Targeting type I interferon in lupus autoimmune haemolytic anaemia: first report with anifrolumab

Objective: Autoimmune haemolytic anaemia (AIHA) occurs in approximately 5-10% of patients with SLE and it is traditionally associated with higher disease activity, increased damage accrual and reduced survival. SLE management recommendations partially address disease-related haematological manifestations without specific indication for AIHA treatment. Indeed, therapeutic approaches are prevalently extrapolated from the haematology field. In the present report, we aimed at describing a case series of patients with SLE and AIHA successfully treated with anifrolumab (ANF). Methods: We described patients with SLE treated by ANF with active AIHA at the drug initiation. Clinical and laboratory data were reported in a standardised electronic form, including laboratory evidence of haemolysis. Overall disease activity was assessed by using the SLE Disease Activity Index 2000 (SLEDAI-2k). We collected patients data at baseline (T0), after 1 month (T1) and every 3 months thereafter. Results: We included seven patients (6F/1M, median age 61 years (IQR 33), median disease duration 48 months (IQR 72)). All the patients had a positive direct Coombs test and laboratory evidence of active haemolysis at ANF starting. During treatment, we observed a progressive increase in haemoglobin (Hb) levels, with a statistically significant difference compared with baseline after 3 months of treatment (p=0.02). In parallel we registered the increase in RBC count, without the need to perform RBC transfusions after ANF starting. Overall disease activity significantly improved during the follow-up, with significant reduction of mean SLEDAI-2k values after 6 months of treatment (p=0.01). Conclusion: In the present case-series study, we provide the first report about the benefit of ANF in the treatment of SLE-related AIHA, a rare but potentially severe manifestation associated with increased morbidity and mortality. In our cohort, ANF treatment was associated with a rapid and sustained increase in Hb levels, evident already at 1 month and progressively improving up to 6 months.