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Scientific relevance. The clinical effects and the expiration of patents for original (reference) biotechnological medicines based on monoclonal antibodies (mAbs) stimulated the development of biosimilar mAbs. The quality profile of a biosimilar mAb should correspond to the quality of the reference medicinal product. When demonstrating biosimilarity and determining the activity of medicines as part of batch quality control, analysts should study the biological properties of mAbs using suitable reference standards. The lack of international standards (ISs) makes mAb manufacturers use in-house reference standards. There is a risk of obtaining non-uniform quality and efficacy data because of the use of in-house reference standards, the heterogeneity and structural complexity of mAbs, and the relationship between the biological activity and efficacy of mAbs.Aim. This study aimed to analyse the relevance of and need for ISs for the biological activity of biotherapeutic mAbs and to define the role of reference medicinal products and ISs in assessing biosimilarity and testing medicines throughout their lifecycle.Discussion. This review covers the issues arising from the lack of ISs for assessing the biological activity of mAbs and the role and significance of reference products and ISs for biosimilars. The authors describe the specifics of studying the biological properties of mAbs and summarise the data on the need to develop and use ISs for the standardisation of biological tests. This review presents the results of studies on the first ISs established by the World Health Organisation to assess the biological activity of mAbs; these results suggest the need to standardise mAbs using ISs to ensure the quality, safety, and efficacy of mAb therapy.Conclusions. The use of ISs for mAbs plays a key role in harmonising biological activity assessments. Publicly available ISs serve as primary standards for the calibration of secondary reference materials. Moreover, ISs are required for the harmonisation of activity evaluation (in IU) between laboratories and for the consistency of the activity of various medicinal products from different manufacturers that share the same INN. The use of ISs by mAb manufacturers will contribute to ensuring the quality of mAbs and clinical monitoring of the effectiveness of their use.

One of the major public health challenges today is development of new vaccines and technologies to optimize the vaccination process. There is a growing scientific interest in vaccine adjuvants that enhance vaccine immunogenicity. At present, numerous studies are underway to develop COVID-19 vaccines, including inactivated and subunit vaccines which contain adjuvants for efficient induction of immune response and solid immunity. The aim of the study was to systematise literature related to the analysis of the structure, mechanisms of action and stimulating properties of vaccine adjuvants (synthetic oligodeoxynucleotides, virosomes, polyoxidonium, sovidone), as well as to summarise data on the effects of adjuvants used in SARS-CoV, MERS-CoV, and SARS-CoV-2 vaccine development studies. The paper analyses the prospects for enhancing the stimulating effect of the adjuvants when used in combination with compounds having a different mechanism of action. It also analyses the results of studies of adjuvanted vaccines against SARS-CoV and MERS-CoV, which may be useful when selecting adjuvants with optimal efficacy and safety profiles to be used in SARS-CoV-2 vaccines under development. It was concluded that understanding of the mechanisms of action of adjuvants that mediate their stimulating effect on the body’s immune system will contribute to safe and effective use of adjuvants to enhance the immunogenicity of both authorised and new vaccines.

One of priority issues of the present-day healthcare system is development of new vaccines and improvement of existing ones due to decreasing immunocompetence of the population, emergence of new infections and reemergence of old ones which were previously thought to be under control. Adjuvants have proven to be integral and important components of modern vaccines, as they enhance immune response to the vaccine antigen. However, despite a lot of effort put into their development, only a small number of adjuvants are currently used in clinical practice. The aim of the study was to systematise literature data on the adjuvants’ mechanisms of action, their specific structure, composition, and stimulation effects that mediate their immunoadjuvant properties. The paper summarises data on adjuvants used as components in licensed vaccines, describes their characteristics, analyses molecular mechanisms of their action in order to establish correlation between their structure and activity, which is important for the development of more efficacious and safe adjuvants. The paper cites advanced developments aimed at enhancing stimulation effects of existing adjuvants. It concludes by stating that the key research area aimed at improving vaccination efficacy is the study of mechanisms that contribute to the development of effective protection against infectious agents, as well as analysis of how to use adjuvants to stimulate the body’s defensive mechanisms, primarily by impacting the innate immunity.

The review is devoted to specific aspects of the development of post-vaccination immunity following immunisation with different types of antiviral vaccines, as well as to ways of increasing immunogenicity of vaccines and effectiveness of preventive vaccination. Vaccines containing highly purified and recombinant antigens obtained using modern technologies have lower reactogenicity and a higher safety profile, but are less immunogenic compared to live vaccines. Effective vaccines have not been developed for many viral infections yet. Therefore, it is critical to search for ways to enhance immunogenic properties of vaccines in order to increase the efficiency of vaccination, and to develop new vaccine formulations that provide reliable protection of the body against infection. The aim of the paper was to analyse specific aspects of immune response development following immunisation with antiviral vaccines, and approaches to increasing their immunogenicity using adjuvants. It reviews different types of antiviral vaccines, as well as specific aspects of immune response development depending on the nature of a specific antigen. The paper substantiates the use of adjuvants to enhance and regulate the induced immune response. It analyses mechanisms that determine the stimulating effect of adjuvants and summarises data on the adjuvants used in the licensed vaccines for human use. The authors highlight the need for further research to increase the efficiency of vaccination and suggest that one of potential solutions is the use of adjuvants based on recombinant human cytokines.

Biotechnological products, like all other medicinal products, have to comply with efficacy, safety and quality requirements. Quality evaluation of medicines includes assessment of test methods used to control medicinal product quality (described in product specification files provided by the manufacturer), laboratory testing of samples using these methods, as well as assessment of the registration dossier materials, including materials on test method validation included into the product specification files. One of the most important quality parameters of biotechnological products is biological activity, i.e. specific ability of a product to induce a desired biological effect. The article presents the results of a detailed analysis of methods used for determination of biological (specific) activity that are described in product specification files of various biotechnological products. The aim of the study was to demonstrate the importance of proper presentation of methods used for assessment of biological (specific) activity of biotechnological products and familiarise specialists engaged in elaboration of product specification files with the principles of presenting data in the «Biological (specific) safety» section. The analysis of documentation helped summarise the most common mistakes and omissions, formulate general recommendations concerning the description of methods, develop a general structure of the «Biological (specific) safety» section with detailed guidance on what to include in each of the subsections. Rationalisation of information presented in this part of the product specification files will help reduce the number of expert body’s requests for additional information/documents and will help ensure that laboratory testing is performed at a high professional level and within a prescribed period of time.

The review looks into various aspects of assessing specific activity of biotechnological products, which is one of their key quality parameters. Approaches to the analysis of this parameter and the choice of test procedures are governed by the nature and characteristics of a medicinal product. Test procedures should be adequate and have sufficient sensitivity and specificity. Specific activity of the products in question can be assessed by biological methods both in vivo using laboratory animals, which demonstrate the most adequate response to the tested product, and in vitro using sensitive cell lines. Assessment of specific biological activity helps to characterize the product’s pharmacological action and systematically examine the mechanisms of therapeutic effects in clinical practice. Therefore, specific activity of biotechnological products should be assessed using methods appropriate for the proposed mechanism of action. Many biotechnological products, such as cytokine system products, mAbs, fusion proteins and some others call for individual methods for assessment of their specific activity. Biotechnological products are successfully used in the treatment of autoimmune, infectious, oncological, and allergic diseases.

The article describes general principles of evidence-based quality assessment research of a recombinant granulocyte colony stimulating factor preparation (G-CSF) under development as well as a confirmation of its similarity to reference preparation (authorized original preparation). Since the quality of biotech preparations is determined by the manufacturing process, when developing a biosimilar one should focus on the manufacturing process details, starting from the selection of the expression system, the composition of excipients, on to the methods of isolation and purification of recombinant protein. Recombinant protein should be characterized in more details, than the quality parameters of the original preparation, included in the specification of the substance or the preparation. Comparative studies include characterization of the active substance and the assessment of the quality of the finished product. The reference preparation in the development of a biosimilar G-CSF

One of the most complicated issues of modern medicine is diagnosis, treatment and prevention of rare diseases. In the structure of rare diseases the vast majority accounts for genetically determined disorders. The introduction of genetic testing methods helped to identify a lot of hereditary diseases, that currently reach the number of 8,000 cases and according to estimations the frequency of their detection is about to increase. Medicinal products for diagnosis or treatment of rare diseases form the group of orphan drugs. Biologicals are the most effective medicinal products in the whole group, due to their ability to bind specifically with the «target receptor», which allows to use them as targeted drugs. Another advantage of biologicals, compared with preparations of chemical origin, is their low toxicity. Orphan drug provision is the most severe issue because the treatment of severe forms of rare diseases may require the prescription of an expensive drug. Manufacturing of orphan drugs may be unprofitable for the reason of the low prevalence of rare diseases. Therefore, the availability of orphan drugs for patients depends on the amount of state participation in manufacture stimulation. In various countries regulatory requirements for the recognition of a disease as a rare disease, and marketing authorization procedures for orphan drugs are developed with due regard to the social and economic characteristics of the country. The article presents the analysis of the regulatory requirements for various countries for the detection of rare diseases, and a common approach to marketing authorization procedure for the drugs used in treatment of rare diseases, exemplified by biological orphan preparations.

Biological preparations differ substantially from low molecular weight chemicals in molecular weight, multidimensional structure of an active substance, presence of post-translational modifications, composition of impurities and excipients, drug manufacturing process, etc. These specific features of biological preparations also influence their pharmacokinetic properties. The assessment of pharmacokinetic properties is essential not only for the confirmation of the efficacy of a biological preparation, but it is also key aspect of demonstrating the similarity/analogy of a biosimilar preparation under development and the reference (original) preparation. High molecular weight biological preparations when administered subcutaneously and intramusculary initially migrate from the injection site into lymphatic vessels and then to blood. Pharmacokinetic properties of drugs with Fc region of immunoglobulin, are affected by their ability to interact with Fcy and FcRn receptors. Almost all biological preparations possess immunogenicity, the appearance of antibodies to a drug causes changes not only in pharmacodynamic but also in pharmacokinetic properties of biological products. The assessment of pharmacokinetic properties is a complicated and time-consuming process, for example, the study of drug distribution may in some cases require the use of a radioactive label.