A Rheumatoid Arthritis Study in Participants on a Background Treatment of Methotrexate

Percentage of Participants With American College of Rheumatology 50% (ACR50) and 70% (ACR70) Response

ACR Responder Index: Composite of clinical, laboratory, and functional measures of RA. ACR50 Responder: had ≥50% improvement from baseline in both 68 tender joint (TJ) and 66 swollen joint (SJ) counts and ≥50% improvement in at least 3 of 5 criteria: participant's (Pt's) and physician's global assessment of disease activity, HAQ-DI (measured Pts' perceived degree of difficulty performing daily activities), joint pain, and CRP. Percentage of Pt achieving ACR50 response=(number (No.) of ACR50 responders) / (No. of Pts treated) \* 100. ACR70 Responder: had ≥70% improvement from baseline in both TJ and SJ counts and ≥70% improvement in at least 3 of same 5 criteria for ACR50. Percentage of Pts achieving ACR70 response= (No. of ACR70 responders) / (No. of Pts treated) \* 100. All NR at Week 16 as well as all Pts who discontinued study treatment at any time for any reason were defined as NR starting at that time-point and going forward, including Weeks 24 and 52 endpoints.

Time frame: Baseline through 24 weeks and 52 weeks

Change From Baseline in Disease Activity Score Based on 28 Joint Count and C-Reactive Protein Level (DAS28-CRP)

Disease Activity Score (DAS) modified to include 28 joint count (DAS28) consisted of composite score of following variables: tender joint count (TJC28), swollen joint count (SJC28), CRP \[milligrams per liter (mg/L)\], and participant's global assessment of disease activity using visual analog scale (VAS) (participant global VAS). DAS28-CRP=0.56\*square root (sqrt)(TJC28)+0.28\*sqrt(SJC28)+0.36\*natural log(CRP+1)+0.014\*participant global VAS+0.96. Scores ranged from 1.0-9.4, where lower scores indicated less disease activity and remission is DAS28-CRP \<2.6. A decrease in DAS28-CRP indicated an improvement in participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Percentage of Participants With DAS28-CRP Based European League Against Rheumatism (EULAR) Response

EULAR Responder index based on 28 joint counts categorizes clinical response based on improvement since baseline in DAS28-CRP. DAS28-CRP scores range from 1.0-9.4, where lower scores indicated less disease activity. High disease activity: DAS28-CRP \>5.1, low disease activity: DAS28-CRP \<3.2, and remission: DAS28-CRP \<2.6. Participants are categorized as EULAR responders or NR based on improvement of DAS28-CRP scores from baseline. EULAR DAS28-CRP responder index defines a good (absolute: \<3.2 or \>1.2 improvement from baseline), moderate (absolute: 3.2-5.1 or 0.6-1.2 improvement from baseline), or no response (absolute: \>5.1 or \<0.6 improvement from baseline). Percentage of participants with DAS28-CRP based EULAR response =(number of participants with specific response) / (number of participants analyzed in the group) \* 100.

Time frame: Baseline through 24 weeks and 52 weeks

Change From Baseline in Medical Outcomes Study 36-Item Short Form (SF-36) Health Survey Domain Scores and Summary Scores

SF-36 is a health-related survey that assesses participant's quality of life and consists of 36 questions covering 8 health domains: physical functioning, bodily pain, role limitations due to physical problems and emotional problems, general health, mental health, social functioning, vitality, 2 component scores (CS), physical CS (PCS) and mental CS (MCS). Domain scores were calculated by summing each item for each domain and transforming scores into a 0-100 scale. Higher scores indicated better health status. If \< 50% of the questions within a domain were answered, raw scores were not calculated. PCS score consisted of physical functioning, bodily pain, role-physical, and general health scales. MCS score consisted of social functioning, vitality, mental health, and role-emotional scales. Both PCS and MCS range from 0-100. Higher score indicated better mental or physical health. LS means were calculated using ANCOVA with treatment, region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Brief Fatigue Inventory (BFI) Individual Items and Impact Score

The BFI is a brief participant-reported questionnaire for the rapid assessment of fatigue severity and the impact of fatigue on daily functioning in the past 24 hours. The BFI contains 10 items; however, Item 1 is not included in the scoring of the scale as it asks about usual fatigue over the past week with the participant answering 'yes' or 'no'. The remaining 9 items assess fatigue severity (3 items) and impact of fatigue on daily functioning (6 items) using an 11-point numeric scale, with 0=no fatigue and 10=fatigue as bad as you can imagine. The fatigue impact subscale score is the average of the non-missing responses to 6 items: general activity, mood, walking ability, normal work, relations with other people, and enjoyment of life. If more than 3 items within the fatigue impact subscale were not answered by a participant, the subscale is set to missing. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Duration of Morning Stiffness (Minutes)

The Investigator asks participants about the duration of their morning stiffness (in minutes) in and around the joints and records the duration. The Investigator should ask the participants about duration of morning stiffness on the day prior to the study visit to capture actual symptoms. If morning stiffness duration is longer than 12 hours (720 minutes), it was truncated to 720 minutes for statistical presentations and analyses. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Brief Pain Inventory Short Form (BPI-SF) Individual Items and Interference Scores

The BPI-SF is a self-reported scale that measures the severity of pain based on the worst pain, least pain, average pain experienced during the past 24-hours and pain based on the pain right now with scores ranging from 0 (no pain) to 10 (pain as severe as you can imagine). Pain interference score is the average of the responses in past 24-hours to 7 items: general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life \[each item scored from 0 (does not interfere) to 10 (completely interferes)\]. If more than 3 items of the Pain Interference Score are not answered by a participant, the score were set to missing. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Percentage of Participants With Major Clinical Response (MCR) During 52 Weeks

Time frame: Baseline through 52 weeks

Percentage of Participants With Change From Baseline in mTSS Less Than or Equal to (≤) 0

The mTSS quantifies the extent of bone erosions and joint space narrowing for 44 and 42 joints. X-rays of the hands/wrists and feet are scored for erosions on a scale from 0 (no damage) to 5 (complete collapse) and joint space narrowing on a scale from 0 (no damage) to 4 (ankylosis or complete dislocation). Erosions scores (range=0 to 220 for 44 joints) and narrowing scores (range=0 to 168 for 42 joints) were added to obtain the mTSS (range = 0 \[normal\] to 388 \[maximal disease\]). Percentage of participants = (number of participants with mTSS ≤0 at Week 24) / (total number of participants analyzed in the group) \* 100.

Time frame: Baseline through 24 weeks

Change From Baseline to Week 52 in B Cell Subset Counts

B cell subset counts are: cluster designation (CD)19+ B cell counts, Immature/transitional \[CD19+immunoglobulin D (IgD)-CD27-\], Mature naïve (CD19+IgD+CD27-), Non-switched memory (CD19+IgD+CD27+) and Memory (CD19+IgD-CD27+). A positive or negative change indicated an increase or decrease, respectively in B cell count. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 52 weeks

Population Pharmacokinetics (PK): Constant Clearance

Population estimate of constant clearance as determined by population PK analysis. A 2-compartment model was used in PK modeling. Constant clearance is the PK parameter which describes the linear elimination of LY2127399 from serum.

Time frame: Baseline through 52 weeks

Percentage of Participants Developing Anti-LY2127399 Antibodies

Participants with treatment-emergent anti-drug antibodies (ADA) were participants who had any sample from baseline up to and through Week 24 that was a 4-fold increase (2-dilution increase) in immunogenicity titer over baseline titer, or participants who tested negative at baseline and positive post-baseline (at titer of ≥1:20). Percentage of participants with ADA=(number of participants with treatment-emergent ADA) / (number of participants assessed) \* 100.

Time frame: Baseline through 52 weeks

Percentage of Participants With No Structural Progression at Week 52

No structural progression is defined as the change in mTSS from baseline ≤0. The mTSS quantifies the extent of bone erosions and joint space narrowing for 44 and 42 joints. X-rays of the hands/wrists and feet are scored for erosions on a scale from 0 (no damage) to 5 (complete collapse) and joint space narrowing on a scale from 0 (no damage) to 4 (ankylosis or complete dislocation). Erosions scores (range=0 to 220 for 44 joints) and narrowing scores (range=0 to 168 for 42 joints) were added to obtain the mTSS (range=0 \[normal\] to 388 \[maximal disease\]). Percentage of participants=(number of participants with mTSS ≤0 at Week 52) / (total number of participants analyzed in the group) \* 100.

Time frame: Baseline through 52 weeks

Change From Baseline to Week 24 in mTSS

The mTSS quantifies the extent of bone erosions and joint space narrowing for 44 and 42 joints. X-rays of the hands/wrists and feet are scored for erosions on a scale from 0 (no damage) to 5 (complete collapse) and joint space narrowing on a scale from 0 (no damage) to 4 (ankylosis or complete dislocation). Erosions scores (range=0 to 220 for 44 joints) and narrowing scores (range=0 to 168 for 42 joints) were added to obtain the mTSS (range=0 \[normal\] to 388 \[maximal disease\]). LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks

Change From Baseline in Serum Immunoglobulin (Ig) Levels

Immunoglobulins (Ig), or antibodies, are large proteins used by the immune system to identify and neutralize foreign particles such as bacteria and viruses. Their normal blood levels indicate proper immune status. Change from baseline serum immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) levels are reported. A negative change indicated a decrease in Ig levels. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 52 weeks

Change From Baseline in Joint Space Narrowing Score and Bone Erosions Score (Components of mTSS)

The mTSS quantifies the extent of bone erosions and joint space narrowing for 44 and 42 joints. X-rays of the hands/wrists and feet are scored for erosions on a scale from 0 (no damage) to 5 (complete collapse) and joint space narrowing on a scale from 0 (no damage) to 4 (ankylosis or complete dislocation). Erosions scores (range=0 to 220 for 44 joints) and narrowing scores (range=0 to 168 for 42 joints) were added to obtain the mTSS (range=0 \[normal\] to 388 \[maximal disease\]). LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

American College of Rheumatology Percent Improvement (ACR-N)

ACR-N is a continuous measure of clinical, laboratory, and functional outcomes in RA that characterizes percentage (%) of improvement in disease activity from baseline based on ACR core set. This index was calculated as minimum of either a) % change in TJ count, b) % change in SJ count, or c) the median % change of remaining 5 ACR core criteria: If ≥3 components of the 5 ACR core criteria were missing, then c) was set to missing; if any of 3 components a), b), or c) were missing, then ACR-N was set to missing. Percentage of improvement was truncated to range of -100 to 100 to minimize impact of outliers (greater values indicate greater % improvement) and negative scores indicate a decline. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline DAS28-CRP as a covariate.

Time frame: Baseline through 24 weeks and 52 weeks

Change From Baseline in Tender Joint Count (68 Joint Count)

Tender joint count is the number of tender and painful joints determined for each participant by examination of 68 joints. Joints were assessed by pressure and joint manipulation on physical examination. Participants were asked for pain sensations on these manipulations and watched for spontaneous pain reactions. Any positive response on pressure, movement, or both was translated into a single tender-versus-nontender dichotomy. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Swollen Joint Count (66 Joint Count)

Swollen joint count is the number of swollen joints determined for each participant by examination of 66 joints. Joints were classified as either swollen or not swollen. Swelling was defined as palpable fluctuating synovitis of the joint. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Participant's Assessment of Pain [Visual Analog Scale (VAS)]

Participant's assessment of their current arthritis pain using VAS ranged from 0 millimeters (mm) (no pain) to 100 mm (worst possible pain). A decrease in pain score indicated an improvement in the participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Participant's Global Assessment of Disease Activity (VAS)

Participant's assessment of their current arthritis disease activity using VAS ranged from 0 mm (no arthritis activity) to 100 mm (extremely active arthritis). A decrease in disease activity score indicated an improvement in the participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline in Physician's Global Assessment of Disease Activity (VAS)

Physician's assessment of the participant's current arthritis disease activity using VAS ranged from 0 mm (no arthritis activity) to 100 mm (extremely active arthritis). A decrease in disease activity score indicated an improvement in the participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks

Change From Baseline to Week 52 in HAQ-DI

The HAQ-DI questionnaire assesses the participant's self-perception on the degree of difficulty \[0 (without any difficulty), 1 (with some difficulty), 2 (with much difficulty), and 3 (unable to do)\] when dressing and grooming, arising, eating, walking, hygiene, reaching, gripping, and performing other daily activities. Scores for each functional area were averaged to calculate HAQ-DI scores, which ranged from 0 (no disability) to 3 (severe disability). A decrease in HAQ-DI score indicated an improvement in the participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 52 weeks

Change From Baseline to Week 52 in Absolute B Cell Counts

Cell-surface marker cluster designation (CD) 3 negative, CD20 positive (CD3-CD20+) defines total mature B cells. B-lymphocyte antigen CD20 is an activated-glycosylated phosphoprotein expressed on the surface of all mature B cells. A positive or negative change indicated an increase or decrease, respectively in B cell count. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 52 weeks

Percentage of Participants With ACR20 at Week 52

ACR Responder Index: Composite of clinical, laboratory, and functional measures of rheumatoid arthritis (RA). ACR20 Responder: had ≥20% improvement from baseline in both 68 tender and 66 swollen joint counts and ≥20% improvement in at least 3 of 5 criteria: participant's and physician's global assessment of disease activity, HAQ-DI (which measured participants' perceived degree of difficulty performing daily activities), joint pain, and CRP. Percentage of participants achieving ACR20 response=(number of ACR20 responders) /( number of participants treated) \* 100. All NR at Week 16 as well as all participants who discontinued study treatment at any time for any reason were defined as NR starting at that time-point and going forward, including Week 52 endpoint.

Time frame: Baseline through 52 weeks

Time to ACR20 Response

ACR Responder Index: Composite of clinical, laboratory, and functional measures of rheumatoid arthritis (RA). ACR20 Responder: had ≥20% improvement from baseline in both 68 tender and 66 swollen joint counts and ≥20% improvement in at least 3 of 5 criteria: participant's and physician's global assessment of disease activity, HAQ-DI (which measured participants' perceived degree of difficulty performing daily activities), joint pain, and CRP. The Kaplan-Meier was used to estimate time to ACR20 response over the Treatment Period (52 weeks). Time to ACR20 response = (Date of the first post-baseline visit during the Treatment Period meeting ACR20 response criteria - Date of first injection of study treatment + 1) / 7. Week 16 NR are counted as responders if they responded prior to Week 16. Otherwise, they are censored at the date of the Week 16 injection. All participants ongoing at Week 52 and had not yet responded are censored at the date of the Week 52 visit.

Time frame: Baseline through 52 weeks

Change From Baseline in CRP

CRP is an indicator of inflammation. A negative change indicated an improvement in the participant's condition. LS means were calculated using ANCOVA with treatment and region as fixed factors and baseline as a covariate.

Time frame: Baseline, 24 weeks and 52 weeks