Generic entry timeline

Zulresso generics — when can they launch?

Zulresso (BREXANOLONE) · Sage Therap · 8 active US patents · 0 expired

Earliest patent expiry

2029-03-13

3 years remaining

Full patent estate to

2037-03-08

complete protection through 2037

FDA approval

2019

Sage Therap

Where Zulresso sits in the generic timeline

Imminent generic cliff: earliest active US patent for Zulresso expires in 2029 (~3 years 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.

Formulation — 6 patents
Method of Use — 2 patents

FDA U-codes carved out by Zulresso 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-2552`	(no description)

Sample patent estate

Showing 6 of 8 active US patents. View full estate on the Zulresso drug page →

US8410077 Formulation · expires 2029-03-13

This patent protects compositions of sulfoalkyl ether cyclodextrin and methods for making and using them.

USPTO title: Sulfoalkyl ether cyclodextrin compositions
US9200088 Formulation · expires 2029-03-13

This patent protects compositions of sulfoalkyl ether cyclodextrin and methods for making and using them.

USPTO title: Sulfoalkyl ether cyclodextrin compositions
US9750822 Formulation · expires 2029-03-13

This patent protects compositions of sulfoalkyl ether cyclodextrin and methods for making and using them.

USPTO title: Sulfoalkyl ether cyclodextrin compositions
US10117951 Formulation · expires 2029-03-13

This patent protects compositions of sulfoalkyl ether cyclodextrin and methods for making and using them.

USPTO title: Sulfoalkyl ether cyclodextrin compositions
US7635773 Formulation · expires 2029-03-13

This patent protects compositions of sulfoalkyl ether cyclodextrin with low levels of phosphate and specific absorption properties.

USPTO title: Sulfoalkyl ether cyclodextrin compositions
US10322139 Formulation · expires 2033-01-23

This patent protects formulations of neuroactive steroids, such as allopregnanolone, and methods of using them to treat central nervous system disorders.

USPTO title: Neuroactive steroid formulations and methods of treating CNS disorders

Sources

FDA Orange Book — patents listed against Zulresso (NDA filed 2019)
Zulresso drug profile — full patent estate, indications, clinical trials, pricing
Sage Therap 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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