Weight management claimants jumped 42% while all therapies grew just 2.9%
One product accounted for 6.6 percent of all drug spending in Canada's largest non-profit drug plan book in 2025, and it grew 47.7 percent year over year.
Semaglutide, sold as Ozempic, Rybelsus and Wegovy, topped the list of drug products by cost in the 2026 GreenShield Drug Trends Report, drawn from 38.7 million claims adjudicated in 2025.
Total drug costs reached $3bn, a nine percent increase and the slowest growth rate since 2022.
Claimants numbered 2.8 million, and total cost per claimant rose to $1,062 from $1,003.
Weight management claimants increased 42 percent, against 2.9 percent claimant growth across all therapies.
The category's share of total drug costs rose to 3.2 percent from 2.0 percent in 2024, with Wegovy alone accounting for 2.7 percent.
Prevalence peaked at 2.2 percent among claimants aged 45 to 54, and the fastest growth came from claimants 65 and over at 51.8 percent.
Mark Rolnick, executive vice president, head of provider solutions at GreenShield, said in the organization's release announcing the report that more people are living with chronic conditions such as diabetes and obesity and "the conversation must move beyond treatment alone."
The top 15 percent of claimants represented 74.4 percent of total adjudicated drug costs, the report states, with 54.2 percent tied to the top five percent and 29.6 percent to the top one percent.
Average annual cost among the top five percent was $11,509, roughly 22 times the $513 average for the remaining 95 percent.
Of the top five percent of claimants in 2025, 51.6 percent also ranked in the top five percent in both 2023 and 2024.
Mental health comorbidity was present in 42.5 percent of them, and diabetes medications were their second-highest cost category at 10.2 percent.
Claimants in the $5,001 to $20,000 annual cost range drove nearly 73 percent of the cost increase between 2021 and 2025 while making up 2.8 percent of the claimant population.
Within non-specialty drugs, the $4,000 to $4,999 band grew 125.2 percent in 2025 against a compound annual rate of 34.2 percent from 2020 to 2024.
Weight management made up 84.0 percent of that band's cost and contributed more than 100 percent of its total increase.
Generic products made up 70.2 percent of all claims in 2025, up from 68.4 percent and passing 70 percent for the first time.
Public plans in Canada have reached 73 percent generic utilization, the report states, citing the Patented Medicine Prices Review Board's CompassRx ninth edition, while US generic utilization has passed 90 percent.
Biosimilar total drug cost reached $158m, up nearly $19m, and biosimilars grew to 16 percent of specialty expenditure from three percent in 2021.
Biosimilar share of claims hit 87.7 percent for adalimumab and 38.5 percent for ustekinumab, the latter up 36.7 points in a single year.
Plan sponsors weighing biosimilar substitution strategies saw rheumatoid arthritis, Crohn's, colitis and psoriasis spend grow 9.6 percent against 11.6 percent across all specialty products, which the report attributes to biosimilar pressure.
Fewer than 0.2 percent of claimants across the four older biologic molecules switched from a biosimilar back to the originator.
ADHD spend fell 10.4 percent even as ADHD claimants rose 14.2 percent, with generic uptake in the category climbing to 61 percent from 36 percent.
Anxiety and depression cost growth slowed to 0.8 percent.
According to the report's generics pipeline, Ozempic and Rybelsus reached the end of their exclusivity periods in 2026, with Wegovy's generic entry expected in 2027.
Nine cancer drugs including Jakavi, Imbruvica and Xtandi carry 2026 expiries.
Specialty drugs accounted for $850.8m, or 28.8 percent of total drug cost, across more than 40,000 claimants representing 1.5 percent of the population.
Products costing over $100,000 a year made up 10.5 percent of specialty cost, up from 8.8 percent in 2021, with Trikafta at $122,399 per claimant driving 73 percent of the $100,000 to $249,999 band.
Eli Lilly's orforglipron and Novo Nordisk's CagriSema are under Health Canada review, and the GLP-1 pipeline facing Canadian drug plans includes retatrutide, survodutide, MariTide and petrelintide in development.
More than one million people in Canada lack access to prescription drug coverage.
