WHO/KFDA joint workshop on implementing WHO guidelines on evaluating similar biotherapeutic products, Seoul, Republic of Korea 24–26 August, 2010

Regulatory challenges with biosimilars: an update from 20 countries

The World Health Organization (WHO) issued guidelines for the regulatory evaluation of biosimilars in 2009 and has provided considerable effort toward helping member states implement the evaluation principles in the guidelines into their regulatory practices. Despite this effort, a recent WHO survey (conducted in 2019–2020) has revealed four main remaining challenges: unavailable/insufficient reference products in the country; lack of resources; problems with the quality of some biosimilars (and even more with noninnovator products); and difficulties with the practice of interchangeability and naming of biosimilars. The following have been identified as opportunities/solutions for regulatory authorities to deal with the existing challenges: (1) exchange of information on products with other regulatory authorities and accepting foreign licensed and sourced reference products, hence avoiding conducting unnecessary (duplicate) bridging studies; (2) use of a “reliance” concept and/or joint review for the assessment and approval of biosimilars; (3) review and reassessment of the products already approved before the establishment of a regulatory framework for biosimilar approval; and (4) setting appropriate regulatory oversight for good pharmacovigilance, which is essential for the identification of problems with products and establishing the safety and efficacy of interchangeability of biosimilars.

The regulatory landscape of biosimilars: WHO efforts and progress made from 2009 to 2019

The World Health Assembly in 2014 adopted a resolution that mandates both Member States and the WHO Secretariat to facilitate access to biotherapeutic products in a way that ensures their quality, safety and efficacy. The availability of biosimilars is expected to increase access to biotherapeutic products by providing more treatment options triggering competition which would lead to a consistent reduction in the average price of treatment. Since the WHO guidelines for regulatory evaluation of biosimilars were issued in 2009, WHO has provided immense effort towards harmonizing the terminology and the regulatory framework for biosimilars globally. This article describes the progress made and the regulatory landscape changes for biosimilars in 21 countries during the past ten years. Based on the information from regulators and from publicly available data, the following has been identified: 1) WHO guidelines have contributed to setting the regulatory framework for biosimilars in countries and increasing regulatory convergence at global level; 2) terminology used for biosimilars is more consistent than in the past; 3) biosimilars are now approved in all participating countries; and 4) the dominant product class for candidate biosimilars under development is monoclonal antibodies.

International standards for monoclonal antibodies to support pre- and post-marketing product consistency: Evaluation of a candidate international standard for the bioactivities of rituximab

The intrinsic complexity and heterogeneity of therapeutic monoclonal antibodies is built into the biosimilarity paradigm where critical quality attributes are controlled in exhaustive comparability studies with the reference medicinal product. The long-term success of biosimilars will depend on reassuring healthcare professionals and patients of consistent product quality, safety and efficacy. With this aim, the World Health Organization has endorsed the need for public bioactivity standards for therapeutic monoclonal antibodies in support of current controls. We have developed a candidate international potency standard for rituximab that was evaluated in a multi-center collaborative study using participants' own qualified Fc-effector function and cell-based binding bioassays. Dose-response curve model parameters were shown to reflect similar behavior amongst rituximab preparations, albeit with some differences in potency. In the absence of a common reference standard, potency estimates were in poor agreement amongst laboratories, but the use of the candidate preparation significantly reduced this variability. Our results suggest that the candidate rituximab standard can support bioassay performance and improve data harmonization, which when implemented will promote consistency of rituximab products over their life-cycles. This data provides the first scientific evidence that a classical standardization exercise allowing traceability of bioassay data to an international standard is also applicable to rituximab. However, we submit that this new type of international standard needs to be used appropriately and its role not to be mistaken with that of the reference medicinal product.

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.

Potential cost savings from chemotherapy-induced febrile neutropenia with biosimilar filgrastim and expanded access to targeted antineoplastic treatment across the European Union G5 countries: a simulation study

PURPOSE

The objectives of this study were to simulate for the European Union G5 countries the potential cost savings of converting patients from originator granulocyte colony-stimulating factor (G-CSF) filgrastim and pegfilgrastim to a biosimilar filgrastim, to evaluate how reallocating these savings could increase patient access to antineoplastic therapy, and to estimate the number of patients needed to convert to provide antineoplastic treatment to one patient.

METHODS

Three models were built: (1) to estimate the costs of using originator G-CSFs and the savings generated from switching to a biosimilar G-CSF, (2) to estimate the incremental number of patients who could be provided antineoplastic therapy-rituximab or trastuzumab-in a hypothetical panel of 10,000 patients with cancer, and (3) to calculate the number of patients needed to convert to provide access to anticancer therapy. Scenarios were developed in which the rate of conversion was varied to estimate the effect on total cost savings. This study took the perspective of the payer in the European Union.

FINDINGS

The savings associated with the biosimilar filgrastim over the originator filgrastim ranged from €785 (day 4) to €2747 (day 14) and increased with longer duration of therapy. By contrast, the savings associated with the biosimilar filgrastim over pegfilgrastim decreased over time, ranging from €6199 (day 4) to €471 (day 14). In a hypothetical panel of 10,000 patients with cancer, the savings associated with the biosimilar filgrastim over the originator filgrastim and the expanded access to antineoplastic therapy improved over time, irrespective of conversion rates. Conversely, in the same hypothetical panel, the savings associated with the biosimilar filgrastim over pegfilgrastim reduced over time, irrespective of conversion rates, along with the expanded access to antineoplastic treatment. Under conversion of the originator filgrastim to the biosimilar filgrastim, the number needed to convert to expand access to rituximab ranged from 4 to 14 patients, and the number needed to convert to expand access to trastuzumab ranged from 11 to 38 patients. Under conversion of pegfilgrastim to the biosimilar filgrastim, the number needed to convert to expand access to rituximab ranged from 2 to 24 patients, and the number needed to convert to expand access to trastuzumab ranged from 5 to 63 patients.

IMPLICATIONS

Use of biosimilar G-CSFs for supportive cancer care could yield potential cost savings and improve patient access to antineoplastic therapy in a budget neutral way-a financial effect with an ethical perspective.

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.