Cost-Effectiveness of Biosimilars vs Leflunomide in Patients With Rheumatoid Arthritis.

Importance: Among patients with rheumatoid arthritis (RA) who had an inadequate response to methotrexate, a treatment sequence initiated with biosimilar disease-modifying antirheumatic drugs (DMARDs) provides better clinical efficacy compared with conventional synthetic DMARDs recommended by current treatment guidelines; but its cost-effectiveness evidence remains unclear. Objective: To evaluate the cost-effectiveness of the treatment sequence initiated with biosimilar DMARDs after failure with methotrexate vs leflunomide and inform formulary listing decisions. Design, Setting, and Participants: This economic evaluation's cost-effectiveness analysis was performed at a Hong Kong public institution using the Markov disease transition model to simulate the lifetime disease progression and cost for patients with RA, using monetary value in 2022. Scenario and sensitivity analyses were performed to test the internal validity of the modeling conclusion. Participants included patients diagnosed with RA from 2000 to 2021 who were retrieved retrospectively from local electronic medical records to generate model input parameters. Statistical analysis was performed from January 2023 to March 2024. Interventions: The model assesses 3 competing treatment sequences initiated with biosimilar infliximab (CT-P13), biosimilar adalimumab (ABP-501), and leflunomide; all used in combination with methotrexate. Main Outcomes and Measures: Lifetime health care cost and quality-adjusted life-years (QALYs) of the simulated cohort. Results: In total, 25 099 patients with RA were identified (mean [SD] age, 56 [17] years; 19 469 [72.7%] women). In the base-case analysis, the lifetime health care cost and QALYs for the treatment sequence initiated with leflunomide were US $154 632 and 14.82 QALYs, respectively; for biosimilar infliximab, they were US $152 326 and 15.35 QALYs, respectively; and for biosimilar adalimumab, they were US $145 419 and 15.55 QALYs, respectively. Both biosimilar sequences presented lower costs and greater QALYs than the leflunomide sequence. In the deterministic sensitivity analysis, the incremental cost-effectiveness ratio (US$/QALY) comparing biosimilar infliximab sequence vs leflunomide sequence and biosimilar adalimumab sequence vs leflunomide sequence ranged from -15 797 to -8615 and -9088 to 10 238, respectively, all below the predefined willingness-to-pay threshold (US $48 555/QALY gain). In the probabilistic sensitivity analysis, the probability of treatment sequence initiated with leflunomide, biosimilar infliximab, and biosmilar adalimumab being cost-effective out of 10 000 iterations was 0%, 9%, and 91%, respectively. Conclusions and Relevance: In this economic evaluation study, the treatment sequences initiated with biosimilar DMARDs were cost-effective compared with the treatment sequence initiated with leflunomide in managing patients with RA who experienced failure with the initial methotrexate treatment. These results suggest the need to update clinical treatment guidelines for initiating biosimilars immediately after the failure of methotrexate for patients with RA.

Risk of autoimmune diseases following COVID-19 and the potential protective effect from vaccination: a population-based cohort study.

Background: Case reports suggest that SARS-CoV-2 infection could lead to immune dysregulation and trigger autoimmunity while COVID-19 vaccination is effective against severe COVID-19 outcomes. We aim to examine the association between COVID-19 and development of autoimmune diseases (ADs), and the potential protective effect of COVID-19 vaccination on such an association. Methods: A retrospective cohort study was conducted in Hong Kong between 1 April 2020 and 15 November 2022. COVID-19 was confirmed by positive polymerase chain reaction or rapid antigen test. Cox proportional hazard regression with inverse probability of treatment weighting was applied to estimate the risk of incident ADs following COVID-19. COVID-19 vaccinated population was compared against COVID-19 unvaccinated population to examine the protective effect of COVID-19 vaccination on new ADs. Findings: The study included 1,028,721 COVID-19 and 3,168,467 non-COVID individuals. Compared with non-COVID controls, patients with COVID-19 presented an increased risk of developing pernicious anaemia [adjusted Hazard Ratio (aHR): 1.72; 95% Confidence Interval (CI): 1.12-2.64]; spondyloarthritis [aHR: 1.32 (95% CI: 1.03-1.69)]; rheumatoid arthritis [aHR: 1.29 (95% CI: 1.09-1.54)]; other autoimmune arthritis [aHR: 1.43 (95% CI: 1.33-1.54)]; psoriasis [aHR: 1.42 (95% CI: 1.13-1.78)]; pemphigoid [aHR: 2.39 (95% CI: 1.83-3.11)]; Graves' disease [aHR: 1.30 (95% CI: 1.10-1.54)]; anti-phospholipid antibody syndrome [aHR: 2.12 (95% CI: 1.47-3.05)]; immune mediated thrombocytopenia [aHR: 2.1 (95% CI: 1.82-2.43)]; multiple sclerosis [aHR: 2.66 (95% CI: 1.17-6.05)]; vasculitis [aHR: 1.46 (95% CI: 1.04-2.04)]. Among COVID-19 patients, completion of two doses of COVID-19 vaccine shows a decreased risk of pemphigoid, Graves' disease, anti-phospholipid antibody syndrome, immune-mediated thrombocytopenia, systemic lupus erythematosus and other autoimmune arthritis. Interpretation: Our findings suggested that COVID-19 is associated with an increased risk of developing various ADs and the risk could be attenuated by COVID-19 vaccination. Future studies investigating pathology and mechanisms would be valuable to interpreting our findings. Funding: Supported by RGC Collaborative Research Fund (C7154-20GF).

Risk and Factors associated with disease manifestations in systemic lupus erythematosus - lupus nephritis (RIFLE-LN): a ten-year risk prediction strategy derived from a cohort of 1652 patients.

Objectives: Lupus nephritis (LN) remains one of the most severe manifestations in patients with systemic lupus erythematosus (SLE). Onset and overall LN risk among SLE patients remains considerably difficult to predict. Utilizing a territory-wide longitudinal cohort of over 10 years serial follow-up data, we developed and validated a risk stratification strategy to predict LN risk among Chinese SLE patients - Risk and Factors associated with disease manifestations in systemic Lupus Erythematosus - Lupus Nephritis (RIFLE-LN). Methods: Demographic and longitudinal data including autoantibody profiles, clinical manifestations, major organ involvement, LN biopsy results and outcomes were documented. Association analysis was performed to identify factors associated with LN. Regression modelling was used to develop a prediction model for 10-year risk of LN and thereafter validated. Results: A total of 1652 patients were recruited: 1382 patients were assigned for training and validation of the RIFLE-LN model; while 270 were assigned for testing. The median follow-up duration was 21 years. In the training and validation cohort, 845 (61%) of SLE patients developed LN. Cox regression and log rank test showed significant positive association between male sex, age of SLE onset and anti-dsDNA positivity. These factors were thereafter used to develop RIFLE-LN. The algorithm was tested in 270 independent patients and showed good performance (AUC = 0·70). Conclusion: By using male sex, anti-dsDNA positivity, age of SLE onset and SLE duration; RIFLE-LN can predict LN among Chinese SLE patients with good performance. We advocate its potential utility in guiding clinical management and disease monitoring. Further validation studies in independent cohorts are required.