A Study to Assess the Pharmacokinetics of Certolizumab Pegol in Adults With Active Rheumatoid Arthritis

Inclusion Criteria: * Participant must be 18 to 69 years of age inclusive, at the time of signing the informed consent * Participant must have a diagnosis of moderately-to-severely active rheumatoid arthritis (RA) * Participant must have had an inadequate response to, or intolerance to, at least 1 disease modifying antirheumatic drug (DMARD) (nonbiologic or biologic) * Participant has a negative interferon-gamma release assay (IGRA) at Screening * Participant has a body mass index within the range 18.0 kg/m2 to 35.0 kg/m2 (inclusive) * Male or female * A female participant is eligible to participate if: i) she is not pregnant, ii) not breastfeeding, iii) at least one of the following conditions applies: 1. Not a woman of childbearing potential (WOCBP) OR 2. A WOCBP who agrees to follow the contraceptive guidance during the Treatment Period and until the Safety Follow-up (SFU) Visit Exclusion Criteria: * Participant has a known hypersensitivity to any components of the study medication(including polyethylene glycol) or comparative drugs (and/or an investigational device) as stated in this protocol * Participant has clinically significant electrocardiogram (ECG) abnormalities at Screening * Participant has previously been exposed to certolizumab pegol (CZP) * Participant has failed treatment with ≥1 tumor necrosis factor (TNF) α inhibitor or was a primary failure for any TNFα antagonist. A primary failure is defined as no clinical disease improvement within the first 12 weeks of treatment (study participants who demonstrated clinical response within 12 weeks of treatment and subsequently lost response after 12 weeks of treatment are eligible) * Participant has received a live vaccination within 6 weeks prior to Screening or intends to have a live vaccination during the course of the study or within 3 months following CZP treatment in the study * Participant has received any investigational drug or experimental procedure within 90 days prior to the first dose of IMPinvestigational medicinal product (IMP) * Participant has a laboratory abnormality at Screening, including any of the following: 1. \>3.0x upper limit of normal (ULN) of any of the following: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP); or \>ULN total bilirubin (\>1.5x ULN total bilirubin if the participant has a documented pre-study diagnosis of Gilbert's syndrome) 2. white blood cell count \<3.00x103/μL 3. absolute neutrophil count (ANC) \<1.5x103/μL 4. lymphocyte count \<500 cells/μL 5. hemoglobin \<8.5 g/dL 6. Any other laboratory abnormality, which, in the opinion of the Investigator, will prevent the study participant from completing the study or will interfere with the interpretation of the study results