ACR20 response: greater than or equal to (>=) 20 percent (%) improvement in tender joint count; >=20% improvement in swollen joint count; and >=20% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of the Health Assessment Questionnaire [HAQ]); and C-Reactive Protein (CRP).

Full Analysis Set (FAS): all randomized participants who received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed)=participants evaluable for this measure.

HAQ-DI: participant-reported assessment of ability to perform tasks in 8 functional categories of daily living activities: dress/groom; arise; eat; walk; reach; grip; hygiene; and common activities over past week. Each item scored on 4-point scale from 0 to 3: 0=no difficulty; 1=some difficulty; 2=much difficulty; 3=unable to do. Overall score was computed as the sum of domain scores and divided by the number of domains answered. Total possible score range 0-3, 0=least functional difficulty and 3=extreme functional difficulty.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n' signifies those participants who were evaluable at given time points for each group respectively.

DAS28-4 (ESR) calculated from swollen joint count (SJC) and tender/painful joint count (TJC) using 28 joint count, erythrocyte sedimentation rate (ESR) (millimeters per hour [mm/hour]) and patient's global assessment (PtGA) of disease activity (transformed score ranging 0 to 10; higher score indicated greater affectation due to disease activity). Total score range:0 to 9.4, higher score indicated more disease activity. DAS28-4 (ESR) less than or equal to (=<) 3.2 implied low disease activity, greater than (>) 3.2 to 5.1 implied moderate to high disease activity and less than (<) 2.6=remission.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR20 response: >= 20% improvement in tender joint count; >=20% improvement in swollen joint count; and >=20% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of the HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR20 response: >= 20% improvement in tender joint count; >=20% improvement in swollen joint count; and >=20% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of the HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR50 response: greater than or equal to >=50% improvement in tender joint count; >=50% improvement in swollen joint count; and >=50% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR50 response: greater than or equal to >=50% improvement in tender joint count; >=50% improvement in swollen joint count; and >=50% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR70 response: >=70% improvement in tender joint count; >=70% improvement in swollen joint count; and >=70% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

ACR70 response: >=70% improvement in tender joint count; >=70% improvement in swollen joint count; and >=70% improvement in at least 3 of 5 remaining ACR core measures: participant assessment of pain; participant global assessment of disease activity; physician global assessment of disease activity; self-assessed disability (disability index of HAQ); and CRP.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

DAS28-4 (ESR) calculated from SJC and TJC using 28 joint count, ESR (mm/hour) and PtGA of disease activity (transformed score ranging 0 to 10; higher score indicated greater affectation due to disease activity). Total score range:0 to 9.4, higher score indicated more disease activity. DAS28-4 (ESR) =<3.2 implied low disease activity, >3.2 to 5.1 implied moderate to high disease activity and <2.6 implied remission.

FAS population. 'N' (number of participants analyzed)=participants evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

DAS28-4 (ESR) calculated from swollen joint count (SJC) and tender/painful joint count (TJC) using 28 joint count, erythrocyte sedimentation rate (ESR) (millimeters per hour [mm/hour]) and patient's global assessment (PtGA) of disease activity (transformed score ranging 0 to 10; higher score indicated greater affectation due to disease activity). Total score range:0 to 9.4, higher score indicated more disease activity. DAS28-4 (ESR) less than or equal to (=<) 3.2 implied low disease activity, greater than (>) 3.2 to 5.1 implied moderate to high disease activity and less than (<) 2.6=remission.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

DAS28-3 (CRP) was calculated from SJC and TJC using 28 joint count and CRP (milligram per liter [mg/L]). Total score range: 0 to 9.4, higher score indicated more disease activity. DAS28-3 (CRP) =<3.2 implied low disease activity, >3.2 to 5.1 implied moderate to high disease activity and <2.6 implied remission.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

DAS28-3 (CRP) was calculated from SJC and TJC using 28 joint count and CRP (mg/L). Total score range: 0 to 9.4, higher score indicated more disease activity. DAS28-3 (CRP) =<3.2 implied low disease activity, >3.2 to 5.1 implied moderate to high disease activity and <2.6 implied remission.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

HAQ-DI: participant-reported assessment of ability to perform tasks in 8 functional categories of daily living activities: dress/groom; arise; eat; walk; reach; grip; hygiene; and common activities over past week. Each item scored on 4-point scale from 0 to 3: 0=no difficulty; 1=some difficulty; 2=much difficulty; 3=unable to do. Overall score was computed as the sum of domain scores and divided by the number of domains answered. Total possible score range 0-3, 0=least functional difficulty and 3=extreme functional difficulty.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

HAQ-DI: participant-reported assessment of ability to perform tasks in 8 functional categories of daily living activities: dress/groom; arise; eat; walk; reach; grip; hygiene; and common activities over past week. Each item scored on 4-point scale from 0 to 3: 0=no difficulty; 1=some difficulty; 2=much difficulty; 3=unable to do. Overall score was computed as the sum of domain scores and divided by the number of domains answered. Total possible score range 0-3, 0=least functional difficulty and 3=extreme functional difficulty.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Participants assessed the severity of their arthritis pain using a 100 millimeter (mm) visual analog scale (VAS). The scale ranged from 0 (no pain) to 100 (most severe pain), measurement on a scale corresponds to the magnitude of their pain.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'n'=participants evaluable at given time point for each group respectively.

Participants assessed the severity of their arthritis pain using a 100 mm visual analog scale (VAS). The scale ranged from 0 (no pain) to 100 (most severe pain), measurement on a scale corresponds to the magnitude of their pain.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Participants answered: "Considering all the ways your arthritis affects you, how are you feeling today?" Participants responded by using a 0 - 100 mm Visual Analog Scale where 0 = very well and 100 = very poorly.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Participants answered: "Considering all the ways your arthritis affects you, how are you feeling today?" Participants responded by using a 0 - 100 mm Visual Analog Scale where 0 = very well and 100 = very poorly.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Physician Global Assessment of Arthritis was measured on a 0 to 100 mm VAS, where 0 mm = very good and 100 mm = very bad.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'n'=participants evaluable at given time point for each group respectively.

Physician Global Assessment of Arthritis was measured on a 0 to 100 mm VAS, where 0 mm = very good and 100 mm = very bad.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

SF-36 is a standardized survey evaluating 8 aspects of functional health and well being: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional and mental health. The score for a section is an average of the individual question scores, which are scaled 0-100 (100=highest level of functioning) and is reported as 2 summary scores; Physical Component Score and Mental Component Score. Total score range for the summary scores = 0- 100, where higher score represents higher level of functioning.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

SF-36 is a standardized survey evaluating 8 aspects of functional health and well being: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional and mental health. The score for a section is an average of the individual question scores, which are scaled 0-100 (100=highest level of functioning) and is reported as 2 summary scores; Physical Component Score and Mental Component Score. Total score range for the summary scores = 0- 100, where higher score represents higher level of functioning.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

Participant-rated 12 item questionnaire assess constructs of sleep over past week.7 subscales: sleep disturbance, snoring, awakened short of breath, sleep adequacy, somnolence (range:0-100); sleep quantity(range:0-24), optimal sleep(yes or no). 9 item index measures of sleep disturbance provide composite scores: sleep problem summary, overall sleep problem. Except Adequacy, Optimal, Quantity of sleep, higher scores=more impairment. Scores transformed(actual raw score minus lowest possible score divided by possible raw score range*100);total score range:0-100,higher score=more intensity of attribute.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

MOS-SS: participant-rated 12 item questionnaire to assess constructs of sleep over past week. It included 7 subscales: sleep disturbance, snoring, awakened short of breath, sleep adequacy, somnolence, sleep quantity and optimal sleep. Participants responded whether their sleep was optimal or not by choosing yes or no. Number of participants with optimal sleep are reported.

FAS population. 'n'=participants evaluable at given time point for each group respectively.

Participant-rated 12 item questionnaire assess constructs of sleep over past week.7 subscales: sleep disturbance, snoring, awakened short of breath, sleep adequacy, somnolence (range:0-100); sleep quantity(range:0-24), optimal sleep(yes or no). 9 item index measures of sleep disturbance provide composite scores: sleep problem summary, overall sleep problem. Except Adequacy, Optimal, Quantity of sleep, higher scores=more impairment. Scores transformed(actual raw score minus lowest possible score divided by possible raw score range*100);total score range:0-100,higher score=more intensity of attribute.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

MOS-SS: participant-rated 12 item questionnaire to assess constructs of sleep over past week. It included 7 subscales: sleep disturbance, snoring, awakened short of breath, sleep adequacy, somnolence, sleep quantity and optimal sleep. Participants responded whether their sleep was optimal or not by choosing yes or no. Number of participants with optimal sleep are reported.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

FACIT-Fatigue is a 13-item questionnaire. Participant scored each item on a 5-point scale: 0 (Not at all) to 4 (Very much). The larger the participant's response to the questions (with the exception of 2 negatively stated), the greater the fatigue. For all questions, except for the 2 negatively stated ones, the code was reversed and a new score was calculated as 4 minus the participant's response. The sum of all responses resulted in the FACIT-Fatigue score for a total possible score of 0 (worse score) to 52 (better score). A higher score reflected an improvement in the participant's health status.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

FACIT-Fatigue is a 13-item questionnaire. Participant scored each item on a 5-point scale: 0 (Not at all) to 4 (Very much). The larger the participant's response to the questions (with the exception of 2 negatively stated), the greater the fatigue. For all questions, except for the 2 negatively stated ones, the code was reversed and a new score was calculated as 4 minus the participant's response. The sum of all responses resulted in the FACIT-Fatigue score for a total possible score of 0 (worse score) to 52 (better score). A higher score reflected an improvement in the participant's health status.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

EQ-5D: participant rated questionnaire to assess health-related quality of life in terms of a single utility score. Health State Profile component assesses level of current health for 5 domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression; 1 indicates better health state (no problems); 3 indicates worst health state ("confined to bed"). Scoring formula developed by EuroQol Group assigns a utility value for each domain in the profile. Score is transformed and results in a total score range -0.594 to 1.000; higher score indicates a better health state.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

EQ-5D: participant rated questionnaire to assess health-related quality of life in terms of a single utility score. Health State Profile component assesses level of current health for 5 domains: mobility, self-care, usual activities, pain and discomfort, and anxiety and depression; 1 indicates better health state (no problems); 3 indicates worst health state ("confined to bed"). Scoring formula developed by EuroQol Group assigns a utility value for each domain in the profile. Score is transformed and results in a total score range -0.594 to 1.000; higher score indicates a better health state.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

Rheumatoid Arthritis (RA)-HCRU assessed healthcare usage during last 3 months for direct, indirect medical cost domains. Direct cost:visit to doctor,non-medical practitioner,nursing home,hospital,surgery,emergency room(ER) treatment,diagnostic tests, over-night stay,home healthcare services, aids/devices used. Indirect costs associated with functional disability:employment status,willingness to work,work disability due to RA,sick leave,part time work,ability to perform chores,chores done by family/friends/housekeeper. Assessment was based on 0 to 2-point scale;higher score=higher medical cost.

FAS population. Participants with at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint were included. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Rheumatoid Arthritis (RA)-HCRU assessed healthcare usage during last 3 months for direct, indirect medical cost domains. Direct cost:visit to doctor,non-medical practitioner,nursing home,hospital,surgery,emergency room(ER) treatment,diagnostic tests, over-night stay,home healthcare services, aids/devices used. Indirect costs associated with functional disability:employment status,willingness to work,work disability due to RA,sick leave,part time work,ability to perform chores,chores done by family/friends/housekeeper. Assessment was based on 0 to 2-point scale;higher score=higher medical cost.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains. Any RA/non-RA related number of visits to doctor, non-medical practitioner, hospital ER treatment, hospitalizations, number of surgeries, diagnostic tests, and devices/aids used were reported.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains. Any RA/non-RA related number of visits to doctor, non-medical practitioner, hospital ER treatment, hospitalizations, number of surgeries, diagnostic tests, and devices/aids used were reported.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains.Any RA or non-RA related number of days spent in hospital, nursing home, aids/devices used, on sick leave, work per week, performed part time work, performed paid work, chores done by housekeeper and chores done by family/friends.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains.Any RA or non-RA related number of days spent in hospital, nursing home, aids/devices used, on sick leave, work per week, performed part time work, performed paid work, chores done by housekeeper and chores done by family/friends.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains. Any RA or non-RA related number of hours spent per day for home healthcare services, chores done by housekeeper, chores done by family or friends, work done and work missed were reported.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

RA-HCRU assessed healthcare usage during previous 3 months for direct or indirect medical cost domains. Any RA or non-RA related number of hours spent per day for home healthcare services, chores done by housekeeper, chores done by family or friends, work done and work missed were reported.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Work performance of participants on number of days bothered was based on a 0 to 10-point scale, where higher score indicated lower work performance.

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

Work performance of participants on number of days bothered was based on a 0 to 10-point scale, where higher score indicated lower work performance.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

Participants assessed the severity of their arthritis pain using a 100 millimeter (mm) visual analog scale (VAS). The scale ranged from 0 (no pain) to 100 (most severe pain), measurement on a scale corresponds to the magnitude of their pain.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

Participants answered: "Considering all the ways your arthritis affects you, how are you feeling today?" Participants responded by using a 0 - 100 mm Visual Analog Scale where 0 = very well and 100 = very poorly.

FAS: all participants who were randomized to study, received at least 1 dose of study drug (CP-690550/placebo), had at least 1 post-baseline measurement, and baseline measurement for change from baseline endpoint. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure.

WLQ: participant-reported 25-item scale to evaluate degree to which health problems interfere with an ability to perform job roles along 4 dimensions: Time Management scale (5-items); Physical Demands scale (6-item); Mental-Interpersonal Demands Scale (9-items); Output Demands scale (5-items). All the scales ranged from 0 (limited none of the time) to 100 (limited all of the time). Work Loss Index, which represented percentage of lost work over time period relative to a normative population, was derived (total score:0[no loss] to 100[complete loss of work]).

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given time point for each group respectively.

WLQ: participant-reported 25-item scale to evaluate degree to which health problems interfere with an ability to perform job roles along 4 dimensions: Time Management scale (5-items); Physical Demands scale (6-item); Mental-Interpersonal Demands Scale (9-items); Output Demands scale (5-items). All the scales ranged from 0 (limited none of the time) to 100 (limited all of the time). Work Loss Index, which represented percentage of lost work over time period relative to a normative population, was derived (total score:0[no loss] to 100[complete loss of work]).

FAS population. 'N' (number of participants analyzed) signifies those participants who were evaluable for this measure. 'n'=participants evaluable at given parameter for each group respectively.