EFFICACY OF PROLONGED MAINTENANCE MONOTHERAPY WITH RITUXIMAB IN PATIENTS WITH PRIMARY SJOGREN'S SYNDROME: THREE-YEAR FOLLOW-UP

Background There are currently no effective systemic therapies of primary Sjogren’s syndrome (pSS); however, open label series have suggested that rituximab may be beneficial for systemic and glandular manifestations. Objectives To estimate clinical efficacy and safety of prolonged maintenance B-cell targeted monotherapy for pSS. Methods 25 with pSS ACR-EULAR criteria, 2016 were included in this research. Indications for treatment were significant immunological activity (high titres of rheumatoid factor (RF) and anti-nuclear antibodies) and/or hypergammaglobulinemia in 20 patients, parotid enlargement (lymphoma was excluded) – 5, arthritis – 3, lymphadenopathy – 3, severe keratoconjunctivitis sicca in 7, of them corneal ulceration – 3, leukopenia – 4 patients. Patients were treated initially with 2 infusions of rituximab (1000 mg) given once every two weeks with premedication (methylprednisolone (250 mg) and chloropyramine). Then all patients received maintenance therapy with rituximab 500 mg every 6 months. Duration of treatment and follow-up was at least 3 years. Median follow-up was 45 months (36–90). Patients were evaluated, using immunologic, subjective parameters, salivary/lacrimal function at baseline and in 24 weeks and then every year during the follow-up. Patients were not concomitantly treated with another immunosuppressant agent or glucocorticoids daily. Results All patients were women with a mean age at diagnosis of 49 years [29–70] and median duration of disease was 6 years (1–20). The average cumulative dose of rituximab was 10000 mg (7000–12000 mg). The median European Sjogren’s Syndrome disease activity index (ESSDAI) decreased from 2.5 (2–3) to 0 (0–1) (p=0.01) by the end of the study. The increase in salivation and lacrimation according to Schirmer test and tear film break-up time was insufficient, however, in all patients the size of the salivary glands normalised and the recurrent parotitis stopped. Furthermore, 7 patients with severe keratoconjunctivitis sicca improved the course of the disease. The healing of corneal ulceration in all patients was observed one year after the initiation of therapy. A significant decrease in the RF level (from 198 IU/ml (51–442) to 71 IU/ml,30–73 p=0,002) and gammaglobulins (from 28%±5% to 19,3%±3,5%, p=0,001) was observed one year after this study beginning. Unreliable decrease of immunoglobulins was noted in 23% of patients by the end of the follow-up, that did not increase the risk of secondary infections. We observed good tolerability of therapy, only 4 patients had mild infusion reactions. Conclusions Rituximab therapy is highly effective, well tolerated and helps to avoid long-term use of glucocorticoids/cytotoxic agents in pSS. Disclosure of Interest None declared