Lynparza (AstraZeneca and Merck) is expected to face US generic competition from 2027. Merck 10-K: US basic patent 2027. AstraZeneca and Merck have sued generic filers since 2023. Sales as reported by AstraZeneca; Merck books $1.5B of alliance revenue.
Lynparza'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 small-molecule drug, so copies are generics. Generic launches usually take most of the US volume within months.
Among past small-molecule drugs facing generics: Tecfidera's US sales fell to 21% of their 2019 level in its first full year of generics (2021); Revlimid's US sales fell to 96% of their 2021 level in its first full year of generics (2022) and 57% two years later. Where settlements cap generic volumes, as with Revlimid, the decline is slower. See how past cliffs played out →
Filed with the FDA Four generic makers have filed. None challenges the compound patent, which expires in September 2027, so that is the earliest the FDA can approve them. AstraZeneca and Merck sued over the other patents; a trial is expected in 2026.
| Company (product) | Stage |
|---|---|
| Natco | Generic filed; in litigation |
| Sandoz | Generic filed; in litigation |
| Cipla | Generic filed; in litigation |
| Zydus | Generic filed; in litigation |
Checked September 2026. Sources: Merck 10-K 2025
Lynparza is 5.6% of AstraZeneca's 2025 revenue ($3.3B of $58.7B). With Farxiga, Imfinzi, Tagrisso, Calquence and Ultomiris, the drugs tracked here add up to 57% of AstraZeneca's revenue losing US exclusivity by 2035.
Lynparza is 2.2% of Merck's 2025 revenue ($1.4B of $65.0B). With Keytruda and Gardasil, the drugs tracked here add up to 59% of Merck's revenue losing US exclusivity by 2028.
Bars show each company's tracked drugs as a share of its total 2025 revenue. Lynparza is highlighted.