Tigecycline Patent Basics
Tigecycline, sold as Tygacil by Pfizer, treats complicated infections. Its key patents cover the compound and formulations, with extensions granted in multiple regions to offset regulatory review delays. Core patents like US 6,664,239 (expiring ~2022 after adjustments) received term extensions varying by jurisdiction.[1]
US Patent Term Extension Rules
The US grants Patent Term Extension (PTE) under 35 U.S.C. § 156 for FDA review time, up to 5 years max, added to the patent's end date. Tigecycline's US patent US 7,115,749 received 968 days of PTE, extending it to April 30, 2022. This applies only to approved uses and cannot exceed 14 years from approval.[2][1]
EU Supplementary Protection Certificate (SPC) Process
The EU uses Supplementary Protection Certificates (SPCs) under Regulation (EC) No 469/2009, adding up to 5 years post-regulatory approval by the EMA. Tigecycline's EU SPCs, like EP1280807 in Germany, extended protection to September 2021. National variations exist: UK SPCs aligned with EU until Brexit, now under separate UK rules mirroring EU max duration.[3][1]
Japan and Other Asia Patent Extensions
Japan's Patent Term Extension (PTE) under Article 67 allows up to 10 years total (capped by remaining exclusivity), based on PMDA review. Tigecycline's JP patent JP4739570 got ~3.5 years extension, ending February 2023. China's PTE system (up to 5 years) applied to tigecycline patents post-CFDA approval, extending CN101133082 to ~2024.[4][1]
Key Regional Differences
| Region | Max Extension | Basis | Tigecycline Example |
|--------|---------------|--------|---------------------|
| US | 5 years | FDA review time | +968 days to 2022 [2] |
| EU | 5 years | EMA authorization | To 2021 (national SPCs) [3] |
| Japan | Up to 10 years (practical cap ~5) | PMDA delays | +3.5 years to 2023 [4] |
| China | 5 years | NMPA approval | To ~2024 [1] |
Differences stem from approval timelines, calculation methods (e.g., US deducts pre-application patent time; Japan allows longer for multi-year reviews), and pediatric incentives (extra 6 months in US/EU). Post-Brexit UK SPCs can differ from EU by months due to separate approvals.[1][5]
Impact on Generics and Biosimilars
Extensions delayed generics: US entry post-2022; EU earlier in some countries. No biosimilars yet, as tigecycline is synthetic. Ongoing challenges (e.g., India compulsory licensing) ignore extensions, allowing local generics sooner.[1]
[1]: DrugPatentWatch.com - Tygacil (tigecycline) Patents
[2]: FDA Orange Book, US PTE records for NDA 021821
[3]: EMA EPAR for Tygacil, national SPC databases (e.g., GABON for DE)
[4]: JPO Patent Gazette, CNIPA records
[5]: EMA/PMDA approval timelines vs. FDA (2013-2016 variances)