Clinical trials are the most important stage in the development of effective and safe medicinal products. Yu.N. Linkova, Candidate of Medical Sciences, Vice President for Clinical Research and Development at BIOCAD, shares her perspective on clinical trial regulation in the Russian Federation.

Scientific relevance. The development of new medicinal products to treat influenza is motivated by the limitations of existing treatment options, the emergence of drug resistance, and the health consequences of influenza epidemics associated with the highly contagious nature of the virus. Proper planning and implementation of clinical programmes providing reliable data on the efficacy and safety of medicinal products under development requires adherence to recommendations of the regulatory authorities. At the moment, the Russian Federation, the Eurasian Economic Union, and the European Union lack documented recommendations on conducting clinical trials of anti-influenza medicines. There is a need in national guidelines that will reflect the procedure for conducting clinical trials and establish the required amount of data to be submitted with marketing applications for new anti-influenza products.

Aim. The study was aimed to analyse possible regulatory approaches to planning clinical development programmes for anti-influenza medicinal products.

Discussion. The article pays particular attention to phase III studies, as the main studies confirming efficacy and safety. The authors described a clinical development strategy and the requirements for the volume and quality of efficacy and safety data. This article is based on the current Russian recommendations for the design and development of medicinal products and guidelines on their evaluation, as well as the recommendations by the U.S. Food and Drug Administration (FDA).

Conclusions. The analysis results demonstrate the necessity for elaborating Russian recommendations for clinical studies of medicinal products for the treatment of influenza that will take into account the national legislation and clinical development practices. Such recommendations will streamline the implementation of new effective anti-influenza medicinal products.

Scientific relevance. Obesity is a significant public health problem. Currently, the Russian Federation and the other Member States of the Eurasian Economic Union (EAEU) do not have regulatory documents and recommendations for planning clinical trials (CTs) of new (original) medicines for the treatment of obesity.

Aim. The study aimed to provide recommendations on the basic principles of planning and conducting CTs of medicines for the treatment of obesity.

Discussion. The authors reviewed the requirements for conducting CTs of medicines for the treatment of obesity set forth by the European Medicines Agency (EMA) and the US Food and Drug Administration (FDA). In addition, the authors analysed approaches to CTs providing for a reliable evaluation of the efficacy and safety of medicines for the treatment of obesity. The primary endpoint of such CTs is a statistically significant loss of at least 5% of the baseline weight after 12 months of treatment. Secondary endpoints include assessments of abdominal obesity reduction, subcutaneous and visceral fat reduction, and the medicinal product’s effect on maintaining a reduced body weight.

Conclusions. In addition, CTs should investigate the effects of treatment on cardiovascular risk factors and cardiovascular morbidity/mortality. A CT protocol should define the intercurrent events that should be considered in the analysis of trial results. When investigating the safety of medicines for the treatment of obesity, studies should focus on neuropsychiatric safety, the potential for abuse/addiction and withdrawal reactions, and the development of valvulopathy and pulmonary hypertension. These recommendations may be of use to experts evaluating clinical development programmes or marketing authorisation submissions for medicines for the treatment of obesity.

Scientific relevance. Direct-acting antivirals have significantly improved the effectiveness of treatment for hepatitis C. However, Russia and the Eurasian Economic Union lack recommendations for the clinical development of medicinal products from this pharmacotherapeutic group.

Aim. The study aimed to analyse the requirements and recommendations for planning safety and efficacy clinical trials of direct-acting antivirals for chronic viral hepatitis C, outlined in the regulatory documents of the European Union and the United States.

Discussion. Upon analysing the requirements and recommendations, the authors explained the reasons behind choosing the target population and the design for the efficacy and confirmatory studies. The article covers the clinical development of direct-acting antivirals in special populations, including patients with hepatitis C and HIV co-infection, a liver transplant, and prior treatment experience. According to the authors, patients who achieved a sustained virological response should be followed up for a full year after the end of treatment in order to confirm the durability of their response. A dose-finding study should first identify a suitable dose range for monotherapy and, subsequently, for combined therapy. Current treatment regimens should be optimised, and studies should be conducted to reduce treatment duration.

Conclusions. The authors outlined the main approaches and a methodology for clinical trial programmes that should take into account the degree of correlation between the efficacy of direct-acting antivirals and the genotype/subtype of hepatitis C virus.

Scientist relevance. Antibacterials can have nephrotoxic effects because medicinal products of this class are primarily excreted by the kidneys.

Aim. The study aimed to analyse literature data on the mechanisms, risk factors and specific features of toxic nephropathy development during antibiotic therapy.

Discussion. The article considers mechanisms of development of acute interstitial nephritis, acute tubular necrosis, crystal deposits in the tubules, proximal or distal tubulopathy with electrolyte abnormalities during the use of antibiotics. Nephrotoxicity was shown to be most often associated with the use of aminoglycosides, beta-lactams, and vancomycin. The authors analysed the dependence of nephrotoxicity on antibacterial agent lipophilicity and drug–drug interactions. The main risk factors for developing nephropathy are older age; male sex; black race; hypovolaemia; arterial hypotension; angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, non-steroidal anti-inflammatory drugs or their combinations; and individual genetic characteristics. Nephrotoxicity is associated with genetic characteristics of the systems responsible for metabolism and excretion of antibacterial products: cytochrome P450 isoenzymes, P-glycoprotein, multidrug resistance protein (MRP), multidrug and toxin extrusion (MATE), breast cancer resistance protein (BCRP), and organic anion transporters. Severe generalised infections change pharmacokinetic parameters of antibacterial products. This should be taken into account when prescribing the hydrophilic antibiotics that are excreted by tubular secretion and reabsorbed in the renal tubules.

Conclusions. The study demonstrated the effectiveness of the method comprising a combination of dose adjustment based on therapeutic drug monitoring results and renal function monitoring for improving the safety of antibiotic therapy.

Scientific relevance. A key anti-ischaemic mechanism of some medicinal products involves their effects on the metabolism of endothelial vasodilators, particularly the synthesis of nitric oxide from arginine and its precursor citrulline.

Aim. The study was aimed to determine whether the plasma time course of guanidine derivatives (arginine precursors) is applicable to laboratory control of anti-ischaemic therapy effectiveness using a single oral dose of nicorandil in patients with coronary heart disease as a case study.

Materials and methods. The authors used high-performance liquid chromatography to determine metabolites. Blood samples for analysis were obtained from 30 patients with angina pectoris (Grade II–III, Canadian Cardiovascular Society) and 30 healthy donors. All the study participants received a single oral dose of 20 mg nicorandil after 10 h of fasting.

Results. At baseline, patients showed significantly higher plasma citrulline levels than donors. However, the elevated levels decreased to the healthy range after nicorandil administration. Plasma arginine levels in patients showed a statistically significant increase following nicorandil administration. Plasma homoarginine levels in patients remained reduced both before and after dosing. Nicorandil did not influence elevated levels of the endogenous nitric oxide synthase inhibitor (asymmetrical dimethylarginine).

Conclusions. In addition to the established mechanisms responsible for altering cell metabolism, nicorandil enhances the contribution of citrulline to arginine resynthesis. It is reasonable to include citrulline and arginine, which are involved in the vasodilator response, in model schemes for laboratory control of the effectiveness of anti-ischaemic therapy.

Scientific relevance. The biological activity of medicinal products may vary depending on the method of production (i.e. biological or recombinant products). The widening variety of gonadotrophin preparations, the diversity of their production methods, and the irreplaceability of biological activity bioassays with physicochemical tests require improvement of animal testing conditions.

Aim. This study aimed to determine the biological activity of follicle-stimulating hormone (FSH) in several rat lines, analyse the findings, and select the most optimal testing conditions.

Materials and methods. The biological activity was determined using in vivo methods. The comparative analysis used test results obtained over several years in inbred and outbred rats treated with FSH. In all cases, the authors used a three-dose randomised method based on the determination of the biological activity of test samples by comparison with that of the WHO international standard (IS) containing 183 IU of FSH bioactivity and 177 IU of LH bioactivity per ampoule (NIBSC code: 10/286). The study included immature female rats, inbred (Wistar-Kyoto or Sprague Dawley) and outbred. Testing conditions depended on the selected rat line, with the main variables being the test dose and the number of animals per group.

Results. The authors compared responses of inbred and outbred rats to various doses of the FSH IS and test samples. Given the narrow range of the analytical procedure, Wistar-Kyoto rats showed a relatively weak dose–response relationship. The study demonstrated that the doses and testing duration depended on the sensitivity of the animals. Test results were less variable in inbred rats than in outbred ones. The statistical analysis of the results of FSH bioactivity testing in inbred and outbred rats showed that, with inbred rats, the number of animals could be halved without compromising the validity of the test.

Conclusions. The approach proposed in this study provides for testing the biological activity of FSH with fewer experimental animals, improved cost-effectiveness, and the same reliability of results.

Scientific relevance. Sound recommendations for preclinical studies of transporter- mediated pharmacokinetic interactions of medicinal products can help increase the likelihood of identifying potentially nephrotoxic and hepatotoxic medicinal products at the development and authorisation stages. However, overly strict requirements for the number of studies to be performed may lead to a significant increase in the cost of finished medicinal products.

Aim. The aim was to compare regulatory documents on studying transporter-mediated drug–drug interactions (DDIs).

Discussion. This review examines changes in regulatory requirements for studying DDIs in chronological order from the first guidelines that appeared in 1997. As exemplified in this article, the multiplicity of transporters and the lack of specific inhibitors pose significant challenges in assessing the role of a particular transporter in drug distribution and drug–drug interactions. This comparative review shows that extrapolating from in vitro transporter inhibition studies to in vivo pharmacokinetics can be misleading.

Conclusions. A unified approach to studying transporter-mediated DDIs will increase the likelihood of identifying potentially toxic agents at the stage of new molecule screening. At the same time, it is advisable to limit the number of in vitro and in vivo transporter studies and recommend conducting these studies only for medicinal products with a narrow therapeutic index.

Scientific relevance. Cardiac glycosides have been used in medicine for over two centuries. Current studies suggest that biologically active substances from this group can be used to treat not only heart conditions but also viral infections, cancers, and other diseases. Therefore, quality control methods for cardiac glycosides are becoming increasingly relevant.

Aim. Based on a review of Russian and international quality standards, as well as up-to-date scientific data, this study aimed to identify promising methods for the identification and quantification of cardiac glycosides in herbal drugs and herbal medicinal products, as well as to evaluate the possibility of substituting physicochemical methods for biological methods.

Discussion. The methods that are currently used to standardise cardiac glycosides are either not selective or require laboratory animals (biological test systems). According to a study of pharmacopoeial methods for the identification of cardiac glycosides in herbal drugs and herbal medicinal products, chemical identification tests and thin-layer chromatography continue to be relevant. Quantitative testing of herbal drugs and extracts uses biological and non-selective (spectrophotometry) methods, whereas chromatography is described only in general and individual monographs for herbal drug preparations containing individual cardiac glycosides and medicinal products containing these preparations. Upon analysing quality standards and scientific publications, the authors identified potentially promising methods for the quantification of cardiac glycosides in herbal drugs, herbal drug preparations, and herbal medicinal products, namely chromatographic methods.

Conclusions. Reverse-phase high-performance liquid cjromatography (HPLC) with spectrophotometric detection is the most suitable method for pharmacopoeial analysis. The development of an HPLC-based analytical procedure to determine the cardiac glycoside content will provide an opportunity to advance from biological or non-selective methods to more ethical and selective up-to-date techniques.

Scientific relevance. Hypromellose phthalate is a component of enteric coatings used to modify active substance release from oral medicinal products in the small intestine. The release rate directly depends on the non-stoichiometric composition of the polymer, first of all, on the proportion of phthalate groups in the macromolecule. It is therefore necessary to develop reliable analytical procedures for determining the structure of hypromellose phthalate to evaluate the dissolution rate of medicinal products containing the polymer.

Aim. The study aimed to develop an analytical procedure for quantifying the proportion of phthalate groups in hypromellose phthalate samples using NMR spectroscopy and to determine the relationship between the polymer dissolution rate in aqueous buffer solutions and its structural features (degree of molar substitution and molecular mass).

Materials and methods. The study examined hypromellose phthalate samples isolated from enteric coatings of proton-pump inhibitors and used the reference standard for hypromellose phthalate. The non-stoichiometric composition of the polymer was determined by 13C NMR spectroscopy.

Results. The authors established the conditions required to separate hypromellose phthalate from the other coating components and identified the characteristic 13C NMR signals that may be used to differentiate between the structural fragments of hypromellose phthalate. The study demonstrated the relationship between the dissolution rate and the structure of the polymer. Commercial grades of hypromellose phthalate were shown to differ in composition and, as a result, in their dissolution kinetics (in particular, the threshold pH for the onset of dissolution (5.0–5.5), as well as the dissolution rates at the same pH).

Conclusions. The authors developed NMR-based procedures to determine the proportion of phthalate groups on the basis of their mass fraction in a weighted hypromellose phthalate sample and the degree of molar substitution of the polymer. The results support the applicability of these analytical procedures to the characterisation of sample composition in polymer dissolution rate studies. In principle, it is possible to derive a multiple linear regression equation that describes the dissolution rate of hypromellose phthalate as a function of the molecular mass and the molar substitution with phthalate groups. Further investigation of a larger number of polymer samples with different compositions is needed to improve the regression model and demonstrate its statistical significance. In addition to the proportion of phthalate groups, the pharmacopoeial analysis of hypromellose phthalate should also control the molecular mass of the polymer.

Scientific relevance. The gradual transition to the common pharmaceutical market within the Eurasian Economic Union (EAEU) is expected to be completed by the end of 2025, and a new regulatory framework is currently being developed at both the national and supranational levels. The main changes in Russian national legislation are aimed to harmonise it with EAEU legislation. However, Russian national legislation will continue regulating a range of issues related to the life cycle of medicines.

Aim. This study aimed to compare the Russian and EAEU legal frameworks regulating medicines before and after January 2026, as well as to analyse the risks of conflicts of laws between these legal systems.

Discussion. Analysing the causes of potential conflicts of laws between Russian and EAEU legislation, the authors consider solutions for such conflicts outlined in the legal system of the Russian Federation, as well as the applicability of these solutions to specific situations in the national and supranational regulation of medicines. This study analyses the stages in the life cycle of medicines associated with the highest risk of conflicts of laws, including clinical trials, the development of pharmacopoeial requirements, and the designation of orphan medicines. The authors examine the relationships between authorisation procedures during the transition period with both legal systems in effect. The analysis highlights the issues that will continue to be regulated under Russian national legislation after the completion of the transition period, such as the inclusion of active substances in the Russian State Register of Medicines, the authorisation of medicines during armed conflicts or other emergencies, and the interchangeability of medicines. Given the evolving requirements of the regulatory environment, this study provides suggestions for enhancing the regulatory framework and recommendations for applicants.

Conclusions. After the complete transition to the common market in the EAEU, certain requirements of Russian Federal Law No. 61-FZ “On Circulation of Medicines” of 12 April 2010 will remain effective in the Russian Federation. Therefore, during the transition period, applicants for authorisation should consider the partial continuation of national regulation after 2026 when developing their regulatory affairs strategies.