Effect of baricitinib on functional impairment in RA patients with moderate disease activity and an inadequate response to conventional DMARDS

Abstract Background In RA, disease activity correlates with physical function and there is a link between joint damage and functional disability. In many countries, RA patients with inadequate response (IR) to MTX or other conventional DMARDs (cDMARDs) are not eligible for potentially more effective treatments, such as biologic or targeted synthetic DMARDs (tsDMARDs), unless they have high disease activity (HDA). Thus, managing RA patients with persistent moderate disease activity (MDA) despite cDMARD treatment poses a problem. Baricitinib (BARI) is a tsDMARD approved for the treatment of moderate to severe RA in adults. This post-hoc analysis assessed if RA patients with MDA benefit from improved physical function with BARI treatment to the same extent as patients with HDA. Methods Patients analysed were from the modified intention-to-treat populations in the BARI phase 3 studies RA-BEAM (MTX-IR) and RA-BUILD (cDMARD-IR) with moderate to severe disability (HAQ-Disability Index [HAQ-DI] score ≥1), MDA (Simplified Disease Activity Index [SDAI] score 11.1-26.0) or HDA (SDAI score>26.0) and non-missing SDAI data at baseline. All patients fulfilled ACR criteria for RA. Patients from RA-BEAM received BARI 4 mg + MTX once daily (n = 396), adalimumab 40 mg every 2 weeks + MTX (n = 270) or placebo (PBO) + MTX (n = 390); patients from RA-BUILD received BARI 4 mg (n = 189) or 2 mg (n = 186) or PBO (n = 185). Multivariable linear regression (MLR) models were used to estimate mean HAQ-DI scores at baseline and week 24 (W24) for the treatment arms stratified by baseline disease activity (MDA or HDA SDAI). Age, RA duration, BMI, high-sensitivity CRP, baseline SDAI disease activity (MDA/HDA), treatment and treatment-by-baseline SDAI interaction were included as covariates. The MLR model for HAQ-DI at (W24) was further adjusted by baseline HAQ-DI. Results In patients from RA-BEAM with MDA at baseline, the mean adjusted HAQ-DI score at W24 was greater in PBO (1.314) than in BARI 4 mg (0.843) patients (Δ = 0.472; p = 0.001). A similar pattern of improved physical function with BARI was seen in RA-BUILD, but the adjusted mean difference in HAQ-DI score between PBO (1.376) and BARI 4 mg (1.113) was not statistically significant (Δ = 0.263; p = 0.109). In patients with HDA at baseline, the W24 mean adjusted HAQ-DI score was 0.443 points greater (p < 0.001) with PBO (1.387) than with BARI 4 mg (0.944) in RA-BEAM, and 0.257 points greater (p < 0.001) in RA-BUILD. Conclusion MTX-IR and/or cDMARD-IR RA patients with MDA and moderate to severe disability at baseline treated with BARI showed a similar pattern of improvement in physical function vs. PBO-treated patients to that seen in patients with HDA, supporting early use of BARI in MDA patients. As for those with HDA, patients with persistent MDA despite MTX and/or other cDMARD treatment could benefit from access to biologic and tsDMARDs to prevent disability progression. Disclosures B. Kirkham: Consultancies; AbbVie, Eli Lilly, Gilead, Janssen, Novartis, Pfizer. Grants/research support; Eli Lilly, Novartis. E. Nikiphorou: Honoraria; Pfizer, Sanofi, Gilead, Celltrion, Eli Lilly. P. López-Romero: Shareholder/stock ownership; Eli Lilly. Other; Full time employee of Eli Lilly. I. Kouris: Shareholder/stock ownership; Eli Lilly. Other; Full time employee of Eli Lilly. T. Holzkaemper: Shareholder/stock ownership; Eli Lilly. Other; Full time employee of Eli Lilly. L. Zaremba-Pechmann: Other; contractor for Eli Lilly and Company. I. de la Torre: Shareholder/stock ownership; Eli Lilly. Other; Full time employee of Eli Lilly. P.C. Taylor: Consultancies; AbbVie, Biogen, Galapagos, Gilead, GlaxoSmithKline, Janssen, Eli Lilly, Pfizer, Roche, Sanofi, Nordic Pharma, Fresenius, UCB. Grants/research support; Celgene, Galapagos, Janssen, Eli Lilly.