Achievement of intermediate treatment targets for Still’s disease under tocilizumab treatment: a post-hoc analysis of the phase III trial

To evaluate the intermediate treatment targets for Still’s disease proposed by EULAR/PReS recently, we conducted this post-hoc analysis of the Phase III trial of tocilizumab and its long-term extension to assess the achievement probability of these targets with tocilizumab. Additionally, we assessed the associations of the intermediate treatment targets with long-term outcomes, including glucocorticoid-free clinically inactive disease (CID) and recurrence. Given the predefined glucocorticoid tapering schedule, we also evaluated the achievement of CID irrespective of glucocorticoid dosage when assessing treatment targets at Months 3 and 6. Twenty-one patients were followed for a median of 39.8 months. The week 4 target was achieved in 57.1%, while 47.6% and 38.1% achieved CID at months 3 and 6, respectively. At the final visit, 57.1% and 28.6% achieved CID and glucocorticoid-free CID, respectively. Achievement of the week 4 target and CID at month 6 was associated with subsequent glucocorticoid-free CID (50% vs. 0%, p = 0.01; 62.5% vs. 7.7%, p = 0.01). Month 6 CID achievers had higher baseline swollen joint counts and lower interferon-γ levels. In conclusion, achievement of intermediate treatment targets was associated with long-term CID, suggesting that these targets may also be useful in treatment with tocilizumab.Clinical Trial Registration UMIN000012987, UMIN000018414