An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. AEs included both SAEs and non-serious AEs. A summary of other non-serious AEs and all SAEs, regardless of causality is located in the 'Reported AE section'.

Safety analysis set included all randomized participants who received at least 1 dose of study drug. In this set, treatment was assigned based upon the treatment actually received regardless of the assigned treatment.

The number of swollen joints was used to assess lupus arthritis activity. Joint swelling was defined as soft tissue swelling that was detectable along the joint margins. 66 joints were examined for swelling. These joints include the temporomandibular (n = 2), sternoclavicular (n =2), acromioclavicular (n = 2), shoulder (n = 2), elbow (n = 2), wrist (n = 2), metacarpophalageal (n= 10), interphalangeal of thumb (n = 2), distal interphalangeal (n = 8), proximal interphalangeal (n =8), knee (n = 2), ankle mortise (n = 2), ankle tarsus (n = 2), metatarsophalangeal (n = 10), interphalangeal of great toe (n = 2), and proximal/distal interphalangeal of the toes (n = 8).

Modified intent-to-treat (mITT) analysis set included all participants who were randomly assigned to a treatment, regardless of which treatment they actually received, excluding observations after treatment failure. Here 'Overall number of participants analyzed' signifies participants evaluable for this outcome measure.

The number of tender joints was used to assess lupus arthritis activity. Joint tenderness was defined as the presence or absence of tenderness and/or pain in a joint at rest with pressure or on passive movement of the joint and joint manipulation. 68 joints were examined for tenderness. These joints include the temporomandibular (n = 2), sternoclavicular (n =2), acromioclavicular (n = 2), shoulder (n = 2), elbow (n = 2), wrist (n = 2), metacarpophalageal (n= 10), interphalangeal of thumb (n = 2), distal interphalangeal (n = 8), proximal interphalangeal (n =8), hip (n = 2), knee (n = 2), ankle mortise (n = 2), ankle tarsus (n = 2), metatarsophalangeal (n = 10), interphalangeal of great toe (n = 2), and proximal/distal interphalangeal of the toes (n = 8).

The mITT analysis set included all participants who were randomly assigned to a treatment, regardless of which treatment they actually received, excluding observations after treatment failure. Here 'Overall number of participants analyzed' signifies participants evaluable for this outcome measure.