could be used at the same final concentrations as the previous batch, i.e. 1:500 for the primary antibody and 1:400 for the conjugated secondary antibody. A higher background OD than in previous batches was observed, so it is recommended to subtract the background from the OD values obtained in the test in order to plot the sigmoid curve and calculate the titre of test samples. Moreover it is recommended that the first dilutions used for the IS and BRP2 should be 1:2 and 1:20, respectively, in order to achieve the same ODmax as for the previous BRRs batches. The BRRs were adopted by correspondence in October 2018 by the Ph. Eur. Commission and are presented as a set containing Hepatitis A virus primary detection antibody BRR batch 5 and Conjugated secondary detection antibody BRR batch 5. They are available from the EDQM as Hepatitis A vaccine ELISA detection antibodies set BRR batch 5.

Establishment of an erythropoietin CRS with stable measurable dimer content for SEC system suitability qualification

The European Pharmacopoeia (Ph. Eur.) monograph 1316 'Erythropoietin concentrated solution' prescribes that the dimer content of therapeutic erythropoietin (EPO) preparations must not exceed 2% as determined by Size-Exclusion Chromatography (SEC). This report describes the evaluation of a candidate Chemical Reference Substance (cCRS) to serve as system suitability reference material for the qualification of SEC systems used to assess dimer and oligomer content in EPO solutions. The study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) was performed with the participation of six European laboratories which tested the candidate material and the EPO for physicochemical tests CRS batch 1. The candidate material was shown to be a suitable reference material for the determination of the resolving capability of the SEC system for separation of dimer and higher oligomers from monomeric EPO. The cCRS was adopted by the Ph. Eur. Commission as Erythropoietin for SEC system suitability CRS batch 1 following consideration of the report. The importance of the resolving capability of the SEC system, as defined by the peak ratios or the peak-to-valley resolution, together with the asymmetry of the peaks eluted, and the linear response of the UV detector were all seen as critical parameters. Therefore, the monograph Erythropoietin concentrated solution (1316) was revised concomitantly to take account of the CRS and to set acceptance criteria for these critical parameters..

Calibration of pertussis toxin BRP batch 1 in a standardised CHO cell-based clustering assay

The European Pharmacopoeia (Ph. Eur.) pertussis toxin (PT) Biological Reference Preparation (BRP) is used as a working standard for safety testing of acellular pertussis vaccines as prescribed in the Ph. Eur. monographs 1356 "Pertussis vaccine (acellular, component, adsorbed)" and 1595 "Pertussis vaccine (acellular, co-purified, adsorbed)". The BRP was calibrated in 2006 in the murine histamine sensitisation test (HIST) against the World Health Organization (WHO) 1^st International Standard (IS) for PT. In recent years, there have been increasing efforts to replace the in vivo test with in vitro methods. The Chinese hamster ovary (CHO) cell clustering assay has been used for many years by manufacturers to monitor residual PT activity in detoxified non-adjuvanted bulks. More recently a standardised protocol has been developed for this assay and a PT reference preparation was needed. Due to low stocks, the WHO 1^st International Standard for Pertussis Toxin (JNIH-5) needed to be replaced and therefore a joint study between the European Directorate for the Quality of Medicines & HealthCare (EDQM) and WHO was initiated to calibrate the PT BRP for the CHO clustering assay and to replace the IS. The collaborative study involved 14 laboratories from Europe, North America and Asia. The outcome of the study confirmed that the BRP is suitable for use as a reference preparation in the CHO clustering assay. The material was assigned a potency of 1360 IU per vial for the CHO clustering assay.

Collaborative study for the establishment of human immunoglobulin BRP replacement batches

Human immunoglobulin products are used for the treatment of a number of diseases, such as primary or secondary immunodeficiencies and autoimmune conditions due to the complete absence of antibodies or the production of defective immunoglobulins. Quality control of human immunoglobulin products is essential to ensure therapeutic functionality and safety. This includes testing for Fc function and anticomplementary activity (ACA), as well as verification of appropriate molecular size distribution using size-exclusion chromatography as prescribed in the European Pharmacopoeia (Ph. Eur.) monographs 0338, 0918, 2788 and 1928. To this end, specific biological reference preparations (BRPs) must be used. Stocks of these BRPs were running low and therefore a collaborative study was run by the European Directorate for the Quality of Medicines & HealthCare (EDQM), under the aegis of the Biological Standardisation Programme, to calibrate replacement batches. Seventeen laboratories, including manufacturers and Official Medicines Control Laboratories, took part in the study. Several batches of candidate BRPs were calibrated against human immunoglobulin (ACA and molecular size) BRP batch 1 and human immunoglobulin (Fc function and molecular size) BRP batch 1 to ensure continuity. Based on the study results, the candidate BRPs were adopted by the Ph. Eur. Commission as Ph. Eur. human immunoglobulin for anticomplementary activity BRP batch 1 and batch 2, Ph. Eur. human immunoglobulin for Fc function BRP batch 1 and batch 2 and Ph. Eur. human immunoglobulin (molecular size) BRP batch 2 and batch 3.

Establishment of detection antibodies BRRs batch 4 for in vitro potency assay of hepatitis A vaccines by ELISA

The European Pharmacopoeia (Ph. Eur.) standard ELISA method for determination of antigen content of hepatitis A vaccines (HAV) requires specific coating and detection Biological Reference Reagents (BRRs). The 3^rd batch of detection antibodies BRRs was established in 2015 for use in conjunction with the Ph. Eur. general chapter 2.7.14 'Assay of hepatitis A vaccine'. Stocks of these BRRs were running low and therefore the European Directorate for the Quality of Medicines & HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies batch 4 were prepared under appropriate conditions from starting materials similar to previous batches to ensure continuity. During the collaborative study, the new batches of antibodies were compared to previous batches of BRRs. Results confirmed that they were suitable to be used for the intended purpose, and could be used at the same final concentrations as the previous batch, i.e. 1:500 for the primary antibody and 1:400 for the conjugated secondary antibody. They were adopted in June 2017 by the Ph. Eur. Commission as Hepatitis A virus primary detection antibody BRR batch 4 and Conjugated secondary detection antibody BRR batch 4, respectively. They are available from the EDQM as Hepatitis A vaccine ELISA detection antibodies set BRR batch 4.

Calibration of the Ph. Eur. human coagulation Factor VIII concentrate BRP batch 5

The European Pharmacopoeia Biological Reference Preparation (Ph. Eur. BRP) for Factor VIII Concentrate batch 5 was established through a collaborative study involving 14 laboratories organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe) to be used as working standard for potency determination of human coagulation Factor VIII (FVIII) preparations. The potency of the BRP batch 5 was assigned with reference to the WHO 8^th International Standard (IS) for FVIII Concentrate and the BRP batch 4. Participants were instructed to perform 3 independent Factor VIII potency assays following their own routine validated methods by the chromogenic assay as it is the assay prescribed by the European Pharmacopoeia. This publication reports the results obtained during the study. The consensus potency, 9.9 IU/ampoule (n = 14) when assessed against both standards, with inter-laboratory geometric coefficients of variation (GCV) of 3.2 % and 1.9 % against the WHO 8^th IS and the BRP batch 4 respectively, was consistent with the expected value. The Ph. Eur. BRP batch 5 is a freeze-dried, plasma-derived concentrate. Based on accelerated degradation studies, the stability of the material is suitable as a reference preparation. The Ph. Eur. BRP batch 5 was adopted at the 151^st session of the European Pharmacopoeia Commission in March 2015 and is available from the EDQM.

Establishment of the Ph. Eur. Hepatitis A virus RNA for NAT testing BRP batch 1

Detection of viral contamination in plasma donations is critical to prevent transmission of infectious diseases. The European Pharmacopoeia (Ph. Eur.) monograph 1646 'Human plasma (pooled and treated for virus inactivation)', requires that plasma pools used for the manufacture of this product be tested, among others, for the presence of hepatitis A virus RNA by nucleic acid testing (NAT) using a positive control containing 100 International Units (IU) of hepatitis A virus (HAV) RNA per mL. To this end, the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe) organised an international collaborative study under the aegis of the Biological Standardisation Programme, for the establishment of the 1^st Biological Reference Preparation (BRP) for HAV RNA for NAT testing. A freeze-dried candidate material was thus prepared and calibrated against the WHO 2^nd International Standard for HAV for NAT (00/562) in a study in which thirteen European and North American laboratories including Official Medicines Control Laboratories (OMCLs), manufacturers of plasma-derived products, producers of in vitro diagnostic kits and a blood transfusion centre participated. Based on the outcome of the study, an HAV RNA content of 40 000 IU/vial (corresponding approximately to 4.6 log₁₀ IU/vial) was assigned to the BRP, which was adopted by the Ph. Eur. Commission in March 2016 as Ph. Eur. hepatitis A virus RNA for NAT testing BRP batch 1.

Validation of ELISA methods for quantification of the major birch allergen Bet v 1 (BSP090)

To date, the potency of allergen products in Europe is expressed in manufacturer-specific units relative to a product-specific in-house reference. Consequently, cross-product comparability of allergen products from different manufacturers with respect to strength and efficacy is impossible. The Biological Standardisation Programme (BSP) project BSP090 addresses this issue via the establishment of reference standards in conjunction with ELISA methods for the quantification of major allergens in allergen products. Since the initiation of BSP090, the recombinant major allergen Bet v 1 has been adopted by the European Pharmacopoeia Commission as a Chemical Reference Substance (CRS). In parallel, two sandwich ELISA systems for quantification of Bet v 1 were found suitable in preliminary phases of BSP090 to be validated in a large collaborative study. In this study, the candidate ELISA systems were compared with respect to accuracy, precision and variability. Thirteen participating laboratories tested model samples containing the CRS as well as spiked and unspiked birch pollen extracts. Both in pre-testing and in the collaborative study, the 2 candidate ELISA systems confirmed their suitability to quantify recombinant and native Bet v 1. As no clear-cut decision for one of the ELISA systems could be made based on the results of the collaborative study, a post-study testing was performed. Bet v 1 content of 30 birch pollen allergen products was determined in parallel in both ELISA systems. Consequently, 1 candidate ELISA system was selected to be proposed as the future European Pharmacopoeia standard method for Bet v 1 quantification.

Collaborative study on saccharide quantification of the Haemophilus influenzae type b component in liquid vaccine presentations

Before release onto the market, it must be demonstrated that the total and free polysaccharide (poly ribosyl-ribitol-phosphate, PRP) content of Haemophilus influenzae type b (Hib) vaccine complies with requirements. However, manufacturers use different methods to assay PRP content: a national control laboratory must establish and validate the relevant manufacturer methodology before using it to determine PRP content. An international study was organised by the World Health Organization (WHO), in collaboration with the Biological Standardisation Programme (BSP) of the Council of Europe/European Directorate for the Quality of Medicines & HealthCare (EDQM) and of the European Union Commission, to verify the suitability of a single method for determining PRP content in liquid pentavalent vaccines (DTwP-HepB-Hib) containing a whole-cell pertussis component. It consists of HCl hydrolysis followed by chromatographic separation and quantification of ribitol on a CarboPac MA1 column using high-performance anion exchange chromatography coupled with pulsed amperometric detection (HPAEC-PAD). The unconjugated, free, PRP is separated from the total PRP using C4 solid-phase extraction cartridges (SPE C4). Ten quality control laboratories performed two independent analyses applying the proposed analytical test protocol to five vaccine samples, including a vaccine lot with sub-potent PRP content and very high free PRP content. Both WHO PRP standard and ribitol reference standard were included as calibrating standards. A significant bias between WHO PRP standard and ribitol reference standard was observed. Study results showed that the proposed analytical method is, in principle, suitable for the intended use provided that a validation is performed as usually expected from quality control laboratories.

Assessment of UV spectrophotometry for determination of plasmid DNA concentration in vector preparations for human gene therapy products

The European Pharmacopoeia (Ph. Eur.) general chapter 5.14. Gene transfer medicinal products for human use suggests the use of absorbance measurements at 260 nm to determine the DNA concentration of plasmid vectors used for the preparation of gene therapy products for human use. An international collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to confirm the suitability of UV spectrophotometry for the quantification of plasmid vectors used in gene therapy (GT). Three Official Medicine Control Laboratories (OMCLs of the European OMCL Network) and members of the OMCL Working Group for GT products took part in the study, in which various types of spectrophotometers were assessed using common test samples. Results of the study demonstrated that UV spectrophotometry can be considered suitable for the quantification of plasmid DNA in GT products regardless of the instrument used.

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Inactivated poliomyelitis vaccines are an important part of the World Health Organization (WHO) control strategy to eradicate poliomyelitis. Requirements for the quality control of poliomyelitis vaccines (inactivated) include the use of an in vitro D antigen quantification assay for potency determination on the final lot as outlined in the European Pharmacopoeia (Ph. Eur.) monograph 0214. Performance of this assay requires a reference preparation calibrated in International Units (IU). A Ph. Eur. biological reference preparation (BRP) for poliomyelitis vaccine (inactivated) calibrated in IU has been established for this purpose. Due to the dwindling stocks of batch 2 of the BRP a collaborative study was run as part of the European Directorate for the Quality of Medicines & HealthCare (EDQM) Biological Standardisation Programme to establish BRP batch 3 (BRP3). Twelve laboratories including Official Medicines Control Laboratories (OMCLs) and manufacturers participated. The candidate BRP3 (cBRP3) was from the same source and had the same characteristics as BRP batch 2 (BRP2). During the study the candidate was calibrated against the 3^rd International Standard for inactivated poliomyelitis vaccine using in-house D antigen ELISA assays in line with the Ph. Eur. monograph 0214. The candidate was also compared to BRP2 to evaluate the continuity. Based on the results of the study, values of 320 DU/mL, 78 DU/mL and 288 DU/mL (D antigen units/mL) (IU) for poliovirus type 1, 2 and 3 respectively were assigned to the candidate. In June 2016, the Ph. Eur. Commission adopted the material as Ph. Eur. BRP for poliomyelitis vaccine (inactivated) batch 3.

Collaborative study for the calibration of replacement batches for the heparin low-molecular-mass for assay biological reference preparation

The European Pharmacopoeia (Ph. Eur.) prescribes the control of the activity of low molecular mass heparins by assays for anti-Xa and anti-IIa activities (monograph 0828), using a reference standard calibrated in International Units (IU). An international collaborative study coded BSP133 was launched in the framework of the Biological Standardisation Programme (BSP) run under the aegis of the Council of Europe and the European Commission to calibrate replacement batches for the dwindling stocks of the Heparin low-molecular-mass for assay Biological Reference Preparation (BRP) batch 8. Thirteen official medicines control and manufacturers laboratories from European and non-European countries took part in this study to calibrate two freeze-dried candidate batches against the 3rd International Standard (IS) for heparin, low molecular weight (11/176; 3rd IS). The Heparin low-molecular-mass for assay BRP (batch 8) was also included in the test panel to check the continuity between subsequent BRP batches. Taking into account the stability data, the results of this collaborative study and on the basis of the central statistical analysis performed at the European Directorate for the Quality of Medicines & HealthCare (EDQM), the 2 candidate batches were officially adopted by the Commission of the European Pharmacopoeia as Heparin low-molecular-mass for assay BRP batches 9 and 10 with assigned anti-Xa activities of 102 and 100 IU/vial and anti-IIa activities of 34 and 33 IU/vial respectively.

Collaborative study for the validation of an improved HPLC assay for recombinant IFN-alfa-2

The current European Pharmacopoeia (Ph. Eur.) texts for Interferon (IFN)-alfa-2 include a nonspecific photometric protein assay using albumin as calibrator and a highly variable cell-based assay for the potency determination of the protective effects. A request was expressed by the Official Medicines Control Laboratories (OMCLs) for improved methods for the batch control of recombinant interferon alfa-2 bulk and market surveillance testing of finished products, including those formulated with Human Serum Albumin (HSA). A HPLC method was developed at the Medical Products Agency (MPA, Sweden) for the testing of IFN-alfa-2 products. An initial collaborative study run under the Biological Standardisation Programme (BSP; study code BSP039) revealed the need for minor changes to improve linearity of the calibration curves, assay reproducibility and robustness. The goal of the collaborative study, coded BSP071, was to transfer and further validate this improved HPLC method. Ten laboratories participated in the study. Four marketed IFN-alfa-2 preparations (one containing HSA) together with the Ph. Eur. Chemical Reference Substance (CRS) for IFN-alfa-2a and IFN-alfa-2b, and in-house reference standards from two manufacturers were used for the quantitative assay. The modified method was successfully transferred to all laboratories despite local variation in equipment. The resolution between the main and the oxidised forms of IFN-alfa-2 was improved compared to the results from the BSP039 study. The improved method even allowed partial resolution of an extra peak after the principal peak. Symmetry of the main IFN peak was acceptable for all samples in all laboratories. Calibration curves established with the Ph. Eur. IFN-alfa-2a and IFN-alfa-2b CRSs showed excellent linearity with intercepts close to the origin and coefficients of determination greater than 0.9995. Assay repeatability, intermediate precision and reproducibility varied with the tested sample within acceptable ranges. Test accuracy estimated by comparing the values obtained by the participants to the declared contents determined by the manufacturers was good despite the absence of a common reference preparation. In conclusion, the present study showed that the new method is suitable, reproducible and transferable. Proposals for the revision of Ph. Eur. texts are presented.

Transferability study of CHO cell clustering assays for monitoring of pertussis toxin activity in acellular pertussis vaccines

Current regulations for acellular pertussis (aP) vaccines require that they are tested for the presence of residual or reversion-derived pertussis toxin (PTx) activity using the mouse histamine sensitisation test (HIST). Although a CHO cell clustering assay can be used by manufacturers to verify if sufficient inactivation of the substance has occurred in-process, this assay cannot be used at present for the final product due to the presence of aluminium adjuvants which interfere with mammalian cell cultures. Recently, 2 modified CHO cell clustering assays which accommodate for the adjuvant effects have been proposed as alternatives to the HIST. These modified assays eliminate the adjuvant-induced cytotoxicity either through dilution of the vaccine (called the Direct Method) or by introducing a porous barrier between the adjuvant and the cells (the Indirect Method). Transferability and suitability of these methods for testing of products present on the European market were investigated during a collaborative study organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). Thirteen laboratories participated in this study which included 4 aP-containing vaccines spiked by addition of PTx. This study also assessed the transferability of a standardised CHO cell clustering assay protocol for use with non-adjuvanted PTx preparations. Results showed that the majority of laboratories were able to detect the PTx spike in all 4 vaccines at concentrations of 4 IU/mL or lower using the Indirect Method. This sensitivity is in the range of the theoretical sensitivity of the HIST. The Direct Method however did not show the expected results and would need additional development work.

prekallikrein activator in albumin BRP batches 4, 5 and 6

An international collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe) to calibrate replacement batches for the current European Pharmacopoeia (Ph. Eur.) prekallikrein activator (PKA) in albumin biological reference preparation (BRP), whose stocks were dwindling. The study was run in the framework of the Biological Standardisation Programme (BSP) of the Council of Europe and the European Union (EU) Commission. Twenty three laboratories from official medicines control authorities and manufacturers in Europe and outside Europe took part in the study. Three candidate replacement batches were produced from the same material as the one used for the World Health Organization (WHO) 2(nd) International Standard (IS) for PKA in albumin (02/168) and the Ph. Eur. PKA in albumin BRP batches 1, 2 and 3. Participants were requested to evaluate the candidate batches against the current WHO IS using their routine assay method. The Ph. Eur. PKA in albumin BRP batch 3 (BRP3) was also included in the test panel to ensure the continuity of the consecutive BRP batches. The study confirmed the stability of the PKA content of the current BRP3. The candidate batches were found to be comparable. Previous data on the starting material support its high stability. Thermal stress study on the candidate batches confirmed the stability of their PKA activity. The Commission of the Ph. Eur. officially adopted in November 2013 the 3 candidate batches as Ph. Eur. PKA in albumin BRP batches 4, 5 and 6 with an assigned content of 38 IU/vial. The activity of the 3 new batches of Ph. Eur. PKA in albumin BRP will be regularly monitored.

Collaborative study for the establishment of the 2(nd) International Standard for Bleomycin Complex A2/B2

Organization (WHO) International Standard (IS) for bleomycin complex A2/B2. Eight laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 1(st) IS for bleomycin complex A2/B2 was used as a reference. Based on the results of the study, the 2(nd) IS for bleomycin complex A2/B2 was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2014 with an assigned potency of 12 500 International Units (IU) per vial. The 2(nd) IS for bleomycin complex A2/B2 is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Establishment of hepatitis A vaccine (inactivated, non-adsorbed) BRP batches 2 and 3

The current hepatitis A vaccine (HAV), inactivated, non-adsorbed, European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) is used for the in vitro potency assay of HAV as prescribed by the Ph. Eur. general chapter 2.7.14 Assay of hepatitis A vaccine. This reference preparation was calibrated in 2008 through an international collaborative study and was assigned a potency of 12 IU/mL. During use of this BRP it appeared to be inapplicable in certain cases due to a low nominal antigen content. Consequently, the European Directorate for the Quality of Medicines and HealthCare (EDQM) established replacement batches for this BRP, calibrated against the 1(st) WHO International Standard (IS) for HAV (inactivated), using the standard in vitro ELISA (enzyme-linked immunosorbent assay) method validated previously. The results of the study showed that the candidate BRPs were suitable for the intended purpose, and following completion of the study, they were adopted in November 2014 by the Ph. Eur. Commission as HAV (inactivated, non-adsorbed) BRP batches 2 and 3, with an assigned potency of 1350 IU/mL, for in vitro antigen content determination by ELISA. As the amount of material in each vial largely exceeds the amount required for the performance of a single assay, the BRPs are to be aliquoted by users as single-use aliquots and refrozen below -50 °C prior to their use as reference preparations.

EDQM biological reference preparation for rabies vaccine (inactivated) for veterinary use

Rabies is a deadly zoonotic disease. Control of rabies in animals by vaccination is an important strategy to protect humans from infection and control the spread of the disease. Requirements for the quality control of rabies vaccines (inactivated) for veterinary use include an in vivo quantitative potency determination as outlined in the Ph. Eur. monograph 0451. Performance of this assay requires a reference preparation calibrated in International Units (IU). A European Pharmacopeia (Ph. Eur.) Biological Reference Preparation (BRP) for rabies vaccines (inactivated) for veterinary use, calibrated in IU, has been established for this purpose. Due to the dwindling stocks of the current batch (batch 4) of Ph. Eur. BRP for rabies vaccines (inactivated) for veterinary use, a collaborative study was run as part of the EDQM Biological Standardisation Programme to establish BRP batch 5. Ten laboratories, including Official Medicines Control Laboratories and manufacturers, participated. The candidate BRP5 was assayed against the 6(th) International Standard for rabies vaccine using the in vivo vaccination-challenge assay (monograph 0451) to assign a potency value. The candidate was also compared to BRP batch 4 to establish continuity. Taking into account the results from the comparisons a potency of 10 IU/vial was assigned and in March 2015 the Ph. Eur. Commission adopted the material as Ph. Eur. BRP for rabies vaccines (inactivated) for veterinary use batch 5. In addition to the in vivo assay 3 laboratories tested the candidate material using their in-house in vitro assays for information.

Establishment of the Ph. Eur. erythropoietin chemical reference substance batch 1

The Erythropoietin (EPO) European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) batch 3 was calibrated in 2006 by in vivo bioassay and was used as a reference preparation for these assays as well as for the physicochemical methods in the Ph. Eur. monograph Erythropoietin concentrated solution (1316). In order to avoid the frequent replacement of this standard and thus reduce the use of animals, a new EPO Chemical Reference Substance (CRS) was established to be used solely for the physicochemical methods. Here we report the outcome of a collaborative study aimed at demonstrating the suitability of the candidate CRS (cCRS) as a reference for the physicochemical methods in the Ph. Eur. monograph. Results from the study demonstrated that for the physicochemical methods currently required in the monograph (capillary zone electrophoresis (CZE), polyacrylamide gel electrophoresis (PAGE)/immunoblotting and peptide mapping), the cCRS is essentially identical to the existing BRP. However, data also indicated that, for the physicochemical methods under consideration for inclusion in a revised monograph (test for oxidised forms and glycan mapping), the suitability of the cCRS as a reference needs to be confirmed with additional work. Further to completion of the study, the Ph. Eur. Commission adopted the cCRS as "Erythropoietin for physicochemical tests CRS batch 1" to be used for CZE, PAGE/immunoblotting and peptide mapping.

Collaborative study for the establishment of the 4(th) International Standard for Streptomycin

An international collaborative study was organised to establish the 4(th) World Health Organization (WHO) International Standard (IS) for Streptomycin. Fourteen laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 3(rd) IS for Streptomycin was used as a reference. Based on the results of the study, the 4(th) IS for Streptomycin was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2015 with an assigned potency of 76 000 International Units (IU) per vial. The 4(th) IS for Streptomycin is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Collaborative study for the establishment of erythropoietin BRP batch 4

The European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for erythropoietin (EPO) is used as a working standard for potency determination of EPO preparations by in vivo bioassay as prescribed in the Ph. Eur. monograph Erythropoietin concentrated solution (1316). The BRP batch 3 was calibrated in 2006 and its stocks are depleted. The European Directorate for the Quality of Medicines & HealthCare (EDQM) thus initiated a project to calibrate a replacement batch in International Units against the WHO 3(rd) International Standard (IS) for Erythropoietin, recombinant, for bioassay (11/170). A Ph. Eur. Chemical Reference Substance (CRS) was established recently for use as reference in some of the physicochemical tests prescribed in the monograph. Therefore, the EPO BRP batch 4 was only calibrated for the normocythaemic and polycythaemic mouse in vivo bioassays described in the Assay section of the Ph. Eur. monograph (1316). The collaborative study involved seven laboratories from Europe, the USA and South America. The results confirmed that the candidate BRP (cBRP) is suitable for use as a reference preparation in the potency determination of EPO medicinal products by bioassay (using the normocythaemic or polycythaemic mouse methods). The outcome of the study enabled the Ph. Eur. Commission to establish the proposed standard as erythropoietin BRP batch 4 in November 2014 for use as a reference preparation solely for the polycythaemic and normocythaemic mouse bioassay, with an assigned potency of 13 000 IU/vial. Furthermore, the potency of BRP3 was confirmed during the study, thus warranting a good continuity of the IU.

Establishment of the human albumin for electrophoresis Ph. Eur. BRP batches 3 and 4

Due to the diminished stocks of the 2nd batch of the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for human albumin for electrophoresis, the European Directorate for the Quality of Medicines & HealthCare (EDQM) initiated in 2014 an international collaborative study for the establishment of two replacement batches. The study was run under the aegis of the Biological Standardisation Programme (BSP). Thirteen laboratories participated in the collaborative study to verify the suitability of the candidate reference preparations according to the Ph. Eur. monograph 0255 using the zone electrophoresis (ZE) method with either cellulose acetate and/or agarose as the testing medium. The candidate preparations were found suitable for the intended purpose and were subsequently adopted in June 2015 by the Ph. Eur. Commission as human albumin for electrophoresis BRP batches 3 and 4 with an assigned range for albumin of 93.8 per cent to 98.3 per cent of the total protein content.

endotoxin biological reference preparation batch 5 and the USP Reference Standard for Endotoxin Lot H0K354

An international collaborative study was organised jointly by the World Health Organization (WHO)/National Institute for Biological Standards and Control (NIBSC), the United States Pharmacopeia (USP) and the European Directorate for the Quality of Medicines & HealthCare (EDQM/Council of Europe) for the establishment of harmonised replacement endotoxin standards for these 3 organisations. Thirty-five laboratories worldwide, including Official Medicines Control Laboratories (OMCLs) and manufacturers enrolled in the study. Three candidate preparations (10/178, 10/190 and 10/196) were produced with the same material and same formulation as the current reference standards with the objective of generating a new (3(rd)) International Standard (IS) with the same potency (10 000 IU/vial) as the current (2(nd)) IS, as well as new European Pharmacopoeia (Ph. Eur.). and USP standards. The suitability of the candidate preparations to act as the reference standard in assays for endotoxin performed according to compendial methods was evaluated. Their potency was calibrated against the WHO 2(nd) IS for Endotoxin (94/580). Gelation and photometric methods produced similar results for each of the candidate preparations. The overall potency estimates for the 3 batches were comparable. Given the intrinsic assay precision, the observed differences between the batches may be considered unimportant for the intended use of these materials. Overall, these results were in line with those generated for the establishment of the current preparations of reference standards. Accelerated degradation testing of vials stored at elevated temperatures supported the long-term stability of the 3 candidate preparations. It was agreed between the 3 organisations that batch 10/178 be shared between WHO and EDQM and that batches 10/190 and 10/196 be allocated to USP, with a common assigned value of 10 000 IU/vial. This value maintains the continuity of the global harmonisation of reference materials and unitage for the testing of endotoxins in parenteral pharmaceutical products. Based on the results of the collaborative study, batch 10/178 was established by the European Pharmacopoeia Commission as the Ph. Eur. Endotoxin Biological Reference Preparation (BRP) batch 5. The same batch was also established by the Expert Committee on Biological Standardisation (ECBS) of WHO as the WHO 3(rd) IS for Endotoxin. Batch 10/190 was adopted as the USP Endotoxin Reference Standard, lot H0K354 and vials from this same batch (10/190) will serve as the United States Food and Drug Administration (USFDA) Endotoxin Standard, EC-7.

Establishment of hepatitis A detection antibodies set BRR batch 3 for antigen content determination by ELISA

The current batch of the European Pharmacopoeia (Ph. Eur.) Biological Reference Reagents (BRRs) used for the in vitro potency assay of hepatitis A vaccines (HAV) by ELISA (enzymelinked immunosorbent assay) was established in 2012 for use in conjunction with Ph. Eur. general chapter 2.7.14 Assay of hepatitis A vaccine. It is composed of a coating reagent and a set of detection antibodies. As stocks of the latter are running low, the European Directorate for the Quality of Medicines & HealthCare (EDQM) organised a collaborative study to qualify replacement batches. The candidate BRR antibodies (primary monoclonal antibody and labelled secondary antibody) were prepared under appropriate conditions from starting materials similar to those used for the current batches. The new batches of antibodies were tested alongside previous batches of BRRs to ensure continuity, and the results confirmed that they were suitable for use in the potency assay of hepatitis A vaccines by ELISA using the standard method referenced in Ph. Eur. general chapter 2.7.14 at the same final concentrations as the previous batches, i.e. 1:500 for the primary monoclonal antibody and 1:400 for the secondary conjugated antibody. The outcome of the study allowed their establishment by the Ph. Eur. Commission in March 2015 as anti-hepatitis A virus primary detection antibody BRR batch 3 and conjugated secondary detection antibody BRR batch 3 respectively. They are available from the EDQM as hepatitis A vaccine ELISA detection antibodies set BRR batch 3.

BRP batch 3

Due to the diminished stocks of the 2(nd) batch of the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) for human immunoglobulin for electrophoresis, in 2013, the European Directorate for the Quality of Medicines and HealthCare (EDQM) initiated an international collaborative study for the establishment of a replacement batch. The study was run under the aegis of the Biological Standardisation Programme (BSP). Seventeen laboratories participated in the collaborative study to verify the suitability of the candidate reference preparation according to the Ph. Eur. monographs 0338 and 0918 using the zone electrophoresis (ZE) method with either cellulose acetate and/or agarose as the testing medium. The candidate preparation was found suitable for the intended purpose and was subsequently adopted by the Ph. Eur. Commission as the human immunoglobulin for electrophoresis BRP batch 3 with an assigned range for immunoglobulin of 79.8 % to 86.4 % of the total protein content.

Heparin sodium BRP batch 3 for chromogenic potency assays

Following the heparin adulteration crisis, the European Pharmacopoeia (Ph. Eur.) Group of Experts on Biologicals (Group 6) considered a revision of the general chapter 2.7.5. Assay of heparin with regard to the assay of the anticoagulant activity of heparin in order to replace the clotting method with more specific chromogenic methods for anti-IIa and anti-Xa activities. An international collaborative study was carried out in 3 phases under the aegis of the Biological Standardisation Programme (BSP) of the Council of Europe and the European Commission in order to recalibrate Heparin sodium Biological Reference Preparation (BRP) batch 3 for these new assays. Phase 1 confirmed the feasibility of the project, but also indicated that the composition of the buffers affects the assay results, thereby highlighting the importance of using common assay procedures. Phase 2 consisted of a collaborative study involving 15 laboratories to calibrate the anti-IIa and anti-Xa activities of Heparin sodium BRP batch 3. The collaborative study confirmed that Heparin sodium BRP batch 3 is suitable for use as a reference preparation in the proposed chromogenic assays for unfractionated heparin. It also showed that the currently defined acceptance limits (90 % to 111 %) can be maintained in the revised Ph. Eur. texts. Phase 3 of the study collected data on the impact of the new unitage on the release of products marketed in Europe. The data from 5 manufacturers, who each reported results from both the clotting and chromogenic assays for a total of 23 batches, indicated that the replacement of the pharmacopoeial method is unlikely to cause batch release issues. Based on the results of this study, the Ph. Eur. Commission assigned Heparin sodium BRP batch 3 with a potency of 1000 IU/vial for both anti-IIa and anti-Xa activities in the chromogenic assays.

Collaborative study for the establishment of the 2nd international standard for neomycin B

An international collaborative study was organised to establish the World Health Organization (WHO) 2nd International Standard (IS) for neomycin B. Seven laboratories from different countries participated. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches of the WHO IS, the 1st IS for neomycin B was used as reference. Based on the results of the study, the 2nd IS for neomycin B was adopted at the meeting of the WHO Expert Committee for Biological Standardization (ECBS) in 2012 with an assigned potency of 17640 International Units (IU) per vial. The 2nd IS for neomycin B is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).

Calibration of Ph. Eur. BRP batch 4 for oral poliomyelitis vaccine (OPV)

Poliomyelitis (polio) is a highly infectious disease that affects mostly young children and which may lead to paralysis and death. Prevalence of polio has considerably decreased. However, the effort of global eradication through immunisation needs to be continued to prevent infection risks in non-vaccinated populations by wild, as well as vaccine-derived, polioviruses. In addition, the stockpile of oral poliomyelitis vaccine (OPV) must be maintaine for emergency cases even after eradication. To this end relevant reference standards must be available for the quality control (QC) of polio vaccines. Stocks of the European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation (BRP) batch 3 for the assay of OPV are dwindling and therefore a collaborative study was initiated by the European Directorate for the Quality of Medicines and HealthCare (EDQM) with the goal to establish a replacement batch as a working standard. Ten laboratories took part in the collaborative study to calibrate the candidate BRP (cBRP), a commercial trivalent OPV containing live attenuated poliovirus types 1, 2 and 3 (Sabin strain), against the WHO 2(nd) International Reference Reagent (IRR) for OPV and, for the sake of continuity, to compare it to the BRP batch 3. Based on the results of the collaborative study, the cBRP appears suitable as a reference standard and the potencies assigned are 7.28, 6.34, 7.01, and 7.52 log10CCID50/mL (CCID50: 50 % Cell Culture Infective Dose) for poliovirus type 1, 2 and 3 and for the total virus content respectively. The cBRP was adopted by the Ph. Eur. Commission at its 146(th) session in June 2013 as Ph. Eur. BRP batch 4 for OPV.

Collaborative study for the establishment of the 3rd international standard for neomycin

An international collaborative study was organised to establish the World Health Organization (WHO) 3(rd) International Standard (IS) for neomycin. Ten laboratories from different countries participated in the collaborative study. The potency of the candidate material, a freeze-dried preparation, was estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 2(nd) IS for neomycin was used as a standard. Based on the results of the study, the 3(rd) IS for neomycin was adopted at the meeting of the WHO Expert Committee on Biological Standardization (ECBS) in 2012 with an assigned potency of 19,050 IU per vial. The 3(rd) IS for neomycin is available from the European Directorate for the Quality of Medicines & HealthCare (EDQM).