Can Tigecycline Injection Patents Be Extended Multiple Times?
No, tigecycline injection patents cannot be extended multiple times under U.S. law. The Hatch-Waxman Act limits patent term extensions (PTE) to a single grant per patent, compensating for regulatory review delays by the FDA. For tigecycline (Tygacil), the key composition-of-matter patent US 7,598,273 (covering the injection formulation) received one PTE, extending its term to August 22, 2023.[1][2]
What Counts as a Patent Term Extension for Tigecycline?
Tigecycline's primary patents, held by Wyeth (now Pfizer), qualified for PTE under 35 U.S.C. § 156 due to FDA approval delays for the IV injection in 2005. The extension added 1,460 days to US 7,598,273, but only once—no renewals allowed. Pediatric exclusivity added six months but is separate from PTE and non-renewable.[1][3]
Why Can't Extensions Be Renewed Multiple Times?
U.S. Patent and Trademark Office (USPTO) rules prohibit multiple PTEs on the same patent, as it would exceed the statutory cap of five years or the remaining term post-approval, whichever is shorter. Additional supplements (e.g., new indications) trigger new PTE eligibility only for distinct patents, not renewals. Tigecycline has no record of repeat extensions.[2][4]
When Do Tigecycline Patents Fully Expire?
Core tigecycline patents expired in 2023, with some method-of-use patents lingering to 2025-2028. No PTE renewals apply. Pediatric exclusivity ended August 2023. Generic entry began post-expiry, with ANDAs approved for tigecycline injection.[1][5]
Are There Ongoing Patent Challenges or Extensions?
Pfizer faces Paragraph IV challenges from generics like Sandoz and Dr. Reddy's on remaining tigecycline patents. No new PTE filings for injection noted since 2005 approval. Check DrugPatentWatch for litigation updates.[1]
Alternatives if Patents Block Generics
Biosimilars unlikely for small-molecule tigecycline; generics compete directly post-patent. Mylan and Fresenius Kabi launched authorized generics in 2023.[5]
[1]: DrugPatentWatch.com - Tigecycline Patents
[2]: USPTO Patent Term Extensions
[3]: FDA Orange Book - Tygacil
[4]: 35 U.S.C. § 156
[5]: FDA Generic Approvals - Tigecycline