Safety and Tolerability, Pharmacokinetics (PK), Pharmacodynamics (PD) and Efficacy of Repeat Doses of GSK2982772 in Subjects With Moderate to Severe Rheumatoid Arthritis (RA)

Inclusion Criteria

• Between 18 and 75 years of age inclusive, at the time of signing the informed consent.
• Subjects that do not have any medical conditions, other than moderate to severe RA, that in the opinion of the Investigator put the subject at unacceptable risk or interfere with study assessments or integrity of the data. These medical conditions should be stable at the time of screening and are expected to remain stable for the duration of the study.
• Subject has had a confirmed diagnosis of rheumatoid arthritis according to the revised 2010 ACR-EULAR classification criteria.
• Disease duration of >=12 weeks (time from onset of patient-reported symptoms of either pain or stiffness or swelling in hands, feet or wrists) at screening.
• Swollen joint count of >=4 (28-joint count) and tender joint count >=4 (28-joint count) at screening.
• Subject has a DAS28 CRP disease activity score of >= 3.2 and CRP >= 5.0 mg/liter (L) (>=4.76 nanomole (nmol)/L) at screening.
• Subject must have received at least 12 weeks of non-biologic DMARD monotherapy or MTX/DMARD combination therapy prior to screening and must be on stable dose throughout the study.
• Subject is naive to any biological therapies for RA or subject may have had previous exposure to a single anti-tumor necrosis factor (TNF) biologic agent which was discontinued for reasons other than primary non-response more than 8 weeks (or 5 half lives whichever is longer) from first dose.
• For subjects who have consented to synovial joint biopsy:
• Subject has an involved knee, wrist, or ankle suitable for biopsy, as assessed by a rheumatologist at screening.
• A body mass index (BMI) within range of 18.5 - 35 kilogram/meter^2 (Kg/m^2) (inclusive) at screening.
• Male and female subjects Males: Male subjects with female partners of child bearing potential must comply with the contraception requirements specified in the protocol.

Females: A female subject is eligible to participate if she is not pregnant (as confirmed by a negative serum human chorionic gonadotropin [HCG] test), not lactating, and at least one of the following conditions applies:

• Non-reproductive potential as defined as pre-menopausal females with either documented tubal ligation or Documented hysteroscopic tubal occlusion procedure with follow-up confirmation of bilateral tubal occlusion or Hysterectomy or Documented Bilateral Oophorectomy. For Postmenopausal females as 12 months of spontaneous amenorrhea in questionable cases a blood sample with simultaneous follicle stimulating hormone (FSH) and estradiol levels consistent with menopause. Females on hormone replacement therapy (HRT) and whose menopausal status is in doubt will be required to use one of the highly effective contraception methods if they wish to continue their HRT during the study. Otherwise, they must discontinue HRT to allow confirmation of post-menopausal status prior to study enrollment..
• Reproductive potential and agrees to follow one of the options listed in the Modified List of Highly Effective Methods for Avoiding Pregnancy in Females of Reproductive Potential (FRP) from 30 days prior to the first dose of study medication and until at least 30 days after the last dose of study medication and completion of the follow-up visit.
• The Investigator is responsible for ensuring that subjects understand how to properly use these methods of contraception.
• Capable of giving signed informed consent as described in the protocol which includes compliance with the requirements and restrictions listed in the consent form and in this protocol.

Exclusion Criteria

• Subject with a positive anti-double stranded deoxyribonucleic acid (DNA [anti-dsDNA]) and confirmed diagnosis of systemic lupus erythematosus (SLE).
• Subject with current history of Suicidal Ideation Behavior (SIB) as measured using the Columbia Suicide Severity Rating Scale (C-SSRS) or a history of attempted suicide.
• An active infection, or a history of infections as fol