Recent data has shown that once-daily oral 4 mg of baricitinib for patients with systemic lupus erythematosus (SLE) who receive standard background therapy, is associated with significant clinical improvements compared to placebo.
Baricitinib is an oral selective inhibitor of Janus kinase 1 and 2. This agent has been approved for the treatment of rheumatoid arthritis (RA) in over 40 countries in the European Union, the United States, and Japan, and has prompted research in other fields such as systemic lupus erythematosus (SLE). On the first day of EULAR 2018, Dr. Wallace (Cedars-Sinai Medical Center/UCLA, Los Angeles, USA) reported the results from a 24-week global, Phase 2, double-blind, placebo-controlled study of baricitinib in patients with SLE who received standard therapy. A total of 314 patients with positive antinuclear antibodies or anti-double-stranded DNA (dsDNA), clinical Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) ≥4, arthritis or rash were randomised 1:1:1 to placebo (n=105) or baricitinib (2 or 4 mg, n=105 and n=104, respectively) once daily.
The primary endpoint of the study was the resolution of SLEDAI-2K for arthritis or rash at week 24. Of this population, 79% of patients on placebo, 82% on baricitinib 2 mg and 83% on baricitinib 4 mg completed 24 weeks of treatment. At week 24, a significantly greater proportion of patients who received baricitinib 4 mg achieved resolution of SLEDAI-2K arthritis or rash compared to placebo (67% vs 53%, P<0.05) and Systemic Lupus Erythematosus Responder Index 4 (SRI-4) response (64% vs 48%, P<0.05). At week 24, the proportion of patients achieving flare reduction (SELENA-SLEDAI Flare Index), lupus low disease activity state, and tender joint count change from baseline were also significantly improved for baricitinib 4 mg compared to placebo. Researchers did not observe any statistically significant differences between baricitinib 2 mg and placebo in any of the above endpoints.
With regard to the occurrence of adverse events (AEs), AEs leading to treatment discontinuation and serious AEs were higher for both baricitinib dose groups compared to placebo, with both around 10% for baricitinib. No deaths, malignancies, major adverse cardiovascular events, cases of tuberculosis, or serious herpes zoster infections were reported, although there was one SAE (deep vein thrombosis) reported in a Korean patient with known risk factors in the baricitinib 4 mg group. It was concluded that the safety and tolerability profile of baricitinib remained satisfactory as no new events occurred. Dr. Wallace concluded that these interesting findings support further study of baricitinib 4 mg as a potential therapy for patients with SLE (1).
1. Wallace DJ, et al. Baricitinib in systemic lupus erythematosus (SLE): Results from a phase 2, randomized, double-blind, placebo-controlled study. Abstract OP0019. EULAR 2018.