Philip Timmerman

EBF recommendation on the validation of bioanalytical methods for dried blood spots

Over the last few years bioanalysts, pharmacokineticists and clinical investigators have rediscovered the technique of dried blood spots. The revival has provided pharmaceutical R&D a wealth of opportunities to optimize the drug-discovery and development process with respect to animal and patient ethics, new scientific insights and costs savings. On the bioanalytical front, multiple experiments have been performed and a lot of experience has been gained. Nevertheless, the technique still has a number of bioanalytical challenges. The European Bioanalysis Forum discussed the advantages and hurdles of the technique and summarized their current thinking in a recommendation on the validation of bioanalytical methods for dried blood spots, which can be used as a cornerstone for further discussions and experiments.

Best practices in a tiered approach to metabolite quantification: views and recommendations of the European Bioanalysis Forum.

The relationship between the exposure to drug metabolites and overall drug safety has become an integral part of the drug-development process. In-depth discussions in the scientific community, as well as recent guidelines on Drug Safety Testing of Metabolites from the US FDA (often referred to as the MIST guidance and ICH M3(R2) from the International Conference on Harmonization (ICH), has brought clarity to the regulatory requirements of the sponsor company in providing documentation on circulating levels of qualifying metabolites. However, less attention has been given to the challenges now faced by the bioanalytical community in supporting these new guidance policies. In this paper, the European Bioanalysis Forum (EBF) is providing a recommendation on which quality standards to apply when assessing the (relative) abundance or absolute concentrations of metabolites. This paper is the result of both an intensive consultation within the EBF (through internal surveys amongst EBF member companies and discussions) and consultation of the broader bioanalytical community (through discussions at international conferences). These recommendations will provide an increased understanding of how to apply a tiered approach to metabolite quantification as part of the bioanalytical strategy. As such, it aims to provide support to the bioanalytical community on the appropriate level of validation required at each stage of the drug-development process.

The effect of hematocrit on bioanalysis of DBS: results from the EBF DBS-microsampling consortium.

BACKGROUND The European Bioanalysis Forum dried blood spots (DBS)/microsampling consortium is reporting back from the experiments they performed on further documenting the potential hurdles of the DBS technology. This paper is focused on the impact of hematocrit changes on DBS analyses. RESULTS The hematocrit can have an effect on the size of the blood spot, on spot homogeneity and on extraction recovery in a compound-dependent manner. The extraction recovery can change upon aging in an hematocrit-dependent way. Different card materials can give different outcomes. CONCLUSIONS The results from the conducted experiments show that the issues of DBS in regulated bioanalysis are real and that the technology will need improvements to be ready for use as a general tool for regulated bioanalysis.

Incurred sample reproducibility: views and recommendations by the European Bioanalysis Forum

Following intensive discussions, review, alignment of procedures and multiple surveys among their member companies, the European Bioanalysis Forum (EBF) is providing a recommendation on how to integrate incurred sample reproducibility (ISR) in the bioanalytical process. The recommendation aims to provide guidance throughout the lifecycle of a validated method, including the application of the method in study support. In its recommendation, the EBF considers both the internal discussions with EBF member companies, as well as the input provided in international meetings where ISR was discussed. The ultimate goal of the EBF recommendation is to ensure that bioanalytical methods can provide accurate and reproducible concentration data for pharmacokinetic and/or toxicokinetic evaluation, without any compromise, while safeguarding the optimal use of laboratory resources.

Request for Global Harmonization of the Guidance for Bioanalytical Method Validation and Sample Analysis

The 2001 US FDA Bioanalytical Method Validation (BMV) guidance document has been widely accepted and adopted by the bioanalytical community worldwide. As such, it has become the cornerstone of regulated bioanalytical laboratory procedure. In recent years, clarifications to these FDA guidelines and subsequent enhancements were discussed at North American-and European-hosted meetings and conferences. The outcome of these meetings, published in White Papers, conference reports or recommendations, are currently being implemented in many bioanalytical laboratories around the world. Nevertheless, differences in expectations or interpretation of the guidelines from individual auditors/inspectors or regional health authorities are a growing concern for the bioanalytical community. Further globalization of the pharmaceutical industry is also impacting the bioanalytical community. Bioanalytical labs are booming in regions outside the EU and North America, and regional authorities are looking to accommodate this growth or being confronted with the lack of guidance within their own regulations. Consequently, this creates a stimulus for these countries/regions to draft or issue their own guidance documents. The European Medicines Agency (EU), Medicines and Healthcare Products Regulatory Agency (UK), Agência Nacional de Vigilância Sanitária (Brazil) and Therapeutic Goods Administration (Australia) are the most prominent and recent examples. Although the 2001 FDA BMV guidance is often the basis of the emerging guidelines, there is an inherent risk that new sets of quality standards or nuances to the existing guidance will become effective. Over the last few months, following discussions at international meetings that brought together health authorities and industry experts on bioanalysis, the industry has expressed their concerns that multiple regulations on a similar topic will not benefit data generated in bioanalytical laboratories worldwide. Bioanalysis has become a true global discipline and, as such, the bioanalytical community should be served with globally harmonized standards. Therefore, the undersigned would like to ask health authorities worldwide to consider a collaboration and work towards a global harmonization of the guidelines on bioanalytical method validation and sample analysis for preclinical and clinical studies. Standardization and harmonization will largely contribute to the quality, transparency and efficiency of the data generated. These aspects are clearly of immediate benefit for the health authorities (ease of review of data) and laboratories (one set of standards), but eventually also for the patient and the community. We are confident that all involved parties (health authorities and industry) will be equally supportive of this initiative. We are open to any suggestion on how to reach this goal …

Assay methods for sufentanil in plasma : radioimmunoassay versus gas chromatography-mass spectrometry

BackgrondThe terminal pharmacokinetic parameters of sufentanil have, until now, been poorly characterized. This is probably because of the poor sensitivity or unreliability of the assay methods used. Radioimmunoassay (RIA) can be a very helpful assay method for sufentanil. However, before application to key pharmacokinetic studies, it requires adequate validation, e.g., by comparison with a method of proven sensitivity and specificity, such as gas chromatography-mass spectrometry (GC-MS). MethodsSpiked control plasma samples and 135 plasma samples obtained from five patients receiving intravenous doses of 500 or 750 μg sufentanil, as a 10–20-min infusion, were analyzed by an improved, sensitive RIA and capillary GC-MS. ResultsBoth techniques had comparable limits of quantitation (0.02 ng/ml). Between-day coefficients of variation in the 0.05–10-ng/ml concentration range were 8.5–10.5% for the RIA and less than 10% for the GC-MS method. The patient plasma concentrations determined by RIA (y) and GC-MS (x) showed a good agreement (y = 1.01x + 0.002) and a correlation coefficient of 0.97. ConclusionsThe results demonstrate the validity of the improved RIA method for the determination of sufentanil plasma concentrations.

Tiered approach into practice: scientific validation for chromatography-based assays in early development – a recommendation from the European Bioanalysis Forum

The principles of tiered approach have been part of the bioanalytical toolbox for some years. Nevertheless, an in spite of many valuable discussions in industry, they remain difficult to apply in a harmonized way for a broad array of studies in early drug development where these alternative approaches to regulated validation would make sense. The European Bioanalysis Forum has identified the need to proposes some practical workflows for five categories of studies for chromatography based assays where scientific validation will allow additional freedom while safeguarding scientific rigor and robust documentation: quantification of metabolites in plasma in relation to ICH M3(R2), urine analysis, tissue homogenate analysis, and preclinical and clinical studies in early stages of drug development. The recommendation would introduce a common language and harmonized best practice for these study categories and can help to refocus towards optimized scientific and resource investments for bioanalysis in early drug development.

Implementing Dried Blood Spot Sampling for Clinical Pharmacokinetic Determinations: Considerations from the IQ Consortium Microsampling Working Group

This paper was developed with the support of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ). IQ is a not-for-profit organization of pharmaceutical and biotechnology companies with a mission of advancing science-based and scientifically driven standards and regulations for pharmaceutical and biotechnology products worldwide. Within the IQ, various working groups (WG) have been formed, where the microsampling WG is committed to providing a scientific forum for the advancement of both wet and dry microsampling techniques within the pharmaceutical industry. This first output from the microsampling WG is to summarize and reflect on the current knowledge and opinions on DBS sampling, to stimulate discussion, and to encourage future creative applications of DBS sampling. Dried blood spot (DBS) sampling has established itself as an innovative sampling technique where wet blood is spotted onto absorbent paper or other paper materials and allowed to dry (1–4). DBS offers several potential benefits inherent to the technique, namely a low blood volume, simplified blood sample collection (5), and convenient sample storage and transfer. In certain applications, DBS sampling has been shown to stabilize certain analytes or metabolites without the addition of chemical modifiers (6–9). DBS has been routinely applied for decades in neonatal screening for phenylketonuria and other congenital metabolic disorders (10). The utility of DBS sampling has also been demonstrated for therapeutic drug monitoring (11) and for epidemiological studies (e.g., HIV and HBV detection/monitoring) (12) due to the practical advantages along with simplified sample collection and handling procedures. Finally, DBS can also be used for quantitative biomarker (PD) assessment from blood, where appropriate. However, the technique is relatively new to the pharmaceutical industry and to government regulators overseeing new drug applications. Nevertheless, over the past 5 to 7 years, the technique has been extensively evaluated for quantifying drug exposure in nonclinical and/or clinical studies in various stages of drug discovery and development. The ease to collect, transfer, store, and process small volumes of blood samples has generated considerable interest in providing utility in volume-limited situations (e.g., small rodent, human pediatric studies) for toxicokinetic (TK), pharmacokinetic (PK), or pharmacodynamic (PD) sampling. Discovery and nonclinical studies Rodent animal models are typically employed in these studies. The reduced blood volumes required for DBS can enable serial bleeding and, consequently, elimination of satellite animal groups and reduction of compound use. The ability to eliminate the satellite animal groups enables the assessment of exposure and toxic effects within the same animal. Studies involving expensive animal models (i.e., transgenic mice, knock-out mice, humanized mice, etc.) further highlight a persuasive scientific and economic case for DBS sampling since a complete pharmacokinetic profile can be obtained from a single study animal without the need for extra rodents merely for generating exposure data. These are perfectly in line with the principles of the 3Rs: reduction, refinement, and replacement of humane animal research (13–15). With greater emphasis from the regulatory authorities to study new drugs for infants, neonates, and pediatric populations, the requirement to conduct associated nonclinical juvenile rodent toxicity studies serves as an ideal scenario where the advantage of low blood volume in DBS sampling is undeniable. Although the advantages of DBS heavily favor rodent studies, it can also be used to refine non-rodent studies.

Conference Report: Connecting strategies on dried blood spots

The European Bioanalysis Forum is a non-profit organization comprised of European pharmaceutical companies (25 members to date). Their activities focus on bringing together managers and scientists in the broad field of bioanalysis to discuss topics related to science, process and regulations. There has been much interest over the past few years in the potential application of dried blood spots as an alternative to traditional plasma collection in pharmacokinetic studies. The success of the technique has been highlighted by several companies. We know that seven of the European Bioanalysis Forum member companies are using dried blood spots intensively and that 22 out of 25 companies are using it or plan to use it very soon, initially in nonregulated studies. However, most companies have less than 1 year of experience with dried blood spots and, beyond the scientific merit, it is less clear just how the technique is perceived by key client groups, such as toxicology, clinical and regulatory authorities. The ...

Tiered Approaches to Chromatographic Bioanalytical Method Performance Evaluation: Recommendation for Best Practices and Harmonization from the Global Bioanalysis Consortium Harmonization Team

ABSTRACTThe A2 harmonization team, a part of the Global Bioanalysis Consortium (GBC), focused on defining possible tiers of chromatographic-based bioanalytical method performance. The need for developing bioanalytical methods suitable for the intended use is not a new proposal and is already referenced in regulatory guidance language. However, the practical implementation of approaches that differ from the well-established full validation requirements has proven challenging. Advances in technologies, the need to progress drug development more efficiently, and emerging new drug compound classes support the use of categorized tiers of bioanalytical methods. This paper incorporated the input from an international team of experienced bioanalysts to surmise the advantages and the challenges of tiered approaches and to provide recommendations on paths forward.