A Randomized, Placebo-Controlled, Double-Blind, Multicenter Study to Assess the Efficacy and Safety of Branebrutinib Treatment in Subjects With Active Systemic Lupus Erythematosus or Primary Sjögren's Syndrome, or Branebrutinib Treatment Followed by Open-label Abatacept Treatment in Subjects With Active Rheumatoid Arthritis

The purpose of this study is to evaluate the safety and effectiveness of treatment with branebrutinib treatment in participants with active systemic Lupus Erythematosus (SLE) or Primary Sjögren's Syndrome (pSS), or branebrutinib treatment followed by open-label abatacept treatment in study participants with active Rheumatoid Arthritis (RA).