Efficacy, pharmacokinetics and safety of subcutaneous versus intravenous CT-P13 in rheumatoid arthritis: a randomized phase I/III trial.

OBJECTIVE: To assess non-inferiority of s.c. to i.v. CT-P13 in RA. METHODS: Patients with active RA and inadequate response to MTX participated in this phase I/III double-blind study at 76 sites. Patients received CT-P13 i.v. 3 mg/kg [week (W) 0 and W2] before randomization (1:1) at W6 to CT-P13 s.c. via pre-filled syringe (PFS) 120 mg biweekly until W28, or CT-P13 i.v. 3 mg/kg every 8 weeks until W22. Randomization was stratified by country, W2 serum CRP and W6 body weight. From W30, all patients received CT-P13 s.c. In a usability sub-study, patients received CT-P13 s.c. via auto-injector (W46-54) then PFS (W56-64). The primary endpoint was change (decrease) from baseline in disease activity score in 28 joints (DAS28)-CRP at W22 (non-inferiority margin: -0.6). RESULTS: Of 357 patients enrolled, 343 were randomized to CT-P13 s.c. (n = 167) or CT-P13 i.v. (n = 176) at W6. The least-squares mean change (decrease) from baseline (standard error) in DAS28-CRP at W22 was 2.21 (0.22) for CT-P13 s.c. (n = 162) and 1.94 (0.21) for CT-P13 i.v. [n = 168; difference 0.27 (95% CI: 0.02, 0.52)], establishing non-inferiority. Efficacy findings were similar between arms at W54. Safety was similar between arms throughout: 92 (54.8%; CT-P13 s.c.) and 117 (66.9%; CT-P13 i.v.) patients experienced treatment-emergent adverse events (from W6). There were no treatment-related deaths or new safety findings. Usability was similar for CT-P13 s.c. via auto-injector or PFS. CONCLUSION: CT-P13 s.c. was non-inferior to CT-P13 i.v. in active RA. The convenience of s.c. administration could benefit patients. TRIAL REGISTRATION: ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT03147248.

The Role of Single-Nucleotide Variants of NOS1, NOS2, and NOS3 Genes in the Comorbidity of Arterial Hypertension and Tension-Type Headache.

Patients with tension-type headache (TTH) have an increased risk of developing arterial hypertension (AH), while hypertensive subjects do seem to have an increased risk of TTH. We searched for full-text English publications in databases using keywords and combined word searches over the past 15 years. In addition, earlier publications of historical interest were included in the review. In our review, we summed up the single nucleotide variants (SNVs) of Nitric Oxide Synthases (NOSs) genes involved in the development of essential AH and TTH. The results of studies we discussed in this review are contradictory. This might be due to different designs of the studies, small sample sizes in some of them, as well as different social and geographical characteristics. However, the contribution of genetic and environmental factors remains understudied. This makes the issue interesting for researchers, as understanding these mechanisms can contribute to a search for new approaches to pathogenetic and disease-modifying treatment of the AH and TTH phenotype. New drugs against AH and TTH can be based on inhibition of nitric oxide (NO) production, blockade of steps in the NO-cGMP pathway, or NO scavenging. Indeed, selective neuronal NOS (n-NOS) and inducible NOS (i-NOS) inhibitors are already in early clinical development.

Primary efficacy of netakimab, a novel interleukin-17 inhibitor, in the treatment of active ankylosing spondylitis in adults.

OBJECTIVES: Netakimab (NTK) is a humanised monoclonal antibody targeting interleukin-17A, previously investigated in a phase 1 trial in healthy volunteers. Here, we report the results of a phase 2 trial, conducted to assess safety and pharmacokinetics (PK), to establish a therapeutic dose of NTK in a target population of patients with active ankylosing spondylitis (AS). METHODS: 89 patients with active AS, despite non-steroidal anti-inflammatory (NSAID) drug treatment, were randomised to receive 40, 80 or 120 mg of subcutaneous NTK or placebo at weeks 0, 1, 2 and q2wk thereafter until week 12. The primary endpoint was to achieve a proportion of patients with ≥20% improvement in Assessment of Spondyloarthritis. RESULTS: Rates of ASAS20 response at week 16 for NTK with 95%CI for difference in ASAS20 rates NTK vs. placebo were 72.73% [1.69%;58.05%], 81.82% [12.36%;65.56%], 90.91% [23.71%;72.39%] at doses of 40, 80 and 120 mg. The response rate in the placebo arm was 42.86%. The pre-specified margin of clinically non-meaningful difference was 10%. Superiority to placebo was confirmed for doses 80 and 120 mg. The most frequent adverse events (AEs) were lymphocytosis, neutropenia, and asymptomatic bacteriuria. No dose-dependent toxicity or serious adverse events (SAEs) were observed. The most effective dose with the fastest response onset and favourable safety profile was 120 mg. CONCLUSIONS: The data obtained demonstrate the efficacy and favourable safety profile of NTK in active AS. Clinical development of NTK will be continued in a phase 3 trial aimed to evaluate the efficacy of 1-year treatment with NTK 120 mg in patients with AS.

Efficacy and safety of switching from rituximab to biosimilar CT-P10 in rheumatoid arthritis: 72-week data from a randomized Phase 3 trial.

OBJECTIVE: To evaluate the efficacy and safety of CT-P10, a rituximab biosimilar after a single switch, during a multinational, randomized, double-blind Phase 3 trial involving patients with RA. METHODS: Patients received 48 weeks' treatment with CT-P10 or United States- or European Union-sourced reference rituximab (US-RTX and EU-RTX, respectively). Patients entering the extension period (weeks 48-72) remained on CT-P10 (CT-P10/CT-P10; n = 122) or US-RTX (US-RTX/US-RTX; n = 64), or switched to CT-P10 from US-RTX (US-RTX/CT-P10; n = 62) or EU-RTX (EU-RTX/CT-P10; n = 47) for an additional course. Efficacy endpoints included Disease Activity Score using 28 joints (DAS28), American College of Rheumatology (ACR) response rates, and quality of life-related parameters. Pharmacodynamics, immunogenicity and safety were also assessed. RESULTS: At week 72, similar improvements were observed by disease activity parameters including DAS28 and ACR response rate in the four extension period treatment groups. Quality of life improvements at week 72 vs baseline were similarly shown during the extension period in all groups. Newly developed anti-drug antibodies were detected in two patients following study drug infusion in the extension period. Similar pharmacodynamic and safety profiles were observed across groups. CONCLUSION: Long-term use of CT-P10 up to 72 weeks was effective and well tolerated. Furthermore, switching from reference rituximab to CT-P10 in RA was well tolerated and did not result in any clinically meaningful differences in terms of efficacy, pharmacodynamics, immunogenicity and safety. TRAIL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT02149121.

A multicentre randomised controlled trial to compare the pharmacokinetics, efficacy and safety of CT-P10 and innovator rituximab in patients with rheumatoid arthritis.

OBJECTIVE: To demonstrate pharmacokinetic equivalence of CT-P10 and innovator rituximab (RTX) in patients with rheumatoid arthritis (RA) with inadequate responses or intolerances to antitumour necrosis factor agents. METHODS: In this randomised phase I trial, patients with active RA were randomly assigned (2:1) to receive 1000 mg CT-P10 or RTX at weeks 0 and 2 (alongside continued methotrexate therapy). Primary endpoints were area under the serum concentration-time curve from time zero to last quantifiable concentration (AUC0-last) and maximum serum concentration after second infusion (Cmax). Additional pharmacokinetic parameters, efficacy, pharmacodynamics, immunogenicity and safety were also assessed. Data are reported up to week 24. RESULTS: 103 patients were assigned to CT-P10 and 51 to RTX. The 90% CIs for the ratio of geometric means (CT-P10/RTX) for both primary endpoints were within the bioequivalence range of 80%-125% (AUC0-last: 97.7% (90% CI 89.2% to 107.0%); Cmax: 97.6% (90% CI 92.0% to 103.5%)). Pharmacodynamics and efficacy were comparable between groups. Antidrug antibodies were detected in 17.6% of patients in each group at week 24. CT-P10 and RTX displayed similar safety profiles. CONCLUSIONS: CT-P10 and RTX demonstrated equivalent pharmacokinetics and comparable efficacy, pharmacodynamics, immunogenicity and safety. TRIAL REGISTRATION NUMBER: NCT01534884.

Monitoring of breast cancer progression via aptamer-based detection of circulating tumor cells in clinical blood samples.

Introduction: Breast cancer (BC) diagnostics lack noninvasive methods and procedures for screening and monitoring disease dynamics. Admitted CellSearch® is used for fluid biopsy and capture of circulating tumor cells of only epithelial origin. Here we describe an RNA aptamer (MDA231) for detecting BC cells in clinical samples, including blood. The MDA231 aptamer was originally selected against triple-negative breast cancer cell line MDA-MB-231 using cell-SELEX. Methods: The aptamer structure in solution was predicted using mFold program and molecular dynamic simulations. The affinity and specificity of the evolved aptamers were evaluated by flow cytometry and laser scanning microscopy on clinical tissues from breast cancer patients. CTCs were isolated form the patients' blood using the developed method of aptamer-based magnetic separation. Breast cancer origin of CTCs was confirmed by cytological, RT-qPCR and Immunocytochemical analyses. Results: MDA231 can specifically recognize breast cancer cells in surgically resected tissues from patients with different molecular subtypes: triple-negative, Luminal A, and Luminal B, but not in benign tumors, lung cancer, glial tumor and healthy epithelial from lungs and breast. This RNA aptamer can identify cancer cells in complex cellular environments, including tumor biopsies (e.g., tumor tissues vs. margins) and clinical blood samples (e.g., circulating tumor cells). Breast cancer origin of the aptamer-based magnetically separated CTCs has been proved by immunocytochemistry and mammaglobin mRNA expression. Discussion: We suggest a simple, minimally-invasive breast cancer diagnostic method based on non-epithelial MDA231 aptamer-specific magnetic isolation of circulating tumor cells. Isolated cells are intact and can be utilized for molecular diagnostics purposes.

Development of DNA aptamers for visualization of glial brain tumors and detection of circulating tumor cells.

Here, we present DNA aptamers capable of specific binding to glial tumor cells in vitro, ex vivo, and in vivo for visualization diagnostics of central nervous system tumors. We selected the aptamers binding specifically to the postoperative human glial primary tumors and not to the healthy brain cells and meningioma, using a modified process of systematic evolution of ligands by exponential enrichment to cells; sequenced and analyzed ssDNA pools using bioinformatic tools and identified the best aptamers by their binding abilities; determined three-dimensional structures of lead aptamers (Gli-55 and Gli-233) with small-angle X-ray scattering and molecular modeling; isolated and identified molecular target proteins of the aptamers by mass spectrometry; the potential binding sites of Gli-233 to the target protein and the role of post-translational modifications were verified by molecular dynamics simulations. The anti-glioma aptamers Gli-233 and Gli-55 were used to detect circulating tumor cells in liquid biopsies. These aptamers were used for in situ, ex vivo tissue staining, histopathological analyses, and fluorescence-guided tumor and PET/CT tumor visualization in mice with xenotransplanted human astrocytoma. The aptamers did not show in vivo toxicity in the preclinical animal study. This study demonstrates the potential applications of aptamers for precise diagnostics and fluorescence-guided surgery of brain tumors.

Features of Peripheral Blood Th-Cell Subset Composition and Serum Cytokine Level in Patients with Activity-Driven Ankylosing Spondylitis.

Th cells may exhibit pathological activity depending on the regulatory and functional signals sensed under a wide range of immunopathological conditions, including ankylosing spondylitis (AS). The relationship between Th cells and cytokines is important for diagnoses and for determining treatment. Accordingly, the aim of this study was to investigate the relationship between Th-cell subset composition and serum cytokine profile for patients with activity-driven AS. In our study, patients were divided into two groups according to disease activity: low-activity AS (ASDAS-CRP < 2.1) and high-activity AS (ASDAS-CRP > 2.1). The peripheral blood Th cell subset composition was studied by flow cytometry. Using multiplex analysis, serum cytokine levels were quantified and investigated. It was found that only patients with high-activity AS had reduced central memory (CM) Th1 cells (p = 0.035) but elevated numbers of CM (p = 0.014) and effector memory (EM) Th2 cells (p < 0.001). However, no activity-driven change in the Th17 cell subset composition was observed in AS patients. Moreover, low-AS activity patients had increased numbers of Tfh17 EM cells (p < 0.001), whereas high-AS activity was associated with elevated Tfh2 EM level (p = 0.031). The serum cytokine profiles in AS patients demonstrated that cues stimulating cellular immunity were increased, but patients with high-AS activity reveled increased IL-5 level (p = 0.017). Analyzing the data obtained from AS patients allowed us to conclude that Th cell subset differentiation was mainly affected during the CM stage and characterized the IL-23/IL-17 regulatory axis, whereas increased humoral immunity was observed in the high-AS activity group.

Using Pharmacogenetics of Direct Oral Anticoagulants to Predict Changes in Their Pharmacokinetics and the Risk of Adverse Drug Reactions.

Dabigatran, rivaroxaban, apixaban, and edoxaban are direct oral anticoagulants (DOACs) that are increasingly used worldwide. Taking into account their widespread use for the prevention of thromboembolism in cardiology, neurology, orthopedics, and coronavirus disease 2019 (COVID 19) as well as their different pharmacokinetics and pharmacogenetics dependence, it is critical to explore new opportunities for DOACs administration and predict their dosage when used as monotherapy or in combination with other drugs. In this review, we describe the details of the relative pharmacogenetics on the pharmacokinetics of DOACs as well as new data concerning the clinical characteristics that predetermine the needed dosage and the risk of adverse drug reactions (ADRs). The usefulness of genetic information before and shortly after the initiation of DOACs is also discussed. The reasons for particular attention to these issues are not only new genetic knowledge and genotyping possibilities, but also the risk of serious ADRs (primarily, gastrointestinal bleeding). Taking into account the effect of the carriership of single nucleotide variants (SNVs) of genes encoding biotransformation enzymes and DOACs metabolism, the use of these measures is important to predict changes in pharmacokinetics and the risk of ADRs in patients with a high risk of thromboembolism who receive anticoagulant therapy.

Clinical application of chromosome 9p21.3 genotyping in patients with coronary artery disease.

The aim of the present study was to investigate the susceptibility of two coronary artery disease (CAD)-associated single nucleotide polymorphisms on 9p21 (rs1333049 and rs10757278) to myocardial infarction (MI) in a primary (stratification of high risk group for MI) and secondary prevention setting. The prospective observational study included 500 patients with MI [411 males (82.2%) and 89 females (17.8%)] under 65 years. The risk of MI for carriers of the homozygous CC genotype of rs1333049 and homozygous GG genotype of rs10757278 was 1.77 [95% confidence interval (CI): 1.36-2.37], and 1.70 (95% CI: 1.24-2.32) respectively. The risk of MI for heterozygous allele carriers was slightly lower. Specifically, the risk of MI was 1.58 (95% CI: 1.18-2.11) for both heterozygous and homozygous carriers of the rs1333049 C allele, and 1.36 (95% CI: 1.01-1.83) for the carriers of the rs10757278 G allele. A logistic regression model including sex, age, presence of excess weight or obesity, abdominal obesity, diabetes mellitus, arterial hypertension, hypercholesterolemia, positive family history and smoking status parameters revealed that rs1333049 CC genotype was an independent predictive factor of myocardial infraction [OR=1.71 (95% CI: 1.16-2.52), P=0.006]. Patients who underwent percutaneous coronary intervention (PCI) during index hospitalization and patients who did not receive PCI were followed up for two years after discharge. Compared with patients with MI who underwent PCI, the risk of recurrent acute coronary syndrome (re-ACS) was higher among rs1333049 C allele carriers who did not receive PCI during index hospitalization. One year after MI, the OR of re-ACS was 4.91 (95% CI: 1.45-16.66), while two years after MI, OR was 3.77 (95% CI: 1.50-9.52) in those patients who did not receive PCI during index hospitalization. There was no statistically significant association between polymorphic variants of rs1333049 and MI follow-up outcomes in patients who underwent PCI. The present study indicated clinical utility of 9p21.3 genotyping to predict the outcomes for patients with MI without PCI. Due to the small sample size, this association study forms basis for larger, nationwide studies investigating clinical applications of genetic data.

Long-Term Efficacy and Safety of Biosimilar CT-P10 Versus Innovator Rituximab in Rheumatoid Arthritis: 48-Week Results from a Randomized Phase III Trial.

OBJECTIVE: The aim of this study was to investigate long-term clinical outcomes of extended treatment with CT-P10, a rituximab biosimilar, compared with rituximab reference products sourced from the USA and the EU (US-RTX and EU-RTX) in rheumatoid arthritis (RA) for up to 48 weeks. METHODS: In this multinational, randomized, double-blind trial, adults with active RA received up to two courses of CT-P10, US-RTX, or EU-RTX alongside methotrexate. Efficacy endpoints included Disease Activity Score 28-joint count (DAS28) and American College of Rheumatology (ACR) response rates. Pharmacokinetics, pharmacodynamics, immunogenicity, and safety were also assessed. RESULTS: Of 372 patients randomized to the study drug, 330 (88.7%) completed the second treatment course. Mean change from baseline to week 48 in DAS28-C-reactive protein was comparable in the CT-P10 and combined rituximab (US-RTX and EU-RTX) groups (- 2.7 and - 2.6, respectively). ACR20, ACR50, and ACR70 response rates at week 48 indicated no differences between groups (80.6%, 55.4%, and 31.7% vs. 79.8%, 53.9%, and 33.7% in the CT-P10 and combined rituximab groups, respectively). Similar improvements in the Health Assessment Questionnaire Disability Index and all medical outcomes in the Short Form 36-Item Health Survey, including physical and mental health, were seen in all groups. At week 48, antidrug antibodies were detected in 4.9%, 9.4%, and 8.6% of patients in the CT-P10, US-RTX, and EU-RTX groups, respectively. CT-P10 and rituximab displayed similar pharmacokinetic, pharmacodynamic, and safety profiles. CONCLUSION: CT-P10 was similar to EU-RTX and US-RTX in terms of efficacy, pharmacokinetics, pharmacodynamics, immunogenicity, and safety up to week 48. CLINICALTRIALS. GOV IDENTIFIER: NCT02149121.

Comparison of biosimilar CT-P10 and innovator rituximab in patients with rheumatoid arthritis: a randomized controlled Phase 3 trial.

This multinational, randomized, double-blind trial, (ClinicalTrials.gov identifier NCT02149121) was designed to demonstrate equivalence in pharmacokinetics and efficacy between CT-P10 and innovator rituximab (RTX) in patients with rheumatoid arthritis (RA). Adults with active RA were treated with CT-P10, United States-sourced RTX (US-RTX; Rituxan®), or European Union-sourced RTX (EU-RTX; MabThera®) at weeks 0 and 2. The co-primary pharmacokinetic endpoints were area under the serum concentration-time curve (AUC) from time zero to last measurable concentration (AUC0-last), AUC from time zero to infinity (AUC0-∞), and maximum concentration (Cmax) after two infusions. The primary efficacy endpoint was change from baseline to week 24 in Disease Activity Score using 28 joints-C-reactive protein (DAS28-CRP). Pharmacodynamics, immunogenicity, and safety were also assessed. 372 patients were randomly assigned to CT-P10 (n = 161) or RTX (n = 211 [US-RTX, n = 151; EU-RTX, n = 60]). For the co-primary pharmacokinetic endpoints, 90% confidence intervals (CI) for ratios of geometric means (CT-P10/US-RTX, CT-P10/EU-RTX or EU-RTX/US-RTX) all fell within the equivalence margin of 80-125%. Adjusted least squares (LS) mean (standard error) change from baseline in DAS28-CRP at week 24 was -2.13 (0.175) for CT-P10 and -2.09 (0.176) for RTX. The 95% CI (-0.29, 0.21) of the estimated treatment difference between CT-P10 and RTX (-0.04) was entirely within the efficacy equivalence margin of ±0.5. Pharmacodynamics, immunogenicity, and safety profiles were similar for CT-P10 and RTX. The pharmacokinetics of CT-P10, US-RTX, and EU-RTX were equivalent. CT-P10 and RTX were also equivalent in terms of efficacy and displayed similar pharmacodynamic, immunogenicity, and safety profiles up to week 24.

Efficacy, Safety and Pharmacokinetics of Up to Two Courses of the Rituximab Biosimilar CT-P10 Versus Innovator Rituximab in Patients with Rheumatoid Arthritis: Results up to Week 72 of a Phase I Randomized Controlled Trial.

BACKGROUND: CT-P10 is a biosimilar of innovator rituximab (RTX), a biological therapy used to treat patients with rheumatoid arthritis (RA) who have responded inadequately to anti-tumor necrosis factor agents. OBJECTIVE: Our objective was to compare the clinical profile of CT-P10 versus RTX in patients with RA who received up to two courses of treatment and were followed for up to 72 weeks. METHODS: In this multicenter double-blind phase I study, patients were randomized 2:1 to receive CT-P10 1000 mg or RTX 1000 mg at weeks 0 and 2. Based on disease activity, patients could receive a second course of treatment between weeks 24 and 48. Efficacy endpoints, including mean change from baseline in Disease Activity Score using 28 joints (DAS28), safety, immunogenicity, pharmacokinetics, and pharmacodynamics were evaluated. RESULTS: In total, 154 patients were randomized to CT-P10 or RTX (n = 103 and 51, respectively); 137 (n = 92 and 45) completed the first course of treatment, of whom 83 (n = 60 and 23) were re-treated. Improvements from baseline in all efficacy endpoints were highly similar between the CT-P10 and RTX groups over both treatment courses. At week 24 after the second course, mean change from week 0 of the first course in DAS28 erythrocyte sedimentation rate was -2.47 and -2.04 for CT-P10 and RTX, respectively, (p = 0.1866) and in DAS28 C-reactive protein was -2.32 and -2.00, respectively (p = 0.3268). The proportion of patients positive for antidrug antibodies at week 24 after the second treatment course was 20.0% and 21.7% in the CT-P10 and RTX groups, respectively. The safety profile of CT-P10 was comparable to that of RTX, and pharmacokinetic and pharmacodynamic properties were similar. CONCLUSIONS: In patients with RA, efficacy, safety, and other clinical data were comparable between CT-P10 and RTX after up to two courses of treatment over 72 weeks. (ClinicalTrials.gov identifier NCT01534884).

Efficacy and Safety of Switching from Innovator Rituximab to Biosimilar CT-P10 Compared with Continued Treatment with CT-P10: Results of a 56-Week Open-Label Study in Patients with Rheumatoid Arthritis.

BACKGROUND: CT-P10 is a biosimilar candidate of innovator rituximab (RTX) that demonstrated a comparable clinical profile to RTX in a phase I randomized controlled trial (RCT) in rheumatoid arthritis (RA) (ClinicalTrials.gov identifier: NCT01534884). OBJECTIVE: This open-label extension (OLE) study (NCT01873443) compared the efficacy and safety of CT-P10 in patients with RA who received CT-P10 from the outset (i.e., from the start of the RCT and also in the OLE; 'maintenance group') with those who received RTX during the RCT and switched to CT-P10 during the OLE ('switch group'). METHODS: Patients who completed the RCT were recruited. Based on the Disease Activity Score using 28 joints (DAS28) and predefined safety criteria, patients could receive up to two courses of CT-P10 during the OLE. Efficacy [DAS28 and European League Against Rheumatism (EULAR) response], safety and immunogenicity were assessed. RESULTS: Eighty-seven patients were enrolled; 58 and 29 had previously received CT-P10 or RTX, respectively, in the RCT. Of these, 38 (65.5%) and 20 (69.0%) were treated with CT-P10 in the OLE and therefore comprised the maintenance and switch groups, respectively. The mean change in DAS28-erythrocyte sedimentation rate (ESR) from baseline (week 0 of RCT) at week 24 of the first OLE treatment course in the maintenance and switch groups was -2.7 and -2.4, respectively. The proportion of patients with good/moderate EULAR responses was also comparable between groups. Antidrug antibodies were detected in 13.2 and 15.0% of patients in the maintenance and switch groups, respectively, at week 24 of the first OLE course. CT-P10 treatment was well-tolerated when administered for up to 2 years or after switching from RTX. CONCLUSION: In this study population, comparable efficacy and safety profiles were observed in patients who switched from RTX to CT-P10 and those maintained on CT-P10 throughout treatment.

Association of ADRB1 gene polymorphism with atrial fibrillation.

AIM: The purpose of this study was to establish the probability and patterns of atrial fibrillation (AF) inheritance in families, and to find an association of primary and secondary AF with polymorphism Ser49Gly of the gene encoding beta1-adrenoreceptor (ADRB1). METHODS: We examined 103 probands with AF and 301 relatives. Physical examination, electrocardiography (ECG), echocardiography, Holter's monitoring of ECG, and other methods of functional diagnostics have been performed for all patients and their relatives. Genetic study has been performed using DNA extracted from peripheral blood leukocytes. RESULTS: Our results show that probands with primary AF and their relatives have a prevalence of the heterozygous genotype (Ser49Gly) of ADRB1 gene compared with the control group: 15 (50.0%) probands and 11 (44.0%) relatives, respectively, and 38 (19.2%) in the control group (p < 0.05). Significant prevalence of heterozygous genotype (Ser49Gly) of ADRB1 gene was observed in patients of the second subgroup with secondary AF: 14 (46.7%) persons in comparison with 38 (19.2%) persons of the control group (p < 0.05). CONCLUSION: Heterozygous genotype (Ser49Gly) of ADRB1 gene can be considered as one of the genetic predictors for development of primary or secondary AF. Relatives of probands with primary AF and genotype Ser49Gly should be included in the risk group for developing AF.