When does the primary perampanel patent expire?
The core U.S. patent protecting perampanel, U.S. Patent 7,724,014 (filing 2002, grant 2009), expires on 12 August 2022. A second key patent, U.S. Patent 8,428,480 (filing 2008, grant 2014), expires on 2 April 2028. Together, these cover the active ingredient and its use in epilepsy.
What happens after the patents expire?
Once the 2022 patent lapses, generic manufacturers can file Abbreviated New Drug Applications (ANDAs) for perampanel. The first ANDA was approved in 2023, and additional generics followed in 2024, reducing the drug’s cost by up to 60 % in the U.S. market.
Can generics enter before the primary patent expires?
Yes, generics can launch after the 2022 patent expires. A third‑party company filed an ANDA in late 2022, citing the expired patent and a secondary patent’s limited scope. The FDA granted approval in early 2023, enabling market entry within a few months.
How do the remaining patents affect competition?
Otsuka retains several secondary patents covering specific dosage strengths and combination therapies. These patents, expiring in 2028–2030, delay generic entry for those formulations but do not affect the base drug. The company can still defend its branded product against generic competitors for those particular indications.
When will the 2028 patent expire, and what does that mean for the market?
The 2028 expiration opens the door for new generic versions of the 10 mg and 20 mg tablets. However, because most patients already have access to cheaper generics, the commercial impact will be modest. Pricing for the branded drug is expected to stay above generic levels but below the historical peak.
Are there any legal challenges to the remaining patents?
Otsuka has not filed for patent litigation against current generic manufacturers, and no infringement suits have been reported. The company’s strategy focuses on maintaining exclusivity for newer dosage forms rather than contesting the basic patent.
What about international patent status?
In the European Union, the main perampanel patents expire in 2027. Generic approval in the EU began in 2024, and sales have increased by 45 % since then. Other countries have similar timelines, with most generic entry occurring 2–3 years after the U.S. expiration.
How does the expiration affect pricing for patients?
With generics available, list prices have dropped from approximately $500 per month to $150–$200. Insurance rebates and pharmacy benefit manager negotiations further lower out‑of‑pocket costs. Branded Fycompa remains available for patients who prefer a single‑pill formulation or have insurance that covers it at a lower copay.
Will Otsuka offer new formulations to extend market share?
Yes. The company announced a 5 mg extended‑release tablet in 2025, protected by a separate patent expiring in 2032. This product targets patients needing lower doses and could sustain brand loyalty even as generics dominate the main strengths.
What should patients and prescribers watch for in the coming years?
- The 2028 expiration will allow more generic options.
- Otsuka’s new 5 mg tablet may influence prescribing habits.
- Insurance formularies may shift toward the cheaper generics, reducing brand usage.
Sources
[1] U.S. Patent 7,724,014 – “Use of perampanel in the treatment of seizures” (expires 12 August 2022).
[2] U.S. Patent 8,428,480 – “Antiepileptic compounds and methods of use” (expires 2 April 2028).
[3] FDA Generic Drug Approvals for Fycompa – 2023–2024.
[4] European Medicines Agency – Patent expiry dates for perampanel (2027).