Phase IIb Study of Evobrutinib in Subjects With Rheumatoid Arthritis

Disease Activity Score (DAS) based on a 28 joint count hsCRP consisted of composite numerical score of following variables: tender joint count (TJC28), swollen joint count (SJC28), hsCRP (mg/mL), and participant's global assessment of disease activity. DAS28-hsCRP was calculated using following formula: DAS28-hsCRP equals to (=) 0.56*square root (sqrt) (TJC28) plus (+) 0.28*sqrt (SJC28) + 0.36*natural log(hsCRP+1) + 0.014* participant's global assessment of disease activity + 0.96. Scores ranged 0-9.4, where lower scores indicated less disease activity. Percentage of participants with low DAS28 < 3.2 based on DAS28- hsCRP at Week 12 were reported.

Disease Activity Score (DAS) based on a 28 joint count hsCRP consisted of composite numerical score of following variables: tender joint count (TJC28), swollen joint count (SJC28), hsCRP (mg/mL), and participant's global assessment of disease activity. DAS28-hsCRP was calculated using following formula: DAS28-hsCRP equals to (=) 0.56*square root (sqrt) (TJC28) plus (+) 0.28*sqrt (SJC28) + 0.36*natural log(hsCRP+1) + 0.014* participant's global assessment of disease activity + 0.96. Scores ranged 0-9.4, where lower scores indicated less disease activity. A DAS28 score less than (<) 2.6 indicated clinical remission. Percentage of participants with low DAS28 < 2.6 based on DAS28- hsCRP at Week 12 were reported.

ACR50 response: a participant has at least 50% improvement in both tender joint counts (based on a total of 68 joints) and swollen joint counts (based on a total of 66 joints) together with 50% improvement in at least 3 of the following: 1) participant's assessment of pain; 2) participant's global assessment of disease activity; 3) physician's global assessment of disease activity; 4) participant's assessment of physical function measured by Health Assessment Questionnaire - Disability Index [HAQ-DI]; and 5) acute phase reactant as measured by High-sensitivity C-reactive protein [hsCRP]. Percentage of participants with ACR50 response = Number of participants with ACR50 response divided by total mITT participants * 100.

ACR70 response: a participant has at least 70% improvement ACR70 response in both tender joint counts (based on a total of 68 joints) and swollen joint counts (based on a total of 66 joints) together with 70% improvement in at least 3 of the following: 1) participant's assessment of pain; 2) participant's global assessment of disease activity; 3) physician's global assessment of disease activity; 4) participant's assessment of physical function measured by Health Assessment Questionnaire - Disability Index [HAQ-DI]; and 5) acute phase reactant as measured by High-sensitivity C-reactive protein [hsCRP]. Percentage of participants with ACR70 response = Number of participants with ACR70 response divided by total mITT participants * 100.

Adverse event (AE) was defined as any untoward medical occurrence in a participant, which does not necessarily have causal relationship with treatment. A serious AE was defined as an AE that resulted in any of the following outcomes: death; life threatening; persistent/significant disability/incapacity; initial or prolonged inparticipant hospitalization; congenital anomaly/birth defect or was otherwise considered medically important. TEAEs: events between first dose of study drug that were absent before treatment/that worsened relative to pre-treatment state up to 16 weeks. TEAEs included both serious TEAEs and non-serious TEAEs. Number of participants with TEAEs and serious TEAEs were reported.

Severity of TEAEs were graded using NCI-CTCAE v4.03 toxicity grades, as follows: Grade 1= Mild; Grade 2 = Moderate; Grade 3 = Severe; Grade 4 = Life-threatening and Grade 5 = Death. Number of participants with TEAEs by severity were reported.

Vital signs included body temperature, systolic and diastolic blood pressure, pulse rate, respiratory rate, weight and height. Clinical significance was determined by the investigator. The number of participants with clinically significant changes from baseline in vital signs were reported.

Laboratory investigation included hematology, biochemistry, urinalysis and coagulation. Clinical significance was determined by the investigator. The number of participants with clinically significant changes from baseline in laboratory parameters were reported.

12-lead ECG recordings included rhythm, heart rate (as measured by RR interval), PR interval, QRS duration, and QT interval. The corrected QT interval (QTcF) was calculated using Fridericia's formula. 12-lead ECG recordings were obtained after the participants have rested for at least 10 minutes in semisupine position. Clinical significance was determined by the investigator. The number of participants with clinically significant changes from baseline in 12-lead ECG findings were reported.

Change in the serum levels of IgG, IgA, IgM were assessed.

Flow cytometry analysis of lymphocyte populations using four-color fluorescence-activated cell sorting was performed for the analysis of B cell counts.

ACR-EULAR Boolean remission was when a participant satisfied all of the following: tender joint count, swollen joint count (both based on a 28-joint assessment), C-reactive Protein (in milligrams per deciliter [mg/dL]), and participant's global assessment (visual analog scale [VAS]: 0 centimeter (cm) [very well] to 10 cm [worst], higher scores indicated worse health condition) and all scores were less than or equal to (<=) 1. Percentage of participants with ACR-EULAR Boolean Remission were reported.

CDAI: a composite index (without acute-phase reactant) for assessing disease activity. The CDAI was calculated based on following formula: CDAI = 28 joint count for swelling (SJC28) + 28 joint count for tenderness (TJC28) + GH + PhGA where, GH = general health component of the Disease Activity Score [DAS] (i.e., Participant's Global Assessment of Disease Activity, assessed using a scale of 0 to 10 centimeter (cm) Visual Analogue Scale (VAS) where 0 = very well and 10 = very poor activity and PhGA = Physician's Global Assessment of Disease Activity assessed using a scale of 0 to 10 cm VAS, where 0 = very well and 10 = very poor activity. The total CDAI score ranges from 0 to 76, where 0 (none) to 76 (extreme disease activity). CDAI score =< 2.8 indicated clinical remission. Percentage of participants with CDAI score =< 2.8 were reported.

SDAI was calculated based on following formula: SDAI = 28 joint count for swelling (SJC28) + 28 joint count for tenderness (TJC28) + GH + PGA + hsCRP where, GH = general health component of the Disease Activity Score [DAS] (i.e., Participant's Global Assessment of Disease Activity, assessed using a scale of 0 to 10 centimeter (cm) Visual Analogue Scale (VAS) where 0 = very well and 10 = very poor activity and PhGA = Physician's Global Assessment of Disease Activity assessed using a scale of 0 to 10 cm VAS, where 0 = very well and 10 = very poor activity. The total SDAI score ranges from 0 to 86, where 0 (none) to 86 (extreme disease activity). SDAI score =< 3.3 indicated clinical remission. Percentage of participants with SDAI score =< 3.3 at Week 12 were reported.

EULAR Responder index based on 28 joint counts categorizes clinical response based on improvement since baseline in DAS28-CRP. DAS28-CRP scores range from 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. EULAR DAS28-CRP responder index: 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 Good or Moderate EULAR Responses were reported.

The hybrid ACR combines the ACR 20/50/70 response with the mean percent change in all 7 ACR core components, thus providing a percent improvement from baseline on a continuous scale. For each participant, the mean percent improvement from baseline across the 7 ACR core set measures (tender joint count, swollen joint count, Patient's Global Assessment of Disease Activity, Physician's Global Assessment of Disease Activity, disability index of the Health Assessment Questionnaire [HAQ], and C-reactive protein [CRP]) was calculated (a positive change indicated improvement, and the maximum worst change was limited to -100%) and the ACR20, ACR50, and ACR70 response is determined. The hybrid ACR is determined from a reference table taking into account both ACR response and mean percent improvement in the core set measures. Scores can range from -100% (maximal worsening) to 100% (maximal improvement).

DAS28 was a composite score used for measuring disease activity in participants with rheumatoid arthritis. The calculation was based on the tender joint count (out of 28 joints), swollen joint count (out of 28 joints), hsCRP (milligrams per liter [mg/L]) and Participant's Global Assessment of Disease Activity. Total DAS28-hsCRP score ranged from 0 (none) to 9.4 (extreme disease activity). DAS28-hsCRP < 3.2 implied low disease activity and >= 3.2 to <= 5.1 implied moderate disease activity, > 5.1 implied high disease activity. DAS28-hsCRP = 0.56*sqrt(TJC28) + 0.28*sqrt(SJC28) + 0.36*ln(hsCRP in mg/L +1) + 0.014* Participant's Global Assessment of Disease Activity + 0.96; ln = natural logarithm, sqrt = square root.

The CDAI was a composite index (without acute-phase reactant) for assessing disease activity. The CDAI was calculated based on following formula: CDAI = 28 joint count for swelling (SJC28) + 28 joint count for tenderness (TJC28) + GH + PhGA where, GH = general health component of the DAS (i.e., Participant's Global Assessment of Disease Activity, assessed using a scale of 0 to 10 centimeter (cm) Visual Analogue Scale (VAS) where 0 = very well and 10 = very poor activity and PhGA = Physician's Global Assessment of Disease Activity assessed using a scale of 0 to 10 cm VAS, where 0 = very well and 10 = very poor activity. The total CDAI score ranges from 0 to 76, where 0 (none) to 76 (extreme disease activity).

SDAI was numerical sum of 5 outcome parameters: 28 joint count for swelling (SJC28) + 28 joint count for tenderness (TJC28) + GH + PGA + hsCRP where, GH = general health component of the DAS (i.e., Participant's Global Assessment of Disease Activity, assessed using a scale of 0 to 10 centimeter (cm) Visual Analogue Scale (VAS) where 0 = very well and 10 = very poor activity and PhGA = Physician's Global Assessment of Disease Activity assessed using a scale of 0 to 10 cm VAS, where 0 = very well and 10 = very poor activity. The total SDAI score ranges from 0 to 86, where 0 (none) to 86 (extreme disease activity).

Sixty-eight joints were assessed and classified as tender/not tender and Sixty-six joints were classified as swollen/not swollen by pressure and joint manipulation on physical examination.

The participant's overall assessment of disease activity was recorded using the 100 millimeter (mm) horizontal visual analog scale (VAS). The scale ranged from 0-100 mm, where 0 indicated no disease activity (symptom free and no arthritis symptoms) and 100 represented maximum disease activity (maximum arthritis disease activity).

The participants were asked to assess their level of pain by marking a vertical tick on a 100 mm horizontal VAS scale. The scale ranged from 0-100 mm, where 0 indicated no pain and 100 indicated worst possible pain.

HAQ-DI score was an evaluation of the functional status for a participant. The 20-question instrument assessed the degree of difficulty a person had in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and activities of daily living). Responses in each functional area were scored from 0, indicated no difficulty, to 3, indicated inability to perform a task in that area. Overall score was computed as the sum of domain scores and divided by the number of domains answered. Total possible score range: 0-3 where 0 = least difficulty and 3 = extreme difficulty.

The Physician's Global Assessment of Disease Activity was recorded using the 100 mm horizontal VAS. Physician rated participant's arthritis disease activity on a scale ranged from 0-100 mm, where 0 indicated no disease activity (no arthritis) and 100 represented maximum disease activity (maximum arthritis).

hsCRP was the American College of Rheumatology (ACR) Core Set measure of acute phase reactant. It was measured at the central laboratory to help assess the effect of M2951 on the participant's rheumatoid arthritis.

Sixty-eight joints were assessed and classified as tender/not tender and Sixty-six joints were classified as swollen/not swollen by pressure and joint manipulation on physical examination.

The participant's overall assessment of disease activity was recorded using the 100 millimeter (mm) horizontal visual analog scale (VAS). The scale ranged from 0-100 mm, where 0 indicated no disease activity (symptom free and no arthritis symptoms) and 100 represented maximum disease activity (maximum arthritis disease activity).

The participants were asked to assess their level of pain by marking a vertical tick on a 100 mm horizontal VAS scale. The scale ranged from 0-100 mm, where 0 indicated no pain and 100 indicated worst possible pain.

HAQ-DI score was an evaluation of the functional status for a participant. The 20-question instrument assessed the degree of difficulty a person had in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and activities of daily living). Responses in each functional area were scored from 0, indicated no difficulty, to 3, indicated inability to perform a task in that area. Overall score was computed as the sum of domain scores and divided by the number of domains answered. Total possible score range: 0-3 where 0 = least difficulty and 3 = extreme difficulty.

The Physician's Global Assessment of Disease Activity was recorded using the 100 mm horizontal VAS. Physician rated participant's arthritis disease activity on a scale ranged from 0-100 mm, where 0 indicated no disease activity (no arthritis) and 100 represented maximum disease activity (maximum arthritis).

hsCRP was the American College of Rheumatology (ACR) Core Set measure of acute phase reactant. It was measured at the central laboratory to help assess the effect of M2951 on the participant's rheumatoid arthritis.

A total of 8 joints in the hand and wrist were evaluated for RAMRIS synovitis. Individual joint scores were assessed on a scale of 0 (no synovitis) to 3 (67 to 100 percent volume enhancement). The final synovitis score was the sum of the individual joint scores. The total score from 8 joints ranges from 0 to 24, with 0 implying normal (no synovitis) and 24 implying 67 to 100 percent volume enhancement.

A total of 25 locations in the hand and wrist were evaluated for RAMRIS bone edema or osteitis. Individual location scores range from 0 (no edema) to 3 (67 to 100 percent involvement of original articular bone) based on the proportion of estimated originally non-eroded bone involved. The final bone edema or osteitis score is the sum of the individual location scores. The total score from the 25 locations ranges from 0 to 75, with 0 implying no bone edema or osteitis and 75 implying 67 to 100 percent involvement of original articular bone.

The HAQ-DI questionnaire assessed 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 (worst disability). A decrease in HAQ-DI score indicated an improvement in the participant's condition.

The 36-Item Short-Form Health Survey (SF-36) was a standardized survey evaluating 8 aspects of functional health and well-being. These eight subscales were summarized as relating to either physical health or mental health. Physical component summary (PCS) was based primarily on physical functioning, role-physical, bodily pain, and general health scales and mental component summary (MCS) encompasses vitality, social functioning, role-emotional, and mental health scales. Score from mental health, role emotional, social functioning, and vitality domains were averaged to calculate MCS. Total score range for MCS was 0-100 (100 = highest level of mental functioning). Score from physical function, role physical, bodily pain, and general health domains were averaged to calculate PCS. Total score range for PCS was 0-100 (100 = highest level of physical functioning).

The FACIT-Fatigue score was calculated according to a 13-item questionnaire that assess self-reported fatigue and its impact upon daily activities and function. It uses a 5-point Likert-type scale (0 = not at all; 1 = a little bit; 2 = somewhat; 3 = quite a bit; 4 = very much). The sum of all responses resulted in the FACIT-Fatigue score for a total possible score of 0 (worse possible score) to 52 (best score). A higher score reflected an improvement in the participant's health status.