Objective: Cclinical evaluation of the effectiveness and safety of the effect of the regulatory polypeptide drug on neurogenic overactive bladder (OAB) in patients with multiple sclerosis (MS).Materials and methods: 41 patients with MS and urodynamically confirmed detrusor overactivity were included in a prospective, single-center, simple comparative clinical trial with sequential drug changes. The initial function of the lower urinary tract and its dynamic changes during therapy were studied by filling out a voiding diary and questionnaires using the EDSS, NBSS, SF-Qualiveen, I-QOL questionnaires. The control drug Solifenacin (patient group 1) is a specific competitive antagonist of muscarinic receptors of the M3 subtype, which causes detrusor contraction. The Study Drug (patient group 2) is a complex of regulatory polypeptides that have an organotropic effect on the bladder. Drug administration: control drug for 4 weeks, then an observation period of 4 weeks, after which - taking the Study Drug for 30 days. The results were monitored immediately after the end of taking the Study Drugs, after which they were compared with the initial data. Statistical analysis was carried out by the program “Statistica 10” (StatSoft Inc., USA), using non-parametric data analysis with median analysis, Wilcoxon test and Mann-Whitney U-test search. The results of differences were considered statistically significant if the probability of error was <5% (p<0.05).Results: Vvoiding diary: 14.6% and 24.4% of patients in groups 1 and 2, respectively, were freed from urinary incontinence; from nocturia —- 31.7% and 56.1% of patients for groups 1 and 2, respectively, the frequency of daily urination was normalized in 53.6% and 70.7% of patients in groups 1 and 2, respectively. NBSS questionnaire: decrease in the total questionnaire score by 29.2% and 47.4% for groups 1 and 2, respectively. SF-Qualiveen questionnaire: an increase in the overall assessment score by 42.3% for group 1 versus +66.5% for group 2. I-QOL questionnaire: improvement in quality of life by 56.0% and 80.4% for groups 1 and 2, respectively. The Study Drug has a higher safety profile compared to Solifenacin.Conclusion: Tthe effectiveness of the Study Drug in the correction of neurogenic OAB is higher in comparison with Solifenacin, which is reflected in a decrease in urgency, pollakiuria, the number of episodes of urinary incontinence and a significant improvement in the quality of life of these patients. The Study Drug demonstrates a high safety profile in the study.