The goal of this clinical study is to evaluate the efficacy and safety of Longidaza®, lyophilisate for preparation of solution for injection, at a dose of 3000 IU compared to placebo in the treatment of adult patients with residual changes in the lungs after COVID-19 infection

The main objective of the clinical study was to prove the superiority of the efficacy of the drug Longidaza® over placebo when used in adult patients with residual changes in the lungs after COVID-19 infection based on the dynamics of respiratory function

Inclusion Criteria:

1. Male and female patients aged 18 to 80 years, who signed an informed consent form.
2. The condition after infection with COVID-19, documented in the period from 1 to 12 months before screening (ICD-10: U07.1, U07.2), including accompanied by hospitalization of the patient.
3. The presence of a negative result of the polymerase chain reaction test (PCR) during screening and an express test for the SARS-CoV-2 antigen at visit 2.
4. The presence of respiratory symptoms (at least dyspnea), while the severity of dyspnea on the mMRC during screening is ≥ 1 point.
5. The value of hemoglobin oxygen saturation: SpO2 < 95% at rest at the screening; and/or desaturation (decrease of SpO2 by ≥ 4% in the 6MWT relative to the value at rest) at the screening.
6. The presence of residual changes in the lung parenchyma characteristic of previous COVID-19 infection, > 10% of the area, according to CT at the screening
7. Respiratory dysfunction of the restrictive type at the screening: FVC < 80%, FVC 1 / FVC > 70%.

Exclusion Criteria:

1. A history of chronic respiratory diseases (interstitial lung disease, chronic obstructive pulmonary disease, bronchial asthma, bronchiectasis, lung cancer).
2. Clinical signs or anamnesis data on the presence of diseases that, according to the researcher, can lead to restrictive changes in respiratory function (pronounced kyphoscoliosis, pleural effusion, neuromuscular diseases), pathological obesity, etc.
3. Clinical signs or anamnesis data on the presence of unstable angina pectoris, stable angina pectoris of high functional class, clinically significant cardiac arrhythmias, chronic heart failure, pulmonary hypertension, suffered pulmonary embolism or acute myocardial infarction in within 6 months prior to screening.
4. Dyspnea of any other etiology: thyrotoxicosis, anemia (hemoglobin less than 100 g/l), pathological obesity (BMI ≥ 40 kg/m2), metabolic acidosis, neuromuscular diseases according to anamnesis or screening examination.
5. The presence of an acute infectious process of any etiology and localization.
6. Allergic reactions to the administration of azoximer bovhyaluronidase or an auxiliary component of the studied drug (mannitol) in the anamnesis.
7. Clinical signs of pulmonary hemorrhage and/or hemoptysis during examination and in the anamnesis.
8. Confirmed eye injuries with vitreous hemorrhage during the last 6 months according to the medical history.
9. Malignant neoplasms of any localization in the anamnesis, with the exception of in situ carcinoma, which required only surgical treatment.
10. Renal failure.
11. Taking drugs of prohibited therapy since the start of screening in this study.
12. Serological test positive for HIV infection, viral hepatitis B and C.
13. Pregnancy or breastfeeding.
14. Participation in clinical trials of an experimental drug within 30 days prior to screening for participation in the current study.
15. Any other medical or social conditions that, in the opinion of the research physician, do not allow the patient to participate in this study.