OBJECTIVES: Plaque psoriasis (PsO) biologics can be categorized as old-generation (anti-tumour necrosis factor and anti-interleukin (IL) 12/23 biologics) or new-generation (IL-17 and -23 inhibitors), the latter demonstrating improved efficacy in head-to-head trials. There is also an opportunity cost paid for originator biologics after loss of exclusivity (LoE) given the delayed launches and limited uptake of biosimilars in Canada. The aims of this study were to review the current funding and exclusivity status, comparative evidence, and utilization of PsO biologics, and estimate expenditures on these drugs since LoE in Canada.

METHODS: An environmental scan of public formularies and exclusivity status, an appraisal of network meta-analyses (NMAs), and a utilization analysis were conducted.

RESULTS: NMAs have shown greater efficacy with the new-generation relative to the old-generation molecules. New-generation biologics are also less costly compared to the most utilized old-generation biologic (ustekinumab) on an average per patient basis at list price for new biologic patients. Physicians continue to prescribe old-generation drugs to these patients (25% in 2020); however, coverage criteria can impact prescribing, as jurisdictions with biologic tiering demonstrate more frequent new-generation biologic use. Biosimilars for most old-generation biologics launched several years after their eligibility, and 2 of these drugs (ustekinumab and certolizumab pegol) do not currently have biosimilars in the market. Public payers have spent over $28 million on patients who initiated a biologic beyond its LoE since 2016.

CONCLUSIONS: Decision-makers must continually review the place in therapy of treatments as new evidence emerges, and the value of costly biologics in Canada should be assessed to ensure their appropriate use. Given delayed biosimilars launches in Canada, there is even more rationale to review drugs at or beyond exclusivity, given the expenditures on old-generation originators and impending LoE of the new-generation molecules; some IL-17 biologics will soon lose data protection, which can further increase this opportunity cost.