PO:16:227 | Anifrolumab for Systemic Lupus Erythematosus: Preliminary Safety and Efficacy Findings from the Italian Experience

Paola Bizioli^1|2, Chiara Orlandi^1|2, Claudia Barison^1|2, Cesare Tomasi³, Alessia Caproli¹, Silvia Piantoni^1|2, Simona Signorini⁴, Emirena Garrafa⁴, Cecilia Nalli¹, Micol Frassi¹, Ilaria Cavazzana^1|2, Micaela Fredi^1|2, Franco Franceschini^1|2 | ¹Rheumatology and Clinical Immunology Unit - ERN ReCONNET, ASST Spedali Civili of Brescia, Italy; ²Department of Clinical and Experimental Sciences, University of Brescia, Italy; ³Department of Clinical and Experimental Sciences, University of Brescia, Italy; ⁴Laboratory of Clinical Chemistry, Department of Molecular and Translational Medicine, University of Brescia, Italy

Objectives. Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease. Anifrolumab, a monoclonal antibody targeting the type I interferon receptor, was approved in Italy in March 2023 for refractory or moderately active SLE. Real-world data are limited. This study aimed to evaluate the real-life efficacy and safety of anifrolumab in SLE.

Methods. Patients starting anifrolumab by 30-Apr-2025 were included. Demographics, clinical data, disease activity scores (SLEDAI-2K, SLE-DAS), treatment, and adverse events were collected. Longitudinal data (SLEDAI-2K, SLE-DAS, complement, anti-dsDNA, corticosteroid (CSI) dose, haemoglobin, leukocyte, platelet) were assessed at predefined timepoints: T–3 (screening), T0 (treatment start), T1 (1 month), T2 (3 months), T3 (6 months), T4 (9 months) and T5 (1y ear). Statistical tests included paired t-test and GLM repeated measures.

Results. Twenty-four patients (F:M 5:1; 75% Caucasian) started anifrolumab at a mean age of 40.2 ± 14.5 years, with disease duration of 13.8 ± 12.3 years. Cumulative organ involvement included mucocutaneous (95.8%), articular (79.2%), haematological (54.2%) and renal (20.8%) manifestations. Treatment was mainly initiated for mucocutaneous (91.7%) and joint (58.3%) activity. Five patients (20.8%) were biologic-naïve; the mean number of prior conventional DMARDs was 2.67 ± 1.78. Baseline corticosteroid dose averaged 8.6 ± 7.3 mg/day. Mean SLEDAI-2K and SLE-DAS at T0 were 6.4 ± 2.3 and 7.0 ± 2.2, respectively. Thirteen patients (54.2%) developed infections (n=18), including 9 respiratory (4 pneumonias); 3 patients (12.5%) required hospitalization. No Herpes Zoster was observed; two patients developed labial herpes. There were 13 temporary and 3 permanent discontinuations (12.5%); temporary interruptions were not due to drug related adverse events but to infections or patient-related logistical issues. No specific corelation was observed between pneumonia and ongoing immunosuppressive therapy or CSI dosage. Baseline disease activity and serological markers were assessed in 22/24 patients. Disease activity at T0 was significantly higher than at T-3 (p<0.001), with progressive improvement and stabilization after T2. CLASI-A scores also improved (p=0.023). Complement, haemoglobin and leukocyte remained stable. Platelet counts increased significantly up to T2 (p=0.008), with a non-significant drop at T3. Anti-dsDNA positivity was less frequent at T3 vs T0, suggesting a trend toward seroreversion, though not statistically significant (p=0.063). CSI use declined significantly over time (p=0.009). Discussion In this small real-world cohort, anifrolumab was mainly used for mucocutaneous and articular SLE, showing rapid and significant disease activity reduction, followed by stabilization. CLASI-A improved significantly. CSI use decreased over time, supporting a steroid-sparing effect. Laboratory markers were mostly unchanged, except for a significant rise in platelet counts, with a later drop likely related to sample attrition at later timepoints. Infections were frequent but mostly mild. The main limitation is the small sample size (<30), which limits statistical power and generalizability.