Eisai Co., Ltd. — Patent Portfolio
2 drugs with active patents · 8 active patents · 0 expired · 2 biologics with BPCIA exclusivity
Verdict Eisai's pharmaceutical portfolio is moderately strong, with a significant cliff year in 2031 and no revenue at risk in the next 5 years.
Portfolio overview Eisai's portfolio consists of 109 drugs, with 8 active US patents and no expired US patents. The average vulnerability score is 60, indicating a moderate level of patent protection. Notably, there are no ironclad patents, and the company has 2 biologics with BPCIA exclusivity.
Cliff calendar In 2031, 1 drug will lose exclusivity, including Dayvigo. This marks a significant cliff year for the company.
Most exposed drugs Dayvigo is the most exposed drug in the portfolio, with an earliest active patent expiry date of 2031-09-20 and an average vulnerability score of 60. Unfortunately, the annual revenue for Dayvigo is not available.
Biologic exclusivity Eisai has 2 biologics in its portfolio, LEQEMBI (BLA761269) and LECANEMAB AUTOINJECTOR (BLA761375). LEQEMBI's BPCIA 12-year reference product exclusivity ends on 2035-01-06, while LECANEMAB AUTOINJECTOR's exclusivity ends on 2037-08-29.
Strategic implications With no revenue at risk in the next 5 years, Eisai has an opportunity to focus on lifecycle management strategies, such as subQ switches, label extensions, and combination filings, to maximize the value of its existing portfolio.
Loss of exclusivity calendar · next 12 years
Drugs facing US patent or BPCIA biologic exclusivity loss per year. Click any year to see the broader cliff calendar for the industry.
Patent estate by drug
LEQEMBI (LECANEMAB-IRMB)
Dayvigo (LEMBOREXANT)
Cliff 2031 · 5y- US8268848 Vuln 68 2031-09-20
- US8268848 Vuln 68 2031-09-20
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US10188652
Vuln 62
2035-10-21
This patent protects compositions and methods for treating insomnia using a specific compound as an orexin receptor antagonist.
Patent classification breakdown · active patents
By US patent type. Method-of-use patents are most vulnerable to design-around; composition-of-matter patents are the strongest protection.
- Method of Use 4 patents
- Formulation 4 patents
Sources
- FDA Orange Book — small-molecule patents listed against approved NDAs.
- FDA Purple Book — biologic BPCIA 12-year reference product exclusivity.
- USPTO Patent Public Search — title, abstract, claim text grounding.
- AI summaries generated by Drug Landscape, grounded in source claim text.
Patent term extensions (PTR, SPC, pediatric exclusivity) may shift effective expiry. Not legal advice.
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