Patent Expirations and Market Impact
Sitagliptin (Januvia)
Mechanism of Action: Dipeptidyl peptidase 4 inhibitors Drug class: Small molecules Originator: Merck & Co; Merck Sharp & Dohme Developer: Banyu; Merck & Co; Merck Sharp & Dohme; Ono Pharmaceutical; University of Colorado at Denver; Washington University School of Medicine Indication: Type 2 diabetes mellitus Patent expiry: November 2026
Januvia market revenue over ten years (2015-2024)
Over the past eleven years, Januvia (sitagliptin) has demonstrated a strong and sustained contribution to the global type 2 diabetes market, remaining one of Merck’s key revenue-generating brands for much of the last decade. From the mid-2010s, Januvia’s annual revenues steadily increased, reflecting broad physician adoption, a favourable safety profile, and its established position as a leading DPP-4 inhibitor.
This upward trajectory continued through 2018 and 2019, when Januvia reached peak revenue levels, supported by strong demand in major markets and combination use with metformin (Janumet).
However, a notable dip in revenue occurred in 2020, marking a turning point in the brand’s performance. This decline was primarily driven by intensifying generic competition, pricing pressure, and the gradual shift in prescribing toward newer diabetes drug classes such as GLP-1 receptor agonists and SGLT2 inhibitors.
Despite this dip, Januvia continued to generate substantial revenue in subsequent years, underscoring its enduring role in diabetes management even as the market evolved. Overall, the eleven-year trend highlights Januvia’s long-term commercial strength, followed by a predictable post-peak decline as the product matured and competitive dynamics changed.
“Even as the diabetes market evolved, Januvia continued to generate substantial revenue—reflecting long-term commercial strength followed by a predictable post-peak decline as competition intensified.”
Market revenue of Sitagliptin (2015- 2024)
Fig 7: Market revenue of Sitagliptin
How will the patent expiry of Januvia affect the market?
Although no generic version of Januvia is currently available in the U.S., multiple generic manufacturers have reached settlement agreements with Merck that permit U.S. launches beginning in May 2026. Merck sought to delay generic entry through a salt/polymorph patent extending to 2027. Still, legal challenges have weakened this strategy, meaning the full impact of generic competition may be staggered, with some versions potentially entering the market in 2027–2028.