Background Abatacept, a selective co-stimulation modulator of T lymphocytes, could be a new treatment option for primary Sjögren’s syndrome (pSS).

Objectives To assess short-term efficacy and safety of abatacept treatment in early pSS patients.

Methods 15 pSS patients (12 female, 3 male) were included in the open-label ASAP (Active Sjögren Abatacept Pilot) study. All patients met the revised AECG criteria. Disease duration was <5 years. DMARDs or corticosteroids were discontinued at least 1 month before baseline. Patients were biological DMARD naïve. All patients were treated with 8 abatacept infusions (≈10 mg/kg of body weight) administered intravenously on days 1, 15, and 29 and then every 28 days for 5 months. Follow-up was conducted at 4, 12, 24 (on treatment), 36, and 48 weeks (off treatment). Follow-up data up to 24 weeks are available for all patients. Disease activity was assessed with the EULAR Sjögren Syndrome Patient Reported Index (ESSPRI) and Disease Activity Index (ESSDAI). Other objective and laboratory variables included stimulated whole saliva, rheumatoid factor (RF), IgG, and T and B cell counts. Generalized estimating equations were used to analyse parameters over time.

Results Median age and disease duration were 43 years and 11 months. Significant improvements during treatment were found for ESSPRI and ESSDAI (Fig.1). Furthermore, RF levels decreased significantly from 43 kIU/l at baseline to 28 kIU/l at week 24, and IgG levels dropped from 20.2 g/l to 16.5 g/l. Absolute numbers of T- and B-cells decreased slightly (<10%). Stimulated whole saliva remained stable. Abatacept treatment was well tolerated. No deaths, serious adverse events or serious/opportunistic infections were seen.

Conclusions The promising interim results of this first open-label pilot study indicate that abatacept treatment is well tolerated, safe and presents a clinically meaningful improvement of disease activity and laboratory parameters. It is worthwhile to further explore the efficacy and safety of abatacept in future trials.

Acknowledgements Supported by an unrestricted grant and study medication by BMS, France

Disclosure of Interest None Declared