A Study to Evaluate the Safety and Efficacy of XC221 in Patients With Uncomplicated Influenza or Other Acute Viral Upper Respiratory Infections

A Double-blind, Randomized, Placebo-controlled, Comparative, Multicenter Phase III Clinical Trial to Study the Clinical Efficacy and Safety of XC221, Tablets, 100 mg in Patients With Uncomplicated Influenza or Other Acute Respiratory Viral Infections

The main purpose of the study was to evaluate the effectiveness of XC221, tablets, at a dose of 200 mg/day compared to placebo in patients with uncomplicated influenza or other acute respiratory viral infections (ARIs).

An additional purpose of the study was to evaluate the safety of XC221, tablets, at a dose of 200 mg/day compared to placebo in patients with uncomplicated influenza or other ARIs.

Inclusion Criteria:

1. Men and women between the ages of 18 and 65 years inclusive;
2. Presence of written consent to participate in the study in accordance with applicable law;
3. Clinical signs of mild to moderate influenza or other acute respiratory infections (ARIs): an increase in body temperature, measured at the axilla, with a value between 38.0 °C and 39.5 °C, inclusive, during the current illness and without taking antipyretics within the last 8 h at the time of screening; at least one respiratory manifestation of influenza or other ARI (cough, runny nose/ stuffy nose, sore throat) of at least 2 points on a 4-point scale; at least one systemic manifestation of influenza or other ARI (headache, muscle pain, chills/sweating, fatigue) of at least 2 points on a 4-point scale.
4. No indication for hospitalization at the time of enrollment in the study;
5. Duration of illness from manifestation of symptoms to the first dose of study drug/placebo not more than 48 hours;
6. Negative pregnancy test for women of preserved reproductive potential;
7. Consent to use adequate contraceptive methods throughout the study and for 30 days after study completion;
8. Ability to understand the requirements for study participants, to give written consent to participate in the study (including the use and communication of patient health information relevant to the study) and to comply with the procedures of the study protocol.

Exclusion Criteria:

1. Pregnant and breastfeeding women;
2. Known hypersensitivity to the study drug, including the active and/or excipients.
3. Lactase deficiency, lactose intolerance, glucose-galactose malabsorption, galactose intolerance;
4. Diagnosis of COVID-19 established or probable at present (based on examination and analysis of epidemiological history);
5. Positive result of rapid test for SARS-CoV-2;
6. Blood oxygen saturation (SpO2) ≤ 95%, respiratory rate ≥ 22/min.
7. Complicated course of influenza or other acute respiratory infections;
8. Participation in any other clinical trial within 90 days prior to the screening period;
9. Known (based on medical history) or suspected alcohol abuse, psychotropic drugs, drug dependence, drug addiction;
10. Presence of mental illness, including a history of mental illness;
11. Clinical suspicion of pneumonia or other bacterial infections (including sinusitis, otitis media, urinary tract infection, meningitis, sepsis, etc.) requiring prescription of antibacterial drugs;
12. Taking antibiotics, antivirals, or immunomodulatory drugs for < 48 h before the study and/or plans to use these groups of drugs (other than the study drug) during the study;
13. Use of systemic, inhaled, or nasal glucocorticosteroids within 30 days prior to the study and/or plans to use glucocorticosteroids (except topical cutaneous agents) during the study;
14. Failure to withdraw for the duration of the study other medications that may affect the outcome of this study, such as antiviral medications, or medications that are incompatible with the study therapy;
15. Any cardiovascular, renal, hepatic, gastrointestinal, endocrine or nervous system diseases, severe decompensated chronic (including chronic kidney disease and chronic liver disease) or acute diseases or any other condition/disease that, in the opinion of the investigator, would make it unsafe for the patient to participate in the study;
16. Any vaccination of the patient within 90 days prior to inclusion in the study;
17. Diabetes mellitus in decompensation;
18. Obesity of 2-3 degrees (body mass index of 35 kg/m2 or more).
19. Patients who have undergone surgery within 30 days prior to the Screening Visit and patients who are scheduled to undergo surgery, including diagnostic procedures, or a hospital stay during the study;
20. The presence of cancer, including a history of cancer (with the exception of a cured tumor with sustained remission for more than 5 years);
21. The presence of HIV infection, tuberculosis, including in the anamnesis;
22. Meningeal syndrome;
23. Disturbance of consciousness (in the form of stunting, soporus, delirium, delirium, etc.).
24. Symptoms of pneumonia and possible acute respiratory distress syndrome (ARDS): cough with foaming sputum with blood, shortening of the pulmonary sound on percussion, a large number of different-caliber wet rales and abundant crepitation on auscultation, a sharp drop in blood pressure, deafness of heart tones and arrhythmia;
25. Patient's refusal to use approved contraception or to completely abstain from sexual intercourse for the duration of study participation, beginning at Visit 1, and for 30 days after completion of study participation;
26. Other reasons that, in the opinion of the investigator, prevent the patient from participating in the study or create an unreasonable risk.

Withdrawal Criteria:

1. Patient's desire to stop participating in the study (withdrawal of informed consent). Each patient has the right to stop participating in the study at any time without giving a reason. Withdrawal from the study will not affect the medical care provided to the patient in the future.
2. The decision by the research physician that the patient should be excluded is in the patient's own interest;
3. The need to prescribe etiotropic or any other treatment prohibited in the study, as determined by the investigating physician.
4. Patient refuses to cooperate with the investigator or is undisciplined;
5. Causes/occurrence during the study of situations that threaten patient safety (e.g., hypersensitivity reactions, serious adverse events, etc.);
6. Inclusion of a patient in the study with inclusion/inclusion criteria not met (prior to randomization);
7. Significant treatment failure; Significant failure is defined as a) skipping study drug/placebo for 2 consecutive days or more or b) taking, in total, < 80% or > 120% of the full course (full course = 10 pills).
8. Positive pregnancy test;
9. A confirmed diagnosis of COVID-19;
10. Occurrence in the course of the study of other reasons that prevent the study according to the protocol.
11. Death of a patient.