AB1329 COMPARATIVE EFFICACY AND SAFETY OF GLUCOCORTICOIDS, METHOTREXATE AND TOCILIZUMAB IN THE TREATMENT OF NEW-ONSET LARGE VESSEL GIANT CELL ARTERITIS
Authors: F. Davanzo, L. Iorio, P. Delvino, E. Fiorin, M. Codirenzi, D. Sorace, C. Campochiaro, S. Nannipieri, L. Dagna, A. Doria, S. Monti, A. Tomelleri, R. Padoan
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Patients with large vessel giant cell arteritis (LV-GCA) often experience disease relapses, determining a prolonged exposure to steroid treatment and a subsequent increased risk of side effects. The question of whether a specific treatment regimen can effectively control large vessel inflammation is still an unmet need. <h3>Objectives:</h3> The aim of the present study was to assess the efficacy and safety of different regimens in achieving clinical or metabolic remission and in preventing damage accrual. <h3>Methods:</h3> Consecutive newly-diagnosed active LV-GCA inpatients and outpatients, classified as GCA, were retrospectively enrolled in three referral centers. Patients received their first treatment, which was either glucocorticoid (GC)-monotherapy, methotrexate (MTX) or tocilizumab (TCZ) based on the physician's decision, according to the standard of care. All the patients underwent to at least 2 consecutive <sup>18</sup>FDG PET-CT or PET-MR scans, not earlier than 6 months of treatment, between January 2009 and November 2023. Before every PET scan, demographic, clinical data and disease activity were assessed. Remission was defined as absence of signs and symptoms attributable to GCA and normalization of erythrocyte sedimentation rate (ESR &lt;30 mm/H) and C-reactive protein (CRP &lt;10 mg/L). For each PET scan the vessel's metabolic activity was evaluated using the Meller's grading and the PETVAS (PET Vasculitis Activity Score). The damage was evaluated using the Large Vessel Vasculitis Index of Damage (LVVID). Safety profile was assessed according to treatment regimens. <h3>Results:</h3> The study included 75 GCA patients who started first line treatment of their GCA as per the standard of care. Overall, 41 patients were treated with GC monotherapy, 25 with MTX, and 9 with TCZ. Demographic, clinical, laboratory and imaging features at baseline were similar except for higher rate of hypercholesterolemia in those receiving GC (p=0.012). Tocilizumab led to better remission rate at last follow-up when compared to the other treatments (GC 64.1 %, MTX 40.9 %, TCZ 100%, p=0.047) and significantly lower levels of ESR and CRP at last follow-up, p=0.020 and p= 0.037, respectively. Significant improvement in PETVAS at last follow-up was observed with all regimens: GC treated 13 [6-21] vs 7 [2-13] (p=0.001), MTX treated 18 [9-21] vs 4 [1-18] (p=0.010), and TCZ treated 18 [15-21] vs 0 [0-2] (p=0.011). PETVAS score at 24 months and at last follow-up was significantly lower (p=0.019 and p=0.015, respectively) in the TCZ cohort compared to the others. Daily prednisone dose at last examination was 5 [0-7.5] mg/d in the MTX group vs 0 [0-0] mg/d in the TCZ group (p=0.016). GC withdrawal rate was significantly higher in TCZ group, compared to the other two (GC 22.5%, MTX 30.4%, TCZ 88.9%, p&lt; p=0.001). At last evaluation LVVID was similar in the three groups (1 [1-3] vs 2 [1-3] vs 3 [1-2], p=0.491). There were no statistically significant differences observed among the three groups in terms of infections (p=0.756). However, a higher frequency of adverse events leading to discontinuation was noted in TCZ-treated patients (p=0.023). <h3>Conclusion:</h3> <sup>18</sup>F-FDG PET may be useful in assessing disease activity and monitoring response to therapy. TCZ therapy led to better remission rate and significantly reduce vessel's metabolic activity over time, when compared to conventional treatment, showing a strong GC sparing effect. None of the three different treatment regimens halted the damage accrual. <h3>REFERENCES:</h3> <b>NIL.</b> <b>Table 1.</b> <h3>Acknowledgements:</h3> <b>NIL.</b> <h3>Disclosure of Interests:</h3> <b>None declared.</b>