INTRODUCTION. Rabies is an invariably fatal disease having no adequate cure; in some cases it requires administration of rabies immunoglobulin combined with rabies vaccine. Given the supply constraints of rabies immunoglobulin derived from donor blood, research is underway worldwide to develop preparations based on neutralising monoclonal antibodies (mAbs), which are potentially relevant for the Russian healthcare system.

AIM. This study aimed to perform a narrative review of the development, clinical trials, and post-marketing safety and efficacy studies of rabies monoclonal antibodies intended for post-exposure prophylaxis in combination with rabies vaccination.

DISCUSSION. Currently, three rabies mAb drugs have been registered worldwide. Of them, two are manufactured in India (a recombinant human anti-rabies antibody; a combination drug of docaravimab and miromavimab) and one in China (ormutivimab). Preclinical studies of these drugs have confirmed their ability to neutralise the rabies virus, including wild strains. Clinical trials have established a favourable safety profile for these anti-rabies mAbs (adverse events are generally transient and self-resolving) and a lack of immune interference with administered rabies vaccines. Administration of all the above drugs did not change immune response to the complete course of anti-rabies vaccination, unlike human immunoglobulin preparations. On Day 42 (4 weeks after the last dose of rabies vaccine), virus-neutralising antibody titers reached 31.12 IU/mL for the recombinant human rabies antibody preparation and 122 IU/mL for docaravimab and miromavimab combination. Controlled clinical trials and post-registration studies of the recombinant human rabies antibody and docaravimab-miromavimab combination showed no rabies episodes in patients receiving post-exposure prophylaxis with the study drugs and the rabies vaccine.

CONCLUSIONS. Anti-rabies mAb preparations are an effective and safe option for post-exposure rabies prophylaxis, confirmed by their worldwide use. Integrating these drugs into comprehensive patient care will help overcome the potential shortage of rabies immunoglobulins in the Russian Federation. When registering anti-rabies mAbs, key objectives are to assess cross-reactivity with human tissues ex vivo and confirm neutralising activity against viral isolates common in Russia and the neighbouring countries.

INTRODUCTION. Medicinal products based on monoclonal antibodies (mAbs) is one of the promising options for post-exposure rabies prophylaxis. Since Russian pharmaceutical market does not offer anti-rabies mAbs, a combined docaravimab and miromavimab preparation requires a preclinical study of its protective properties against street strains of the rabies virus circulating in the Russian Federation. In this regard, the need to conduct experimental studies is urgent in order to substantiate the efficacy of such products.

AIM. This study aimed to investigate protective efficacy of the combined anti-rabies mAb preparation of docaravimab and miromavimab against the classical rabies virus in BALB/c mice.

MATERIALS AND METHODS. A combination of anti-rabies mAbs, docaravimab and miroma-­vimab, was used as a test drug, while anti-rabies immunoglobulin Rebinolin served as a comparator drug. Street rabies virus strains were used: 777-M, Russia/Samara/2018, RABV/Russia/SP48SolMak/2020, and fixed CVS strain. In the efficacy study, 960 BALB/c mice (480 females, 480 males) were used, forming 23 groups of 20 animals each (10 males and 10 females). Mice groups 3–18 were intramuscularly infected with the rabies virus, and after 6 or 24 hours, either docaravimab and miromavimab combination or a comparator drug (Rebinolin) was administered intramuscularly. Mice from group 1 and 2 were injected with 0.9% sodium chloride solution (placebo). Mice from groups 19–22 served as a dose control for the virus; group 23 served as an intact control. To assess protective properties, mice were weighed; incubation and clinical period, average life span, and protection from clinical manifestations and death was determined. Virus infectivity was evaluated on BALB/c mice after their intracerebral infection. The specific cause of animal death was confirmed using real-time reverse transcriptase polymerase chain reaction.

RESULTS. A combined preparation based on anti-rabies mAbs docaravimab and miromavimab resulted in a significantly increased body weight, average life span, and protection from clinical rabies manifestations in infected mice compared with rabies virus dose control groups. The combined preparation demonstrated high protective efficacy against rabies virus strains, not inferior to that of the comparator. Administration of the combined preparation to mice 6 hours after infection (strains 777-M, Russia/Samara/2018, RABV/Russia/SP48SolMak/2020, CVS) showed 90–100% protection of male and female mice against death; after 24 hours — 90–100% of male and 96–100% of female mice.

CONCLUSIONS. An experiment in mice shows high protective efficacy of a combined docaravimab and miromavimab preparation against street strains of the classic rabies virus relevant to the Russian Federation. Protective efficacy of the combined preparation is not inferior to the comparator, thus warranting further preclinical and clinical studies.

INTRODUCTION. Еvaluation of pharmacokinetics of monoclonal antibodies (mAb) products requires careful selection of the relevant animal models to ensure translational relevance of the data. To solve this problem, the pharmacokinetic parameters of two human monoclonal antibodies neutralising SARS-CoV-2 were evaluated in two types of laboratory animals — Syrian hamsters and mice.

AIM. This study aimed to evaluate the pharmacokinetic parameters of two different human IgG1 kappa antibodies (mAb iC1 and mAb iB20) neutralising SARS-CoV-2 after a single intravenous administration to Syrian hamsters and ICR CD1 outbred mice.

MATERIALS AND METHODS. A pilot study was performed on 15 male Syrian hamsters who received a single 5 mg/kg intravenous dose of mAb iC1. Blood samples were collected prior to administration and at 10 time points for 144 hours. In the main study, ICR CD1 mice (4 groups of 60 animals) received single intravenous doses of mAb iC1 and mAb iB20 at doses of 5 and 50 mg/kg. Blood samples were collected prior to administration and at 11 time points for 504 hours. Serum antibody concentrations were determined by enzyme-linked immunosorbent assay (ELISA). The ELISA assay was validated by following parameters: selectivity, lower limit of quantitation, calibration range, accuracy, precision, and analyte stability. Pharmacokinetic parameters — mean maximum concentration (C_max), area under the curve (AUC_0–t), mean residence time (MRT), half-life (T_1/2), and clearance (Cl) — were calculated using model-independent method of statistical moments.

RESULTS. The ELISA assays for mAb iC1 and mAb iB20 in animal blood serum were validated in the analytical range of 1.25–25.0 μg/mL and 1.25–20.0 μg/mL, respectively. C_max, AUC_0–t, and AUC_0–∞ increased significantly with the dose for both antibodies. After administration of 5 and 50 mg/kg mAb iC1 to mice the mean C_max values were about 235 and 1228 μg/mL, AUC_0–t — 6458 and 71,193 h×μg/mL. For mAb iB20 C_max values were about 359 and 4442 μg/kg, AUC_0–t — 6344 and 76,251 h×μg/mL, respectively. MRT and T_1/2 values did not depend on the administered dose. Combined with low clearance values, this indicates long-term presence of analytes in the bloodstream.

CONCLUSIONS. Pharmacokinetic parameters of mAb iC1 and mAb iB20 were determined after single administration to Syrian hamsters and ICR CD1 mice. Key parameters (C_max, AUC_0–t) were found to be dose-dependent. The obtained results can be used for further preclinical and clinical development of the medicinal products.

INTRODUCTION. Despite the decreasing acute hepatitis B (HBV) incidence due to active vaccine prophylaxis, HBV-specific post-exposure prophylaxis is still a relevant problem for both global and Russian healthcare. Advanced post-exposure prophylaxis, particularly intravenous specific immunoglobulin with its higher bioavailability and fast formation of protective titre, will better protect high-risk groups. Preparations of hepatitis B human immunoglobulins available in Russia are Antigep (Russia) for intravenous administration and Neohepatect (Germany). Enhancing vaccine prophylaxis of hepatitis B and import substitution requires development studies of the first hepatitis B immunoglobulin for intravenous administration produced in Russia.

AIM. This study aimed to develop Russian human HBV immunoglobulin for intravenous administration and perform quality control, safety and pharmacokinetics study.

MATERIALS AND METHODS. Human HBV immunoglobulin (Antigep-Neo) was obtained from the blood plasma of donors with high anti-HBV levels. Antigep-Neo was evaluated according to physico-chemical, biological, and molecular parameters, immunoglobulin A level, activity of the Fc function, and thrombogenic potential. Pharmacokinetic properties were studied in preclinical (rabbit) and clinical (healthy volunteers) studies. Neohepatect and Antigep immuno­globulin preparations were used as comparator drugs.

RESULTS. Production of human antiglobulin is based on the standard Cohn fractionation followed by chromatographic purification and three virus removal and inactivation steps. Antihep-Neo is safe, it contains more than 95% of the human IgG, of them more than 99% are monomers and dimers. The product showed low anticomplementary activity (0.17±0.06 CH₅₀/mg IgG) and low concentration of prekallikrein activator (7.45±2.11 IU/mL) and had no thrombogenic potential. Bioequivalence of Antigep-Neo and Neohepatect was confirmed in preclinical and clinical trials (differences in the pharmacokinetic profiles were not statistically significant).

CONCLUSIONS. The developed human HBV immunoglobulin (Antigep-Neo) meets quality and safety regulatory requirements. Preclinical and clinical studies have confirmed similar pharmacokinetic profile of Antigep-Neo and Neohepatect (comparator).

INTRODUCTION. Pharmaceutical production uses reference standards as an integral part of metrological support for analytical methods. A systematic literature analysis on standardisa­tion of human immunoglobulin preparations, particularly specific and special-purpose ones, will allow evaluating the metrological support in the Russian Federation and identifying new approaches to obtaining and using reference standards to assess specific potency.

AIM. This study aimed to analyse published data on the range of reference standards used to evaluate potency of human immunoglobulins in the Russian Federation and abroad.

DISCUSSION. PubMed, eLIBRARY.RU, and ConsultantPlus® legal research system showed that the list of international reference standards includes Rh₀(D), hepatitis B, tetanus, staphylococcal and cytomegalovirus infections, rabies, and smallpox human immunoglobulins. No reference standard is available for human immunoglobulin against tick-borne encephalitis, since no specific human immunoglobulin is produced in the European Union. There is an absolute dependence on the import of international reference standards for assessing the potency of human hepatitis B, cytomegalovirus, and rabies immunoglobulins. Reference standards are typically obtained from ready-to-use batches of medicinal products and then stabilised, bottled under sterile conditions, and lyophilised. The Register of the State Pharmacopoeia of the Russian Federation includes reference standards for Rh0(D), anti-tetanus serum, and staphylococcal immunoglobulin. Unlike international reference standards, pharmacopoeial standards are produced as solutions, thus significantly reducing antibody stability. For pharmacopoeial reference standards, statistical uncertainty of the certified value is established in the Russian Federation; however, while certifying international reference standards, their certification is not obligatory. According to literature analysis, the key requirements for reference standards are stability and composition / properties similar to standardised preparations. Russian and foreign certification requirements of reference standards have certain differences. The number of Russian reference standards based on human immunoglobulin G is limited, since they are mostly obtained from horse blood serum.

CONCLUSIONS. Russian pharmaceutical industry shows a deficit of national reference standards used for assessing specific potency of human immunoglobulins and donor plasma for their production. Thus, such reference standards should be released as lyophilisates and certified in international units, with an evaluation of statistical uncertainty of the antibody content.

INTRODUCTION. One of the reasons for increased pertussis cases is the pathogen adapting to the existing collective immunity formed under conditions of vaccine prophylaxis. Monitoring immunobiological properties of Bordetella pertussis strains is necessary to track changes in the pathogen adaptive potential triggered by vaccination.

AIM. This study aimed to compare immunobiological properties of isolated circulating Bordetella pertussis strains and strains used to produce whole-cell pertussis vaccine.

MATERIALS AND METHODS. The study used nine isolates of modern circulating strains of B. pertussis. Experimental series of whole-cell pertussis vaccine was made using strains iso­lated from the patients with pertussis in 2016–2020. The series was evaluated by the following parameters: serological properties and antigenic structure (serotypes); haemagglutinating, haemolytic, and dermonecrotic effect; virulence; residual toxicity and protective properties. The study used outbred and inbred F1 mice (C57Bl/6J×CBA) and evaluated morphological and cultural properties of the bacteria. Experimental data were compared with the requirements for production strains set out in the local guidelines MUK 4.2.2317-08 (Selection, testing and storage of production strains of pertussis, parapertussis and bronchisepticosis bacteria).

RESULTS. Strains 16-16 and 33-18 were obtained from nine isolates of circulating B. pertussis strains meeting the requirements for production strains. The assessment results of protective activity for strains 25-16, 37-18, and 2-20 were analysed and showed the necessity of further confirming this value due to the limited experimental material. Four B. pertussis strains, 31(2)-17, 28(1)-18, 25-16, and 2-20, did not show the required protective activity (<8 IU/mL).

CONCLUSIONS. The properties of isolates 16-16 and 33-18 of B. pertussis meet all the requirements for production strains. The test strains have a modern genotype and are prospectively applicable as candidates for replacing obsolete B. pertussis strains in production of pertussis vaccines.

INTRODUCTION. Medicinal products based on various bacterial antigens effectively prevent diseases caused by opportunisitic bacteria. However, their large-scale use will require improved composition and production process. A promising approach is to develop an antigen complex from Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris, and Staphylococcus aureus.

AIM. This study aimed to examine protective properties and toxicity of antigens from K. pneumoniae, E. coli, P. vulgaris, S. aureus, and the antigen complex in experiments on mice.

MATERIALS AND METHODS. Antigens of K. pneumoniae 204, E. coli F147, P. vulgaris 177, the complex of two S. aureus antigens (1986 and 1991), and the complex of the above antigens were used in the study. Toxicity was evaluated in white male and female SHK mice weighing 18–20 g. A single dose of antigens (50, 100 or 200 μg per mouse) or antigen complex (0.1, 0.2, 0.4, 0.6 mL per mouse) was injected intraperitoneally. Protective properties were studied in female SHK mice weighing 14–16 g. Animals were immunised twice and then infected with live homologous strains of K. pneumonia 204, E. coli F147, P. vulgaris 177, S. aureus 1986, and P. aeruginosa PA103 heterologous strain. For seven days, their survival was monitored; LD50 value and efficiency index was determined.

RESULTS. E. coli, S. aureus and P. vulgaris antigens at all tested doses, and K. pneumoniae antigens at doses of 50 and 100 µg, did not cause toxic effects in mice. 200 µg of K. pneumoniae antigens caused weight loss and animal mortality. Injection of 0.1–0.4 mL of the antigen complex did not cause toxic effects; however, injection of 0.6 mL resulted in manifestations of toxicity. Double immunisation with 0.1 mL antigen complex protected mice against infection with homologous and heterologous strains. Efficiency index was 7.99 for K. pneumonia 204, 11.56 for E. coli F147, 25.90 for P. vulgaris 177, 7.45 for S. aureus 1986, and 4.00 for P. aeruginosa PA103 (р<0,05).

CONCLUSIONS. Test antigens of K. pneumoniae, E. coli, P. vulgaris, S. aureus, and the antigen complex had an acceptable toxicological profile. The antigen complex has shown significant protective properties both against homologous strains (K. pneumoniae, E. coli, P. vulgaris, and S. aureus) and heterologous strain of P. aeruginosa. Thus, the studied antigens and their complex can be used to develop a medicinal product preventing a wide range of opportunistic bacterial infections.

INTRODUCTION. Developing high-dose interferon-based medicinal products (MPs) is particularly relevant for effective causal treatment of acute respiratory viral infections, influenza, and COVID-19 coronavirus infection. Inhalation drops both act directly on mucous membranes and stimulate powerful immune response and increased safety profile. In 2021, a new medicinal product, interferon alpha-2b-based inhalation drops, was developed to treat influenza and acute respiratory viral infections of various aetiologies.

AIM. This study aimed to assess preclinical efficacy, subchronic toxicity, and toxicokinetics of a new MP based on interferon alpha-2b and administered by inhalation.

MATERIALS AND METHODS. The new MP is based on human recombinant interferon alpha-2b. Its efficacy was studied on female BALB/c mice. The animals inhaled 3 mL of the investigational product for 10 minutes twice a day for 8 days. Animals were infected with A(H1N1)pdm2009 on Day 2 of inhalation. The dynamics of body weight and mortality, as well as influenza titre in the murine lung tissues, were evaluated 4 days after infection. MP toxicity was studied on white non-linear rats of both sexes. MP was administered using an inhaler once a day for 7 weeks at doses exceeding human therapeutic dose by 5.3 and 53 times. Pathomorphological and histopathological examination was performed on Days 29 and 43 of administration. Haematological and biochemical blood parameters, heart rate, and behavioural functions were measured prior to administration, 4 weeks into administration, and 2 weeks after the last administration. Toxicokinetics was studied on satellite groups of male rats; administration scheme was similar to toxicity studies.

RESULTS. Experiments showed that inhalation of investigational product at 923,000 IU/kg/day twice a day for 8 days inhibited A(H1N1)pdm2009 replication in the murine lungs, significantly reduced animal mortality and weight loss, and increased animal life expectancy 1.35–1.5-fold. The study doses showed no pronounced toxic, local irritant or systemic effect.

CONCLUSIONS. The inhalation investigational product has shown its efficacy and safety in preclinical studies on rodents.

INTRODUCTION. Varicella zoster virus remains a serious threat to public health and is a sig­nificant burden on the health system due to treatment costs. Vaccination coverage against varicella zoster (VZ) and herpes zoster (HZ) remains low for a number of reasons, including lack of sufficient vaccines. Improving the existing vaccines, creating new genetically engineered, effective products with a high safety profile, and updating their assessment protocols (including cellular immune response parameters in the algorithms) is a prerequisite for further vaccine prevention of diseases caused by high-risk factors. Systematising status of VZ and HZ vaccines will help developers enhance preclinical and clinical research protocols.

AIM. This study aimed to analyse the experience of developing and introducing modern vaccines to prevent diseases caused by varicella virus, as well as assessing the ways of further developments of preventive vaccines.

DISCUSSION. Live vaccines are recommended for prevention of VZ and HZ, as they mimic the body’s natural immune response to a viral agent and activate both humoral and cellular immune responses. To date, seven live vaccines for VZ prevention and two live vaccines for HZ prevention are registered worldwide. However, under conditions of reduced immunity, live vaccines are not recommended due to high risk of vaccine-associated diseases. A recombinant glycoprotein E (gpE)-based vaccine with adjuvant system is indicated for HZ prevention in people over 50 years and allowed in immunocompromised patients.

CONCLUSIONS. Research of vaccine development based on recombinant, RNA and DNA technologies shows the best prospects, since their safety is superior to live vaccines in a number of parameters and they can be used in immunocompromised patients. Both live attenuated and recombinant vaccines against diseases associated with the varicella virus are under development in Russia.