Mixed results with baricitinib in biological-resistant adult-onset Still's disease and undifferentiated systemic autoinflammatory disease.

This clinical case series describes our experience with the use of Janus kinase 1/2 inhibitor baricitinib in two patients suffering from refractory adult-onset Still's disease (AOSD) as well as in one case suffering from AOSD-like autoinflammatory disease in the context of myelodysplastic syndrome. All patients suffered from disease non-responsive to conventional Disease-modifying antirheumatic drugs (DMARDs) as well as biological therapies including interleukin (IL)-1 and IL-6 blockade, relying instead on high daily doses of prednisolone. We also report the first case of Pneumocystis jirovecii infection following baricitinib use. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.