An adverse event (AE) was defined as any untoward medical occurrence in a participant who was administered a study treatment regardless of whether or not the event has a causal relationship with the treatment. An AE, therefore, could be any unfavorable or unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the study treatment, whether or not related to the treatment. A SAE was any untoward medical occurrence that at any dose resulted in death, was life threatening, required hospitalization or prolongation of hospitalization or resulted in disability/incapacity, and congenital anomaly/birth defect. AEs included SAEs as well as non-serious AEs.

Safety population

An AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. AEs included SAEs as well as non-serious AEs. Causality of AEs based on physician's discretion: certain (AE after drug intake, not explained by other drugs, reaction on drug cessation [DC], relapse on re-intake of drug), probable/likely (AE after drug intake, not explained by other drugs, reaction on DC, no information on re-intake), possible (AE after drug intake, explained by other drugs, no information on DC), unlikely (not related to drug intake time, explained by other drugs). AEs with causality of certain, probable/likely, and possible were considered TCZ related.

Safety population

Adverse events of special interest (AESI) for this study included: infections (including opportunistic infections), myocardial infarction/acute coronary syndrome, gastrointestinal perforation and related events, malignancies, anaphylaxis / hypersensitivity reactions, demyelinating disorders, stroke, bleeding events and hepatic events.

Safety population

AESI for this study included: infections (including opportunistic infections), myocardial infarction/acute coronary syndrome, gastrointestinal perforation and related events, malignancies, anaphylaxis / hypersensitivity reactions, demyelinating disorders, stroke, bleeding events and hepatic events. Percentage of participants with AESI related to the drug were presented. Causality of AESIs based on physician's discretion: certain (AE after drug intake, not explained by other drugs, reaction on DC, relapse on re-intake of drug), probable/likely (AE after drug intake, not explained by other drugs, reaction on DC, no information on re-intake), possible (AE after drug intake, explained by other drugs, no information on DC), unlikely (not related to drug intake time, explained by other drugs). AESIs with causality of certain, probable/likely, and possible were considered TCZ related.

Safety population

An AE was any untoward medical occurrence attributed to study drug in a participant who received study drug. Percentage of participants with AE causing drug discontinuation, interruption and increase or decrease in dose of drug was presented.

Safety Population

Criteria for potentially clinically important (PCI) change in vital signs: heart rate value of less than (<) 40 beats per minute and value greater than (>) 150 beats per minute, systolic blood pressure (SBP) of < 80 or >210 millimeter of mercury (mmHg), diastolic blood pressure (DBP) of <40 or >130 mmHg, body temperature <32 or > 40 degrees Celsius, respiratory rate of <10 or > 50 breaths/minute and criteria for PCI change in physical examination: >/=10% increase or decrease of body weight in kilograms (kg).

Safety population

Criteria for laboratory tests clinically significant abnormalities included: hemoglobin, hematocrit and red blood cells (RBCs)(< 0.8*lower limit of normal[LLN]); leucocytes (<0.6/greater than [>]1.5*upper limit of normal [ULN]); platelets (<0.5*LLN></0>1.75*ULN); neutrophils, lymphocytes (<0.8*LLN></0>1.2*ULN); eosinophils, basophils, monocytes (>1.2*ULN); total bilirubin, direct bilirubin, indirect bilirubin (>1.5*ULN); aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (>3*ULN), total protein, albumin (<0.8*LLN></0>1.2*ULN); creatinine, urea (>1.3*ULN); glucose (<0.6*LLN></0>1.5*ULN); uric acid (>1.2*ULN); sodium, potassium, chloride, calcium, bicarbonate (<0.9*LLN></0>1.1*ULN); urine RBCs, urine white blood cells (WBCs) (> or equal[=]20 high-powered field), urine bacteria >20 high-powered field. Overall percentage of participants with any clinically significant laboratory abnormality was reported.

Safety population

Safety population

The DAS 28 ESR score is a measure of the participant's disease activity calculated using the tender joint count (TJC) [28 joints], swollen joint count (SJC) [28 joints], patient's global assessment (PtGA) of disease activity (visual analog scale [VAS]: 0 millimeter [mm] = no disease activity to 100 mm=maximum disease activity) and the erythrocyte sedimentation rate (ESR in millimeters per hour [mm/hr]). DAS28 was calculated using following formulas: DAS28-ESR = 0.56*square root (sqrt) (TJC28) + 0.28*sqrt (SJC28) + 0.70*natural logarithm (ln) (ESR) + 0.014*PtGA of disease activity. A total possible score of 0 to approximately 10, with higher score indicating more severe disease activity. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, 'n' represents the number of participants available for assessment at a given time point.

The SDAI was calculated as (SJC [28 joints] + TJC [28 joints] + VAS ptGA + VAS physician global assessment of disease activity + C-reactive Protein (CRP) level in milligram/deciliter [mg/dL]). VAS assessments: 0 centimeters (cm)=no disease activity to 10 cm=maximum disease activity. SDAI score ranged from 0 to 86, with higher scores indicating increased disease activity. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, N (number of participants analyzed) represents the number of participants evaluable for this outcome and 'n' represents the number of participants available for assessment at a given time point.

For TJC a total of 28 joints were assessed. The presence of a tender joint was scored as 1 and absence as 0. Total score is calculated by adding the scores, which is ranging from 0 (best possible score or no tender joint) to 28 (worse possible score or all tender joints). Lower scores indicate no tender joint and higher scores indicate worsening tender joints. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, 'n' represents the number of participants available for assessment at a given time point.

For SJC, a total of 28 joints were assessed. The presence of a swollen joint was scored as 1 and absence as 0. Total score is calculated by adding the scores, which is ranging from 0 (best possible score or no swollen joint) to 28 (worse possible score or all swollen joints). Lower scores indicate no swollen joint and higher scores indicate worsening swollen joints. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, 'n' represents the number of participants available for assessment at a given time point.

Clinical remission defined as:DAS28-ESR score < 2.6 and/or SDAI score \

Safety population. Here, N (number of participants analyzed) represents the number of participants evaluable for this outcome and 'n' represents the number of participants available for assessment at a given time point.

Safety population. Here, N (number of participants analyzed) represents the participants who received concomitant corticosteroids.

Safety population. Here, N (number of participants analyzed) represents the participants who received concomitant corticosteroids.

Time to corticosteroid discontinuation = (End date of corticosteroid treatment - date of first drug intake of this extension study) + 1.

Safety population. Here N (number of participants analyzed) represents the participants who discontinued concomitant corticosteroids

Time to corticosteroid dose reduction (days) = (Date of the first dose reduction of corticosteroid treatment - date of first drug intake of this extension study) + 1.

Safety population. Here, N (number of participants analyzed) represents the participants who had concomitant corticosteroid dose reduction.

PtGA of disease activity over the previous 24 hours using a 100 mm VAS where left end of the line 0 mm =no disease activity and right end of the line 100 mm =maximum disease activity. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, 'n' represents the number of participants available for assessment at a given time point.

Patient's assessment of pain over the previous 24 hours: using a VAS, left end of the line 0 mm=no pain to right end of the line 100 mm=unbearable pain. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety Population. Here, 'n' represents the number of participants available for assessment at a given time point.

The HAQ-DI questionnaire measures functional status (disability) and health-related quality of life. It measures the participant's ability to perform everyday tasks. The index consists of 20 questions regarding the function of the upper and lower extremities. These questions are summarized in 8 categories: dressing and grooming, arising, eating, walking, hygiene, reach, grip, and common activities over past week. Each question is evaluated according to the degree of severity on a 4-point scale. Total score for HAQ-DI was the average of all questions and ranges from 0 = without any difficulty to 3 = unable to do. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population, Here, N (number of participants analyzed) represents the participants who were evaluable for this outcome and 'n' represents the number of participants available for assessment at a given time point.

The Physician's Global Assessment of disease activity was assessed using a 0 to 100 mm horizontal VAS. The left-hand extreme of the line equals 0 mm, and is described as "no disease activity" (symptom-free and no arthritis symptoms) and the right-hand extreme equals 100 mm, as "maximum disease activity". Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, N (number of participants analyzed) represents the participants who were evaluable for this outcome and 'n' represents the number of participants available for assessment at a given time point.

Blood samples were collected for ESR, which is an acute phase reactant and provides a non-specific measure of inflammation. The test assesses the rate at which red blood cells fall in a test tube. Normal range is 0-30 millimeters per hour (mm/hr). A decrease in the level indicates reduction in inflammation and therefore improvement. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, 'n' represents the number of participants available for assessment at a given time point.

Blood samples were collected for CRP, which is an acute phase reactant and a measure of inflammation. Completer last visit: Last visit data for participants who completed the study. Last visit: Last visit data for all participants (including those who discontinued prematurely). Early withdrawal: Data at the time of early withdrawal for those participants who discontinued prematurely.

Safety population. Here, N (number of participants analyzed) represents the participants who were evaluable for this outcome and 'n' represents the number of participants available for assessment at a given time point.