OP0134 NOVEL INTERFERON GENE EXPRESSION SCORES PREDICT REFRACTORY SEVERE CUTANEOUS DISEASE FOLLOWING RITUXIMAB THERAPY IN SLE

Background:We developed and validated two continuous interferon-stimulated gene (ISG) expression scores (IFN-Score-A and IFN-Score-B) that predict clinical outcomes in SLE. IFN-Score-A includes ISGs typically present in a global interferon signature while IFN-Score-B includes additional ISGs potentially responsive to multiple IFN subtypes [1].We have previously shown that these scores associate with treatment response following rituximab (RTX) therapy within the British Isles Lupus Assessment Group (BILAG) Biologics Register (BILAG-BR), a UK wide study of patients treated with RTX for active SLE following cyclophosphamide and/ or mycophenolate mofetil treatment failure. Specifically, multivariable analysis showed higher baseline IFN-Score-B independently predicted BILAG response at 6 months post treatment [2].We also showed that response of cutaneous lupus to RTX can be poor even when other organs respond well, and that interferons are enriched in the skin of patients with SLE where dysregulated keratinocytes are a source of IFNк [3]. MASTERPLANS is a consortium aimed at identifying therapeutic biomarkers in SLE.Objectives:To investigate how IFN-Score-A and -B associated with skin disease and response to RTX.Methods:Pre-treatment whole blood samples were collected in TEMPUS tubes from subjects undergoing first RTX treatment within BILAG-BR. IFN-Scores were derived using a custom Taqman array as previously described [1]. Clinical response was defined as improvement in BILAG-2004 disease activity, with a maximum of one domain showing persistent BILAG-2004 grade B disease, and no new BILAG grade A or B disease flares at 6 months. The mucocutaneous domain of BILAG was then analysed separately.Results:147 patients were studied, of whom 90 had follow up data available. Baseline BILAG-2004 grade A/B disease activity predominantly affected the mucocutaneous domain in 74/147 (50.3%), musculoskeletal in 61 /147 (41.5%) and renal domain 66/147 (37.4%).At 6 months 59/90 (65.6%) achieved an overall treatment response. Responders showed significantly higher mean IFN-Score-B compared with non-responders (-1.8 vs -2.4, p = 0.04). Among those with active grade A/B BILAG-2004 mucocutaneous disease at baseline, 38/50 (76%) showed improvement within this domain at 6 months. However, among overall non-responders, 7/31 (22.6%) had new or residual BILAG-A mucocutaneous disease at 6 months post RTX, indicating it to be a substantial component of overall treatment failure. In contrast, persistent grade A musculoskeletal disease was seen in 9.7% of non-responders. BILAG-A mucocutaneous disease is characterised by severe manifestations including extensive rashes covering > 18% of body surface area, severe bullous lupus or panniculitis and disabling deep mucosal ulceration. Neither IFN-Score-A nor IFN-Score-B were significantly associated with the severity of mucocutaneous disease at baseline. However, individuals with persistent or new BILAG-A mucocutaneous disease at six months following RTX displayed significantly lower baseline IFN-Score-B than those with improving or residual less severe disease (-3.0 vs -2.1, p = 0.04) after RTX.Conclusion:Low IFN score-B status identified an endotype of severe mucocutaneous SLE which was resistant to RTX therapy in the BILAG-BR cohort. We previously showed that high IFN-score-B independently predicts overall therapeutic response to rituximab. Further work will aim to refine IFN status as overall and organ specific biomarkers in SLE.References:[1] El-Sherbiny et al., Sci. Rep. 2018; 8: 5793.[2] Alase et al., ARD 2019;78:763-764[3] Psarras et al., Nat Commun. 2020; 11: 6149Acknowledgements:We would like to thank the Medical Research Council, National Institute of Health Research, UK for funding the MASTERPLANS projectDisclosure of Interests:Lucy Marie Carter: None declared, Adewonuola Alase: None declared, Zoe Wigston: None declared, Antonios Psarras: None declared, Agata Burska: None declared, Md Yuzaiful Md Yusof: None declared, Elizabeth Hensor: None declared, John Reynolds: None declared, Miriam Wittmann Consultant of: Abbvie, Celgene, Janssen, L’Oreal, Novartis and Pfizer, Ian N. Bruce Speakers bureau: GlaxoSmithKline, UCB Pharma, Consultant of: AstraZeneca, Eli Lilly, GlaxoSmithKline, ILTOO Pharma, MedImmune, Merck Serono, Grant/research support from: Genzyme Sanofi, GlaxoSmithKline, Edward Vital Consultant of: Roche, GSK and AstraZeneca, Grant/research support from: Roche, GSK and AstraZeneca

P169 A validated two-score system for interferon is a predictor of response to rituximab in SLE

Background/Aims We developed two interferon-stimulated gene (ISG) expression scores (IFN-Score-A and IFN-Score-B) that predict clinical outcomes in SLE better than a conventional “interferon signature”. IFN-Score-A includes the ISGs usually present in an interferon signature. IFN-Score-B includes additional ISGs responsive to multiple IFN subtypes and was better at predicting development of SLE among ANA-positive individuals, development of RA among CCP-positive individuals, and subclinical synovitis in SLE. Here, we investigate whether IFN-Score-A and IFN-Score-B predict response to Rituximab (RTX) therapy. The British Isles Lupus Assessment Group Biologics Register (BILAG-BR) is a UK wide study enrolling patients undergoing treatment with RTX for active SLE despite previous treatment with cyclophosphamide or mycophenolate mofetil. MASTERPLANS is a consortium aimed at identifying therapeutic biomarkers in SLE. Methods We studied all BILAG-BR subjects undergoing their first cycle of RTX in whom a pre-treatment RNA sample was available. Disease activity was measured blind to biomarker status, using BILAG-2004. Response was defined as improvement in BILAG-2004 disease activity by at least one grade, with a maximum of one domain showing persistent BILAG-2004 grade B activity, and no new BILAG grade A or B disease flares at 6 months. Whole blood was collected into TEMPUS tubes and RNA extracted for measurement of IFN-Scores using a custom Taqman array as previously described. Multivariable logistic regression was used to test IFN-Scores and key baseline clinical covariates as predictors of response at 6 months. Results 147 patients were recruited, of whom there were 6 month BILAG data in 90. 59/90 (65.6%) were responders. In univariable and multivariable analysis, higher IFN-Score-B expression was significantly associated with clinical response (Table 1). Other characteristics typically associated with more severe SLE (younger age, African ancestry, and autoantibody repertoire) also independently predicted response. Conclusion High expression of interferon scores predicts better response to RTX. The novel IFN score-B was more predictive than a typical interferon signature. Future work will validate this biomarker in a replication cohort and integrate other with data on IFN biomarkers in other contexts. P169 Table 1:Baseline VariableNon respondersRespondersUnivariable OR (95% CI)P valueMultivariable OR (95% CI)P valueInterferon Score-A, median (IQR)-1.75 (-4.7,-1.0)-1.1 (-2.24,-0.1)1.21 (0.98,1.48)0.070.94 (0.58,1.53)0.81Interferon Score-B, median (IQR)-2.4 (-3.2,-1.6)-1.6 (-2.6,-1.11.56 (1.04,2.33)0.033.27 (1.39,7.68)0.007Age years, median (IQR)44 (38,52)38 (30,50)0.97 (0.94,1.00)0.060.92 (0.86,0.97)0.005African ancestry, n/N (%)8/31 (26)4/59 (7)0.21 (0.06,0.76)0.020.005 (0.000,0.22)0.006Numerical BILAG-2004, median (IQR)21 (20,25)18 (13,24)0.91 (0.86,0.93)0.010.80 (0.67,0.94)0.010Count of ANA subtypes, median (IQR)1 (1,3)2 (1,3)1.28 (0.84,1.95)0.252.38 (1.06,5.31)0.034Count of ANA subtypes is sum of positive Ro, La, Sm, RNP & dsDNA by local laboratories. Disclosure L.M. Carter: None. A. Alase: None. Z. Wigston: None. A. Burska: None. A. Psarras: None. Y. Yusof: None. J. Reynolds: None. M. Wittmann: Honoraria; Abbvie, Celgene, Janssen, L’Oreal, Novartis and Pfizer. I. Bruce: Consultancies; AstraZeneca, Eli Lilly, GlaxoSmithKline, ILTOO Pharma, MedImmune, Merck Serono. Member of speakers’ bureau; GlaxoSmithKline, UCB Pharma. Grants/research support; Genzyme Sanofi & GlaxoSmithKline. E.M. Vital: Honoraria; Roche, GSK and AstraZeneca. Grants/research support; Roche, GSK and AstraZeneca.

P175 MASTERPLANS: prediction of response to rituximab in SLE using a validated two-score system for interferon

Background Rituximab is used for resistant SLE, but clinical response varies. We previously validated two interferon-stimulated-gene expression scores (IFN-Score-A and IFN-Score-B) that improved prediction of clinical outcomes in SLE. IFN-Score-A included most reported ISGs and predicted flares and glucocorticoid requirements. IFN-Score-B included ISGs that respond to multiple IFN subtypes and predicted development of SLE in At-Risk individuals. Diagnosis of SLE was associated with both scores, while only IFN-Score-B was elevated in RA. The British Society for Rheumatology Biologics Registry (BILAG-BR) collects samples for RTX-treated patients in the UK. MASTERPLANS ISA consortium to identify predictors of drug response. Methods Patients were recruited if they were starting a first cycle of RTX for active SLE (BILAG A or 2xBILAG B) despite previous cyclophosphamide or mycophenolate mofetil. Disease activity was measured using BILAG-2004. Clinical response was defined as improvement by > =1 grade in active BILAG-2004 systems with no worsening in other systems. Whole blood was collected into TEMPUS tubes and RNA extracted. IFN-Scores were measured using a custom Taqman array as previously described [El Sherbiny et al., 2018]. Multivariate logistic regression was used to test IFN-Scores and baseline clinical covariates as predictors of BILAG response at 6 months. Results Samples were available from 147 patients, of whom 84 had complete baseline and 6-month clinical data available and were included in this analysis. 40/84 (47.6%) patients had BILAG response at 6 months. In univariate and multivariate analysis, high IFN-Score-B expression was significantly associated with clinical response (see Table 1). Conclusion This preliminary analysis suggests that assessment of IFN activity has a role in predicting response to RTX. A novel IFN score (Score B) was more predictive than classic ISGs (Score A). These results add to a body of work showing that IFN-Score-B predicts clinically significant outcomes independently of overall IFN activity. Future work will analyse this biomarker in a larger cohort of patients and integrate with other putative clinical and biological predictors of response. Disclosures A. Alase None. Z. Wigston None. A. Burska None. M. Md Yusof None. J. Reynolds None. M. Wittmann None. I. Bruce None. E.M. Vital None.

Stabilization of circulating thyroglobulin mRNA transcripts in patients treated for differentiated thyroid carcinoma

Background The clinical utility of serum thyroglobulin in the follow-up of patients with differentiated thyroid carcinoma may be compromised by the presence of endogenous antithyroglobulin antibodies. To prevent interference by antithyroglobulin antibodies several groups have developed real-time PCR-based assays for quantification of blood thyroglobulin mRNA levels. For accurate quantification of thyroglobulin mRNA in blood preanalytical factors must be recognized and controlled. In this study, we evaluate the effect of different blood RNA stabilizing systems – the Tempus Blood RNA system and the PAXgene Blood RNA system – and storage time on RNA yield and quality, and thyroglobulin mRNA stability. Methods Blood samples from 11 patients previously treated for differentiated thyroid carcinoma were collected in K2-EDTA, Tempus and PAXgene tubes and maintained at room temperature. RNA was isolated following storage for 0 and 72 h, and RNA yield, integrity and purity was determined. Thyroglobulin, GAPDH and ACTB mRNA levels were quantified by semi-quantitative real-time PCR. Results The RNA yield was significantly higher for blood collected in Tempus tubes compared with PAXgene tubes following storage for 72 h at room temperature ( P = 0.0011). High-quality RNA could be extracted from blood collected in PAXgene and Tempus tubes. Blood collected in K2-EDTA tubes, but not in PAXgene and Tempus tubes, showed significant changes in thyroglobulin mRNA levels following storage for 72 h at room temperature ( P = 0.0263). Conclusions Stabilization of blood in PAXgene and Tempus tubes enables storage at room temperature for up to 72 h, without compromising thyroglobulin mRNA levels.