Waiving in vivo studies for monoclonal antibody biosimilar development: National and global challenges

Biosimilars: Science, Implications, and Potential Outlooks in the Middle East and Africa

Biosimilars are biological products that efficiently replicate the function of the originator products. They have changed the prognosis of millions of patients with many serious conditions. The main engine beyond their development is to bring competition into the marketplace, accordingly further the healthcare systems' sustainability. Furthermore, by lowering financial obstacles to biological treatments, biosimilars play a critical role in budgetary redistribution and, hence, promote better allocation of scarce healthcare resources. Today, biosimilars have become a substantial component of effective biological therapies anywhere in the world. Alike, most Middle East and African countries are encouraging the domestic biosimilars industry, and the whole region is aware of the biosimilars' importance. However, constraints to increasing biosimilars uptake should be addressed.

Biosimilar monoclonal antibodies: Challenges and approaches towards formulation

Many biologic drug products, particularly monoclonal antibodies (mAbs), were off-patented between 2015 and 2020, and this process is continuing as the number of biologics approvals has increased. However, the availability of affordable biosimilars is delayed by secondary patents related to the formulation and manufacturing process. Therefore, an alternative formulation development is required to avoid infringement of formulation related patents. Several variables must be considered while developing alternative non-infringement formulations, including the time gap between the expiration of the molecule patent and the formulation patent, the ability not to infringe other secondary patents (process-related), and project timelines. As a part of life cycle management, innovator companies are adopting multiple strategies to delay biosimilar competition. Biosimilar companies could use the innovator formulation knowledge space to develop alternative formulations at the expense of time and cost. The present review discusses the key approaches in biosimilar formulation development, and further summarizes the use of innovator formulation knowledge space for biosimilar mAbs product development.

Regulatory Evaluation of Biosimilars: Refinement of Principles Based on the Scientific Evidence and Clinical Experience

The World Health Organization (WHO) guidelines on evaluation of similar biotherapeutic products (SBPs; also called biosimilars) were adopted by the WHO Expert Committee on Biological Standardization (ECBS) in 2009. In 2019, the ECBS considered that a more tailored and potentially reduced clinical data package may be acceptable in cases where this was clearly supported by the available scientific evidence. The goal of this publication is to review the current clinical experience and scientific evidence and to provide an expert perspective for updating the WHO guidelines to provide more flexibility and clarity. As the first step, the relevant guidelines by other regulatory bodies were reviewed in order to identify issues that might help with updating the WHO guidelines. Next, a literature search was conducted for information on the long-term efficacy, safety, and immunogenicity of biosimilars to identify possible long-term problems. Finally, a search for articles concerning the role of clinical studies in the benefit-risk evaluation of biosimilars was conducted. The analysis of other guidelines suggested that the WHO guidelines may need more emphasis on the importance of the state-of-the-art physicochemical and structural comparability exercise and in vitro functional testing. The use of "foreign" reference product will also need clarifications. The value of in vivo toxicological tests in the development of biosimilars is questionable, and the non-clinical part needs revisions accordingly. The concepts of "totality of evidence," "stepwise development," and "residual uncertainty" were applied in the evaluation of the clinical sections of the guideline. The review of long-term safety and efficacy demonstrated the robustness of the current biosimilar development concept. The analysis of the roles of different development phases suggested that the large efficacy, safety, and immunogenicity studies are, in most cases, redundant. The residual uncertainty of safety, immunogenicity, and efficacy of biosimilars that has shaped the current regulatory guidelines is now substantially reduced. This will allow the re-evaluation of the non-clinical and clinical requirements of the current WHO main guideline. The shift of the relative impact of the development phases towards physico-chemical and in vitro functional testing will provide a relief to the manufacturers and new challenges to the regulators.

Analysis of the Regulatory Science Applied to a Single Portfolio of Eight Biosimilar Product Approvals by Four Key Regulatory Authorities

Slow uptake of biosimilars in some regions is often attributed to a lack of knowledge combined with concerns about safety and efficacy. To alleviate physician and patient apprehensions, regulatory reviews from four major regulatory authorities (RAs) (European Medicines Agency, US Food and Drug Administration, Health Canada, and Japan Pharmaceuticals and Medical Devices Authority) across a portfolio of eight biosimilars were analyzed to provide insight into RA review focus and approach. RA queries were evaluated in an unbiased and systematic manner by major classification (Chemistry, Manufacturing and Controls [CMC], nonclinical, clinical or regulatory) and then via detailed sub-classification. There was a consistent, predominant focus on CMC from all RAs. The review focus based on sub-classification of clinical and regulatory queries was influenced by molecular complexity, with significant differences between categories (monoclonal antibody or protein) in the distribution of query topics; specifically, bioanalytical (p = 0.023), comparative safety and efficacy (p = 0.023), and statutory (including the justification of extrapolation) (p = 0.00033). Each biosimilar had a distinct distribution of clinical query topics, tailored to product-specific data. This analysis elucidated areas of heightened RA interest, and validated their application of regulatory science in the evaluation of biosimilar safety and efficacy.

Opportunities for Refinement of Non-Human Primate Vaccine Studies

Non-human primates (NHPs) are used extensively in the development of vaccines and therapeutics for human disease. High standards in the design, conduct, and reporting of NHP vaccine studies are crucial for maximizing their scientific value and translation, and for making efficient use of precious resources. A key aspect is consideration of the 3Rs principles of replacement, reduction, and refinement. Funders of NHP research are placing increasing emphasis on the 3Rs, helping to ensure such studies are legitimate, ethical, and high-quality. The UK's National Centre for the 3Rs (NC3Rs) and the Coalition for Epidemic Preparedness Innovations (CEPI) have collaborated on a range of initiatives to support vaccine developers to implement the 3Rs, including hosting an international workshop in 2019. The workshop identified opportunities to refine NHP vaccine studies to minimize harm and improve welfare, which can yield better quality, more reproducible data. Careful animal selection, social housing, extensive environmental enrichment, training for cooperation with husbandry and procedures, provision of supportive care, and implementation of early humane endpoints are features of contemporary good practice that should and can be adopted more widely. The requirement for high-level biocontainment for some pathogens imposes challenges to implementing refinement but these are not insurmountable.

Innovative approaches to biologic development on the trail of CT-P13: biosimilars, value-added medicines, and biobetters

The biosimilar concept is now well established. Clinical data accumulated pre- and post-approval have supported biosimilar uptake, in turn stimulating competition in the biologics market and increasing patient access to biologics. Following technological advances, other innovative biologics, such as “biobetters” or “value-added medicines,” are now reaching the market. These innovative biologics differ from the reference product by offering additional clinical or non-clinical benefits. We discuss these innovative biologics with reference to CT-P13, initially available as an intravenous (IV) biosimilar of reference infliximab. A subcutaneous (SC) formulation, CT-P13 SC, has now been developed. Relative to CT-P13 IV, CT-P13 SC offers clinical benefits in terms of pharmacokinetics, with comparable efficacy, safety, and immunogenicity, as well as increased convenience for patients and reduced demands on healthcare system resources. As was once the case for biosimilars, nomenclature and regulatory pathways for innovative biologics require clarification to support their uptake and ultimately benefit patients.

Are Biosimilars the Future of Oncology and Haematology?

Biological drugs are vital but often high-cost components of cancer treatment. Several biosimilar versions of these drugs have been approved in Europe and/or the USA, with many more in development. However, there is some disconnect between the biosimilars that are approved for use and those accessible in clinical practice, with availability impacted by factors including patent litigation and complex healthcare insurance policies, particularly in the USA. Provided the barriers to widespread uptake can be overcome, biosimilars offer potential benefits including cost savings and improved patient access versus the reference product (RP). This article provides an up-to-date and focused perspective on the development and use of biosimilars in the haemato-oncology setting. European and US regulatory pathways governing biosimilar licensing demand that there are no clinically meaningful differences between a biosimilar and its RP. Pathways are rigorously enforced and involve comprehensive non-clinical evaluations and clinical trials in selected indications to establish the equivalence or non-inferiority of efficacy, and the comparability of safety, of the biosimilar versus its RP. 'Indication extrapolation' is only permitted if scientifically justifiable considering mechanism(s) of action, pharmacokinetics, immunogenicity and safety in relevant patient populations. Switching treatment from RP to biosimilar is supported by most available data, predominantly from indications other than cancer, and post-marketing pharmacovigilance programmes are warranted. Notably, the potential benefits of biosimilar cancer treatment may extend beyond direct cost savings: for example, the availability of biosimilars of common regimen components may help incentivise the evaluation and/or clinical use of new treatment approaches and novel drugs.

An update on the animal studies conducted for biosimilar approvals - Regulatory requirement vs actual scenario

Nonclinical animal studies are considered as an integral part of biosimilar development program to demonstrate similarity and safety. We have compiled, reviewed and summarized animal studies conducted for European Medicines Agency (EMA) and United States Food and Drug Administration (US FDA) submission from 2006 till December 2018. The commonest animal studies conducted included repeat-dose toxicity study along with toxicokinetic, local tolerance and immunogenicity assessments, while the least common included primary pharmacodynamic, pharmacokinetic, safety pharmacology and single-dose toxicity studies. Animal studies were designed based on pharmacology of the drug, disease condition and innovator studies. Studies mostly used EU-sourced reference products as a comparator. For biosimilars approved both in the US and European Union (EU), similar data packages were submitted to these regions. Despite the regulatory guidelines allowing waiver of animal studies based on analytical data, animal studies have been conducted for almost all the approved biosimilars in the US and EU. There is an increasing need to re-assess the relevance of animal studies to support regulatory approval of biosimilars. Stepwise assessment for biosimilarity and conducting animal studies only if required at the right instance based on residual uncertainties may assist in optimizing animal study requirement for biosimilar development.

Integration of Consortia Recommendations for Justification of Animal Use Within Current and Future Drug Development Paradigms

The pharmaceutical and biotechnology industries continually review the requirements for, and relevance of, safety assessment strategies. Various industry consortia are currently discussing and reviewing data on a range of topics with respect to regulatory toxicology programs. These consortia are charged with critical evaluation of data and the identification of opportunities to promote best practice and to introduce improved approaches to safety assessment. Such improvements may include enhanced predictivity, more efficient ways of working, and opportunities for promoting and implementing the 3Rs (replacement, refinement, or reduction). As each consortium is considering a distinct question, individual outputs and recommendations could be perceived to be conflicting. However, a common theme embraced by the consortia represented here is exploration of the most appropriate use of animals for the safety assessment of new medicinal products. This short review summarizes presentations and discussions from a symposium describing the work of four industry consortia and considers whether their recommendations can be aligned into realistic approaches to improve future toxicology testing strategies, highlighting justification for the appropriate use of different animal species and opportunities for reductions in animal use without compromising patient safety.

Talking to patients about biosimilars

Biologic therapies target aberrant pathways in diseases including diabetes, cancer and autoimmune disorders. Despite recent scientific advances, patient access to these agents can be limited. Biosimilars are designed to be highly similar to the originator biologic, targeting the same biological pathways, with comparable efficacy and safety. Biosimilars have the advantage of lower treatment costs, offering the potential for increased clinical use and patient access. Several biosimilars are approved for clinical use in the USA and Europe; however, there is a lack of awareness about biosimilars among healthcare providers and patients. This overview of the scientific basis of biosimilars and current indications aim to enhance discussions with patients and increase understanding of the role of biosimilars in individual treatment plans.

Global Acceptance of Biosimilars: Importance of Regulatory Consistency, Education, and Trust

Globally, biosimilars are expected to have a key role in improving patient access to biological therapies and addressing concerns regarding the escalating cost of health care. Indeed, in Europe, increased use of biologics and reduced drug prices have been observed after the introduction of biosimilars. Recently, several monoclonal antibody biosimilars of anticancer therapies have been approved, and numerous others are in various stages of clinical development. Biosimilars are authorized via a regulatory pathway separate from that used for generic drugs; they are also regulated separately from novel biologics. Biosimilar approval pathways in many major regulatory regions worldwide are, to a broad degree, scientifically aligned. However, owing to regional differences in health care priorities, policies, and resources, some important regulatory inconsistencies are evident. Acceptance of biosimilars by health care systems, health care professionals, and patients will be a key factor in the uptake of these therapies, and such regulatory variations could contribute to confusion and diminished confidence regarding the quality, efficacy, and reliability of these agents. Furthermore, the need for manufacturers to account for regulatory inconsistencies introduces inefficiencies and delays into biosimilar development programs. These issues should be addressed if biosimilars are to attain their maximal global potential. This review summarizes the evolution of the global biosimilar landscape and provides examples of inconsistencies between regulatory requirements in different regions. In addition, we review ongoing efforts to improve regulatory alignment and highlight the importance of education as a crucial factor in generating trust in, and acceptance of, biosimilars on a worldwide scale.

IMPLICATIONS FOR PRACTICE

Biosimilars of monoclonal antibody anticancer therapies are beginning to emerge, and more are likely to become available for clinical use in the near future. The extent to which biosimilars can contribute to cancer care will depend on their level of acceptance by health care systems, health care professionals, and patients. A better understanding of the regulatory basis for the approval of biosimilars may enhance confidence and trust in these agents. In order to have informed discussions about treatment choices with their patients, oncologists should familiarize themselves with the biosimilar paradigm.

Bevacizumab biosimilars: scientific justification for extrapolation of indications

The first biosimilar of bevacizumab was approved by the US FDA; other potential biosimilars of bevacizumab are in late-stage clinical development. Their availability offers opportunity for increased patient access across a number of oncologic indications. The regulatory pathway for biosimilar approval relies on the totality of evidence that includes a comprehensive analytical assessment, and a clinical comparability study in a relevant disease patient population. Extrapolation of indications for a biosimilar to other eligible indications held by the originator, in the absence of direct clinical comparison, frequently forms part of the regulatory judgment. Herein, we consider the evidence required to demonstrate biosimilarity for bevacizumab biosimilars, with particular focus on the rationale for extrapolation across oncologic indications.

In Vitro Methods for Comparing Target Binding and CDC Induction Between Therapeutic Antibodies: Applications in Biosimilarity Analysis

Therapeutic monoclonal antibodies (mAbs) are relevant to the treatment of different pathologies, including cancers. The development of biosimilar mAbs by pharmaceutical companies is a market opportunity, but it is also a strategy to increase drug accessibility and reduce therapy-associated costs. The protocols detailed here describe the evaluation of target binding and CDC induction by rituximab in Daudi cells. These two functions require different structural regions of the antibody and are relevant to the clinical effect induced by rituximab. The protocols allow the side-to-side comparison of a reference rituximab and a marketed rituximab biosimilar. The evaluated products showed differences both in target binding and CDC induction, suggesting that there are underlying physicochemical differences and highlighting the need to analyze the impact of those differences in the clinical setting. The methods reported here constitute simple and inexpensive in vitro models for the evaluation of the activity of rituximab biosimilars. Thus, they can be useful during biosimilar development, as well as for quality control in biosimilar production. Furthermore, the presented methods can be extrapolated to other therapeutic mAbs.

The Language of Biosimilars: Clarification, Definitions, and Regulatory Aspects

Biologic therapies have revolutionized treatment of a number of diseases. Patents and exclusivity for a number of biologics are expiring. This has created the opportunity for the development and approval of biosimilars. Biosimilars are biologic products developed using a step-wise approach to result in a biologic that demonstrates no clinically meaningful differences in terms of quality attributes, efficacy, safety, and immunogenicity compared with an existing licensed, originator biologic. As more biosimilars receive regulatory approval and reach the market, it is increasingly important for healthcare providers to understand the terminology about biosimilars. To help support healthcare providers, the aim of this manuscript is to (i) support understanding of the language of biosimilars, (ii) review the regulatory and manufacturing processes employed in developing a biosimilar, and (iii) provide information for clinical decisions about the use of biosimilars. Because biologics are large, structurally complex proteins, biosimilars cannot be considered generic equivalents to the originator. Biosimilars are developed and evaluated using rigorous processes involving detailed analytical and functional studies, nonclinical assessments, and clinical trials. Clinical studies evaluating the potential biosimilar are designed differently than those for approval of a novel biologic since the aim is merely to confirm similar efficacy and safety and not to demonstrate clinical benefit per se. Extrapolation of data may be used to grant approval of biosimilars in indications not directly evaluated in clinical studies using the biosimilar.

Extensive preclinical evaluation of an infliximab biosimilar candidate

Infliximab is therapeutic monoclonal antibody (mAb) against TNF-α employed in the treatment of immunoinflammatory diseases. The development of biosimilar mAbs is a global strategy to increase drug accessibility and reduce therapy-associated costs. Herein we compared key physicochemical characteristics and biological activities produced by infliximab and infliximab-Probiomed in order to identify functionally relevant differences between the mAbs. Binding of infliximab-Probiomed to TNF-α was specific and had kinetics comparable to that of the reference product. Both mAbs had highly similar neutralizing efficacy in HUVEC cell cultures stimulated with TNF-α. In vitro induction of CDC and ADCC were also similar between the evaluated products. In vivo comparability was assessed using a transgenic mouse model of arthritis that expresses human TNF-α in a 13-week multiple-administration study. Infliximab and infliximab-Probiomed showed comparable efficacy, safety, and pharmacokinetic profiles. Our results indicate that infliximab-Probiomed has highly similar activities to infliximab in preclinical models, warranting a clinical evaluation of its biosimilarity.

Opportunities to Apply the 3Rs in Safety Assessment Programs

Before a potential new medicine can be administered to humans it is essential that its safety is adequately assessed. Safety assessment in animals forms an integral part of this process, from early drug discovery and initial candidate selection to the program of recommended regulatory tests in animals. The 3Rs (replacement, reduction, and refinement of animals in research) are integrated in the current regulatory requirements and expectations and, in the EU, provide a legal and ethical framework for in vivo research to ensure the scientific objectives are met whilst minimizing animal use and maintaining high animal welfare standards. Though the regulations are designed to uncover potential risks, they are intended to be flexible, so that the most appropriate approach can be taken for an individual product. This article outlines current and future opportunities to apply the 3Rs in safety assessment programs for pharmaceuticals, and the potential (scientific, financial, and ethical) benefits to the industry, across the drug discovery and development process. For example, improvements to, or the development of, novel, early screens (e.g., in vitro, in silico, or nonmammalian screens) designed to identify compounds with undesirable characteristics earlier in development have the potential to reduce late-stage attrition by improving the selection of compounds that require regulatory testing in animals. Opportunities also exist within the current regulatory framework to simultaneously reduce and/or refine animal use and improve scientific outcomes through improvements to technical procedures and/or adjustments to study designs. It is important that approaches to safety assessment are continuously reviewed and challenged to ensure they are science-driven and predictive of relevant effects in humans.

Nonclinical Evaluation of PF-06438179: A Potential Biosimilar to Remicade® (Infliximab)

Introduction

PF-06438179, a potential biosimilar to Remicade^® (infliximab, Janssen Biotech, Inc.), is a chimeric mouse–human monoclonal antibody targeting human tumor necrosis factor alpha (TNF).

Methods

Analytical (small subset reported here) and nonclinical studies compared the structural, functional, and in vivo nonclinical similarity of PF-06438179 with Remicade sourced from the United States (infliximab-US) and/or European Union (infliximab-EU).

Results

The peptide map profiles were superimposable, and peptide masses were the same, indicating identical amino acid sequences. Data on post-translational modifications, biochemical properties, and biological function provided strong support for analytical similarity. Administration of a single intravenous (IV) dose (10 or 50 mg/kg) of PF-06438179 or infliximab-EU to male rats was well tolerated. There were no test article-related clinical signs or effects on body weight or food consumption. Systemic exposures [maximum drug concentration (C_max) and area under the concentration–time curve (AUC)] in rats administered PF-06438179 or infliximab-EU were similar, with mean exposure ratio of PF-06438179 relative to infliximab-EU ranging from 0.88 to 1.16. No rats developed anti-drug antibodies. A 2-week IV toxicity study was conducted with once-weekly administration of 10 or 50 mg/kg of PF-06438179 to male and female rats. PF-06438179-related hyperplasia of sinusoidal cells occurred in the liver in rats administered 50 mg/kg, but was not adverse based on its minimal to mild severity. The no-observed adverse-effect level for PF-06438179 was 50 mg/kg. At this dose, C_max was 1360 µg/mL and AUC at 168 h was 115,000 µg h/mL on day 8.

Conclusions

The analytical and nonclinical studies have supported advancement of PF-06438179 into global comparative clinical trials.

Funding

Pfizer Inc.

Looking to the future of organ-on-chip and toxicity assessment: a regulator's opinion

David R Jones talks to Francesca Lake, Managing Editor: David R Jones is an Expert Pharmaco-Toxicologist within the Licensing Division of the Medicines and Healthcare products Regulatory Agency. We met him at the Organ-on-a-chip Europe 2016 conference in Cambridge (UK), where he presented ‘A UK Regulatory View on the Acceptability of Organ on a Chip Data’.

Excess cerebral TNF causing glutamate excitotoxicity rationalizes treatment of neurodegenerative diseases and neurogenic pain by anti-TNF agents

The basic mechanism of the major neurodegenerative diseases, including neurogenic pain, needs to be agreed upon before rational treatments can be determined, but this knowledge is still in a state of flux. Most have agreed for decades that these disease states, both infectious and non-infectious, share arguments incriminating excitotoxicity induced by excessive extracellular cerebral glutamate. Excess cerebral levels of tumor necrosis factor (TNF) are also documented in the same group of disease states. However, no agreement exists on overarching mechanism for the harmful effects of excess TNF, nor, indeed how extracellular cerebral glutamate reaches toxic levels in these conditions. Here, we link the two, collecting and arguing the evidence that, across the range of neurodegenerative diseases, excessive TNF harms the central nervous system largely through causing extracellular glutamate to accumulate to levels high enough to inhibit synaptic activity or kill neurons and therefore their associated synapses as well. TNF can be predicted from the broader literature to cause this glutamate accumulation not only by increasing glutamate production by enhancing glutaminase, but in addition simultaneously reducing glutamate clearance by inhibiting re-uptake proteins. We also discuss the effects of a TNF receptor biological fusion protein (etanercept) and the indirect anti-TNF agents dithio-thalidomides, nilotinab, and cannabinoids on these neurological conditions. The therapeutic effects of 6-diazo-5-oxo-norleucine, ceptriaxone, and riluzole, agents unrelated to TNF but which either inhibit glutaminase or enhance re-uptake proteins, but do not do both, as would anti-TNF agents, are also discussed in this context. By pointing to excess extracellular glutamate as the target, these arguments greatly strengthen the case, put now for many years, to test appropriately delivered ant-TNF agents to treat neurodegenerative diseases in randomly controlled trials.