Currently, there are data that that make it possible to speak about a high clinical efficacy of the use of succinic salt of tyrosyl-D-alanyl-glycyl-phenylalanyl-leucyl-arginine (hexapeptide succinate) for the COVID-19 treatment. This article is devoted to the results of clinical trials of the original Russian drug based on it.The aim of the study was to evaluate a clinical efficacy, safety and tolerability of intramuscular and inhalation use of hexapeptide succinate in complex therapy in comparison with standard therapy in patients with moderate COVID-19.Materials and methods. The research was conducted from February 28, 2022 to November 22, 2022 based on 10 research centers in the Russian Federation. The study included hospitalized patients (n=312) over 18 years of age with moderate COVID-19 who had undergone a screening procedure and were randomized into 3 groups: group 1 received standard therapy in accordance with the Interim Guidelines in force at the time of the study, within 10 days; group 2 received hexapeptide succinate (Ambervin® Pulmo) intramuscularly at the dose of 1 mg once a day for 10 days; group 3 received hexapeptide succinate (Ambervin® Pulmo) 10 mg once a day by inhalation for 10 days.Results. According to the results of the study, therapy with the drug hexapeptide succinate, both intramuscular and inhaled, provided an acceleration of recovery up to the complete absence of the disease signs in more than 80% of hospitalized COVID-19 patients. By the end of the therapy course with the drug, more than 60% of patients had met the criteria for discharge from hospital and could continue the treatment on an outpatient basis. About 70% of patients in the inhalation group and 80% in the intramuscular hexapeptide succinate injection group had concomitant diseases (hypertension – 28%, obesity – 14%), which indicates the effectiveness of this drug use in comorbid patients. The use of the drug contributed to the restoration of damaged lung tissues, normalization of oxygenation, the disappearance of shortness of breath and a decrease in the duration of the disease symptoms compared with standard therapy. As a result of a comparative analysis of adverse events in terms of their presence, severity, causal relationship with the therapy and outcome, there were no statistically significant differences between the treatment groups.Conclusion. Thus, the results of the clinical study of the succinate hexapeptide efficacy and safety showed the feasibility of using the drug in pathogenetic therapy COVID-19 regimens.