Zovirax generics — when can they launch?
Zovirax (ACYCLOVIR) · Ligand Pharms · 3 active US patents · 0 expired
Where Zovirax sits in the generic timeline
Imminent generic cliff: earliest active US patent for Zovirax expires in 2027 (~1 year from today). ANDA filers are likely already preparing Paragraph IV certifications. Expect first-filer 180-day exclusivity competition imminently.
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.
- Method of Use — 3 patents
FDA U-codes carved out by Zovirax 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-1460 | (no description) |
Sample patent estate
Showing 3 of 3 active US patents. View full estate on the Zovirax drug page →
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This patent protects a mucosal bioadhesive slow release carrier for delivering active principles for a duration of longer than 20 hours.USPTO title: Mucosal bioadhesive slow release carrier for delivering active principles
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This patent protects a mucosal bioadhesive slow release carrier for delivering active principles for a duration of longer than 20 hours.USPTO title: Mucosal bioadhesive slow release carrier for delivering active principles
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This patent protects a method of using prolonged release mucoadhesive buccal tablets to treat or prevent orofacial herpes.USPTO title: Mucoadhesive buccal tablets for the treatment of orofacial herpes
Sources
- FDA Orange Book — patents listed against Zovirax (NDA filed 1982)
- Zovirax drug profile — full patent estate, indications, clinical trials, pricing
- Ligand Pharms patent portfolio
- Patent cliff 2027 — 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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