Subjects will receive placebo (initially weekly, then every other week) in combination with MTX (at a dose between 15-25 mg/week) and folic acid >=5 mg/week.

MTX will be supplied as capsule, tablet or liquid and will be administered orally or as SC injection.

Folic acid will be supplied as capsule, tablet or liquid and will be administered orally.

Placebo is supplied as liquid as sterile 0.9% weight by volume (w/v) sodium chloride solution and will be administered as SC injection

DAS28(CRP) remission is defined as a DAS28 score of <2.6 points. The DAS index combines information relating to the number of swollen and tender joints. The DAS28 is a modification of the original DAS and is based on a count of 28 swollen and tender joints and is used to evaluate a participant's response to treatment. DAS 28 CRP utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal- phalangeal I-V, proximal interphalangeal I-V and knees and is calculated using the following formula: DAS28 (CRP) = 0.56*√(TJC28) +0.28*√(SJC28)+0.014*GH+0.36*ln(CRP+1)+0.96. Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment of disease activity using a 100 mm visual analogue scale with 0 = best, 100 = worst) and CRP= C reactive Protein (in mg/L). It ranges between 0.96 and 8.61. High score (worse outcome) and low scores (better outcome).

DAS28 is a modification of the original DAS and is based on a count of 28 swollen and tender joints and is used to evaluate a participant's response to treatment. DAS 28 CRP utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal- phalangeal I-V, proximal interphalangeal I-V and knees and is calculated using the following formula: DAS28 (CRP) = 0.56*√(TJC28) +0.28*√(SJC28)+0.014*GH+0.36*ln(CRP+1)+0.96. Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment of disease activity using a 100 mm visual analogue scale with 0 = best, 100 = worst) and CRP= C reactive Protein (in mg/L). It ranges between 0.96 and 8.61. High score (worse outcome) and low scores (better outcome). Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post-dose visit value from the Baseline.

The DAS index combines information relating to the number of swollen and tender joints. The DAS28 is a modification of the original DAS and is based on a count of 28 swollen and tender joints and is used to evaluate a participant's response to treatment. DAS 28 CRP utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal- phalangeal I-V, proximal interphalangeal I-V and knees and is calculated using the following formula: DAS28 (CRP) = 0.56*√(TJC28) +0.28*√(SJC28)+0.014*GH+0.36*ln(CRP+1)+0.96. Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment of disease activity using a 100 mm visual analogue scale with 0 = best, 100 = worst) and CRP= C reactive Protein (in mg/L). It ranges between 0.96 and 8.61. High score (worse outcome) and low scores (better outcome). Median time, to remission has been presented.

DAS28(CRP) scores were categorized using EULAR response criteria. Response at a given time point was defined based on the combination of current DAS28 score and the improvement in the current DAS28 score relative to Baseline. The definition of no response, moderate response and good response was as follows: Current DAS28 <=3.2 and DAS28 decrease from Baseline (>1.2=good response), (>0.6 to <=1.2 = moderate response) and (<=0.6 =no response). Current DAS28 >3.2 to <=5.1 and DAS28 decrease from Baseline value (>1.2 =moderate response), (>0.6 to <=1.2 = moderate response) and (<=0.6 =no response). Current DAS28 >5.1 and DAS28 decrease from Baseline value (>1.2=moderate response), (>0.6 to <=1.2 = no response) and (<=0.6 =no response). If the post-Baseline DAS28(CRP) score was missing, then the corresponding EULAR category was set to missing.

The ACR definition for calculating improvement in rheumatoid arthritis is calculated as a 20% improvement (ACR20) in both tender and swollen joint counts and 20% improvement in 3 of the 5 remaining ACR-core set measures: participant and physician global assessments, participant's assessment of arthritis pain, disability, and an acute-phase reactant (i.e. CRP value). Similarly, ACR50 and ACR70 were calculated with the respective percent improvement. The specific components of the ACR assessments are as follows: Tender/Painful Joint count 68 (TJC68), Swollen Joint Count 66 (SJC66), Participant's Assessment of Arthritis Pain, Participant's Global Assessment of Arthritis Disease Activity, Physician's Global Assessment of Arthritis, CRP (mg/L) and Health Assessment Questionnaire - Disability Index (HAQ-DI). For all visits, if any of the component scores were missing, then those scores were considered as not having met the criteria for improvement.

Index-based remission was achieved if the following requirement was met: SDAI <= 3.3. If the SDAI value was missing at an individual assessment point, Index-based remission for that assessment was set to missing.

Boolean-based remission was achieved if all of the following requirements were met at the same time: TJC68 <= 1,SJC66 <= 1,CRP <= 1mg/dL, PtGA <= 10. If one of the components was missing at an individual assessment point, Boolean-based remission for that assessment was set to missing.

CDAI combines information relating to the number of swollen and tender joints, in addition to a measure of general health from both the participants and the physician. CDAI utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal- phalangeal I-V, proximal interphalangeal I-V and knees and is calculated using the following formula: CDAI =TJC28 + SJC28 + GH + GP Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment of disease activity and GP=physician assessment of disease activity using a 10 cm visual analogue scale with 0 = best, 100 = worst). It ranges between 0 and 76. High score indicates worse outcome, low score indicates better outcome. Remission was achieved for a non-missing CDAI value <=2.8.

SDAI combines information relating to the number of swollen and tender joints, in addition to a measure of general health from both the participants and the physician and acute phase reactants. The SDAI utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal-phalangeal I-V, proximal interphalangeal I-V and knees. It is calculated using the following formula: SDAI = TJC28 + SJC28 + GH + GP + CRP Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment, GP= physician assessment of disease activity using a 10 centimetre [cm] visual analogue scale [VAS] with 0 = best, 10 = worst), and CRP= C reactive Protein (in mg/L). It ranges between 0.1 and 86. High score indicates worse outcome, low score indicates better outcome. Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

CDAI combines information relating to the number of swollen and tender joints, in addition to a measure of general health from both the participants and the physician. CDAI utilizing joint scores from the following 28 joints: elbows, shoulders, elbow, wrists, metacarpal- phalangeal I-V, proximal interphalangeal I-V and knees and is calculated using the following formula: CDAI =TJC28 + SJC28 + GH + GP Where TJC - Tender joint Count, SJC= Swollen Joint Count, (GH=participant assessment of disease activity and GP=physician assessment of disease activity using a 10 cm visual analogue scale with 0 = best, 100 = worst). It ranges between 0 and 76. High score indicates worse outcome, low score indicates better outcome. Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

HAQ-DI is 20-question instrument that assesses the degree of difficulty a person has in accomplishing tasks in eight functional areas;dressing and grooming, arising, eating, walking, hygiene, reach, grip, and common daily activities. Each functional area contains at least two questions. For each question, there is a four level response set that is scored from 0 (without any difficulty) to 3 (unable to do). If aids or devices or physical assistance are used for a specific functional area and the maximum response of this functional area is 0 or 1 the according value is increased to a score of 2. HAQ-DI is only calculated if there are at least 6 functional area scores available. The average of these non-missing functional area scores defines the continuous HAQ-DI score ranging from 0 to 3. Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

Participants assessed the severity of their current arthritis pain using a 100 unit visual analog scale (VAS) by placing a mark on the scale between 0 (no pain) and 100 (most severe pain), which corresponds to the magnitude of their pain. Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

SF-36 is a generic health survey containing 36 questions covering 8 domains of health. SF-36 yields an 8-scale profile of functional health and well-being scores as well as PCS and MCS health summary scores. The version 2, 1-week recall questionnaire was used. Recoding, calculations and standardization were done as per the User's manual of SF-36. Domain scores were only calculated if less than half of the item scores were missing. All raw domain scores were transformed on a 0-100 scale (transformed domain scores) and then standardized into norm-based scores using Z-score. Following the transformation of the 8 domain scores into z-scores, the MCS and PCS were aggregated (AGG) using weights as PCS/MCS = 50 + (AGG_PHYS *10/AGG_MENT *10). High score (worse outcome) and low score (better outcome). Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

The FACIT-fatigue questionnaire is a participant reported measure developed to assess fatigue consisting of 13 statements regarding feeling fatigue using a numeric rating scale ranging from 0 to 4. For only two of the items (i.e. Answer 5 [An5] and An7) a higher value represents a lower fatigue; 11 of the item scores (i.e. HI7, HI12, An1, An2, An3, An4, An8, An12, An14, An15, An16) have to be reversed by subtracting the captured value from 4 (0 is turned to a 4; 1 into 3; 3 into 1; 4 into 0). After performing the reversals the sum of the non-missing individual items were multiplied by 13 and divided by the number of the non-missing individual items. The final score ranges from 0 to 52 with higher values representing a lower fatigue (i.e. a better quality of life). Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

BFI is a self-reported instrument consisting of nine questions which correlate well with quality-of-life measures. For this study, Question 3 only was used which asked about fatigue severity at its worst in the last 24 hours. A discrete 11 unit numeric reporting scale was used where 0 =No fatigue, and 10=As bad as you can imagine. Baseline was defined as the last available assessment prior to the start of study treatment. Change from Baseline was calculated by subtracting the post dose visit value from the Baseline value.

An AE is any untoward medical occurrence in a participant or clinical investigation participants, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. SAE is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, is a congenital anomaly/birth defect, is associated with liver injury and impaired liver function or any other situations as per Medical or Scientific judgment. Overall AEs and SAEs for the entire study duration until follow-up have been presented.

An AE is any untoward medical occurrence in a participant or clinical investigation participants, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Serious infections were categorized as AE of special interest. The number of participants with overall serious infections have been presented.

An AE is any untoward medical occurrence in a participant or clinical investigation participants, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. Opportunistic infections were categorized as AE of special interest. The number of participants with overall opportunistic infections have been presented.

Pulmonary assessments were performed to determine the number of participants with pulmonary events including persistent cough, persistent dyspnea, and persistent Diffusing capacity of the lung for carbon monoxide (DLCO). Persistent is defined as any event with duration >=15 days. Baseline was defined as the last available assessment prior to the start of study treatment. The number of participants experiencing pulmonary events have been reported.

Oxygen saturation measures the capacity of blood to transport oxygen to other parts of the body. Oxygen binds to hemoglobin in red blood cells when moving through the lungs. A pulse oximeter uses two frequencies of light (red and infrared) to determine the percentage of hemoglobin in the blood that is saturated with oxygen, that is called as blood oxygen saturation. Baseline was defined as the last available assessment prior to the start of study treatment. The number of participants with blood oxygen level < 80%, 80% to <90% and >=90% have been reported.

Participants received GSK3196165 22.5 mg (0.15 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 45 mg (0.3 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/ divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 90 mg (0.6 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/ divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 135 mg (0.9 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/ divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 180 mg (1.2 mL) liquid drawn into a small (2 mL/3 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 135 mg (0.9 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 180 mg (1.2 mL) liquid drawn into a small (2 mL/3 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

95% CI were constructed using asymptotic Wald confidence limits without correction.

95% CI were constructed using asymptotic Wald confidence limits without correction.

95% CI were constructed using asymptotic Wald confidence limits without correction.

Participants received GSK3196165 22.5 mg (0.15 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 45 mg (0.3 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 90 mg (0.6 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 135 mg (0.9 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 180 mg (1.2 mL) liquid drawn into a small (2 mL/3 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 22.5 mg (0.15 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 45 mg (0.3 mL) liquid drawn into a small (03 mL/0.5 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 90 mg (0.6 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 135 mg (0.9 mL) liquid drawn into a small (1 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.

Participants received GSK3196165 180 mg (1.2 mL) liquid drawn into a small (2 mL/3 mL syringe) administered subcutaneously in the thigh/abdomen up to 52 weeks in combination with MTX tablets (orally)/liquid (subcutaneous injection) at a dose of 7.5 to 25 mg/week and folic acid tablet/capsule (orally) at a dose of >=5 mg/week. MTX was taken as a single weekly dose/divided weekly dose, folic acid was taken the day after and at least 12 hours following MTX administration. Safety was monitored for 1 hour after the injection, for the first 3 injections, then for 30 minutes thereafter.