The filing of patents claiming new crystalline forms, usually 4−6 years after the original product patent, is a typical strategy applied by such companies to extend patent protection. This patent protection approach by big pharma forces generic bulk producers to discover and file patents on new polymorphs if they want to market the drug after expiry of the product patents.
Polymorphism is of paramount importance due to its effect on some physical characteristics of powders such as melting point, flowability, vapour pressure, bulk density, chemical reactivity, apparent solubility and dissolution rate, and optical and electrical properties. In other words, polymorphism can affect drug stability, manipulation, and bioavailability
The patent strategy adopted by Fujisawa to protect the life cycle of Cefdinir (1) was based on the filing of a second patent, several years after the product patent, covering the commercialised anhydrous crystalline form of the drug. As a consequence, to overcome the Cefdinir (1) patent protection of the U.S. and Japanese markets, generic bulk producers had to discover a new crystalline form, with the same bioavailability as the marketed one.
The situation, with competition among several companies, resulted in the generation of a patent “tangle”. In addition to overcoming the Fujisawa patent, the principal aim of generic bulk producers was to generate a competitive market advantage by protecting their new crystal form.
This patent extended the protection of Cefdinir (1) marketed in the United States up to December 2011, 9 years after the expiration of the patent covering the structure........Abbott US2005/0059818
Astellas Pharma Inc. (アステラス製薬株式会社 Asuterasu Seiyaku Kabushiki-gaisha?) is a Japanese pharmaceutical company, formed on 1 April 2005 from the merger of Yamanouchi Pharmaceutical Co., Ltd. (山之内製薬株式会社 Yamanouchi Seiyaku Kabushiki-gaisha?) and Fujisawa Pharmaceutical Co., Ltd. (藤沢薬品工業株式会社 Fujisawa Yakuhin Kōgyō Kabushiki-gaisha?).
Polymorphisms and Patent, Market, and Legal Battles: Cefdinir Case Study
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