First-in-human Study to Evaluate Safety, Tolerability, Pharmacokinetics and Pharmacodynamics of Various Doses of BCD-121 in Healthy Subjects

Inclusion Criteria: * singed informed consent * male gender * 18-45 years of age inclusively * BMI between18.5-30.0 kg/sq.m. * absence of any sings of hepatic, renal, gastrointestinal, cardiovascular, endocrine, respiratory, immunologic, hematologic, dermatologic, or neurologic abnormality at screening or/and in anamnesis * parameters of complete blood count, blood biochemistry, and urinalysis do not exceed reference values, which are used at Study site laboratory * normal hemodynamic parameters * absence of chronic infections (HIV, syphilis, hepatitis В or С, tuberculosis ) and chronic inflammation * absence of infections within 4 weeks before randomization * absence of mental disorders or other conditions (incl. depression), which may affect the ability of participant to follow Protocol * health well-being (by volunteer's opining opinion) for at least 30 days before randomization. * absence of alcohol or drug addiction signs (incl. history of such addiction) * volunteer's ability to follow Protocol procedures * consent of volunteers and their sexual partners with childbearing potential to use adequate contraception Exclusion Criteria: * history of use of monoclonal antibodies against IL-17 or TNFa * known severe allergy (anaphylaxis or multidrug intolerance) * known intolerance to medicines containing monoclonal antibodies (murine, humanized, human) or to any excipients of BCD-121/placebo * major surgery within 30 days prior screening * severe infections (required hospitalization, parenteral use of antimicrobial agents) * systemic use of antimicrobials * more than 4 episodes of respiratory tract infections within 6 months prior the screening * presence of any disorders which may affect pharmacokinetics of BCD-121 * history of fever which was equal or exceeded 40 degrees in Celsius * history of hepatic transaminases increase 2.5 x ULN * history of seizures * actual or prior depression, suicidal tendencies * use of any medicines, vitamins, biologically active additives within 14 days prior the date of BCD-085 injection * use of any medicines which affects hemodynamics or hepatic function within 30 days prior the date of BCD-121 injection * simultaneous participation in any other clinical trial, as well as former participation in other clinical trials within 3 months before this study initiation. * previous participation in this study