Human Genome Editing in the Clinic: New Challenges in Regulatory Benefit-Risk Assessment.

As genome editing rapidly progresses toward the realization of its clinical promise, assessing the suitability of current tools and processes used for its benefit-risk assessment is critical. Although current regulations may initially provide an adequate regulatory framework, improvements are recommended to overcome several existing technology-based safety and efficacy issues.

Development of the First World Health Organization Lentiviral Vector Standard: Toward the Production Control and Standardization of Lentivirus-Based Gene Therapy Products.

Gene therapy is a rapidly evolving field. So far, there have been >2,400 gene therapy products in clinical trials and four products on the market. A prerequisite for producing gene therapy products is ensuring their quality and safety. This requires appropriately controlled and standardized production and testing procedures that result in consistent safety and efficacy. Assuring the quality and safety of lentivirus-based gene therapy products in particular presents a great challenge because they are cell-based multigene products that include viral and therapeutic proteins as well as modified cells. In addition to the continuous refinement of a product, changes in production sites and manufacturing processes have become more and more common, posing challenges to developers regarding reproducibility and comparability of results. This paper discusses the concept of developing a first World Health Organization International Standard, suitable for the standardization of assays and enabling comparison of cross-trial and cross-manufacturing results for this important vector platform. The standard will be expected to optimize the development of gene therapy medicinal products, which is especially important, given the usually orphan nature of the diseases to be treated, naturally hampering reproducibility and comparability of results.

Implementing quality by design for biotech products: Are regulators on track?

Quality by design (QbD) is an innovative approach to drug development that has started to be implemented into the regulatory framework, but currently mainly for chemical drugs. The recent marketing authorization of the first monoclonal antibody developed using extensive QbD concepts in the European Union paves the way for future further regulatory approvals of complex products employing this cutting-edge technological concept. In this paper, we report and comment on insights and lessons learnt from the non-public discussions in the European Medicines Agency's Biologicals Working Party and Committee for Medicinal Products for Human Use on the key issues during evaluation related to the implementation of an extensive QbD approach for biotechnology-derived medicinal products. Sharing these insights could prove useful for future developments in QbD for biotech products in general and monoclonal antibodies in particular.

Manufacturing, characterization and control of cell-based medicinal products: challenging paradigms toward commercial use.

During the past decade, a large number of cell-based medicinal products have been tested in clinical trials for the treatment of various diseases and tissue defects. However, licensed products and those approaching marketing authorization are still few. One major area of challenge is the manufacturing and quality development of these complex products, for which significant manipulation of cells might be required. While the paradigms of quality, safety and efficacy must apply also to these innovative products, their demonstration may be demanding. Demonstration of comparability between production processes and batches may be difficult for cell-based medicinal products. Thus, the development should be built around a well-controlled manufacturing process and a qualified product to guarantee reproducible data from nonclinical and clinical studies.

Biosimilars entering the clinic without animal studies. A paradigm shift in the European Union.

The concept of biosimilars has spread from Europe to other regions throughout the world, and many regions have drafted regulatory guidelines for their development. Recently, a paradigm shift in regulatory thinking on the non-clinical development of biosimilars has emerged in Europe: In vivo testing should follow a step-wise approach rather than being performed by default. To not require animal testing at all in some instances can well be seen as a revolutionary, but science-based, step. Here, we describe the internal discussions that led to this paradigm shift. The mainstay for the establishment of biosimilarity is the pharmaceutical comparability based on extensive physicochemical and biological characterization. Pharmacodynamic comparability can be evaluated in in vitro assays, whereas pharmacokinetic comparability is best evaluated in clinical studies. It is considered highly unlikely that new safety issues would arise when comparability has been demonstrated based on physicochemical and in vitro comparative studies.

Biosimilars: the science of extrapolation.

Despite the establishment of a specific approval pathway, the issuance of detailed scientific guidelines for the development of similar biological medicinal products (so-called "biosimilars") and the approval of several biosimilars in the European Union, acceptance of biosimilars in the medical community continues to be low. This is especially true in therapeutic indications for which no specific clinical trials with the biosimilar have been performed and that have been licensed based on extrapolation of efficacy and safety data from other indications. This article addresses the concerns frequently raised in the medical community about the use of biosimilars in such extrapolated indications and explains the underlying scientific and regulatory decision making including some real-life examples from recently licensed biosimilars.

A roadmap toward clinical translation of genetically-modified stem cells for treatment of HIV.

During the past decade, successful gene therapies for immunodeficiencies were finally brought to the clinic. This was accomplished through new gene therapy vectors and improved procedures for genetic modification of autologous hematopoietic stem cells. For HIV, autologous hematopoietic stem cell (HSC) gene therapy with 'anti-HIV genes' promises a functional cure for the disease. However, to develop such a therapy and translate it into a clinical application is rather challenging. The risks and benefits of such a therapy have to be understood, and regulatory hurdles need to be overcome. In this joint paper by academic researchers and regulators, we are, therefore, outlining a high level roadmap for the early stage development of HSC gene therapy as a potential functional cure for HIV.

Clinical development of gene therapy needs a tailored approach: a regulatory perspective from the European Union.

Gene therapy is a rapidly evolving field that needs an integrated approach, as acknowledged in the concept article on the revision of the guideline on gene transfer medicinal products. The first gene therapy application for marketing authorization was approved in the International Conference on Harmonisation (ICH) region in 2012, the product being Alipogene tiparvovec. The regulatory process for this product has been commented on extensively, highlighting the challenges posed by such a novel technology. Here, as current or previous members of the Committee for Advanced Therapies, we share our perspectives and views on gene therapy as a treatment modality based on current common understanding and regulatory experience of gene therapy products in the European Union to date. It is our view that a tailored approach is needed for a given gene therapy product in order to achieve successful marketing authorization.

The risks of risk aversion in drug regulation.

Drugs are approved by regulatory agencies on the basis of their assessment of whether the available evidence indicates that the benefits of the drug outweigh its risks. In recent years, regulatory agencies have been criticized both for being overly tolerant of risks or being excessively risk-averse, which reflects the challenge in determining an appropriate balance between benefit and risk with the limited data that is typically available before drug approval. The negative consequences of regulatory tolerance in allowing drugs onto the market that turn out to be unsafe are obvious, but the potential for adverse effects on public health owing to the absence of new drugs because of regulatory risk-aversion is less apparent. Here, we discuss the consequences of regulatory risk-aversion for public health and suggest what might be done to best align acceptance of risk and uncertainty by regulators with the interests of public health.

The committee for advanced therapies' of the European Medicines Agency reflection paper on management of clinical risks deriving from insertional mutagenesis.

In the European Union, the Committee for Advanced Therapies of the European Medicines Agency takes the lead in the scientific assessment for marketing authorization applications for advanced therapy medicinal products, which include gene therapy medicinal products, somatic cell therapy medicinal products, and tissue-engineered products. The Committee for Advanced Therapies also takes the lead in defining the scientific framework for the quality, nonclinical and clinical development of such products. This reflection paper represents the Committee's current thinking on management of clinical risks deriving from insertional mutagenesis. A multidisciplinary approach to insertional mutagenesis is provided. This reflection paper has been adopted by the committee in its April 2013 meeting.

Risk of tumorigenicity in mesenchymal stromal cell-based therapies--bridging scientific observations and regulatory viewpoints.

In the past decade, the therapeutic value of mesenchymal stromal cells (MSCs) has been studied in various indications, thereby taking advantage of their immunosuppressive properties. Easy procurement from bone marrow, adipose tissue or other sources and conventional in vitro expansion culture have made their clinical use attractive. Bridging the gap between current scientific knowledge and regulatory prospects on the transformation potential and possible tumorigenicity of MSCs, the Cell Products Working Party and the Committee for Advanced Therapies organized a meeting with leading European experts in the field of MSCs. This meeting elucidated the risk of potential tumorigenicity related to MSC-based therapies from two angles: the scientific perspective and the regulatory point of view. The conclusions of this meeting, including the current regulatory thinking on quality, nonclinical and clinical aspects for MSCs, are presented in this review, leading to a clearer way forward for the development of such products.

Development and regulation of biosimilars: current status and future challenges.

Biologic medicinal products developed via rDNA technology as recombinant protein-based medicines that have been in clinical use since the early 1980s as original biopharmaceuticals have greatly contributed to the therapy of severe metabolic and degenerative diseases. The recent expiration of the data protection or patents for most of them created opportunities for the development of copy versions of original biopharmaceuticals with similar biologic activity (termed biosimilars). Production of these new products is expected to meet worldwide demand, promote market competition, maintain the incentives for innovation, and sustain the healthcare systems. The licencing of these products, however, relies on the experience gained with the original biopharmaceuticals. Critical issues related to this class of medicinal products include their terminology (to avoid confusion with generics and non-innovator copy versions that have not been tested according to the biosimilar guidelines), manufacturing, and regulation. The European Union (EU) has been the first to establish a regulatory framework for marketing authorization application (MAA) and has named these products biosimilars, a term also recently adopted by the US FDA. Unlike the conventional, more common small molecular weight human medicines and chemical generics, protein-based medicines exhibit higher molecular weight, complexity in structure and function that can be affected by changes in the manufacturing process. Therefore, biosimilars represent a relatively heterogeneous class of medicinal products that make their regulation quite challenging. According to the current understanding in the EU, a biosimilar is a copy version of an already authorized biopharmaceutical (or reference product) with similar biologic activity, physicochemical characteristics, efficacy, and safety, based on a full comparability exercise at quality, preclinical and clinical level to ensure similar efficacy and safety. Guidance has been provided through several Committee for Medicinal Products for Human Use (CHMP) guidelines as well as individual scientific advice requested from the European Medicines Agency (EMA) by various companies for the development and regulation of biosimilars. This review is mainly focused on the current status of regulation of biosimilars in the EU as well as on future challenges lying ahead for the improvement of the requirements needed for the marketing authorization of biosimilars. Emphasis is given on the quality requirements concerning these medicinal products (biologics).