This is an open-label, dose-escalation phase I study to assess the safety and tolerability of siCoV/KK46 in healthy volunteers. The purpose of this study is to determine the maximum daily dose of siCoV/KK46 as a single agent in adult healthy participants. Based on preclinical data from this institution, the investigators hypothesize that SARS-CoV-2 inhibition with siCoV/KK46 could potentially reduce pulmonary inflammation, thereby improving COVID-19 patient outcomes.

This is an open-label, dose-escalation phase I study to assess the safety and tolerability of single and multiple doses of siCoV/KK46 in healthy male volunteers.

This study include 3 cohorts received 3.7 mg, 11.1 mg, 22.2 mg of the siCoV/KK46, respectively, via inhalation route.

All subjects will undergo scheduled safety and tolerability assessments while in the clinical unit and as outpatients to the end of the follow-up period.

Inclusion Criteria:

1. Healthy men aged 18 to 45 years
2. Able to give informed consent and attend all study visits
3. Blood pressure level: systolic blood pressure 100 to 139 mm Hg, diastolic blood pressure 60 to 89 mm Hg.
4. Heart rate from 60 to 90 beats per minute
5. Body mass index 18.5 -30. The body weight should be ≥ 55 kg;
6. Men must agree to use the reliable contraception while on study medication and for posttrial contraception for 30 days
7. Be able to understand and comply with protocol requirements

Exclusion Criteria:

1. A burdened allergic history.
2. Previous adverse reactions to the active substance and/or excipients included in the drug.
3. Chronic diseases of the cardiovascular, lymphatic, respiratory, nervous, endocrine, digestive, musculoskeletal, integumentary, immune systems, as well as the genitourinary apparatus and hematopoietic organs.
4. Weakness of the inspiratory muscles of respiration (according to spirometry result).
5. Acute infectious diseases symptoms in the last 4 weeks before screening.
6. Treatment with any medicine that have a pronounced effect on hemodynamics and affects the liver function (barbiturates, omeprazole, cimetidine, etc.) within 2 months prior to screening.
7. Regular treatment with any medicine less than 2 weeks prior to screening and single treatment less than 7 days prior screening.
8. Donation of blood or plasma less than 3 months prior to screening.
9. Transfusion of blood and/or its components less than 3 months prior to screening.
10. Participation in other investigational drug or device clinical trials within 90 days prior to screening.
11. Drinking of more than 10 units of alcohol (1 unit of alcohol is equivalent to 330 mL of beer, 150 mL of wine or 40 mL of strong alcoholic drinks) per week within the last month prior to inclusion in the study and/or history of alcohol, drug or chemical abuse.
12. Smoking more than 10 cigarettes currently, or history of smoking this number of cigarettes within 6 months prior to screening.
13. Positive blood tests for HIV, hepatitis B and С, syphilis. Positive PCR test results for SARS-CoV-2(nasal swab).
14. Positive result on a urine drug screening test.
15. Positive test for ethanol vapor in exhaled air.
16. Planned hospitalization during the period of participation in the study, for any reason other than hospitalization specified by this protocol.
17. Inability or inability to follow the protocol, to perform the procedures prescribed by the protocol, to follow a diet, activity regime.
18. Any conditions that, according to the researcher's, may be a contraindication to the participation in the study.