The disfunction or deficiency of the C1 esterase inhibitor (C1INH) is associated with hereditary or acquired angioedema (HAE/AAE), a rare life-threatening condition characterized by swelling in the skin, respiratory and gastrointestinal tracts. The current treatment options may carry the risks of either viral infection (plasma-derived Berinert^®) or immune reaction (human recombinant C1INH from rabbit milk, Ruconest^®). This study describes the physicochemical and biological characterization of a novel recombinant human C1 esterase inhibitor (rhC1INH) from Chinese hamster ovary (CHO) cells for the treatment of hereditary angioedema compared to the marketed products Berinert^® and Ruconest^®. The mass spectrometry results of total deglycosylated rhC1INH revealed a protein with a molecular mass of 52,846 Da. Almost full sequence coverage (98.6%) by nanoLC-MS/MS peptide mapping was achieved. The purity and C1s inhibitory activity of rhC1INH from CHO cells are comparable with Ruconest^®, although we found differences in charge isoforms distribution, intact mass values, and N-glycans profile. Comparison of the specific activity (IC₅₀ value) of the rhC1INH with human C1 esterase inhibitor from blood serum showed similar inhibitory properties. These data allow us to conclude that the novel rhC1INH molecule could become a potential therapeutic option for patients with HAE/AAE.

Some types of immunotherapy of malignant tumours are aimed at restoration of T-cells’ ability to recognize and eliminate cancer. Programmed cell death ligand-1 (PD-L1) overexpression is characteristic of many human tumours and is associated with poor prognosis for patients. The development of monoclonal antibodies (mAbs) specific for PD-L1 or PD-1 is a promising area of immunotherapy of malignant tumours. However, before a therapeutic antibody-based product enters the market, it is necessary to ensure its safety and efficacy, i.e. perform a full scope of preclinical and clinical studies.The aim of the study was to develop and validate a bioanalytical method that does not require additional labeling and that could be used for determination of mAbs specific for human PD-L1 in the blood serum of a biological test system during preclinical studies.Materials and methods: an antigen in the form of a dimer of PD-1 extra-cellular domain covalently bonded to the Fc-fragment of human IgG (R&D Systems, USA) was used in the study. The antigen was immobilised on Dip and Read™ Protein A biosensors (Fortebio, USA). The therapeutic anti-PD-1 antibody GNR-051 was developed and produced by IBC “Generium” (Russia). The healthy cynomolgus monkey serum samples used as matrix were obtained from the Research Institute of Medical Primatology (Sochi, Russia). The assessment of binding was performed using Octet® QKe interferometer (Fortebio, USA) by real-time analysis of the dose-dependent rate of the antigen-antibody complex formation.Results: the paper presents experimental data on the development and validation of the test method for determination of the therapeutic PD-1-binding mAb concentration in cynomolgus monkey serum in the antibody concentration range from 2 to 2500 µg/mL. The authors assessed the calibration curve reliability, between-run and within-run precision and accuracy, dilution linearity, specificity and selectivity of the test method.Conclusions: the authors developed and validated the biolayer interferometry-based method for determination of therapeutic mAbs concentration. The method was shown to comply with the Eurasian Economic Union’s regulatory requirements in terms of the main validation parameters: analytical range, accuracy, precision, and selectivity.

INTRODUCTION. Romiplostim treatment of patients with idiopathic thrombocytopenic purpura is associated with formation of anti-drug antibodies (ADA), which often leads to the serious adverse events. A method based on biolayer interferometry is proposed for determination of binding (total) ADA (bADA) to romiplostim in human serum. From a technological point of view, instruments using this principle have some advantages (higher throughput, prolonged service intervals, low level of equipment contamination during analysis of biosamples) over those based on surface plasmon resonance, which are used to monitor bADA levels during clinical trials of the original drug. The method should be validated to ensure reproducibility of measurements and standardise clinical laboratory trials of the immunogenicity of a biosimilar drug.AIM. To establish the key validation characteristics of a biolayer interferometry-based method for the determination of total anti-drug antibodies to romiplostim in human serum.MATERIALS AND METHODS. The method is used to detect the specific interaction of binding antibodies with biotinylated romiplostim immobilised on the streptavidin-coated biosensors. The method includes a screening test to determine bADA presence or absence in the samples; a confirmatory test to check the specificity of bADA binding to romiplostim; determination of antibody titer and maximal dilution, that allows to detect bADA in the samples. Positive control samples containing different concentrations of polyclonal rabbit antibodies to romiplostim were used in the work. Detection of protein complex formation was performed in real time mode using an Octet® QKe interferometer.RESULTS.  The biological variability factor and the limit of not significant inhibition were 1.481 and 34.2%, respectively. The precision and specificity of the method were confirmed. The lower limit of bADA detection in the absence of romiplostim was 622 ng/mL. The analytical signal of 8 out of 10 blood serum samples after the addition of bADA increased by more than 1.481 times when assessing the matrix effect in the screening test; the percentage inhibition value exceeded 34.2% when analysing 8 out of 10 samples with the addition of bADA in the confirmatory test. There was no high-dose effect at bADA concentrations from 0.8 to 50 μg/mL. The results of bADA determination in the screening test were robust to the presence of 1 ng/mL romiplostim in the samples. Streptavidin-coated biosensors with immobilised romiplostim maintained stability after 14 days of storage at a temperature of (5±3) °С and at least 20 regeneration cycles.CONCLUSIONS. Analysis of the validation results obtained confirms the suitability of the method for reliable and reproducible determination of binding (total) antibodies to romiplostim in human serum.

Background. Enzyme replacement drugs for treatment of mucopolysaccharidosis type II (MPS II) do not penetrate the blood-brain barrier, significantly reducing their efficacy in patients with neuropathic form. Verenafusp alfa (Clotilia®) is a recombinant fusion protein of iduronate-2-sulfatase and a monoclonal antibody Fab fragment to human insulin receptor for distribution of the enzyme into brain. Aim. To evaluate safety, tolerability, and pharmacokinetic parameters of verenafusp alfa after single intravenous administration of escalating doses in healthy volunteers. Materials and methods. This open-label, multicohort study included 20 healthy male volunteers aged 18 to 47 years (26.1±7.8 years). Verenafusp alfa was administered intravenously for 3 hours at single doses of 0.3 mg/kg (n=1), 0.5 mg/kg (n=1), 1 mg/kg (n=6), 2 mg/kg (n=6), and 3 mg/kg (n=6). Safety was assessed based on the incidence of clinical and laboratory adverse events (AEs) and their relationship to the investigational medicinal product. Pharmacokinetic parameters were calculated using a noncompartmental method. Results. All 20 volunteers completed the study. AEs reported in 6 (30%) volunteers were mild in severity and related to changes in individual laboratory and instrumental test data. One AE (increased bilirubin level) was possibly related to the study drug. Pharmacokinetic analysis demonstrated a dose-dependent increase in maximum concentration (Cmax) from 197.60 (0.3 mg/kg) to 10,225.80 ng/mL (3 mg/kg) and area under the concentration-time curve (AUC) from 38,678.60 to 2,714,067.42 ng×min/mL respectively. The half-life ranged from 86.69 to 213.42 minutes, and clearance lowered with the increasing dose from 7.67 to 1.11 mL/min/kg. Conclusion. Single intravenous administration of verenafusp alfa at doses ranging from 0.3 to 3 mg/kg demonstrated a favorable safety profile and good tolerability in healthy volunteers. The drug's pharmacokinetics was nonlinear, with a dose-dependent increase in Cmax and AUC with the dose increment. Volume of distribution volume lowered with increase of the dose.

Background/Objectives: Nusinersen is a synthetic antisense RNA oligonucleotide employed in the management of spinal muscular atrophy, a rare neuromuscular disorder, by modulating the alternative splicing of the survival motor neuron 2 (SMN2) gene. GNR-100 represents the first generic version of the reference listed drug (RLD), containing nusinersen sodium as the active pharmaceutical ingredient. We performed comprehensive evaluations in accordance with FDA guidelines, including side-by-side comparative analyses of critical quality attributes, to thoroughly characterize the structural and functional properties of both nusinersen products. Results/Methods: GNR-100 was comprehensively demonstrated to be highly similar to RLD in terms of oligonucleotide structure, physicochemical properties, impurity profile, and in vitro cell-based assays for SMN-gene splice-switching and SMN-protein activity. Structural analyses confirmed that the oligonucleotide primary sequences and chemical structures were identical. The diastereomeric composition and higher-order structures were also similar between the proposed generic and the reference product. Comparable resistance to phosphodiesterase degradation and nearly identical melting temperatures of the oligonucleotide duplexes with their complementary strand further substantiated the structural sameness of the nusinersen products. The impurity profile of the proposed therapeutic oligonucleotide was consistent with that of RLD, and the collectively reduced levels of impurities, as assessed by orthogonal analytical methods, indicated no meaningful impact on the safety profile. Moreover, both products exhibited comparable biological activity in enhancing the production of full-length SMN2 mRNA transcripts and functional SMN protein in fibroblasts derived from SMA patients. Conclusions: These quality studies demonstrate that GNR-100 exhibits no significant differences from the licensed drug across structural, physicochemical, biophysical, and biological attributes, establishing its potential as a cost-effective therapeutic alternative for patients with spinal muscular atrophy.