Hye-Na Kang

Immunogenicity assessment of biotherapeutic products: An overview of assays and their utility

Biotherapeutic products (BTPs) are the fastest growing medicines in the pharmaceutical market. Despite their clinical success, the immunogenicity of BTPs continues to be a major concern. Assessment of immunogenicity as well as appropriate interpretation of immunogenicity data is therefore, of critical importance for defining safety profile of these products for the purpose of their licensure and use. In the past decade, much progress has been made towards how immunogenicity should be studied. This article reflects the content of the brief presentation on principles of methods used for immunogenicity assessment and their merits and limitations given at the first World Health Organization (WHO) implementation workshop on rDNA derived biotherapeutic products held in the Republic of Korea in May 2014 to support the case studies on immunogenicity presented and discussed during the workshop. The purpose of this article is to provide an overview of the methods used for assessing immunogenicity of biotherapeutic products (BTPs) and the most important considerations in interpreting results in the context of regulatory overview of these products.

WHO Informal Consultation on standardization and evaluation of BCG vaccines Geneva, Switzerland 22-23 September 2009.

The current World Health Organization Requirements for BCG vaccine are in need of revision to address the diversity of sub-strains used for production, potential improvements of quality control assays for lot release, and the establishment of sub-strain specific Reference Reagents. A consultation meeting was organized to discuss issues regarding the standardization and evaluation of BCG vaccines in the forum of regulators, BCG vaccine manufacturers, developers of selected new live tuberculosis (TB) vaccines and researchers. The development of new recombinant BCG and live attenuated TB vaccines and the characterisation of different BCG sub-strains using state-of-the-art technologies were also reviewed. The objective of the meeting was to revise and update the current recommendations focused on the scope, terminology, manufacturing issues, and the incorporation of new reference reagents and new quality control tests.

The role of the quality assessment in the determination of overall biosimilarity: A simulated case study exercise

A determination of biosimilarity is based on a thorough characterization and comparison of the quality profiles of a similar biotherapeutic product and its reference biotherapeutic product. Although the general principles on the role of the quality assessment in a biosimilar evaluation are widely understood and agreed, detailed discussions have not been published yet. We try to bridge this gap by presenting a case study exercise based on fictional but realistic data to highlight key principles of an evaluation to determine the degree of similarity at the quality level. The case study comprises three examples for biosimilar monoclonal antibody candidates. The first describes a highly similar quality profile whereas the second and third show greater differences to the reference biotherapeutic product. The aim is to discuss whether the presented examples can be qualified as similar and which additional studies may be helpful in enabling a final assessment. The case study exercise was performed at the WHO implementation workshop for the WHO guidelines on quality assessment of similar biotherapeutic products held in Xiamen, China, in May 2012. The goal was to illustrate the interpretation of the comparative results at the quality level, the role of the quality assessment in the entire biosimilarity exercise and its influence on the clinical evaluation. This paper reflects the outcome of the exercise and discussion from Xiamen.

Case studies on clinical evaluation of biosimilar monoclonal antibody: Scientific considerations for regulatory approval

The objective of this paper is to provide considerations based on comprehensive case studies important for regulatory evaluation of monoclonal antibodies as similar biotherapeutic products (SBPs) with a special emphasis on clinical aspects. Scientific principles from WHO Guidelines on SBPs were used as a basis for the exercise. Working groups consisted of regulators, manufacturers and academia. The following topics were discussed by the working groups: clinical criteria for biosimilarity, extrapolation approach and the overall regulatory decision making process. In order to determine typical pitfalls in the design of a SBP clinical programme and evaluate the gap of knowledge, amongst different industry and regulatory stakeholders on the appraisal of the data arising from SBP clinical studies, we have presented two fictional but realistic clinical case studies. The first case consists of the fictional development programme for an infliximab SBP candidate. The second case describes clinical studies proposed for a fictional rituximab SBP candidate. In the first scenario a highly similar quality profile has been taken forward into clinical studies whereas there was an important residual difference in functional attributes for the rituximab SBP candidate. These case studies were presented at the WHO implementation workshop for the WHO guidelines on evaluation of similar biotherapeutic products held in Seoul, Republic of Korea, in May 2014. The goal was to illustrate the interpretation of the clinical data arising from studies with SBP candidates and elicit knowledge gaps in clinical assessment. This paper reflects the outcome of the exercise and discussions held in Seoul and offers an analysis of the case studies as a learning opportunity on clinical development and evaluation of SBPs.

Immunogenicity assessment of monoclonal antibody products: A simulated case study correlating antibody induction with clinical outcomes.

Monoclonal antibodies are large molecules with complex structure and functions. They have a wide application for treatment of a broad range of chronic diseases and represent the largest class of biotherapeutic products. Given that biotherapeutic products may induce unwanted humoral and/or cellular immune responses in recipients, it is essential to investigate the immunogenicity of a product prior to licensure. The immune response is influenced by many factors and data generated in the pre-licensure studies are usually somewhat difficult for regulatory review. The knowledge and expertise required for this requires a thorough understanding of animal and human immunology as well as specific product characteristics, including mechanism of action, antibody assays and assessment of results in a given clinical context. The appropriate interpretation of immunogenicity data is of critical importance for defining the safety profile of a monoclonal antibody. Two case studies described in this paper were prepared to mimic a real situation in which regulators need to evaluate immunogenicity studies conducted by manufacturers of monoclonal antibody products. The specific objective of the case studies was to illustrate assessment of unwanted immunogenicity and the important factors that need to be considered in this context. Regulators and manufacturers who attended the World Health Organization (WHO) implementation workshop on Evaluation of Biotherapeutic Products, held in Seoul, Republic of Korea, in May 2014, participated in the case studies and provided valuable input. This article outlines the main aspects of immunogenicity discussed in these case studies and a summary of the lessons learned at this occasion.

Meeting report WHO informal consultation on development of guidelines on procedures and data requirements for changes to approved biotherapeutic products, Seoul, Republic of Korea, 27–28 April 2017

In April 2017, WHO convened an informal consultation to develop WHO guidelines on procedures and data requirements for changes to approved biotherapeutic products. The objective of the meeting was to review the draft of WHO guidelines and the comments received from the public consultation. The guidelines were recognized by the participants as a tool for regulatory convergence and harmonization. Regulation of changes to approved biotherapeutic products is a key in ensuring that products of consistent quality, safety and efficacy are distributed after they receive authorization or licensure. Participants agreed that the guidelines would contribute to assuring the continued quality, safety and efficacy throughout the life-cycle of biotherapeutics as well as continuity in supply and access. In the meeting, participants further requested WHO should assist national regulatory authorities in improving technical expertise in the evaluation of biotherapeutics and their post-approval changes by organizing implementation workshops and developing case studies and e-training modules on various technical topics. At its meeting in October 2017, the WHO Expert Committee on Biological Standardization formally adopted the WHO guidelines on procedures and data requirements for changes to approved biotherapeutic products.

Implementation workshop of WHO guidelines on evaluation of malaria vaccines: Current regulatory concepts and issues related to vaccine quality, Pretoria, South Africa 07 Nov 2014

The current World Health Organization (WHO) guidelines on the quality, safety and efficacy of recombinant malaria vaccines targeting the pre-erythrocytic and blood stages of Plasmodium falciparum were adopted by the WHO Expert Committee on Biological Standardization in 2012 to provide guidance on the quality, nonclinical and clinical aspects of recombinant malaria vaccines. A WHO workshop was organised to facilitate implementation into African (national/regional) regulatory practices, of the regulatory evaluation principles outlined in the guidelines regarding quality aspects. The workshop was used also to share knowledge and experience on regulatory topics of chemistry, manufacturing and control with a focus on vaccines through presentations and an interactive discussion using a case study approach. The basic principles and concepts of vaccine quality including consistency of production, quality control and manufacturing process were presented and discussed in the meeting. By reviewing and practicing a case study, better understanding on the relationship between consistency of production and batch release tests of an adjuvanted pre-erythrocytic recombinant malaria vaccine was reached. The case study exercise was considered very useful to understand regulatory evaluation principles of vaccines and a suggestion was made to WHO to provide such practices also through its Global Learning Opportunities for Vaccine Quality programme.

Review of the current use and evaluation of cell substrates for producing biologicals in selected countries.

In 2010, the WHO guidance document for the evaluation of cell substrates for producing biologicals was replaced with updated recommendations and in May 2013 an implementation workshop on the new recommendations was held in Beijing, China. As part of this workshop, a survey of the use and evaluation of cell substrates for producing biologicals was undertaken and the information obtained was updated in June 2014. The purpose of survey was to capture the status of national requirements related to cell substrates in various countries with particular emphasis on whether or not the updated WHO recommendations had been, or were to be, incorporated into national requirements. This paper reports the outcome of the survey and is based on information provided by regulators in eleven countries. Since the publication of the updated WHO recommendations, several activities such as the implementation workshop and publications have been undertaken by the WHO. The aim of these activities, including the publication of this article, is to contribute to the implementation of WHO recommendations so as to reduce regulatory gaps between national requirements and globally agreed expectations.