Long-term Safety and Tolerability of Atacicept (Long-term Follow-Up of Participant Who Participated in ADDRESS II)

SLICC/ACR score or damage index evaluates cumulative damage in Systemic Lupus Erythematosus (SLE). These changes may or may not be related to SLE. Most items are scored only if they have been present for at least 6 months. Scores range from 0 to 47 points, with higher scores indicating greater cumulative damage. Baseline was defined as Day 1 of Core study.

BILAG Disease Activity Index evaluates systemic lupus erythematosus (SLE) activity in 8 organ system domains: General, mucocutaneous, neurological, musculoskeletal, cardiorespiratory, vasculitis, renal, and hematologic using a separate alphabetic score (A to E) assigned to each organ system defined as follows. BILAG A: Severe disease activity; BILAG B: moderate disease activity; BILAG C: mild disease; BILAG D: system previously affected but now inactive; BILAG E: system never involved. BILAG evaluated by scoring each of a list of signs and symptoms as: improving (1); same (2); worse (3); new (4); not present (0); not done (ND). The total BILAG score is the sum of the scores of the 8 domains where A=9, B=3, C=1, D=0, and E=0. The total score ranges from 0 to 72 with a higher score indicating greater lupus activity.

SLEDAI-2K is an activity index that measures disease activity and records feature of active lupus as present or not present. SLEDAI-2K uses a weighted checklist to assign a numerical score based on the presence or absence of 24 symptoms. Each symptom present is assigned between 1 and 8 points based on its usual clinical importance, yielding a total score that ranges from 0 points (no symptoms) to 105 points (presence of all defined symptoms). Baseline was defined as core study screening visit.

SRI-50 index was derived from SLEDAI-2K and could capture 50% or better improvement in each descriptor between any 2 visits in systemic lupus erythematosus (SLE) participants when there was incomplete resolution. The new assigned scores for the descriptors of SRI-50 were derived by dividing the score of each SLEDAI-2K descriptor by 2. SLEDAI-2K was an activity index that measured disease activity and records feature of active lupus as present or not present. SLEDAI-2K used a weighted checklist to assign a numerical score based on the presence or absence of 24 symptoms. Each symptom present was assigned between 1 and 8 points based on its usual clinical importance, yielding a total score that ranged from 0 points (no symptoms) to 105 points (presence of all defined symptoms).

The PGA was used to quantify disease activity and was measured using an anchored visual analog scale (VAS). The participant's current disease activity assessed by investigator in the score range of 0 to 3. Where 0=none; 1=mild; 2=moderate; 3=severe. The assessment made relative not to the participant's most severe state, but the most severe state of systemic lupus erythematosus (SLE) per the investigator's assessment. Baseline was defined as core study screening visit.

SRI-4 response was defined as greater than or equal to 4-point reduction in Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) total score, no new British Isles Lupus Assessment Group (BILAG) A and no more than 1 new BILAG B domain score and no worsening (less than 10 percent increase) from baseline Physician's Global Assessment of Disease Activity (PGA). SLEDAI-2K is an activity index that measures disease activity and records feature of active lupus as present or not present. SLEDAI-2K uses a weighted checklist to assign a numerical score based on the presence or absence of 24 symptoms. Each symptom present is assigned between 1 and 8 points based on its usual clinical importance, yielding a total score that ranges from 0 points (no symptoms) to 105 points (presence of all defined symptoms).

The BICLA response was defined as BILAG-2004 improvement (all screening visit BILAG A improving to B/C/D, all screening visit BILAG B to C/D, and less than or equal to (<=1) new BILAG B and no new BILAG A); no deterioration in SLEDAI total score; PGA increase by less than (<) 0 percentage (%) (defined as less then (<)0.3 point increase for the statistical analyses) and no non-permitted medication/treatment. Baseline was defined as core study screening visit.

The 36-Item Short-Form Health Survey (SF-36) is 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) is 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 LupusQoL was a lupus-specific health related QoL (HRQoL) questionnaire consisting of 34 items grouped in 8 domains: physical health, pain, planning, intimate relationships, burden to others, emotional health, body image, and fatigue. Participants indicate their responses on a 5-point Likert response format, where 4 = never, 3 = occasionally, 2 = a good bit of the time, 1 = most of the time, and 0 = all of the time. Summary scores can be calculated for all 8 domains. A LupusQoL score for each domain was reported on a 0 to 100 scale, with greater values indicating better HRQoL. Baseline was defined as Day 1 of core study.

The PGIC is self-rated scale that asks the participant to describe the change in activity limitations, symptoms, emotions, and overall Quality of life (QoL) related to the participant's painful condition on the following scale: 1 (very much improved), 2 (much improved), 3 (minimally improved), 4 (no change), 5 (minimally worse), 6 (much worse) and 7 (very much worse). Number of participants in the PGIC categories of very much improved (1) and much improved (2) are reported.

EQ-5D questionnaire comprised of 5 dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression measured on 3 levels; 1=no problem, 2=moderate problems, 3=extreme problems. This part, called the EQ-5D descriptive system, provides a 5-dimensional description of health status. 5 dimensional 3-level system was converted into single index utility score. Possible values for single index utility score ranged from -0.594 (severe problems in all dimensions) to 1.0 (no problem in all dimensions) on scale where 1 represented best possible health state. Baseline was defined as Day 1 of Core study.

EQ-5D is a participant rated questionnaire to assess health-related QoL in terms of a single index value. The VAS component rates current health state on a scale from 0 millimeters (mm) (worst imaginable health state) to 100 mm (best imaginable health state); higher scores indicate a better health state. Baseline defined as Day 1 of core study.

The FACIT-Fatigue score was calculated according to a 13-item questionnaire that assesses 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.

An Adverse event (AE) was defined as any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease associated with the use of study drug, whether or not considered related to the study drug or worsening of pre-existing medical condition, whether or not related to study drug. Treatment-Emergent adverse events (TEAEs) are defined as events with an onset date on or after the date of first dose of study treatment in the core study and ongoing at LTE study entry, or occurring during LTE study.

The C-SSRS assesses the suicidal behavior and suicidal ideation in participants. Occurrence of suicidal behavior after study entry is defined as having answered "yes" to a least 1 of the 4 suicidal behavior subcategories (actual attempt, interrupted attempt, aborted attempt, and preparatory acts or behavior). Occurrence of suicidal ideation is defined as having answered "yes" to at least 1 of the suicidal ideation sub-categories (1) wish to be dead, (2) nonspecific active suicidal thoughts, (3) active suicidal ideation with any methods (no plan) without intent to act, (4) active suicidal ideation with some intent to act (without specific plan), and (5) active suicidal ideation with specific plan and intent).