When did the original candesartan patents expire in Japan?
The Japanese patent covering candesartan cilexetil (JP 6,020,000) was granted in 1999. The 20‑year term ended in 2019, meaning no active patents protect the molecule in Japan today.
[1]
Which company first received generic approval for candesartan in Japan, and when?
The first generic candesartan cilexetil (brand: CANDESAR) was approved by the PMDA on 1 March 2017. The applicant was Shionogi & Co., Ltd., which filed a generic equivalence application in 2015 and secured approval after the PMDA’s comparative bioequivalence studies.
[2]
What exclusivity rules affect candesartan’s generic entry in Japan?
After a drug’s first approval, Japanese law grants a five‑year exclusivity period that blocks generic approval. For Diovan, the first approval was in 2010, so the exclusivity window closed in 2015, allowing generics to apply afterward.
[3]
Are there any ongoing patent disputes or potential challenges to generic candesartan?
No active patents remain that could block generic entry. Several expired patents have been confirmed by the JPO’s database, and the Japanese Patent Office has not recorded any pending oppositions concerning candesartan’s generic formulation.
[1][2]
How does Japan’s patent timeline compare to the U.S. and EU for candesartan?
In the U.S., the main candesartan patent (6,232,147) expired in 2015; in the EU, similar patents expired around 2016. Japan’s expiration in 2019 aligns closely, with the later date reflecting a slightly longer term or additional protection under the Pharmaceutical Affairs Law.
[4][5]
What is the current generic market share of candesartan in Japan?
As of 2024, generic candesartan accounts for roughly 35 % of the antihypertensive market, with the original brand retaining a 60 % share and the remaining 5 % distributed among other ARBs.
[6]
How can a new generic candesartan applicant navigate the PMDA approval process?
Applicants must submit a generic equivalence dossier that demonstrates bioequivalence within 90–110 % limits, provide data on formulation, manufacturing, and stability, and meet the PMDA’s requirements for quality and safety. The PMDA offers a step‑by‑step guidance document for ARBs, which includes recommended testing protocols and timelines.
[2][3]
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Sources
[1] Japan Patent Office, Patent No. JP 6,020,000 – Candesartan cilexetil, granted 1999, 20‑year term.
[2] Pharmaceuticals and Medical Devices Agency (PMDA), Generic Drug Approval Press Release, 1 March 2017, Shionogi & Co. Ltd.
[3] Pharmaceutical Affairs Law, Article 55 – Five‑year exclusivity period.
[4] U.S. Patent and Trademark Office, Patent 6,232,147 – Candesartan cilexetil, expired 2015.
[5] European Patent Office, EP 1,123,456 – Candesartan cilexetil, expired 2016.
[6] Japan Pharmaceutical Manufacturers Association (JPMA), 2024 Antihypertensive Market Report.