Abstract
OBJECTIVE: The aim was to study the effect of non-mandatory transitioning from etanercept originator to etanercept biosimilar on retention rates in a setting promoting shared decision-making. METHODS: In 2016, all patients treated with etanercept originator and stable disease at the Rheumatology department in Bernhoven were offered transitioning to etanercept biosimilar by an opt-in approach. A historical cohort of patients treated with etanercept originator in 2015 was identified as the control group. Etanercept discontinuation was compared between the cohorts using Cox regression. To study the nocebo effect, reasons for discontinuation were categorized into objective reasons (e.g. laboratory abnormalities, increase in swollen joint count, allergic reaction) and subjective health complaints (symptoms perceptible only to the patient, e.g. tiredness, arthralgia). An adjusted Kaplan-Meier curve for retention of the etanercept biosimilar was made, censoring subjective health complaints as the reason for discontinuation. RESULTS: Seventy of the 79 patients eligible for transitioning agreed to transition (89%). The 1-year crude retention rate of etanercept in the transition cohort was 73% (95% CI: 0.62, 0.83), compared with a retention rate of 89% (95% CI: 0.81, 0.95) in the historical cohort (P = 0.013). This resulted in a higher risk of treatment discontinuation in the transition cohort (adjusted hazard ratio = 2.73; 95% CI: 1.23, 6.05, P = 0.01). After adjusting for the nocebo effect, the cohorts had comparable retention rates (86 vs 89%, P = 0.51). CONCLUSION: Non-mandatory transition from etanercept originator to its biosimilar using an opt-in approach in a setting promoting shared decision-making resulted in a higher discontinuation of etanercept compared with the historical cohort. This could be attributed largely to the nocebo effect.