Study of the Efficacy, Safety, Pharmacokinetics, and Immunogenicity of Netakimab in Children with Moderate to Severe Plaque Psoriasis

Inclusion Criteria:

1. Written informed consent of the legal representative and the subject to participatein the study (the study subject signs the appendix to the information sheet for thelegal representative of the clinical study subject with informed consent form).

2. For Stage 1 only: age ≥12 and <18 years at the time of randomization.

3. For Stage 2 only: age ≥6 and <12 years at the time of randomization.

4. A diagnosis of moderate to severe plaque psoriasis with a disease duration of thedisease being at least 3 months before the signing of the ICF.

5. Subjects who are candidates for phototherapy or systemic therapy for psoriasis (including non-responders to systemic therapy or phototherapy), in the opinion ofthe Investigator, or who did not achieve adequate disease control with topicalagents.

6. At the time of the screening examination, the body surface area affected bypsoriasis is >10% of the body surface area (BSA), the Psoriasis Area and SeverityIndex (PASI) score is ≥12, and the static Physician's Global Assessment (sPGA) scoreis ≥3.

7. Subjects with the normal laboratory test results at screening.

8. Subjects with a negative whole blood IFN-γ release test.

9. The ability of the subject and his/her legal representative, in the Investigator'sopinion, to perceive information and follow the Protocol procedures.

10. Willingness of subjects and their sexual partners of childbearing potential to usehighly effective methods of contraception from the signing of the ICF to 12 weeksafter the last dose of the investigational product. This requirement does not applyto subjects who have not reached sexual maturity or who have undergone surgicalsterilization. The subject's legal representative must consent to the subject's useof contraception.

Exclusion Criteria:

1. Erythrodermic, pustular, guttate psoriasis, drug-induced psoriasis or any other skindiseases (e.g. eczema) at screening that can affect/complicate the assessment ofpsoriasis treatment with the investigational product.

2. Use of the following medications:

3. Prior use of drugs based on monoclonal antibodies against interleukin-17 or itsreceptor.

4. Prior use of adalimumab.

5. Prior use of monoclonal antibodies or their fragments within 12 weeks before signingthe ICF.

6. Use of systemic non-biological medicinal products including methotrexate,sulfasalazine, cyclosporine or acitretin within 4 weeks prior to the date of signingthe ICF. If previously used systemic non-biologic drugs are discontinued for anyreason, the screening period can be extended for up to 8 calendar weeks, duringwhich new systemic non-biologic drugs are not prescribed.

7. Use of phototherapy (including selective phototherapy [UV-B] and photochemotherapy [PUVA]) less than 4 weeks before the date of signing the ICF.

8. Vaccination with live vaccines at any time within 12 weeks prior to signing the ICFor an expected need for such vaccination during the study.

9. Recurrent, chronic, or any other active infection in which, in the opinion of theInvestigator, the investigational product may harm the study subject.

10. Sepsis or risk of sepsis. 5. Positive HIV-1 or HIV-2 test. 6. HBV/HCV infections (for details, see Section 6.5.7.2). 7. Established diagnosis or a history ofimmunodeficiency syndrome (e.g., severe combined immunodeficiency syndrome, T and Bcell deficiency syndromes, chronic granulomatous disease), or an infectioncharacteristic of an immunodeficiency (e.g., pneumocystis pneumonia, histoplasmosisor coccidioidomycosis) at the time of signing the ICF.

11. Diagnosis of tuberculosis, including a history of tuberculosis. 9. A clinicallysignificant infection caused by the varicella-zoster virus within 12 weeks prior tosigning the ICF.

12. Body temperature ≥38°C at the screening. These subjects may be re-screened, but notearlier than 4 weeks after the first screening.

13. Other concomitant medical conditions that continued at the time of the screeningexamination, which increase the risk of adverse events during the study or mayaffect the evaluation of psoriasis symptoms, mask, enhance, or alter the symptoms ofpsoriasis, or cause clinical or laboratory symptoms similar to those of psoriasisand confirmed by the source documentation:

14. Active inflammatory diseases or aggravation of chronic inflammatory diseases otherthan psoriasis.

15. Functional class III-IV stable angina of effort, unstable angina or a history ofmyocardial infarction within 1 year before signing the IC.

16. Moderate to severe cardiac failure (NYHA class III-IV).

17. Grade 2 hypertension.

18. A history of atopic asthma, angioedema.

19. Moderate to severe respiratory failure, Grade 3/4 chronic obstructive pulmonarydisease.

20. Decompensated diabetes mellitus; decompensated hypothyroidism, decompensatedthyrotoxicosis.

21. Significant systemic autoimmune diseases according to the Investigator.

22. A history of Crohn's disease, ulcerative colitis.

23. Any other underlying conditions (including but not limited to metabolism,hematology, renal, hepatic, pulmonary, neurological, endocrine, cardiac, andgastrointestinal disorders; infections) that may, in the Investigator's opinion,affect the course of psoriasis, affect the assessment of its symptoms, or put thesubject using the study therapy at unacceptable risk.

24. Malignant and lymphoproliferative diseases, including lymphoma; symptoms indicatingthe development of a lymphoproliferative disease (such as lymphadenopathy and/orsplenomegaly), except for those previously excluded by a biopsy.

25. History of allergic reactions (anaphylactic shock or allergy to 2 or more drugs).

26. Known allergy or intolerance to monoclonal antibody products or any components ofthe investigational product.

27. Major surgery within 30 days before the screening, or a major surgery scheduled atany time during the study.

28. Severe infections (including those that required hospitalization or parenteralantibacterial, antimycotic, or antiprotozoal agents) within 6 months prior tosigning the ICF.

29. Use of systemic antibacterial, antimycotic, or antiprotozoal agents within 2 monthsbefore signing the ICF.

30. More than 4 episodes of respiratory infections over the past 6 months prior tosigning the ICF.

31. Any concomitant diseases in which, in the Investigator's opinion, the study therapymay harm the subject.

32. Signs of premature puberty at the screening examination. 21. Pregnancy,breastfeeding, or planning pregnancy while participating in the study.

33. Any psychiatric disorder, including a history of severe depressive disorders and/orsuicidal thoughts, which, in the opinion of the Investigator, may pose an excessiverisk to the subject or affect the subject's ability to follow the Protocol.

34. Drug addiction, alcoholism, or abuse with drugs or other psychoactive substances (including a history of such disorders).

35. Simultaneous participation in other clinical studies, as well as previousparticipation in other clinical studies less than 3 months before signing the ICF,prior participation in this study.

36. Use of any other investigational products at the time of signing the ICF or lessthan 28 days before the planned date of signing the ICF or 5 half-lives (whicheveris longer) before the date of signing the ICF.