Zofran generics — when can they launch?
Zofran (ondansetron) · GSK (originally Glaxo) · 4 active US patents · 0 expired
Where Zofran sits in the generic timeline
Mid-term cliff: earliest active US patent for Zofran expires in 2029 (~4 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 — 4 patents
Sample patent estate
Showing 4 of 4 active US patents. View full estate on the Zofran drug page →
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This patent protects orally disintegrating film dosage forms for delivering active pharmaceutical agents, such as Zofran.USPTO title: Non-mucoadhesive film dosage forms
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This patent protects orally disintegrating film dosage forms for delivering active pharmaceutical agents, such as Zofran.USPTO title: Non-mucoadhesive film dosage forms
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This patent protects a method for stabilizing amine-containing active pharmaceutical agents in oral film compositions.USPTO title: Stabilized amine-containing actives in oral film compositions
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This patent protects a method for stabilizing amine-containing active pharmaceutical agents in oral film compositions.USPTO title: Stabilized amine-containing actives in oral film compositions
Sources
- FDA Orange Book — patents listed against Zofran (NDA filed 1991)
- Zofran drug profile — full patent estate, indications, clinical trials, pricing
- GSK (originally Glaxo) patent portfolio
- Patent cliff 2029 — 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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