Unithroid generics — when can they launch?
Unithroid (LEVOTHYROXINE SODIUM) · Fresenius Kabi · 116 active US patents · 0 expired
Where Unithroid sits in the generic timeline
Mid-term cliff: earliest active US patent for Unithroid expires in 2031 (~5 years). Generic developers typically begin ANDA bioequivalence studies 3-4 years ahead of this date. Paragraph IV filings + Hatch-Waxman 30-month stays may shift the effective entry by another 18-36 months.
Under US Hatch-Waxman, a generic enters via an ANDA (Abbreviated New Drug Application) and may file with one of four Paragraph IV certifications attacking the brand's listed patents. If the brand sues within 45 days, a 30-month FDA approval stay is triggered. First Para IV filer typically gets 180-day market exclusivity.
Patent estate by type — active patents
Method-of-use patents only carve out specific indications; generics can launch with a "skinny label" omitting those uses. Composition-of-matter patents block the molecule itself.
- Formulation — 101 patents
- Method of Use — 15 patents
FDA U-codes carved out by Unithroid patents
Method-of-use patents are listed against specific FDA Patent Use Codes ("U-codes") representing carved-out indications. Generics can launch with a label that omits these uses.
| U-code | Description |
|---|---|
U-3757 | (no description) |
U-3758 | (no description) |
Sample patent estate
Showing 6 of 116 active US patents. View full estate on the Unithroid drug page →
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This patent protects a method for preparing an oral levothyroxine composition with improved storage stability.USPTO title: Method for the preparation of a levothyroxine solution
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This patent protects a lyophilized solid levothyroxine composition that includes levothyroxine sodium and mannitol.USPTO title: Levothyroxine formulations
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This patent protects a lyophilized solid levothyroxine composition that includes levothyroxine sodium and mannitol.USPTO title: Levothyroxine formulations
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This patent protects a lyophilized solid levothyroxine composition that includes levothyroxine sodium and mannitol.USPTO title: Levothyroxine formulations
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This patent protects a lyophilized solid levothyroxine composition that includes levothyroxine sodium and mannitol.USPTO title: Levothyroxine formulations
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This patent protects a lyophilized solid levothyroxine composition that includes levothyroxine sodium and mannitol.USPTO title: Levothyroxine formulations
Sources
- FDA Orange Book — patents listed against Unithroid (NDA filed 2000)
- Unithroid drug profile — full patent estate, indications, clinical trials, pricing
- Fresenius Kabi patent portfolio
- Patent cliff 2031 — every drug losing US exclusivity that year
Patent term extensions (PTR, pediatric exclusivity), Hatch-Waxman 30-month stays, and FDA regulatory exclusivity (NCE/ODE/PED) may shift the effective generic entry date. Not legal advice.
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