RITUXIMAB IN REFRACTORY SLE: 10 YEARS AFTER

PV275 / #231

Poster Topic: AS24 - SLE-Treatment

Background/Purpose The aim of this cross-sectional study of patients with refractory SLE treated with RTX was to explore for any potential long-term effect(s) of this B cell depletion approach.

Methods We included patients with SLE having had i) received at least 1 cycle of RTX and ii) at least 10yr of follow-up after their first RTX infusion. Response was assessed at 1 year and at their latest evaluation that was ³ 10yr after RTX treatment initiation. In cases where the cSLEDAI-2k was employed, a response was defined as a cSLEDAI-2k of less than 4 in cases were the cSLEDAI-2k was ³ 4. In cases where the cSLEDAI-2k was 2-4 at baseline, a response was defined as a cSLEDAI-2k of 0. For cases of lupus nephritis, a complete response was defined as a proteinuria of < 500 mg/24h and an eGFR 60 ml/min; a partial response was defined as a reduction of the proteinuria of > 50% of baseline values and an eGFR 60 ml/min. In cases of lung involvement, a response was defined as an FVC decline £ 5% predicted values.

Results RTX was administered in 62 patients with SLE treated at the 2 Rheumatology tertiary care centers of southwestern Greece. For this cross-sectional study we enrolled 23 patients (25 cases) with SLE (all Caucasian female, age range: 14 – 72yr, mean: 31yr) with active or relapsing disease, fulfilling inclusion criteria. The median disease duration was 6yr (range: 2mo-27yr) at the time of the first RTX treatment infusion. Clinical manifestations at the time of RTX introduction included lupus nephritis in 8 patients, arthritis in 6, neuropsychiatric involvement in 4, vasculitis in 2, lung involvement in 3 and hematological abnormalities in 3. RTX was also administered in 1 patient with lupus hepatitis and in 1 plasmapheresis-plus-steroid resistant case of thrombotic thrombopenic purpura. RTX treatment was associated with a clinical benefit in 82.14% of our patients after 1yr and in 74.48% after ³10yr. The median cSLEDAI-2K score decreased from 5.83 ± 3.70 at baseline to 1.95 ± 2.40 (p < 0.001) at 1yr and to 2.37 ± 3.00 (p < 0.001) at the ³10yr timepoint of follow-up. Ten out of our 23 patients relapsed. The earliest relapse was seen at 6mo and the latest at 13yr after RTX treatment introduction. Eight relapsed patients were re-treated with RTX and 3/8 re-responded. The mean daily dose of corticosteroids was reduced both at the 1yr and at the ³ 10yr time points; dose reductions were not statistically significant. Regarding safety we report 1 COVID19-related death, viral infections in 2, allergic reactions in 4 and 1 patient with late-onset neutropenia.

Conclusions Our data suggest that RTX may indeed represent an alternative therapeutic option in patients with SLE refractory to standard treatment with an acceptable safety profile and a potential long-term beneficial effect.