BTK and systemic lupus erythematosus: Despite enhanced BTK expression in B cells from patients with systemic lupus erythematosus (SLE) and anti-citrullinated protein antibody+ (ACPA+) but not ACPA– rheumatoid arthritis (RA) (27, 28), evobrutinib only showed mild effects in SLE and RA clinical trials (NCT02975336 and NCT03233230, respectively).