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Marlies Halder

Publications and source records attributed to Marlies Halder.

14 recordsLinked to original sources
PubMed2006

International validation of pyrogen tests based on cryopreserved human primary blood cells.

Pyrogens as fever-inducing agents can be a major health hazard in parenterally applied drugs. For the control of these contaminants, pyrogen testing for batch release is required by pharmacopoeias. This has been done either by the in vivo rabbit pyrogen test (since 1942) or the limulus amoebocyte lysate test (LAL), since 1976. New approaches include cell-based assays employing in vitro culture of human immune cells which respond e.g. by cytokine production (IL-1beta; IL-6) upon contact with pyrogens. Six variants of these assays have been validated in a collaborative international study. The recent successful development of cryopreservation methods promises to make standardized immunoreactive primary human blood cells available for widespread use. Furthermore, the pretesting of donors for infectious agents such as HIV or hepatitis has made it possible to develop a safe and standardised reagent for pyrogen testing. Using a total of 13 drugs, we have validated the pyrogen test based on fresh and cryopreserved human whole blood in four laboratories. The test reached >90% sensitivity and specificity. In contrast to the LAL, the test was capable of detecting non-endotoxin pyrogens derived from Gram-positive bacteria or fungi.

Animal Testing Alternatives↗
PubMed2004

A modular approach to the ECVAM principles on test validity.

The European Centre for the Validation of Alternative Methods (ECVAM) proposes to make the validation process more flexible, while maintaining its high standards. The various aspects of validation are broken down into independent modules, and the information necessary to complete each module is defined. The data required to assess test validity in an independent peer review, not the process, are thus emphasised. Once the information to satisfy all the modules is complete, the test can enter the peer-review process. In this way, the between-laboratory variability and predictive capacity of a test can be assessed independently. Thinking in terms of validity principles will broaden the applicability of the validation process to a variety of tests and procedures, including the generation of new tests, new technologies (for example, genomics, proteomics), computer-based models (for example, quantitative structure-activity relationship models), and expert systems. This proposal also aims to take into account existing information, defining this as retrospective validation, in contrast to a prospective validation study, which has been the predominant approach to date. This will permit the assessment of test validity by completing the missing information via the relevant validation procedure: prospective validation, retrospective validation, catch-up validation, or a combination of these procedures.

Animal Testing Alternatives↗
PubMed2003

ECVAM's response to the changing political environment for alternatives: consequences of the European Union chemicals and cosmetics policies.

The European Centre for the Validation of Alternative Methods (ECVAM) has restructured its services by directly targeting the animal tests that need to be replaced. In view of the short time-lines for making available and implementing validated methods, ECVAM is offering to steer the process by bringing together the inputs of stakeholders and encouraging the early involvement of regulators. In essence, steering groups formed by ECVAM senior staff, and complemented with external experts, will carry out the project management and will coordinate the various inputs.

Administration, Topical↗
PubMed2002

Physicochemical methods for predicting the biological potency of recombinant follicle stimulating hormone: an international collaborative study of isoelectric focusing and capillary zone electrophoresis.

Two methods for predicting the specific in vivo bioactivity of recombinant follicle stimulating hormone (FSH), based on quantitative measures of isoform distribution by isoelectric focusing (IEF)(1) and by capillary zone electrophoresis (CZE)(2) respectively, have been subjected to an international collaborative study by six laboratories from six countries. Both methods were used to estimate the predicted bioactivities of four preparations of follitropin beta, coded FSH A-D, differing widely in their isoform compositions and specific bioactivities. The mean predicted estimate of potency by IEF and CZE for each FSH preparation by each laboratory was within 80-125% of its potency estimated by bioassay, except for the mean estimates by CZE of that for FSH A by one laboratory and of that of FSH D by another. Each of the six laboratories using the IEF method, and each of the five laboratories using the CZE method were able to rank these FSHs according to their bioactivities, namely FSH B>FSH C>FSH A>FSH D. All laboratories were able to use both IEF and CZE to discriminate between FSH A and C, with bioactivities within 76-132% of one another. Four of six laboratories were able to use IEF, and two of five laboratories were able to use CZE, to discriminate between FSH B and C, with bioactivities within 89-112% of one another. This suggests that the accuracy and precision of both these methods should be sufficient to discriminate between FSHs which would meet or fail European Pharmacopoeia requirements for this type of hormone, since these stipulate that estimates of potency should fall between 80-125% of its stated potency. Using in most cases duplicate estimates in two independent assays, and excluding Laboratory 4, the pooled intra-laboratory geometric coefficient of variation (GCV) was about 4% for both IEF and CZE, and the inter-laboratory GCV was about 7% for IEF and about 10% for CZE. The use of one FSH preparation as a standard, with its specific activity as an assigned value, reduced the inter-laboratory variability of estimates for the remaining FSHs by both methods. This increased the accuracy of the predicted estimates of bioactivity for these remaining FSHs in terms of their approximation to the values for their bioactivities estimated by bioassay. These data therefore suggest that both these methods, and particularly IEF, are sufficiently accurate, precise and robust to be used for predicting the bioactivity of batches of follitropin beta, and especially if used with a standard preparation.

Chemical Phenomena↗
PubMed2002

ECVAM's role in the implementation of the Three Rs concept in the field of biologicals.

Biologicals can be defined as products that are derived from living organisms or are produced by them. They include vaccines, hormones, monoclonal and polyclonal antibodies, blood products and rDNA products. The production of conventionally produced biologicals requires an extensive batch-related quality control, to ensure that these products are both safe and potent. As several of the control tests rely on animal models, it is inevitable that the large numbers of animals are used. Many initiatives have been undertaken in the last few decades to reduce and refine the use of animals in this area. ECVAM has been involved in many activities to support the development, validation and implementation of these Three Rs methods. The role that ECVAM has played in a number of validation studies is summarised. It is concluded that ECVAM should continue to support the activities that have been shown to be successful, preferably in collaboration with the regulatory bodies.

Animal Testing Alternatives↗
PubMed2002

ECVAM's activities on biologicals.

This paper summarises key activities initiated and the progress achieved between April 1993 and June 2002 in implementing the Three Rs in one of ECVAM's priority areas - the production and quality control of biologicals. These have included: organising nine key workshops; financially supporting and/or participating in a number of prevalidation and/or validation studies; financial contributions and sponsorship to relevant international workshops, symposia and conferences; and financial support for the compilation of manuals and expert reports, and training in test methods. The paper complements the papers of Hendriksen et al. and Cussler et al. included in these proceedings.

Animal Testing Alternatives↗
PubMed2002

ECVAM'S activities in the EU candidate countries.

ECVAM has been given a special grant for collaborative projects on alternative/advanced testing methods involving eleven Candidate Countries for membership of the European Union (Bulgaria, Cyprus, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia and Slovenia). The project involves the promotion of the Three Rs (reduction, refinement, replacement) concept of Russell & Burch, in cooperation with appropriate individuals and national and international organisations in the Candidate Countries themselves, and elsewhere. The scope of the programme's activities covers: conferences in some of the Candidate Countries, workshops, training courses, training visits, and technology development/transfer initiatives. A database of contacts in the Candidate Countries and in relevant institutions in other countries, is being compiled.

Animal Testing Alternatives↗
PubMed2002

Future activities: ECVAM and the quality control of biologicals.

ECVAM's activities in the field of biologicals have contributed in many ways to the successful incorporation of Three Rs methods, as summarised elsewhere in these proceedings. The progress achieved is impressive, but large numbers of animals are still needed in order to meet the requirements stipulated by various regulations. ECVAM's activities in this area should therefore be continued and extended. Besides the well-established organisation of ECVAM workshops and contributions to conferences, further prevalidation and validation studies should be funded. In addition, studies on refinement, and training courses on validated and well-established Three Rs methods, could be initiated. There is a need for more communication and information exchange, especially between regulators and industry concerning the Three Rs. ECVAM could provide a suitable forum for such activities. An ECVAM Biologicals Task Force should be established in order to define a list of priorities.

Animal Testing Alternatives↗
PubMed1998

AGAATI/ECVAM Workshop on the Validation of Alternative Methods for the Potency Testing of Vaccines.

The workshop on validation of alternative methods for the potency testing of vaccines was organised by ECVAM (European Centre for the Validation of Alternative Methods) and AGAATI (Advisory Group on Alternatives to Animal Testing in Immunobiologicals), and it was held in Angera, Italy, on 14-16 November 1997 under the co-chairmanship of Coenraad Hendriksen (RIVM, Bilthoven, The Netherlands) and Jean-Marc Spieser (EDQM, Strasbourg, France). The 17 participants, all experts in vaccine quality control and/or validation procedures, came from international regulatory bodies and organisations, national control laboratories and vaccine manufacturers. The aim of the workshop was to discuss, in an informal atmosphere, the complex issue of guidelines for the validation of alternative methods to potency testing of vaccines in laboratory animals, in particular: a) to review existing guidelines for validation; b) to discuss specific guidelines for the validation of alternative methods to the potency testing of vaccines and to agree on strategies for the preparation of guidelines; and c) to discuss and make recommendations for the implementation of validated alternative methods for regulatory purposes. The outcome of the discussions and the recommendations will be published in the ECVAM workshop series in ATLA in late 1998.

Journal Article↗
PubMedDate not supplied

ECVAM's contributions to the implementation of the Three Rs in the production and quality control of biologicals.

A summary is presented of the activities initiated, and the progress achieved, between April 1993 and December 2001 in implementing the Three Rs in one of the main priority areas of the European Centre for the Validation of Alternative Methods (ECVAM) - the production and quality control of biologicals. These have included organising eight key workshops, and financial contributions to, and sponsorship of, relevant international workshops, symposia and conferences. Noteworthy activities include financial support and/or participation in a number of prevalidation and validation studies. These involved alternative methods for the batch potency testing of: human tetanus vaccines; human and veterinary tetanus antisera and immunoglobulin; rabies vaccines; Leptospira hardjo vaccines; Clostridium perfringens vaccines; and erysipelas vaccines. They also involved a cell culture test for specific toxicity testing of diphtheria toxoid vaccines. In addition, ECVAM funded a study on the use of humane endpoints for vaccine quality control tests involving severe suffering, such as the potency testing of erysipelas, rabies and pertussis vaccines. ECVAM has also contributed financially to the compilation of manuals and expert reports, and to training in test methods. Following the report of an ECVAM Task Force, ECVAM financially supported the prevalidation of some in vitro methods for the potency testing of a recombinant hormone. A proposal is presented for promotion of regulatory acceptance, and suggestions are made for possible future activities.

Animal Testing Alternatives↗