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Abstract Background Safety remains a significant concern for biologic drugs, and studies are needed to ensure a comparable safety profile for biosimilars and their legacy treatments. Using Canadian administrative health data from 2015–2019, we compared the incidence of serious infection between biosimilars and bio-originators initiators for etanercept and infliximab, two of the most commonly used biologics during this time. Methods We performed a retrospective cohort study using pan-Canadian data (except Quebec) from the National Prescription Drug Utilization Information System linked to hospitalization data. We studied new users of infliximab or etanercept (January/2015-December/2019) and compared incidence rates of serious infection, defined as those which required hospitalization, by using Cox regression models adjusted by biological sex, age at treatment initiation, prior corticosteroid or biologic, province, and calendar year. Results We studied 6,583 etanercept users (mean age 62) and 7,202 infliximab users (mean age 45). Hospitalization with infections occurred in 7% of infliximab and 2% of etanercept users. Comparing the risk of infection between biosimilar to bio-originator, the adjusted hazard ratio (95% confidence interval) was 1.33 (0.77, 2.30) for etanercept and 0.93 (0.72, 1.18) for infliximab. Conclusions Our study found no clear difference between etanercept and infliximab biosimilars and their bio-originators for infection incidence, suggesting a similar safety profile.

Abstract Background Long-term clinical registries are essential tools to evaluate new therapies in a patient population that differs from those in randomized clinical trials. The objectives are to describe the profile of rheumatoid arthritis (RA) patients treated with anti-TNF agents in Canadian routine care. Methods RA patients eligible for treatment with Infliximab (IFX), golimumab (GLM) or intravenous golimumab (GLM-IV) as per their respective Canadian product monographs were enrolled into the BioTRAC registry between 2002 and 2017. Study visits occurred at baseline and every 6 months thereafter. Effectiveness was assessed by changes in disease activity. Safety was evaluated by the incidence of adverse events (AEs) and drug survival. Results Of the 890 IFX-, 530 GLM- and 157 GLM-IV-treated patients, the proportion of females ranged from 77.0–86.6%, the mean ages from 55.8–57.7 and the mean disease duration from 6.5–8.6 years. A significant decrease in baseline disease duration and disease activity parameters (DAS, TJC, SJC, HAQ, AM stiffness, MDGA, PtGA, CRP, ESR) was observed over time. Treatment with IFX, GLM- and GLM-IV significantly improved all disease parameters over time. The incidence of AEs was 105, 113 and 82.6 /100 PYs and the incidence of SAEs was 11.7, 11.2 and 4.68 /100 PYs for IFX, GLM- and GLM-IV-treated patients, respectively. Conclusion Differences in baseline characteristics between patients treated with an anti-TNFs over time shows the evolution of treatment modalities over time. All treatments significantly reduced disease activity and improved functionality in a similar fashion. The incidence of adverse events was consistent with the safety profiles of IFX and GLM. Trial registration ClinicalTrials.gov Identifier: NCT00741793 (Retrospectively registered on August 26, 2008).

Abstract Background Treatment persistence is an important consideration when selecting a therapy for chronic conditions such as rheumatoid arthritis (RA). We assessed the long-term persistence of abatacept or a tumor necrosis factor inhibitor (TNFi) following (1) inadequate response to a conventional synthetic disease-modifying antirheumatic drug (first-line biologic agent) and (2) inadequate response to a first biologic DMARD (second-line biologic agent). Methods Data were extracted from the Rhumadata® registry for patients with RA prescribed either abatacept or a TNFi (adalimumab, certolizumab, etanercept, golimumab, or infliximab) who met the study selection criteria. The primary outcome was persistence to abatacept and TNFi treatment, as first- or second-line biologics. Secondary outcomes included the proportion of patients discontinuing therapy, reasons for discontinuation, and predictors of discontinuation. Persistence was defined as the time from initiation to discontinuation of biologic therapy. Baseline characteristics were compared using descriptive statistics; cumulative persistence rates were estimated using Kaplan-Meier methods, compared using the log-rank test. Multivariate Cox proportional hazard models were used to compare the persistence between treatments, controlling for baseline covariates. Results Overall, 705 patients met the selection criteria for first-line biologic agent initiation (abatacept, n = 92; TNFi, n = 613) and 317 patients met the criteria for second-line biologic agent initiation (abatacept, n = 105; TNFi, n = 212). There were no clinically significant differences in baseline characteristics between the treatments with either first- or second-line biologics. Persistence was similar between the first-line biologic treatments (p = 0.7406) but significantly higher for abatacept compared with TNFi as a second-line biologic (p = 0.0001). Mean (SD) times on first-line biologic abatacept and TNFi use were 4.53 (0.41) and 5.35 (0.20) years, and 4.80 (0.45) and 2.82 (0.24) years, respectively, as second-line biologic agents. The proportion of patients discontinuing abatacept and TNFi in first-line was 51.1% vs. 59.5% (p = 0.1404), respectively. In second-line, it was 57.1% vs. 74.1% (p = 0.0031). The main reasons for stopping both treatments were inefficacy and adverse events. Conclusions Abatacept and TNFi use demonstrated similar persistence rates at 9 years as a first-line biologic agent. As a second-line biologic agent, abatacept had better persistence rates over a TNFi.