A Study to Investigate the Safety and Efficacy of ABBV-105 Alone or in Combination With Upadacitinib (ABBV-599 Combination) in Participants With Active Rheumatoid Arthritis

The CDAI is a composite index for assessing disease activity based on the summation of the total tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), patient global assessment of disease activity measured on a VAS from 0 to 10 cm, and physician global assessment of disease activity measured on a VAS from 0 to 10 cm. The total CDAI score ranges from 0 to 78 with higher scores indicating higher disease activity. A negative change from baseline indicates improvement in disease activity.

The SDAI is a validated measure of rheumatoid arthritis disease activity. Twenty-eight tender joint counts, 28 swollen joint counts, global disease activity assessed by the participant on a visual analogue scale from 0 to 10 (cm), global disease activity assessed by an investigator on a visual analogue scale from 0 to 10 (cm), and serum levels of C-reactive protein (CRP; mg/dL) were included in the SDAI score. Scores on the SDAI range from 0 to 86.with higher scores indicating higher disease activity. A negative change from baseline indicates improvement in disease activity.

The DAS28-CRP is a composite index used to assess rheumatoid arthritis disease activity, calculated based on the tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), Patient's Global Assessment of Disease Activity (0-100 mm), and high-sensitivity C-reactive protein (hsCRP; in mg/L). Scores on the DAS28-CRP range from 0 to approximately 10, where higher scores indicate more disease activity. Clinical remission (CR) based on DAS28 (CRP) is defined as achieving a DAS28 (CRP) of less than 2.6.

The DAS28-CRP is a composite index used to assess rheumatoid arthritis disease activity, calculated based on the tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), Patient's Global Assessment of Disease Activity (0-100 mm), and high-sensitivity C-reactive protein (hsCRP; in mg/L). Scores on the DAS28-CRP range from 0 to approximately 10, where higher scores indicate more disease activity. Low Disease Activity (LDA) based on DAS28 (CRP) is defined as achieving a DAS28 (CRP) of less than or equal to 3.2.

The CDAI is a composite index for assessing disease activity based on the summation of the total tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), patient global assessment of disease activity measured on a VAS from 0 to 10 cm, and physician global assessment of disease activity measured on a VAS from 0 to 10 cm. The total CDAI score ranges from 0 to 78 with higher scores indicating higher disease activity. Low Disease Activity (LDA) based on CDAI is defined as achieving a CDAI of less than or equal to 10.

The CDAI is a composite index for assessing disease activity based on the summation of the total tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), patient global assessment of disease activity measured on a VAS from 0 to 10 cm, and physician global assessment of disease activity measured on a VAS from 0 to 10 cm. The total CDAI score ranges from 0 to 78 with higher scores indicating higher disease activity. Complete Remission (CR) based on CDAI is defined as achieving a CDAI of less than or equal to 2.8.

Participants who met the following 3 conditions for improvement from baseline were classified as meeting the American College of Rheumatology 20% response (ACR20) criteria:

1. ≥ 20% improvement in 68-tender joint count
2. ≥ 20% improvement in 66-swollen joint count and
3. ≥ 20% improvement in at least 3 of the 5 following parameters:

• Patient's Assessment of Pain (Visual Analog Scale [VAS])
• Patient's Global Assessment of Disease Activity (PtGA)
• Physician's Global Assessment of Disease Activity (PhGA)
• Health Assessment Questionnaire Disability Index (HAQ-DI)
• High-sensitivity C-reactive protein (hsCRP)

Participants who met the following 3 conditions for improvement from baseline were classified as meeting the American College of Rheumatology 50% response (ACR50) criteria:

1. ≥ 50% improvement in 68-tender joint count
2. ≥ 50% improvement in 66-swollen joint count and
3. ≥ 50% improvement in at least 3 of the 5 following parameters:

• Patient's Assessment of Pain (Visual Analog Scale [VAS])
• Patient's Global Assessment of Disease Activity (PtGA)
• Physician's Global Assessment of Disease Activity (PhGA)
• Health Assessment Questionnaire Disability Index (HAQ-DI)
• High-sensitivity C-reactive protein (hsCRP)

Participants who met the following 3 conditions for improvement from baseline were classified as meeting the American College of Rheumatology 70% response (ACR70) criteria:

1. ≥ 70% improvement in 68-tender joint count
2. ≥ 70% improvement in 66-swollen joint count and
3. ≥ 70% improvement in at least 3 of the 5 following parameters:

• Patient's Assessment of Pain (Visual Analog Scale [VAS])
• Patient's Global Assessment of Disease Activity (PtGA)
• Physician's Global Assessment of Disease Activity (PhGA)
• Health Assessment Questionnaire Disability Index (HAQ-DI)
• High-sensitivity C-reactive protein (hsCRP)

Sixty-eight joints were assessed for tenderness by physical examination. Pain or tenderness of each joint was classified as present (1) or absent (0), for a total possible score of 0 (0 joints with tenderness) to 68 (worst possible score/68 joints with tenderness). Negative values indicate improvement from baseline.

Sixty-six joints were assessed for swelling by physical examination. Swelling of each joint was classified as present (1) or absent (0), for a total possible score of 0 (0 joints with swelling) to 66 (worst possible score/66 joints with swelling). Negative values indicate improvement from baseline.

Participants rated their pain on a visual analogue scale (VAS) of 0 to 100 (mm), with 0 representing no pain and 100 representing the worst possible pain. Negative values indicate improvement from baseline.

Participants rated their disease activity for the past 24 hours using a Patient's Global Assessment of Disease Activity Global visual analogue scale (VAS). The range is 0 to 100 mm, with 0 representing no disease activity and 100 representing severe disease activity. Negative values indicate improvement from baseline.

The physician assessed a participant's disease activity at the time of the visit using a Physician's Global Assessment of Disease visual analogue scale (VAS). The range is 0 to 100 mm, with 0 representing no disease activity and 100 representing severe disease activity. Negative values indicate improvement from baseline.

The Health Assessment Questionnaire - Disability Index is a patient-reported questionnaire that measures the degree of difficulty a person has in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and errands and chores) over the past week. Participants assessed their ability to do each task on a scale from 0 (without any difficulty) to 3 (unable to do). Scores were averaged to provide an overall score ranging from 0 to 3, where 0 represents no disability and 3 represents very severe, high-dependency disability. A negative change from baseline in the overall score indicates improvement.

C-reactive protein is a blood test marker for inflammation in the body, and levels rise in response to inflammation. A negative change from baseline in indicates improvement.

The DAS28-CRP is a composite index used to assess rheumatoid arthritis disease activity, calculated based on the tender joint count (out of 28 evaluated joints), swollen joint count (out of 28 evaluated joints), Patient's Global Assessment of Disease Activity (0-100 mm), and high-sensitivity C-reactive protein (hsCRP; in mg/L). Scores on the DAS28-CRP range from 0 to approximately 10, where higher scores indicate more disease activity. A negative change from baseline indicates improvement in disease activity.

The DAS28-ESR is a validated index of rheumatoid arthritis disease activity. Twenty-eight tender joint counts, 28 swollen joint counts, the erythrocyte sedimentation rate (ESR; mm/hour), and the participant's assessment of global disease activity (on a visual analog scale [VAS] from 0 to 100 mm) are included in the DAS28 -ESR score. Scores on the DAS28-ESR range from 0 to 10; higher scores indicate more disease activity.

Morning stiffness severity was assessed by a numeric rating-scale (NRS). Participants rated the severity of morning stiffness during the past week from 0 to 10 with 0 representing "not severe" and 10 "very severe". Negative values indicate improvement from baseline.

The Health Assessment Questionnaire - Disability Index is a patient-reported questionnaire that measures the degree of difficulty a person has in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and errands and chores) over the past week. Participants assessed their ability to do each task on a scale from 0 (without any difficulty) to 3 (unable to do). Scores were averaged to provide an overall score ranging from 0 to 3, where 0 represents no disability and 3 represents very severe, high-dependency disability. The minimal clinically important difference (MCID) in HAQ-DI is defined as change from Baseline ≤ -0.22 for rheumatoid arthritis.

The EULAR Boolean-based definition of remission is as follows: at any time point, a participant must satisfy all of the following: tender joint count ≤1, swollen joint count ≤1, C-reactive protein ≤1 mg/dl and Patient Global Assessment (PGA) ≤1 (on a 0-10 scale).