The antitumour necrosis factor (TNF) alfa biological infliximab offers immense value in treating CD, a fluctuating chronic illness which greatly affects quality of life. However, due to the high cost of such biologicals, concerns have been raised over the sustainability of providing such expensive treatments [2].

Lower-cost biosimilar infliximab may address affordability concerns in the treatment of adults with CD, however, evidence regarding the cost-effectiveness of switching from reference to biosimilar is needed. Therefore, Hughes et al. carried out a study to assess the incremental cost of switching from treatment with reference infliximab to biosimilar infliximab compared with maintaining reference infliximab in adults with CD per quality-adjusted life year (QALY) gained.

The authors used data from the NOR-SWITCH study, and other published trials, to carry out a cost-utility analysis from the perspective of the Canadian publicly funded healthcare payer.

NOR-SWITCH was a randomized controlled trial that compared reference infliximab to biosimilar infliximab in CD, ulcerative colitis, spondylarthritis, rheumatoid arthritis, psoriatic arthritis and chronic plaque psoriasis. The study was designed to generate safety and efficacy data to reassure physicians that the biosimilar version is just as good and that could facilitate greater switching of patients who are already receiving the originator product, Johnson & Johnson’s and Merck’s rheumatoid arthritis blockbuster Remicade (infliximab) [3]. Approximately half of the patients were switched to the infliximab biosimilar, Remsima (CT-P13), and the findings showed that efficacy and safety were comparable between this group and those who remained on the originator [4]. Disease worsening was the primary outcome and occurred in 26% of the group maintained on reference infliximab and 30% of the group switched from reference to biosimilar.

Hughes et al. constructed a probabilistic cohort Markov model with 8-week cycle lengths to estimate the incremental costs and effects of switching over a 5-year time horizon from a public payer perspective. Base-case clinical inputs were obtained from NOR-SWITCH subgroup analyses and other published trials. Costs were obtained from Canadian sources. A total of 10,000 simulations were run. Sensitivity analysis was used to test the robustness of the results to variations in uncertain parameters.

The results of the analysis of a one-time switch from reference to biosimilar showed that switching to biosimilar infliximab was less costly but also less effective with incremental savings of CA$46,194 (95% confidence interval [CI]: CA$42,420, CA$50,455) and a loss in QALYs of −0.13 (95% CI: −0.16, −0.07). A total of 83% of the simulations demonstrated incremental cost savings and an incremental loss of effectiveness. The model was sensitive to differences in rates of disease worsening between reference and biosimilar infliximab.

A loss of efficacy has also been reported in other studies, and has shown that in switchers, 276 patients (18%) stopped treatment with the etanercept biosimilar, Benepali, during follow-up, mainly due to loss of efficacy (54%) or adverse event (28%) [5]. This effect, however, has been blamed on the fact that a mandatory switch is probably not the most efficient strategy for the wide diffusion of biosimilars reinforcing the evidence of the necessity of a shared physician–patient decision [6].

Hughes et al. concluded from their study that, ‘while biosimilar infliximab is associated with incremental savings for patients on maintenance therapy who are switched from reference infliximab, funding decision makers must decide whether a small loss of effectiveness is justified’. They added that ‘further evidence will help to inform reimbursement policy’.

Conflict of interest
The authors of the research paper [1] declared that there was no conflict of interest.

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References
1. Hughes A, Marshall JK, Moretti ME, Ungar WJ. A cost-utility analysis of switching from reference to biosimilar infliximab compared to maintaining reference infliximab in adult patients with Crohn’s disease. J Canad Assoc Gastroenterol. gwz045: https://doi.org/10.1093/jcag/gwz045
2. GaBI Online - Generics and Biosimilars Initiative. How to make biological drugs more affordable [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2020 Jun 12]. Available from: www.gabionline.net/Biosimilars/Research/How-to-make-biological-drugs-more-affordable
3. GaBI Online - Generics and Biosimilars Initiative. Norwegian study hopes to increase biosimilars uptake in Europe [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2020 Jun 12]. Available from: www.gabionline.net/Biosimilars/General/Norwegian-study-hopes-to-increase-biosimilars-uptake-in-Europe
4. GaBI Online - Generics and Biosimilars Initiative. NOR-SWITCH study finds biosimilar infliximab not inferior to originator [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2020 Jun 12]. Available from: www.gabionline.net/Biosimilars/Research/NOR-SWITCH-study-finds-biosimilar-infliximab-not-inferior-to-originator
5. GaBI Online - Generics and Biosimilars Initiative. Danish etanercept switching study investigates withdrawal rates [cited 2020 Jun 12]. Available from: www.gabionline.net/Biosimilars/Research/Danish-etanercept-switching-study-investigates-withdrawal-rates
6. GaBI Online - Generics and Biosimilars Initiative. Biosimilars - to switch or not to switch [www.gabionline.net]. Mol, Belgium: Pro Pharma Communications International; [cited 2020 Jun 12]. Available from: www.gabionline.net/Biosimilars/Research/Biosimilars-to-switch-or-not-to-switch

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