Background/Purpose:

Systemic JIA (sJIA) in usual
practice is commonly treated with several agents, including glucocorticoids
(GC), methotrexate (MTX) and biologic agents, most commonly IL1 or IL6
inhibitors, which may be given alone or in combination with GC. The most
effective treatment for new onset sJIA is not known.  The Childhood Arthritis and Rheumatology
Research Alliance (CARRA) developed standardized consensus treatment plans
(CTPs) for new onset sJIA to study the comparative
effectiveness of these treatments using an observational registry. A pilot
study was conducted to assess the feasibility of using the CTPs for this
purpose.

Methods:

New onset untreated sJIA patients
(pts) enrolled in the CARRA Registry at one of 15 pilot sites were treated
according to the CTP selected by the treating physician (GC alone; MTX ±
GC; IL1 inhibitor (IL1i) ± GC; IL6 inhibitor (IL6i) ± GC).
Deviations from the chosen CTP could occur for inadequate response at any time.
If GC was started, the CTPs suggested an aggressive taper (<50% of the
starting dose by 3 months). Data were collected at standard intervals consistent
with usual practice and the primary outcome of clinically inactive disease (CID)
and successful cessation of GC was assessed at the 9 month visit. The CTPs were
compared using chi square, Fisher’s exact, and Wilcoxon rank sum tests.  

Results:

30 patients were enrolled and completed the study (Table). There
were not major differences between patients in each CTP, but patients treated
with GC CTP alone tended to be older, non-white, have oligoarthritis,
and be more likely to have very high ferritin levels. 83% of the MTX CTP
treated patients had physicians who reported that they always select this
treatment, as did 42% of the patients in the IL1i CTP. The study outcome was
achieved by 37% of patients overall. No patients in the GC or MTX CTP achieved
the study outcome, while 42% and 60% in the IL1i and IL6i CTPs did,
respectively. There were 2 serious adverse events; both were infections that
occurred while receiving IL1i. There were 2 episodes of macrophage activation
syndrome: 1 each in IL1i and IL6i CTPs. All patients recovered.

Conclusion:

The CARRA sJIA CTP pilot study was
successfully completed. The patients enrolled appeared reasonably balanced at
baseline. The study outcome was achieved by 37% of patients treated with a
biologic, and by none treated with GC alone or MTX.  Having demonstrated feasibility of the CTPs,
additional patients will be enrolled as part of a larger comparative
effectiveness study to determine the most appropriate treatment strategy for
new onset SJIA.

Table: sJIA Patients Enrolled in CTP Pilot Study and their
Outcomes