Imfinzi (AstraZeneca) is expected to face US biosimilar competition from 2031. AstraZeneca 20-F: US patent protection expected to 2031.
Imfinzi's US exclusivity date is based on company guidance. The date comes from the company's own filings or guidance. Secondary patents, new formulations or litigation can still move it. It is a biologic, so copies are biosimilars. Biosimilars are harder to make and usually erode sales more gradually than generics.
Among past biologics facing biosimilars: Humira's US sales fell to 65% of their 2022 level in its first full year of biosimilars (2023) and 16% two years later; Stelara's US sales fell to 57% of their 2024 level in its first full year of biosimilars (2025). See how past cliffs played out →
Early development Alvotech is developing an Imfinzi biosimilar (AVT34), licensed to Lotus in August 2026. We found no US filing.
| Company (product) | Stage |
|---|---|
| Alvotech (AVT34) | Early development |
Checked September 2026. Sources: Goodwin: Alvotech and Lotus
Imfinzi is 10% of AstraZeneca's 2025 revenue ($6.1B of $58.7B). With Farxiga, Lynparza, Tagrisso, Calquence and Ultomiris, the drugs tracked here add up to 57% of AstraZeneca's revenue losing US exclusivity by 2035.
Bars show each company's tracked drugs as a share of its total 2025 revenue. Imfinzi is highlighted.