Current Patent Status for Tigecycline
Tigecycline, sold as Tygacil by Pfizer, has core patents that expired in the US by 2021-2022, including composition-of-matter (US 5,952,507, expired 2016) and key formulation patents like US 7,485,724 (expired March 2022).[1][2] No active efforts to extend the original patents exist, as they have lapsed, allowing generic entry.
Pfizer's Post-Expiry Strategies
Pfizer pursued pediatric exclusivity extensions, adding six months to some protections until mid-2022, but these have ended.[2] They also listed method-of-use patents in the FDA's Orange Book for indications like complicated intra-abdominal infections, though these face Paragraph IV challenges from generics like those from Mylan and Sun Pharma, with litigation resolved in Pfizer's favor in some cases by 2023.[1][3]
Evercrisp's New Tigecycline Prodrug Patent
In 2024, Evercrisp Biosciences filed for a patent on EC0516, a water-soluble prodrug of tigecycline designed to improve stability and reduce dosing frequency. US Patent Application 20240370700 covers its composition and use for infections resistant to standard tigecycline.[4] This represents a reformulation effort to create new IP, potentially extending market exclusivity beyond original patents, with Phase 1 trials ongoing as of late 2024.
Generic Challenges and Litigation
Generic makers have filed ANDAs challenging remaining Pfizer patents, triggering Hatch-Waxman suits. Courts upheld some (e.g., US 8,410,069 for specific uses) until 2030+, delaying full generic competition.[1][3] No new divisional or continuation patents from Pfizer appear active on DrugPatentWatch.[2]
When Do Remaining Exclusivities End?