Objective To describe the experience of anifrolumab in Systemic Lupus Erythematosus (SLE) patients that entered the Early Access Program (EAP) between 2022 and 2023 in a Portuguese Single Center Cohort.

Methods Patients who were treated with anifrolumab on the EAP were included. Retrospective patients’ clinical charts review to demographic data, clinical manifestations, serological characteristics, previous infections and treatments, clinical and serological response to anifrolumab, time on anifrolumab, reasons to stop treatment and adverse events.

Results Five female Caucasian patients with SLE were treated with anifrolumab between 2022 and 2023 in our center. Age at SLE diagnosis was in average 21 (min 9; max 35) years old, age at first anifrolumab treatment was 41.6 (min 31; max 55) and disease duration before anifrolumab was 19.2 (min 11; max 32) years. When anifrolumab was started constitutional involvement was present in 4 (80%), chilblains in 3 (60%), mucocutaneous in 2 (40%), musculoskeletal in 2 (40%) and serositis in 2 (40%) patients. All the patients had previously been treated with steroids, hydroxychloroquine, azathioprine, methotrexate, belimumab and rituximab.

Mean duration on anifrolumab was 12.0 (min 4; max 19) months. From the four patients who responded to anifrolumab, the average time to clinical response was 7 weeks (min 4; max 10) and to serological response was 21,25 weeks (min 8; max 42). The average prednisolone dosage at the first anifrolumab infusion was 13 mg/day (min 5; max 30), at the last infusion was 6 mg/day (min 2,5: max 10) and the average decrease in prednisolone was 7mg/day (min 0; max 20mg). All the patients with skin and chilblains responded to anifrolumab. The two patients with serositis either didn’t respond (and stopped treatment before 6 months) or lost efficacy (stopped anifrolumab after 11 months due to secondary failure). Four patients postponed anifrolumab treatment: 3 (60%) due to infection (one with hospital admission) and 1 (20%) due to pregnancy but restarted treatment at 16 weeks of pregnancy to due to severe skin flare.

Conclusions Our experience with anifrolumab was based in patients with long disease duration and severe chronic persistent clinical activity, refractory to multiple both classical and biological immunosupressors. Most of them responded clinically few weeks after having started anifrolumab and the prednisolone dosage was reduced in most of them to less than 7,5mg/day. Although still based in few real-world cases, this data brings hope to have a new drug that is effective in severe refractory SLE patients.