Background/Purpose: To estimate the cost impact of non-medical switching from originator etanercept (ETN) to biosimilar ETN in patients with rheumatoid arthritis (RA) in the UK.

Methods: A cohort-based decision tree model was developed with a 1-year time horizon. The model population included patients with stable RA who responded to originator ETN treatment and had no change in treatment in the prior 6 months. Patients could undergo a non-medical switch to an ETN biosimilar (first switch) and then switch again if required (second switch) after 3-6 months. Data on the proportion of patients switching therapies, baseline healthcare resource use (including visits to rheumatologists, nurses, medical imaging, blood tests, hospitalization and emergency room visits), and impact of switching on resource use was sourced from a survey of 150 rheumatologists from EU5 markets. The average impact of switching (based on mean values for change in resource utilization due to switching) was calculated as per-patient costs, with low- and high-impact scenarios (based on lower and upper values of the 95% confidence intervals for change in resource utilization due to switching) also modelled as sensitivity analyses. Cost data were sourced from published UK sources.

Results: The model assumed that 5000 patients were treated with originator ETN, with 1259 (25.2%) switching to a biosimilar. Of those, 875 (69.5%) switched to SB4 and 384 (30.5%) to GP2015. After 3 months, 26.3% of patients who switched treatments did so again: 8.3% back to originator ETN, 3.8% to the other ETN biosimilar, and 14.2% to another biologic (abatacept [ABA], adalimumab or tocilizumab). Annual per-patient cost of continuous originator ETN treatment (drug and other healthcare costs) was £12,742. Originator ETN was more expensive than SB4 or GP2015 (annual per-patient costs of £9295 vs £8528 and £8365, respectively). Across all 3 impact scenarios, switching was more costly than continuous originator ETN (Figure). All switching treatment chains had higher overall annual per-patient costs than continuous originator ETN treatment. Switching from originator ETN to GP2015 or SB4 resulted in the lowest impact of switching vs. continuous originator ETN (mean [low scenario, high scenario] values of £1120 [£110, £2131] and £1283 [£272, £2293], respectively). The highest impact of switching occurred following a second switch to ABA. Cost impact of the ETN→GP2015→ABA treatment chain vs. continuous originator ETN was £10,189 [£6244, £14,134], and for the ETN→SB4→ABA treatment chain was £10,230 [£6285, £14,174].

Conclusion: Non-medical switching can result in increased costs to the healthcare payer because of increased healthcare resource use following switching.

Non-author disclosure: Lorna Forse – Medical writing support funded by Pfizer.