Comparative Evaluation of Pharmacokinetics and Safety of BCD-055 and Remicade in Patients With Ankylosing Spondylitis

Inclusion Criteria: * signed informed consent * active ankylosing spondylitis, which exists in patient within last 3 months * BASDAI score \> or equal to 4 points, spinal pain (by VAS) \> or equal to 4 points * history of NSAID use for the treatment of AS within last 3 months * adequate renal and liver function * absence of severe abnormalities in complete blood count * consent to use adequate contraception * ability to follow Protocol procedures Exclusion Criteria: * previously use of any biologic for AS treatment * total ankylosing of the spine * known allergy to chimeric proteins or any excipients of BCD-055/Remicade * hepatitis B, active hepatitis C, HIV, syphilis * known tuberculosis * latent forms of tuberculosis * any bacterial infection diagnosed within last month which required oral antibiotics (within last 2 weeks) or parenteral antibiotics (within last 4 weeks) * drug or alcohol abuse * any other disease which can affect assessments or masking some symptoms of AS (severe osteoarthrosis, nervous disorders with impairment of sensory or motor functions, another inflammatory joint disease apart from AS, etc.) * severe uncontrolled hypertension * chronic heart failure * decompensated renal or liver disorders * severe uncontrolled diabetes mellitus * chronic obstructive lung disease, atopic bronchial asthma, angioedema in anamnesis * any mental disorder, incl. severe depression or/and suicide thoughts/actions in anamnesis * unstable angina pectoris * myocardial infarction within last 12 months Other exclusion criteria could be found in the Full Study Protocol