A Daas

Publications (54)4.55 Total impact

• Article: International collaborative study for the calibration of the Ph. Eur. Somatropin Chemical Reference Substance Batches 3 and 4 (BSP108).

  M Girard, G Rautmann, A Daas, E Terao, B Lorbetskie, M-A Joly
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  ABSTRACT: An international collaborative study was carried out for the establishment of replacement batches for the European Pharmacopoeia (Ph. Eur.) Somatropin Chemical Reference Substance (CRS) batch 2. The study was organised within the framework of the Biological Standardisation Programme (BSP) of the Council of Europe and the European Commission. Seventeen laboratories from Europe, North America, South America and Australia took part in the collaborative study. The study aimed at calibrating the somatropin content of 2 candidate preparations and demonstrating their suitability to serve as a reference substance in the tests for identification, for related proteins, for dimers and related substances of higher molecular mass (HMM), for charged variants distribution and for the assay of somatropin, as prescribed by the current Ph. Eur. monographs 0950 Somatropin bulk solution, 0951 Somatropin and 0952 Somatropin for injection. Based on the results summarised herein the Ph. Eur. Commission adopted in January 2012 candidate preparation b (cCRS-b, Sample D) as somatropin CRS batch 3 with an assigned content of 3.86 mg of somatropin monomer per vial, and candidate preparation a (cCRS-a, Sample C) as somatropin CRS batch 4 with an assigned content of 2.59 mg of somatropin monomer per vial.
  Pharmeuropa bio & scientific notes. 01/2013; 2013:1-39.
• Article: Collaborative Study for the Establishment of the 3rd International Standard for Dihydrostreptomycin.

  G Rautmann, A Daas, K-H Buchheit
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  ABSTRACT: An international collaborative study was organised to establish the World Health Organization (WHO) 3rd International Standard (IS) for dihydrostreptomycin. Eleven laboratories from different countries participated in the collaborative study. The potency of the candidate batch, a freeze-dried preparation, was estimated by microbiological assays with sensitive microorganisms. To ensure continuity between consecutive batches of the WHO IS, the 2nd IS for dihydrostreptomycin was used as standard. Based on the results of the study, the 3rd IS for dihydrostreptomycin was adopted at the meeting of the WHO Expert Committee on Biological Standardisation (ECBS) in 2011 with an assigned anti-microbiological activity of 19425 International Units (IU) per vial. The 3rd IS for dihydrostreptomycin is available from the EDQM.
  Pharmeuropa bio & scientific notes. 01/2012; 2012:16-38.
• Article: Calibration of the human immunoglobulin BRPs for ACA and molecular size (batch 1) and for Fc function and molecular size (batches 1 & 2).

  E Sandberg, A Costanzo, A Daas, K-H Buchheit
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  ABSTRACT: The current European Pharmacopoeia (Ph. Eur.) Biological Reference Preparation batch 3 (BRP3) for Human Immunoglobulin was established in 2005. Stocks of this BRP are dwindling and a replacement batch is needed to serve as working standard in the tests for distribution of molecular size by HPLC, anticomplementary activity (ACA) and Fc function, in accordance with the requirements of the Ph. Eur. monographs Human normal immunoglobulin (0338) and Human normal immunoglobulin for intravenous administration (0918). The European Directorate for the Quality of Medicines & HealthCare (EDQM) carried out a project (BSP099) to establish replacement batches for this BRP. The project was run in 2 phases, a prequalification phase (Phase 1) and an international collaborative study (Phase 2) involving 19 laboratories. Three batches of candidate materials of various sizes, Samples A, B and C, were procured from 2 different manufacturers on the European market. Based on the results of the study, Sample A was shown to be suitable as a reference standard for the ACA test and for molecular size determination by HPLC, whereas Samples B and C were demonstrated to be suitable for the Fc function test and for the molecular size determination by HPLC. All 3 BRPs are to be used in conjunction with the monographs Human normal immunoglobulin (0338) and Human normal immunoglobulin for intravenous administration (0918). The BRPs were adopted by the Ph. Eur. Commission at its 141st session in November 2011 as official Ph. Eur. Human Immunoglobulin BRPs for ACA and molecular size Batch 1 (Sample A) and Fc function and molecular size Batch 1 and Batch 2 (Samples B and C respectively).
  Pharmeuropa bio & scientific notes. 01/2012; 2012:1-15.
• Article: New BRP for human plasma calibrated for coagulation factors V, VIII, XI and XIII - collaborative study for establishment of batches 1 and 2.

  P Bayer, A Daas, C Milne
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  ABSTRACT: A human plasma reference preparation in International Units (IU) must be used in each potency assay of the human coagulation factors V, VIII and XI in human plasma pooled and treated for virus inactivation, according to the European Pharmacopoeia (Ph. Eur.) monograph 1646 and general chapters 2.7.4 and 2.7.22 respectively, and in the potency assay of human coagulation factor XIII in fibrin sealant kits, according to Ph. Eur. monograph 0903. International reference standards for all of these factors are now established, however, regional reference standards were not available for the required routine use. It was therefore proposed by European OMCLs and manufacturers to establish a European reference preparation, and it was the goal of this study to accomplish that. Two candidate biological reference preparations (BRPs), separate lyophilisation lots of the same normal human plasma bulk material, were calibrated against the International Standards (ISs) for human coagulation factors V, VIII, XI and XIII. Twelve European laboratories including OMCLs and manufacturers participated. The candidate material was tested against the ISs in 4 separate assays for each factor using the methods described in the relevant Ph. Eur. monographs and general chapters. No discernable difference was noted between the activities of the 2 candidates. They were shown to be suitable for their intended use and it was recommended to assign to both batches a potency of 0.73 IU/mL for factor V, 0.74 IU/mL for factor VIII, 0.59 IU/mL for factor XI and 0.79 IU/mL for factor XIII. Candidate batch B is proposed to be used first as lot 1, followed upon its depletion by candidate batch A (lot 2). The BRP batches will be monitored regularly for potency throughout their lifetime. EDQM BRP batches 1 and 2 of coagulation factors V, VIII, XI and XIII plasma were formally adopted by the Ph. Eur. Commission at their session in June 2011.
  Pharmeuropa bio & scientific notes. 11/2011; 2011(2):16-25.
• Article: Collaborative study for the establishment of the second international standard for vancomycin.

  G Rautmann, A Daas, K-H Buchheit
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  ABSTRACT: An international collaborative study has been organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish the World Health Organization (WHO) 2nd International Standard (IS) for Vancomycin. Twelve laboratories from 10 different countries participated. The potency of the candidate material, a freeze-dried preparation, was estimated by microbiological assays with sensitive micro-organisms. As the stocks of the 1st IS for Vancomycin had been completely depleted, in order to ensure continuity between consecutive batches of the WHO IS, the European Pharmacopoeia Chemical Reference Standard (CRS) for Vancomycin batch 2 was used as a standard. It had been calibrated in a large international collaborative study against the WHO 1st IS for Vancomycin. Based on the results of the study, the 2nd IS for Vancomycin was adopted at the meeting of the WHO Expert Committee on Biological Standardisation (ECBS) in 2010 with an assigned antimicrobiological activity of 109,700 IU per vial. The 2nd IS for Vancomycin is available from the EDQM.
  Pharmeuropa bio & scientific notes. 11/2011; 2011(2):1-15.
• Source

  Available from: Emanuele Montomoli

  Article: Collaborative study on influenza vaccine clinical trial serology - part 2: reproducibility study.

  J M Wood, E Montomoli, R W Newman, A Daas, K-H Buchheit, E Terao
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  ABSTRACT: A collaborative study was run by the Biological Standardisation Programme (BSP) under the aegis of the European Directorate for the Quality of Medicines & HealthCare (EDQM, Council of Europe) and the European Union (EU) Commission, to address the issue of the poor standardisation of serological assays used for the evaluation of seasonal influenza vaccines in Europe. The Phase 1 of the study focused on the compliance to Committee for Human Medicinal Products (CHMP) criteria by 6 manufacturers and 5 public laboratories. It confirmed the poor inter-laboratory correlation of haemagglutination inhibition (HI) test results. Phase 2 consisted in a reproducibility study examining the impact of extended method standardisation and the use of reference sera on inter-laboratory variation. Six manufacturers and 5 public laboratories contributed HI results, while the 5 public laboratories also performed single radial haemolysis (SRH) tests on the same sample panels. Results showed that method standardisation failed to significantly improve the inter-laboratory variation. Correction for pre-vaccination titres (Beyer correction) was found to have limited effect to improve the bias constituted by the Protection Rate (PR) criterion. The reasons underlying the difficulty in standardisation of HI and SRH tests are discussed and improved approaches for the compliance testing to CHMP criteria are suggested.
  Pharmeuropa bio & scientific notes. 06/2011; 2011(1):36-54.
• Article: Collaborative study on influenza vaccine clinical trial serology - part 1: CHMP compliance study.

  J M Wood, R W Newman, A Daas, E Terao, K-H Buchheit
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  ABSTRACT: The Quality of Medicines & HealthCare (EDQM, Council of Europe) and the European Union (EU) Commission to evaluate the reproducibility of clinical serology results for seasonal influenza vaccines and to assess the impact of technical differences between laboratories on the compliance with the Committee for Human Medicinal Products (CHMP) criteria set by the European Medicines Agency (EMA). The study was run in 2 phases. The present article reports the 1st phase of the study, which aimed at evaluating the variability of the results obtained by 11 laboratories (5 national control laboratories and 6 influenza vaccine manufacturers) using their routine haemagglutination inhibition (HI) assay to test a common panel of clinical trial sera. The results confirmed the limited inter-laboratory reproducibility of the HI testing of influenza vaccine clinical trial samples. In some cases a good agreement was found between laboratories, while a systematic bias or a random scatter of results was observed in other cases. Analysis of estimated systematic bias confirmed that differences between laboratories can be significant (up to 16-fold) in some cases. Correction for this bias resulted in limited improvement. Differences between laboratories were found to result in discrepant decisions on marketing acceptance of vaccines or to decisions based on compliance to different criteria. The study showed that the seroconversion (SC) and mean fold increase (MFI) criteria are more robust against systematic over- or under-estimation of titres whereas the protection rate (PR) is very sensitive to this effect. The fundamental issues with the PR criteria are discussed.
  Pharmeuropa bio & scientific notes. 06/2011; 2011(1):27-35.
• Article: Calibration of the Ph. Eur. Biological Reference Preparation (BRP) for tetanus vaccine (adsorbed) batch 3.

  R Tierney, J Hockley, P Rigsby, E Terao, A Daas, K-H Buchheit, D Sesardic
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  ABSTRACT: A joint collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) and the World Health Organization (WHO)/National Institute for Biological Standards and Control (NIBSC) to establish replacement batches for the European Pharmacopoeia (Ph. Eur.) Tetanus Vaccine (adsorbed) Biological Reference Preparation (BRP) batch 2 and for the WHO 3rd International Standard (IS) for Tetanus toxoid (adsorbed). Two freeze-dried stabilised tetanus vaccine (adsorbed) candidate preparations (Preparation A, 08/218 and Preparation B, 08/102) were calibrated against the current 3rd IS/BRP batch 2 (Preparation C) using challenge methods in guinea pigs and mice as described in the Ph. Eur. general chapter 2.7.8. Assay of tetanus vaccine (adsorbed). They were also assayed by serology methods. The WHO 2nd IS for Tetanus toxoid adsorbed (TEXA-2) was additionally included in the sample panel as Preparation D. Thirty-four laboratories (regulatory organisations and manufacturers) from 22 countries participated in the collaborative study. The majority of participants performed 2 independent challenge tests. Nine laboratories performed challenge assays in guinea pigs and 30 laboratories performed challenge assays in mice. Eight laboratories performed serology in guinea pigs and 1 laboratory performed serology in mice. For Preparation A, the geometric mean (GM) potency estimate (with 95 % confidence interval (CI)) in guinea pigs for all laboratories that provided valid results (n = 6) was 488.5 (354.2-673.6) IU/ampoule. For valid mouse assays (n = 25) the GM potency (with 95 % CI) was 259.8 (223.5-302.0) IU/ampoule. The inter-laboratory geometric coefficient of variation (GCV) was 36 % for guinea pig assays and 45 % for mouse assays. This compared favourably with the calibration of the 3rd IS/BRP batch 2 where the inter-laboratory GCV was 36 % and 42 % in guinea pigs and mice, respectively. For Preparation B, the GM potency estimate (with 95 % CI) in guinea pigs for all laboratories that provided valid results (n = 6) was 107.9 (64.1-181.7) IU/ampoule. For valid mouse assays (n = 24) the GM potency (with 95 % CI) was 147.9 (126.3-173.1) IU/ampoule. The inter-laboratory GCV was 64.3 % for guinea pig assays and 45.2 % for mouse assays. From the collaborative study, Preparation A appeared more suitable to be the replacement Ph. Eur. BRP as it is similar to the Tetanus vaccine (adsorbed) BRP batch 2, except for nature of the stabiliser. Preparation A was confirmed to have higher potency, readily detectable tetanus toxoid, and confirmed satisfactory stability and performance in challenge assays. Preparation A was adopted in January 2011 by the Ph. Eur. Commission as the Tetanus vaccine (adsorbed) BRP batch 3, with assigned potencies of 490 IU/ampoule in the guinea pig challenge assay and of 260 IU/ampoule in the mouse challenge assay. The same Preparation A was adopted in October 2010 as the WHO 4th IS for Tetanus toxoid (adsorbed), with the assigned activity of 490 IU/ampoule from guinea pig challenge assays. A follow-up study (reporting study) was organised by the EDQM to assess the impact of the potency assigned to the BRP batch 3 for mouse challenge assays on the outcome of batch release testing in Europe. Eight laboratories including official medicines control laboratories (OMCLs) and manufacturers reported the results of their routine testing, using the BRP batch 3 in addition to their regular reference preparation. For each tested product, participants calculated the potency relative to their routine reference and relative to the BRP batch 3. No common sample panel was distributed to participants. In total, data on 40 batches of different marketed tetanus vaccines were reported. Overall, a good concordance was observed between the potencies calculated relative to the BRP batch 2 and relative to the BRP batch 3. On average, the potency estimates were 10 % lower when expressed relative to the BRP batch 3. Cases of discrepant decisions for batch release were very limited and affected mainly batches with specifications close to the pharmacopoeial requirements. The reasons for differences in estimated potencies are discussed. The study showed that the use of the BRP batch 3 with an assigned potency of 260 IU/ampoule does not result in substantial change in the potency of different marketed products. This confirmed that the mouse challenge potency value assigned to the BRP batch 3 is suitable.
  Pharmeuropa bio & scientific notes. 06/2011; 2011(1):1-26.
• Article: Collaborative study for the establishment of replacement batches of heparin low- molecular-mass for assay biological reference preparations.

  E Terao, A Daas, G Rautmann, K-H Buchheit
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  ABSTRACT: A collaborative study was run by the European Directorate for the Quality of Medicines & HealthCare (EDQM) in the context of the Biological Standardisation Programme (BSP), under the aegis of the Council of Europe and the European Commission, to establish replacement batches for the dwindling stocks of the Heparin low-molecular-mass for assay European Pharmacopoeia Biological Reference Preparation (BRP). The replacement batches of BRP are intended to be used in the assays for anti-Xa and anti-IIa activities, as described in the European Pharmacopoeia (Ph. Eur.) monograph Heparins, low-molecular-mass (0828). Three freeze-dried candidate batches were calibrated against the current International Standard (IS) for Heparin, lowmolecular- weight (2nd IS, 01/608). For the purpose of the continuity check between subsequent BRP batches, the current Heparin low-molecular-mass for assay BRP (batch 5) was also included in the test panel. Thirteen official medicines control and manufacturers laboratories from European and non-European countries contributed data. A central statistical analysis of the datasets was performed at the EDQM. On the basis of the results, the 3 candidate materials were assigned a potency of 104 IU/vial for the anti-Xa activity and 31 IU/vial for the anti-IIa activity. Taken into account the preliminary stability data and the results of this collaborative study, the 3 batches of candidate BRP were adopted in June 2010 by the Commission of the Ph. Eur. as Heparin low-molecular-mass for assay BRP batches 6, 7 and 8.
  Pharmeuropa bio & scientific notes. 10/2010; 2010(2):30-6.
• Article: Collaborative study for validation of a serological potency assay for rabies vaccine (inactivated) for veterinary use.

  B Krämer, L Bruckner, A Daas, C Milne
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  ABSTRACT: European Pharmacopoeia (Ph. Eur.) monograph 0451 on Rabies vaccine (inactivated) for veterinary use describes an in vivo batch potency test that is based on the NIH test. This assay uses a large number of mice and results in a significant degree of suffering. In the interest of replacement, reduction and refinement of animal tests (3R) a serological potency assay for Rabies vaccine (inactivated) for animal use, developed and validated at the Paul-Ehrlich-Institut, has been assessed in a collaborative study organised by the EDQM (European Directorate for the Quality of Medicines & HealthCare). The goal was to demonstrate the wider transferability of the proposed assay and confirm its suitability. The study involved 13 laboratories and assessed 4 different vaccines from the EU market. Results of the study confirm that a limit test using a relatively small number of animals in a serological assay is possible, reproducible and reliable. The optimal number of animals per vaccine is product specific but may roughly be indicated to be between 8 and 10 for the products included in this study. Non-responders should be included in the analysis because they may reflect sub-potent vaccines. However, there may be a need to impose a maximum on the number of non-responders allowed for the reference vaccine as a monitor for assay validity. This assay provides a significant 3R improvement in terms of both the number of animals used and the amount of suffering entailed and provides a more reliable and reproducible assay format than the vaccination challenge assay. It also reduces the time required as compared to the vaccination challenge assay. It has been recommended to the Ph. Eur. group of experts 15V that this assay be included as an alternative to the batch potency assay in the Ph. Eur. monograph 0451.
  Pharmeuropa bio & scientific notes. 10/2010; 2010(2):37-55.
• Article: Collaborative study for the establishment of the second international standard for gramicidin.

  G Rautmann, A Daas, K-H Buchheit
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  ABSTRACT: An international collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish the WHO second International Standard (IS) for gramicidin as the stocks of the 1st IS, established in 1964, were close to depletion. The candidate material did not show any sign of potency loss when kept at elevated temperatures of + 4 °C, + 20 °C, + 37 °C and + 45 °C for 3 months. Six laboratories from 5 countries as well as the EDQM laboratory participated in the collaborative study. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 1st IS for gramicidin was used as standard. Based on the results of the study, the 2nd IS for gramicidin was adopted at the meeting of the WHO Expert Committee on Biological Standardization (ECBS) in 2008 with an assigned potency of 1070 International Units per mg (IU/mg). The 2nd IS for gramicidin is available from the EDQM.
  Pharmeuropa bio & scientific notes. 10/2010; 2010(2):56-67.
• Article: Collaborative study for the establishment of the third international standard for nystatin.

  G Rautmann, E Charton, A Daas, K-H Buchheit
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  ABSTRACT: Due to the depletion in stocks of the World Health Organization (WHO) 2nd International Standard (IS) for nystatin, an international collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish a replacement batch. Seventeen laboratories participated in the collaborative study, performing the microbiological diffusion assay to estimate the potency of the candidate 3rd International Standard for nystatin. The 2nd International Standard for nystatin was used as a standard to ensure the continuity of the unitage. Follow-up accelerated degradation studies demonstrated that the IS is stable when at the customary storage temperature of - 20 °C. The 3rd IS for nystatin was adopted by the WHO Expert Committee on Biological Standardization (ECBS) in 2006 with an assigned potency of 5710 International Units per mg (IU/mg). The 3rd IS for nystatin is available from the EDQM.
  Pharmeuropa bio & scientific notes. 10/2010; 2010(2):68-85.
• Article: Collaborative study for the validation of alternative in vitro potency assays for human tetanus immunoglobulins.

  S Gross, S W J Janssen, B de Vries, E Terao, A Daas, K-H Buchheit
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  ABSTRACT: An international collaborative study to validate 2 alternative in vitro methods for the potency testing of human tetanus immunoglobulin products was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM). The study, run in the framework of the Biological Standardisation Programme (BSP) under the aegis of the European Commission and the Council of Europe, involved 21 official medicines control and industry laboratories from 15 countries. Both methods, an enzyme-linked immunoassay (EIA) and a toxoid inhibition assay (TIA), showed good reproducibility, repeatability and precision. EIA and TIA discriminated between low, medium and high potency samples. Potency estimates correlated well and both values were in close agreement with those obtained by in vivo methods. Moreover, these alternative methods allowed to resolve discrepant results between laboratories that were due to product potency loss and reporting errors. The study demonstrated that EIA and TIA are suitable quality control methods for tetanus immunoglobulin, which can be standardised in a control laboratory using a quality assurance system. Consequently, the Group of Experts on Human Blood and Blood Products of the European Pharmacopoeia revised the monograph on human tetanus immunoglobulins to include both the methods as compendial alternatives to the in vivo mouse challenge assay.
  Biologicals 07/2010; 38(4):501-10. · 1.70 Impact Factor
• Article: Collaborative study for the establishment of the second international standard for amphotericin B.

  G Rautmann, A Daas, K-H Buchheit
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  ABSTRACT: An international collaborative study was organised by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish the WHO second International Standard (IS) for amphotericin B as the stocks of the 1st IS, established in 1963, were close to depletion. The candidate material did not show any sign of potency loss when kept at elevated temperatures of + 4 degrees C, + 20 degrees C, + 37 degrees C and + 45 degrees C for 3 months. Ten laboratories from 8 countries participated in the collaborative study. Potencies of the candidate material were estimated by microbiological assays with sensitive micro-organisms. To ensure continuity between consecutive batches, the 1st IS for amphotericin B was used as the standard. Based on the results of the study, the 2nd IS for amphotericin B was adopted at the meeting of the WHO Expert Committee on Biological Standardisation (ECBS) in 2007 with an assigned potency of 944 International Units per mg (IU/mg). The 2nd IS for Amphotericin B is available from the EDQM.
  Pharmeuropa bio & scientific notes. 04/2010; 2010(1):1-13.
• Article: Establishment of a biological reference preparation for hepatitis A vaccine (inactivated, non-adsorbed).

  J Stalder, A Costanzo, A Daas, G Rautmann, K-H Buchheit
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  ABSTRACT: A reference standard calibrated in International Units (IU) is needed for the in vitro potency assay of hepatitis A vaccines prepared by formalin-inactivation of purified hepatitis A virus grown in cell cultures. Thus, a project was launched by the European Directorate for the Quality of Medicines & HealthCare (EDQM) to establish one or more non-adsorbed inactivated hepatitis A vaccine reference preparation(s) as working standard(s), calibrated against the 1st International Standard (IS), for the in vitro potency assay (ELISA) of all vaccines present on the European market. Four non-adsorbed liquid preparations of formalin-inactivated hepatitis A antigen with a known antigen content were obtained from 3 manufacturers as candidate Biological Reference Preparations (BRPs). Thirteen laboratories participated in the collaborative study. They were asked to use an in vitro ELISA method adapted from a commercially available kit for the detection of antibodies to hepatitis A virus. In-house validated assays were to be run in parallel, where available. Some participants also included commercially available hepatitis A vaccines in the assays, after appropriate desorption. During the collaborative study, several participants using the standard method were faced with problems with some of the most recent lots of the test kits. Due to these problems, the standard method did not perform satisfactorily and a high number of assays were invalid, whereas the in-house methods appeared to perform better. Despite this, the overall mean results of the valid assays using both methods were in agreement. Nonetheless, it was decided to base the assignment of the potency values on the in-house methods only. The results showed that all candidate BRPs were suitable for the intended purpose. However, based on availability of the material and on the results of end-product testing, 2 candidate reference preparations, Samples C and D, were selected. Both were from the same batch but filled on different days; no statistically significant difference in potency was observed. They were thus combined in 1 single batch. The candidate preparation (Sample C/D) was adopted at the June 2009 session of the European Pharmacopoeia (Ph. Eur.) Commission as the Ph. Eur. BRP batch 1 for hepatitis A vaccine (inactivated, non-adsorbed), with an assigned potency of 12 IU/ml for in vitro antigen content assays. Accelerated degradation studies have been initiated. The preliminary data show that the BRP is stable at the recommended storage temperature (< -50 degrees C). The BRP will be monitored at regular intervals throughout its lifetime.
  Pharmeuropa bio & scientific notes. 04/2010; 2010(1):15-29.
• Article: Calibration of human coagulation factor VII concentrate Ph. Eur. BRP batch 2.

  J Dodt, A Costanzo, A Daas, A Hunfeld, K-H Buchheit
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  ABSTRACT: The potency assay of human coagulation factor VII concentrate preparations as described in the European Pharmacopoeia (Ph. Eur.) requires a reference preparation calibrated in International Units (IU). The current Ph. Eur. Biological Reference Preparation (BRP) batch 1 was established in 2005 during an international collaborative study. It has an assigned potency of 8.2 IU/vial for the chromogenic assay method. Stocks of this BRP are dwindling and a replacement batch needs to be established. A candidate material was produced by a manufacturer from a plasma-derived concentrate preparation, with the same formulation and approximately the same potency, in the interest of continuity. The candidate material fulfilled the requirements of a BRP with regard to precision and homogeneity of fill, residual water content and stability. The potency of the candidate BRP (cBRP) was determined using chromogenic assays as required by the Ph. Eur. and in-house clotting assays in an attempt to assign a potency for both methods, as is the case for the current batch. The statistical model used for most laboratories was the maximum likelihood of the parallel line model using a logarithmic transformation of the responses. In the chromogenic assay, a potency of 9.9 IU/vial (+/- 1.8 %) was obtained for the cBRP with a very good consistency between laboratories. The results from the clotting assay, however, were less homogenous and yielded consistently higher results (13 IU/vial +/- 12 %), probably due to a higher activated factor VII (FVIIa) content than in the current BRP (3 % as compared to 0.3 %). Due to the large difference between the values obtained with the 2 different methods, it was not possible to reconcile the outcomes with each other. On the other hand, the uncertainty observed with the clotting assay method was quite large and seemed questionable for a reference preparation. Therefore the use of BRP batch 2 as a reference for the clotting assay method is not recommended. Nevertheless, the results of the study showed that the candidate BRP (cBRP) is suitable as a reference standard for the chromogenic assay according to the Ph. Eur. general chapter 2.7.10 Assay of human coagulation factor VII. It was adopted by the Ph. Eur. Commission in December 2009 as an official Ph. Eur. BRP for human coagulation factor VII concentrate with an assigned potency of 9.9 IU/vial.
  Pharmeuropa bio & scientific notes. 04/2010; 2010(1):31-8.
• Article: Collaborative study for the standardisation of the histamine sensitizing test in mice and the CHO cell-based assay for the residual toxicity testing of acellular pertussis vaccines.

  D Xing, A Maes, M-E Behr-Gross, A Costanzo, A Daas, K-H Buchheit
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  ABSTRACT: The European Pharmacopoeia (Ph. Eur.) and the World Health Organisation (WHO) require the performance of extensive quality and safety control testing before the release on the market of vaccine products for human use. Safety testing with regard to residual pertussis toxin (PT) in acellular pertussis combination vaccines is performed through assessment of fatal sensitisation of mice to histamine challenge by the vaccine product under test. Currently, use of different in-house procedures and no requirement for the inclusion of a standard reference in each assay render comparisons of results obtained for identical vaccine batches between different control laboratories very difficult. At the initiative of the European Directorate for the Quality of Medicines and HealthCare (EDQM), an international collaborative study was organised for the standardization of the Histamine Sensitizing Test (HIST) in mice and the Chinese Hamster Ovary (CHO)-cell-based assay (performed at the bulk product level) for the residual toxicity testing of acellular pertussis vaccines or acellular pertussis-based combination vaccines. The study was run under the aegis of the Biological Standardisation Programme, jointly supported by the Council of Europe and the European Commission under the project code BSP076. Ten (10) laboratories participated in the study and were requested to perform 3 independent Histamine Sensitizing Tests in mice and to report results of the lethal end-point measurement as prescribed by the Ph. Eur. monographs. Some of them also reported data from an in-house validated CHO-cell-based assay. In addition, some of the laboratories reported concomitantly data obtained by measurement of the drop in temperature induced after the histamine challenge, a method currently under investigation to be added as an alternative end-point for the HIST in the Ph. Eur. monographs for acellular pertussis-based combination vaccines in order to alleviate animal suffering (in application of the 3Rs principle). Based on the results of the collaborative study, a potency of 7500 IU/vial (International Units per vial) was assigned to the current Ph. Eur. Biological Reference Preparation (BRP) for PT. The results of the study also show that 1) intra- and inter-laboratory variations can be improved by the use of a validated standard operating procedure; 2) inclusion in each assay of a standard reference sample, calibrated in IU, can increase comparability of results among laboratories and thus help to reduce repeat testing; 3) a correlation between mortality data and temperature data was observed although, due to the limited number of data sets and the lack of a common method for the temperature end-point, further investigation of this point is required; 4) the CHO-cell-based assay did not yield comparable results and further standardisation of the assay procedure may be investigated in a follow-up project.
  Pharmeuropa bio & scientific notes. 04/2010; 2010(1):51-63.
• Article: Collaborative study for the validation of alternative in vitro potency assays for human tetanus immunoglobulin.

  S Gross, S W J Janssen, B de Vries, E Terao, A Daas, K-H Buchheit
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  ABSTRACT: The European Pharmacopoeia (Ph. Eur.) monograph Human tetanus immunoglobulin (0398) gives a clear outline of the in vivo assay to be performed to determine the potency of human tetanus immunoglobulins during their development. Furthermore, it states that an in vitro method shall be validated for the batch potency estimation. Since no further guidance is given on the in vitro assay, every control laboratory concerned is free to design and validate an in-house method. At the moment there is no agreed in vitro method available. The aim of this study was to validate and compare 2 alternative in vitro assays, i.e. an enzyme-linked immunoassay (EIA) and a toxoid inhibition assay (TIA), through an international collaborative study, in view of their eventual inclusion into the Ph. Eur.. The study was run in the framework of the Biological Standardisation Programme (BSP), under the aegis of the European Commission and the Council of Europe. The collaborative study reported here involved 21 laboratories (public and industry) from 15 countries. Initially, 3 samples with low, medium and high potencies were tested by EIA and TIA. Results showed good reproducibility and repeatability of the 2 in vitro methods. The correlation of the data with the in vivo potency assigned by the manufacturers however appeared initially poor for high potency samples. Thorough re-examination of the data showed that the in vivo potencies assigned by the manufacturers had to be corrected: one for potency loss at the time of in vitro testing and one because of a reporting error. After these corrections the values obtained by in vivo and in vitro methods were in close agreement. A supplementary collaborative work was carried out to validate the 2 methods for immunoglobulin products with high potencies. Eight laboratories (public and industry) took part in this additional study to test 3 samples with medium and high potencies by EIA and TIA. Results confirmed that the 2 alternative methods are comparable in terms of assay repeatability, precision and reproducibility. In all laboratories, both methods discriminated between the low, medium and high potency samples. Analysis of the data collected in this study showed a good correlation between EIA and TIA potency estimates as well as a close agreement between values obtained by in vitro and in vivo methods. The study demonstrated that EIA and TIA are suitable quality control methods for polyclonal human tetanus immunoglobulin, which can be standardised in a quality control laboratory using a quality assurance system. Consequently, the Ph. Eur. Group of Experts 6B on Human Blood and Blood products decided in April 2009 to include both methods as examples in the Ph. Eur. monograph 0398 on Human Tetanus immunoglobulin.
  Pharmeuropa bio & scientific notes. 10/2009; 2009(1):11-25.
• Article: Establishment of the Ph. Eur. BRP for varicella vaccine batch 1.

  A M Akkermans, G Waeterloos, K Kemiha, A Daas, C Milne
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  ABSTRACT: The European Pharmacopoeia (Ph. Eur.) monograph for varicella vaccine (live) (0648) requires a vial of an appropriate reference material to be titred in triplicate to validate each assay and the virus concentration of the reference preparation is monitored using a control chart to determine the assay consistency. An international collaborative study involving 9 participants from 7 countries and including both OMCLs and manufacturers was carried out to establish a common reference material for this purpose and establish a Ph. Eur. Biological Reference Preparation. Two candidate reference preparations (X and Y), obtained from 2 different EU manufacturers, were assayed by the participants using their in-house PFU assay methods. Both candidates were found to be suitable for this purpose. Based on logistical considerations, candidate X (4.37 log(10)0 PFU/vial) has been established as BRP batch 1 of varicella vaccine (live) and was adopted at the June 2009 session of the European Pharmacopoeia Commission for immediate use. Candidate Y (3.82 log(10) PFU/vial) will be established as BRP batch 2 upon depletion of BRP batch 1 provided that the stability data supports this.
  Pharmeuropa bio & scientific notes. 10/2009; 2009(1):41-54.
• Article: Collaborative study on a Guinea pig serological method for the assay of acellular pertussis vaccines.

  R Winsnes, D Sesardic, A Daas, E Terao, M-E Behr-Gross
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  ABSTRACT: An international collaborative study (coded BSP083) was performed under the aegis of the Biological Standardisation Programme supported by the Council of Europe and the European Commission, with the aim of replacing the in vivo challenge assays for potency determination of combined acellular pertussis (aP) vaccines by a refined procedure also allowing reduction of animal use. This study investigates whether the immunogenicity of aP vaccine components could be assayed in a guinea pig (gp) serology model, using the same vaccine immunising doses as for D and T components potency testing, instead of using separate animals as is currently done. The BSP83 project is a follow up of 3 former collaborative studies (coded BSP019, BSP034 and BSP035) on serological methods for the potency testing of tetanus (T) and diphtheria (D) vaccines for human use. The use of gp instead of mice serology has the advantage of providing a larger volume of good quality antiserum for the assay of several vaccine components in the same sample, hence providing the opportunity for animal sparing. The results of Phase I of the study demonstrated that gp serology may be a useful method for the immunogenicity assay of acellular pertussis vaccines. This was confirmed in Phase II of the study, using 7 different combined aP vaccines in an international collaborative study involving 17 laboratories from both public and private sectors. Clear dose-response relationships were observed for different vaccines by ELISA, for antibodies against aP antigens, i.e. pertussis toxin (PT), filamentous haemagglutinin (FHA), fimbrial agglutinogens-2/3 (Fim 2/3) and pertactin (PRN). Intra- and inter-laboratory variations of aP ELISA results were found to be within an acceptable range. For some combined vaccines, however, the range of vaccine dilutions for immunisation confirmed to be optimal for D and T potency testing may not provide optimal dose-response for all aP components. Method adjustments may thus be required and suitability should therefore be demonstrated for each vaccine combination and product prior to the application of this assay. The results of this study support the use of the gp serological method for the determination of the immunogenicity of aP vaccines. The application of the method for batch release testing of combined D, T and aP vaccines could significantly contribute to the implementation of the 3R principles through reduction of animal use and improved animal welfare, whilst reducing costs. As an outcome of this study, the Group of Experts No. 15 on Sera and Vaccines of the European Pharmacopoeia (Ph. Eur.) decided in February 2009 to include the gp serological assay as an example in the Ph. Eur. General chapter 2.7.16. on acellular pertussis vaccine assay.
  Pharmeuropa bio & scientific notes. 10/2009; 2009(1):27-40.