There are a lot of diseases known today, which are caused by genetic abnormalities. Advances in genetics and biotechnology brought about gene editing technologies that can produce almost any gene, which ultimately led to the emergence of a new class of medicines - gene therapy products (GTPs). The aim of the study was to analyse international experience in development and authorisation of GTPs. The review highlights the challenges in GTP development, related to the search for an optimal approach to therapeutic gene delivery to the target cells. Viral vectors were shown to be a promising gene delivery system, with adenovirus (AV) and adeno-associated virus (AAV) based products demonstrating the highest efficacy and safety. The paper reviews current approaches to gene editing that allow modification of AVs and AAVs to improve GTP efficacy and safety. These modifications are carried out with the aim of, e.g., including a large therapeutic gene into a viral vector, decreasing viral protein expression levels, and decreasing viral vector immunogenicity. The review summarises GTP authorisation procedures in the USA and the European Union, including data on FDA and EMA subcommittees and departments entrusted with advisory functions. The paper mentions that there is one Russian-produced GTP authorised in the Russian Federation, and some other GTPs are in the pipeline. Therefore, the Russian regulatory framework and the Eurasian regulations and recommendations should be updated in order to accommodate for GTP development and authorisation.

Medicines based on recombinant human interferons (rhIFNs) beta-1a and beta-1b are used as first-line treatment of multiple sclerosis. Meanwhile, rhIFN beta-1a and beta-1b have structural differences associated with the eukaryotic or prokaryotic expression systems, respectively. Pharmacopoeias require identification of the primary structure of recombinant proteins by peptide mapping, which involves the use of reference material. Currently, there is no international reference standard available for rhIFN beta-1b structural identification. The aim of the study was development and certification of a pharmacopoeial reference standard for identification of the amino acid sequence of purified rhIFN beta-1b by peptide mapping. Materials and methods: rhIFN beta-1b produced by GENERIUM and endoproteinase Glu-C from Staphylococcus aureus V8 were used in the study. The peptide mapping was performed using reverse-phase high-performance liquid chromatography (RP HPLC) and high-resolution mass spectrometry. Statistical evaluation of the results included calculation of the arithmetic mean, standard deviation, and coefficient of variation. Results: the authors developed and certified a Russian Pharmacopoeia reference standard for structural identification of rhIFN beta-1b (PhRS 3.2.00447). The certified characteristic is the range of retention times of characteristic peaks: the absolute retention time was 42.0–43.2 for the third (reference) peak, the relative retention time was 0.61–0.66 for the first peak, 0.68–0.73 for the second peak, 1.04–1.06 for the fourth peak, 1.14–1.15 for the fifth peak, 1.22–1.24 for the sixth peak, and 1.29–1.30 for the seventh peak. Conclusions: the authors developed requirements for the rhIFN beta-1b pharmacopoeial reference standard. The material chosen as the candidate reference standard was an intermediate rhIFN beta-1b product sampled before addition of human serum albumin. The quality control was carried out in accordance with the developed specification. The authors analysed the amino acid sequence of the molecule, confirmed the presence of the disulfi e bond, and obtained the certifi d characteristic of the reference standard. Comparative analysis of the peptide maps of the certified rhIFN beta-1b pharmacopoeial reference standard and the rhIFN beta-1a reference standard revealed differences between the maps, and, therefore, confirmed the relevance of the developed reference standard.

The development and use of new methods of quality control of medicines involve the use of a lot of reference materials in quality control testing. Specialists of the Russian Research Antiplague Institute “Microbe” have proposed an alternative methodological approach to determination of potency of anti-rabies immunoglobulin in cell culture, which requires the development of an in-house reference standard (RS) certified against the biological reference preparation (BRP) of the European Pharmacopoeia human rabies immunoglobulin. The aim of the study was to develop and evaluate the metrological characteristics of an in-house RS for anti-rabies immunoglobulin potency, to be used in the virus neutralisation test in a Vero cell culture. Materials and methods: The following materials were used in the study: equine rabies immunoglobulin, Vero continuous cell culture, fixed rabies virus (Moscow 3253_Vero strain), human rabies immunoglobulin BRP of the European Pharmacopoeia. The potencies of the candidate in-house RS and rabies immunoglobulin samples were determined in the neutralisation test in cell culture. The results were recorded using a fluorescent microscope. Statistical processing was carried out in accordance with general chapter 1.1.0014.15 of the State Pharmacopoeia of the Russian Federation, 14th edition. Results: the certified value of the in-house RS potency was 180.8±18.8 IU/mL. The confidence limits were determined at the 0.95 probability level. The shelf life of the in-house RS is 1.5 years (when stored according to the sanitary regulation SanPiN 3.3686-21). The certified in-house RS was assigned with the number 41-01-20. A set of technical and operational documentation was developed and approved for the in-house RS. The developed in-house RS can be used for in vitro determination of anti-rabies immunoglobulin potency, expressed in international units, to confirm its compliance with the product specification file. Conclusions: the authors developed an in-house RS for anti-rabies immunoglobulin potency, to be used in the virus neutralisation test in cell culture, certified against the human rabies immunoglobulin BRP of the European Pharmacopoeia.

Assessment of prekallikrein content is essential for safety control of human immunoglobulin and albumin products. The inherent variability of human prekallikrein reagents and chromogenic substrates indicates the need for standardisation of the chromogenic assay, using the components of a reference standard (RS) not only for construction of calibration curves, but also for confirmation of validity, consistency, and reproducibility of results within different established ranges. The aim of the study was to improve the quality control of human plasma products in terms of prekallikrein activator content. Materials and methods: prekallikrein activator content was determined by the chromogenic assay according to the procedure described in General Monograph 1.8.2.0013.18 of the Russian Pharmacopoeia, using various prekallikrein reagents. An RS was developed in a spiking test, using human albumin solution and Hageman factor beta-fragment reagent. Shewhart control charts were prepared based on the results of determination of prekallikrein activator content in the RS control component.

Results: a two-component RS for prekallikrein activator content with an assigned Hageman factor beta fragment content was developed using the spiking test. The authors substantiated the necessity of using a Russian-produced prekallikrein reagent as the RS component. The in-house reference standard IRS 42-28-445 was certified using all available human prekallikrein reagents, and the IRS 42-28-446 was certified using the prekallikrein reagent included in the kit. The certified prekallikrein activator content is: 51 IU in the batches 1 of IRS components intended for prekallikrein determination; 8.3–11.9 IU/mL in the IRS 42-28-445 control component, after reconstitution in 1.0 mL of purified water, and 5.4–6.6 IU/mL after reconstitution in 2.0 mL of purified water; and 9.1–11.1 IU/mL and 5.6–6.4 IU/mL in the IRS 42-28-446 control component after reconstitution in 1.0 mL and 2.0 mL of purified water, respectively. The IRS component intended for prekallikrein determination is designed for calibration curve construction, while the IRS control component is designed for assessing the validity of test results and preparation of control charts. The analysis of the control charts for the control component made it possible to evaluate the consistency of the analytical process. Conclusions: the components of the developed RSs in combination with Shewhart control charts allow for both determination of prekallikrein activator content, and control of the analytical process, as well as assessment of changes related to the replacement of the reagent batch. The RS control component allows for assessment of analytical process consistency and ensures the standardisation of the test procedure.

Interferon beta preparations have demonstrated efficacy in the treatment of multiple sclerosis. One of the most important quality attributes that support efficacy and safety of interferon beta preparations is specific antiviral activity. Interferon beta activity is determined by the biological test method which can lead to an erroneous final result due to the system uncertainties that contribute to the overall uncertainty. Accurate assessment of specific activity plays an important role in adequate determination of the product’s therapeutic dose, therefore the test method standardisation and validation are of particular relevance. The aim of the study was to validate a test procedure for assessing specific activity of human recombinant interferon beta preparations, using various cell/virus combinations, as illustrated by the example of Infibeta^®. Materials and methods: WISH, Vero, A-549, and MDBK cells in combination with mouse encephalomyocarditis virus were used in the study. The testing was performed using the biological test method based on the interferon ability to suppress virus-induced cytopathic effects in cell cultures. The results were processed using methods of mathematical statistics and the GraphPadPrism, Statistical 2/0 software package. Results: the paper compares the results of specific activity determination of Infibeta^® (interferon beta-1b) using various cell/virus combinations. The dose-response curves were used to compare the test results. It was demonstrated that all the tested cell lines could be used in the biological test procedure for determination of interferon beta specific activity. However, the best results were obtained with A-549, WISH cells in combination with mouse encephalomyocarditis virus. The following validation characteristics were determined in the cell/virus systems: specificity, linearity, precision, and robustness. Conclusions: the study validated the test procedure that enables measurement of interferon beta specific activity in the range of 4.8–11.2 IU/mL at a satisfactory accuracy level, which guarantees reliable test results. The study demonstrated robustness, intermediate precision, and reproducibility of the test procedure.

Mucopolysaccharidosis type VI (Maroteaux–Lamy syndrome) is an orphan genetic disease caused by deficiency of the lysosomal enzyme arylsulfatase B (ASB). The need to develop a highly productive cell line for the production of recombinant ASB, is behind the concept and relevance of this study. The most promising approach seems to be the development of CHO producer cell lines coexpressing the target ASB enzyme and an auxiliary formylglycine-generating enzyme (FGE). At the same time, it is important from a practical perspective to have the possibility of cultivating producer cell lines as suspensions free of serum or other components of animal origin. The aim of the study was to develop highly productive cell lines for the production of recombinant ASB by coexpression of the auxiliary FGE. Materials and methods: a suspension CHO cell line was used in the study. CHO cells were transfected by electroporation using the MaxCyte STX system. Monoclonal cell lines were obtained with the help of the Cell Metric system. Enzyme-linked immunosorbent assay was used for determination of ASB concentration in the culture fluid. Culture fluid samples were analysed using polyacrylamide gel electrophoresis and Western blotting. The mRNA level was measured by real-time polymerase chain reaction. Results: producer cell lines coexpressing the target ASB enzyme and auxiliary FGE were obtained. An increase in the yield of the active target ASB enzyme from 2 to 100 mg/L was achieved by selecting the optimal ratio of plasmids during transfection. The highest yield of the target ASB enzyme was achieved at the 90:10 ratio (%) of plasmids encoding the ASB and FGE genes, respectively. Conclusions: the authors developed highly productive cell lines for the production of recombinant ASB, which coexpress the target and auxiliary enzymes. The coexpression of ASB and FGE improves the growth and production characteristics of the cell line, probably due to the modification of the ASB active site. The obtained results will help resolve the problem of low enzyme yield, which is typical of this class of medicines.

The light obscuration method described in the State Pharmacopoeia of the Russian Federation for subvisible particle testing, provides for preparation of a pooled sample with a minimum volume of 25 mL to be used in four measurements, each with 5.0 mL of the test sample. In the case of, for example, ready-to-use 0.2–0.3 mL pre-filled syringes, the method requires pooling the contents of a large number of products, which is economically costly. The use of small volumes of test samples in measurements by the light obscuration method is especially relevant for expensive medicines. Current particle counters allow for testing of 0.1 mL samples, but this requires assessment of the procedure’s accuracy. The aim of the study was to assess the accuracy of subvisible particle testing by the light obscuration method for small volumes of test samples. Materials and methods: we used an HIAC 9703+ liquid particle counter; particle count reference standards containing 0.998×10⁶ particles/mL and 3.800 particles/mL; suspensions of standard latex particles with a known size (20 μm). Results: the study assessed the accuracy of subvisible particle determination by the light obscuration method for small test samples of 0.1‒0.5 mL: trueness was 96–100%; repeatability was 0.8–1.8%; linear correlation coefficients for the calculated versus theoretical number of particles were more than 0.999. The use of 0.1 mL test samples is impractical because of insufficient accuracy of the test results. The relative standard deviation of subvisible particle measurements obtained with 0.2–5.0 mL test samples did not exceed the measurement error of the instrument. The use of small test samples (0.2–1.0 mL) requires the use of a 1 mL sampling syringe. The study demonstrated the need for determination of the pre-run volume (not less than 0.1 mL). Comparative testing of standard (5.0 mL) and small (0.5 mL) samples of protein-based biological products showed comparable results. Conclusions: the study demonstrated that the light obscuration method could be used for small volumes of test samples.