AB0430 EFFECTIVENESS OF RITUXIMAB TREATMENT IN PATIENTS WITH PRIMARY SJÖGREN’S SYNDROME.

BackgroundThe therapeutic management of Sjögren’s Syndrome remains challenging in clinical practice. Randomized clinical trials with rituximab (RTX) fail to submit primary outcomes; nevertheless, some case series show improvement with this treatment.ObjectivesTo evaluate the effectiveness of therapy with RTX in patients with primary Sjögren’s Syndrome (pSS).MethodsA retrospective chart review was conducted among patients with pSS who fulfilled 2002 AECG and 2016 ACR/EULAR criteria and had received RTX in the last 6 years. Patients with Sjögren’s Syndrome associated with other autoimmune diseases were not included. Clinical, serological and radiological variables were analyzed (prior and 6 months after RTX therapy). A descriptive statistical analysis was performed.Results18 patients were analyzed, 72.2% women, with a mean age of 60.9 years (36-83) and a mean duration of disease of 9.7 years (2-28).Reasons for treatment initiation were pulmonary involvement (n=5), renal involvement (n=4), arthritis (n=3), severe ocular/oral dryness (n=3), recurrent mumps (n=2) and autoimmune hepatitis with lymphadenopathy (n=1).Initial regimen was 2 doses of 1 g each administered 15 days apart. In 8 patients the dose was reduced in subsequent cycles to a single dose of 1 g or 500 mg. The mean number of cycles received was 3.2 (1 - 12).In 7 patients its administration persists as maintenance treatment every 6 months. In 5 patients, treatment was suspended because of clinical improvement/stability; in 2 it was stopped due to adverse effects (one for psychosis and the other for infusion reaction).; in 1 patient it was discontinued due to lack of efficacy in dryness; in 1 patient with pulmonary involvement, it was replaced by mycophenolate due to COVID-19 pandemic and clinical stability; in 1 patient it was suspended due to initiation of radiotherapy for epidermoid carcinoma of the scalp and 1 died of large cell neuroendocrine carcinoma.RTX was effective in 5 (100%) patients with pulmonary involvement (clinical, radiological and functional stability and/or improvement); in 4 (100%) patients with renal involvement (clinical and analytical improvement); in 3 (100%) patients with arthritis complete improvement was obtained; in 2 (100%) patients with recurrent mumps relapse was avoided; in 1 (100%) patient with autoimmune hepatitis and lymphadenopathy clinical and radiological improvement was obtained. Of the three patients with dryness: 1 experienced subjective clinical improvement, 1 reported improvement coinciding with the use of therapeutic contact lenses and 1 improved only at the beginning.Subjective improvement in asthenia was observed in 4 patients.Complement levels normalized in 4 of 5 patients with hypocomplementemia as well as in 4 of 4 with increased B2-microglobulin; 3 of 6 patients with hypergammaglobulinemia normalized IgG value. No changes were observed in the four patients who were rheumatoid factor positive.6 of 6 patients receiving corticosteroid treatment, reduced the dose by half and 1 achieved corticoid withdrawal.ConclusionThe observed data suggest that RTX may be useful in selected patients with pSS. Further research is needed to determine its efficacy.References[1]Chen YH, Wang XY, Jin X, Yang Z, Xu J. Rituximab Therapy for Primary Sjögren’s Syndrome. Front Pharmacol. 2021 Sep 2;12:731122[2]Ramos-Casals M, Brito-Zerón P, Bombardieri S, Bootsma H, De Vita S, Dörner T, et al. EULAR recommendations for the management of Sjögren’s syndrome with topical and systemic therapies. Ann Rheum Dis. 2020 Jan;79(1):3-18[3]Mavragani CP, Moutsopoulos HM. Sjögren’s syndrome: Old and new therapeutic targets. J Autoimmun. 2020 Jun;110:102364[4]Mariette X, Criswell LA. Primary Sjögren’s Syndrome. N Engl J Med. 2018 Mar 8;378(10):931-939Disclosure of InterestsNone declared