POS0193 EVALUATION OF CRESS IN THE PHASE 2 RANDOMISED PLACEBO-CONTROLLED STUDY OF SEQUENTIAL BELIMUMAB/RITUXIMAB ADMINISTRATION IN PATIENTS WITH PRIMARY SJÖGREN’S SYNDROME

Background EULAR Sjögren’s syndrome disease activity index (ESSDAI) assesses systemic in patients (pts) with primary (pSS); however, weaknesses include exclusion of patient-reported symptoms, tear and salivary gland function, a marked placebo (PBO) response. Composite Relevant Endpoints for Syndrome (CRESS) is recently developed composite outcome measure validated using data from three Phase 3 randomised controlled trials pts pSS. 1 Concise CRESS (cCRESS) used when ocular staining score ultrasonography are unavailable. ESSDAI was an endpoint 2, PBO-controlled study, evaluating the safety efficacy belimumab (BEL) rituximab (RTX) sequential administration (BEL/RTX), BEL RTX monotherapies Although results numerically favoured BEL/RTX over PBO, this not statistically significant. Objectives To evaluate cCRESS overall responses at Weeks (Wks) 24, 52, 68, individual item Wk 24 pSS who completed 2 study. Methods In double-blind, 68-Wk study ( NCT02631538 ) adults were (2:2:2:1) into 4 treatment arms: (n=24; weekly 200 mg subcutaneous [SC] to followed by PBO SC 52 + 1000 intravenous [IV], 8 10), monotherapy 52), (n=25; IV, or (n=13). Pts classified post hoc as responders ≥3 following 5 items met: 1) Clinical (Clin)ESSDAI <5 (low state); 2) decrease ≥1 point ≥15% baseline (BL) Patient Reported Index (ESSPRI); 3) increase ≥5 mm BL abnormal Schirmer’s test, no change if normal BL; 4) unstimulated whole saliva (UWS) ≥25% BL, any 0 5) rheumatoid factor (RF) titre ≥10% IgG BL. Results Of 86 pts, 60 follow-up 68 (completer population) included analysis. Most female (95%, n=57); mean (SD) age 49.6 (13.0) years. characteristics presented Table 1. Clinical, functional, laboratory parameters Wks (n=8) (n=17) (n=19) (n=16) Pt (SD ClinESSDAI 11.1 (3.76) 11.7 (5.47) 9.2 (3.77) (4.76) ESSPRI 6.4 (2.05) 6.0 (1.97) 6.5 (1.68) 5.9 (2.20) Schirmer, mm/5 min 2.7 (3.25) 5.3 (6.44) 3.3 (3.16) 2.8 (3.15) UWS, ml/min 0.1 (0.11) (0.12) (0.09) (0.14) RF, KU/l 60.8 (42.24) 30.9 (38.20) 37.0 (34.98) 105.0 (200.97) IgG, g/l 20.4 (6.65) 16.7 (5.00) 18.1 (7.19) 16.5 (6.09) responders, n (% (50.0) 9 (52.9) 7 (36.8) (31.3) 10 (58.8) (42.1) (25.0) (12.5) 6 (35.3) (18.8) At proportion higher than either BEL, RTX, but difference significant (Table 1). The contributed relatively equally total response, highest response observed RF/IgG lowest (Schirmer’s test; Figure population Conclusion generally associated rate compared PBO. notable similar ClinESSDAI. greater other arms, perhaps due use instead CRESS. Due small sample size, should be interpreted caution. References [1]Arends S, et al. Lancet Rheumatol 2021;3:553–62 Acknowledgements This analysis GSK Study 201842 funded GlaxoSmithKline (GSK). Medical writing support provided Casmira Brazaitis, PhD, Fishawack Indicia Ltd, UK, part Health, GSK. Disclosure Interests Hendrika Bootsma Consultant of: BSM, Roche, Novartis, Medimmune Union Chimique Belge, Grant/research from: BSM Suzanne Arends: None declared, Liseth de Wolff: Kenneth L Clark Shareholder GSK, Employee Andre van Maurik Prafull Mistry Pragya Shukla Svetlana Nihtyanova Norma Lynn Fox David Roth