Phase II SLEek trial: ABBV-599 and upadacitinib monotherapy in SLE

Results through 104 weeks from a long-term extension (LTE) study of the phase II SLEek trial (NCT04451772), evaluating the efficacy and safety of ABBV-599 (elsubrutinib and upadacitinib combination) and upadacitinib monotherapy in 127 patients with systemic lupus erythematosus (SLE), were presented by Joan Merrill at the European Alliance of Associations for Rheumatology (EULAR) 2025 Congress, June 11–14, 2025, Barcelona, ES.

Key data: By Week 104, SLE Responder Index (SRI-4) response rates were 85.4%, 82.1%, and 61.3% with ABBV-599, upadacitinib, and placebo to ABBV-599, respectively, accompanied by glucocorticoid reductions to 0.3–0.6 mg. Treatments were well tolerated, with treatment-emergent adverse events (TEAEs) in 75.6%, 66.0%, and 85.7% of patients, respectively, and no cases of venous thromboembolism or major adverse cardiovascular events reported.

Key learning: ABBV-599 or upadacitinib monotherapy reduced disease activity and flares, lowered glucocorticoid use, and demonstrated a favorable safety profile through Week 104 in patients with moderately to severely active SLE.