Anakinra Effective in Systemic JIA, Irrespective of HLA-DRB1 and IL1RN Variants Save

A prospective study of first line use anakinra in systemic juvenile idiopathic arthritis (sJIA) proved to be effective and without potentially allergic lung reactions.

While new ACR and EULAR/PRINTO treatment guidelines for sJIA (Still's disease) promote the early, first-line, use of (IL-1 or IL-6) cytokine inhibitors over methotrexate and glucocorticoids, there has been some concer about recent reports of interstitial lung disease (LD), eosinophilia when patients were treated with cytokine inhibitors and that such reactions may be linked to HLA-DRB1*15:01. This study investigated this potential genetic association as well as genetic variants in IL1RN that may be associated with to poor responses to anakinra.

A total of 65 sJIA patients (median age 7.2 years) were treated with anakinra; with 60 patients receiving anakinra as first-line therapy. All patients had at least 12 months of follow-up, and 60 out of 65 patients reached the 2-year follow-up. Clinically inactive disease (CID) was achieved in 89%, 88%, and 88% of patients  at 6 months, 1 year, and 2 years, respectively.

HLA-DRB1*15:01 was found in 17/65 patients (26%) (comparable with the general population) and no difference (4-6%) was seen in HLA-DRB1*15:01 in those who responded, had lung disease or delayed type drug reactions (or not). Of the three patients with severe drug reactions to biologics, one carried HLA-DRB1*15:01. 

No association was seen between specific IL1RN variants and the response to anakinra. 

Macrophage activation syndrome (MAS) was seen in 20% (13/65) of patients.

These findings support the early use of biologic therapy in patients with new-onset sJIA irrespective of HLA-DRB1 background or IL1RN variants.