Objective: We performed a single-center retrospective study to determine the different efficacy of
tocilizumab (TCZ) in the early and late stages and in three phenotypic subgroups (monocyclic, polycyclic, and persistent) of systemic
juvenile idiopathic arthritis (sJIA). Methods: Clinical and serological parameters of 77 sJIA patients treated by TCZ were collected from November 1, 2013 to May 1, 2019. Patients were grouped based on the duration group A < 6 months (n = 41) and group B > 6 months (n = 36) and divided into three phenotypes: monocyclic (n = 12), polycyclic (n = 14), and persistent (n = 51) course. Results: At baseline, group A had pronounced ESR,
fever less active
arthritis than group B (p < 0.05). After 12 weeks of
therapy, TCZ alleviated
fever, ESR, CRP, and systemic-onset
juvenile arthritis disease activity score-27 (sJADAS27) in both group A and group B (p>0.05), while the efficacy of TCZ in relieving active
arthritis in group A was better than that in group B (p<0.05). After 1 year of TCZ
therapy, it showed that patients with monocyclic phenotype had the highest clinical response rate (91.7%, odds ratio = 0, 95% CI: 24-24, p = 0.00), followed by the polycyclic (28.6%, odds ratio = 2.1, 95% CI: 10.5-18.8, p = 0.00) and the persistent course (9.8%, odds ratio = 1.2, 95% CI: 9.5-13.8, p = 0.00). Conclusion: TCZ can quickly relieve
fever and
inflammation, especially when patients have less active
arthritis with shorter disease duration. The long-term efficacy of TCZ is related to the phenotypes, among which the monocyclic is the best, and the persistent is the worst.