PO:35:233 | Tocilizumab is associated with improved relapse-free survival in polymyalgia rheumatica: a multicentre retrospective study

Milena Bond¹, Giovanni Adami², Marianna Tamussin³, Mario Frasca⁴, Sara Zandonella Callegher¹, Marcello Govoni³, Maurizio Rossini², Lorenzo Dagna⁴, Marco Matucci Cerinic⁴, Christian Dejaco¹, Alessandro Tomelleri⁴ | ¹Department of Rheumatology, Brunico Hospital ASAA-SABES, Teaching Hospital of the Paracelsius Medical University Bunico, Italy; ²Rheumatology Unit, University of Verona, Policlinico Borgo Roma Verona, Italy; ³Rheumatology Unit, Department of Medical Sciences, University of Ferrara and Azienda Ospedaliero-Universitaria S. Anna Ferrara, Italy; ⁴Unit of Immunology, Rheumatology, Allergy and Rare Diseases, IRCCS San Raffaele Hospital Milano, Italy

Aim of the study. This study aimed to compare relapse-free survival between patients with polymyalgia rheumatica (PMR) treated with conventional (c) synthetic disease-modifying antirheumatic drugs (DMARDs) and those treated with tocilizumab (TCZ) and to identify baseline clinical predictors of relapse.

Methods. consecutive patients seen from 2015 onwards at three Italian centres with a confirmed clinical diagnosis of PMR, who had received at least one DMARD during their disease course and had a minimum follow-up of 6 months from DMARD initiation, were included. Relapse was defined as the recurrence of PMR symptoms and/or elevated inflammatory markers requiring an increase in glucocorticoid dose or a change in immunosuppressive therapy. A time-to-event (relapse) analysis was performed considering treatment courses as the unit of analysis; each new course was defined by the initiation of a DMARD. Cox proportional hazards models were adjusted for age, sex, initial prednisone dose, prednisone dose at the time of DMARD initiation, number of relapses before DMARD initiation, and C-reactive protein (CRP) level at diagnosis.

Results. We included 409 patients from three Italian tertiary centres; their baseline characteristics are summarized in Table 1. The median follow-up after DMARD initiation was 822 (interquartile range: 502-1167) days. A total of 515 treatment courses were included (431 cDMARDs, 84 TCZ), with 138 and 8 relapses observed, respectively. The most frequent reasons for DMARD initiation were steroid dependency and relapse. In the Cox regression multivariate analysis, TCZ was associated with a 71% reduction of the risk of relapses compared to other DMARDs (aHR 0.29, 95% CI 0.12–0.65, p=0.0017), with a longer relapse-free survival (mean 853 vs. 715 days, long rank p=0.019), as shown in Figure 1. In multivariable analysis, the number of relapses prior to 1st DMARD (aHR 1.50, 95% CI 1.21–1.85) and the prednisone dose at the time of DMARD initiation (aHR 1.07, 95% CI 1.04–1.09) were also independently associated with an increased risk of a subsequent relapse. Sex, age, and CRP levels at diagnosis were not significantly associated with relapse risk.

Conclusions. TCZ was associated with a significantly lower risk of relapse and longer relapse-free survival compared to cDMARDs, supporting its potential role as an effective treatment option in selected patients with PMR.