Inherent Anticipation Invalidates Patent On Compound Formed When Unstable Prior Art Compound Degrades
The same day that the en-banc Federal Circuit vacated a panel decision finding SmithKline Beecham Corp.’s patent on the active ingredient of the popular antidepressant Paxil invalid under the public use doctrine of 35 U.S.C. § 102(b), the panel issued a new opinion on April 8, 2005 invalidating SmithKline Beecham’s patent, but with different reasoning. The Panel’s original opinion had held that SmithKline’s public clinical trials of Paxil did not fall within the “experimental use” exception to 35 U.S.C. § 102(b) since the purpose of the testing was not to reduce the invention to practice. The revised panel opinion, Smithkline Beecham Corp. v. Apotex Corp. Inc. (04/08/05 - No. 03-1285, 03-1313), holds that SmithKline’s patent on the active ingredient of Paxil is invalid under 35 U.S.C. § 102(b) because the active ingredient is inevitably produced when making a related compound claimed in an earlier patent, and thus Paxil’s active ingredient was “inherently anticipated” by the disclosure in the earlier patent of how to make the related compound.
The litigation stems from SmithKline’s attempts to use the patent for Paxil’s active ingredient to block a generic drug manufacturer from producing a competing drug with an active ingredient that is not claimed in the Paxil patent. In the late 1970s a British company invented and patented a new class of compounds that became known as paroxetine. The patent (U.S. Patent No. 4,007,196) claimed paroxetine and its salts and disclosed their antidepressant properties. In 1980, SmithKline licensed the ‘196 Patent from the British company, as well as the technology for producing the crystalline hydrochloride salt of paroxetine, PHC anhydrate. In 1985, a SmithKline chemist discovered a new crystalline form of PHC, PHC hemihydrate, while attempting to produce PHC anhydrate according to the ‘196 patent. SmithKline filed a British patent application in October 1985, and subsequently obtained a United States patent (the ‘723 Patent”) that claimed the new compound. Claim 1 of the application reads, in its entirety, “Crystalline paroxetine hydrochloride hemihydrate”. PHC hemihydrate became the active ingredient in SmithKline’s wildly successful antidepressant Paxil, which SmithKline placed on the market in 1993.
In 1998, an affiliate of the defendant, Apotek, filed an Abbreviated New drug Application (ANDA) with the FDA, seeking approval to market its own PHC antidepressant, and identifying the active ingredient as PHC anhydrate. Apotek’s ANDA indicated Apotek’s intent to market the drug before the expiration of SmithKline’s ‘723 Patent on PHC hemihydrate and stated that it would not infringe the ‘723 Patent. Despite the fact that the ‘723 Patent does not cover Apotek’s active ingredient, PHC anhydrate, SmithKline sued Apotek for infringement of the ‘723 Patent’s claim for PHC hemihydrate.
SmithKline itself presented the evidence that the Federal Circuit used to invalidate SmithKline’s patent. SmithKline’s experts presented evidence to the district court that PHC anhydrate is an unstable compound, and that small quantities of PHC anhydrate originally produced by the method disclosed in the ‘196 patent at some point morphed into PHC hemihydrate. With this new form or polymorph in existence, the general environment became “seeded” with crystals of PHC hemihydrate, and in this seeded environment, PHC anhydrate converts to PHC hemihydrate upon its inevitable contact with seeds of PHC hemihydrate. Thus, according to SmithKline’s experts, creation of pure PHC anhydrate has now become extremely difficult, if not impossible, because of this phenomenon, which they dubbed the “seeding” or “disappearing polymorph” theory. Whenever PHC anhydrate is produced, a small quantity of PHC hemihydrate is also produced, and thus, SmithKline argued, production of PHC anhydrate according to the teachings of the ‘196 patent inevitable results in infringement of SmithKline’s ‘723 patent for PHC hemihydrate. The district court did not make findings of fact regarding precisely how or when PHC hemihydrate first came into existence, and on appeal, Apotek did not dispute that it was unable to prove precisely when PHC hemihydrate came into existence.
Both the majority and the concurring judge on the Federal Circuit panel were troubled by the prospect of SmithKline being able to use its patent on PHC hemihydrate to prevent a competitor from practicing the prior art to create PHC anhydrate, a compound that SmithKline’s patent did not claim. Judge Rader, writing for the panel majority, invalidated SmithKline’s patent on PHC hemihydrate, reasoning that the ‘196 patent for making PHC anhydrate inherently anticipated claim 1 of the ‘723 patent for PHC hemihydrate because of the evidence that producing PHC anhydrate now inevitably results in the production of at least trace amounts of PHC hemihydrate. The majority reiterated prior Federal Circuit authority holding that inherent anticipation does not require a person of ordinary skill in the art to recognize the inherent disclosure in the prior art at the time the prior art is created.
The district court had reasoned that Apotek failed to meet its burden of proving inherent anticipation because Apotek had been unable to prove by clear and convincing evidence that it was impossible to make pure PHC anhydrate in the United States before the critical date of the ‘723 patent. The Federal Circuit rejected the district court’s reasoning as contrary to precedent. Whether it was actually possible to make pure PHC anhydrate before the critical date of the ‘723 patent was irrelevant. Because the ‘196 patent disclosed a method of manufacturing PHC anhydrate that now naturally results in the production of PHC hemihydrate, the ‘196 patent is anticipating prior art that invalidates the ‘723 patent’s claim for PHC hemihydrate.
Judge Gajarsa, concurring in the result, reasoned that Claim 1 of the ‘723 Patent was unpatentable under 35 U.S.C. § 101. He seized on the evidence that PHC anhydrate could, under normal climactic conditions and with no human intervention, bond with water molecules and convert itself into PHC hemihydrate. He reasoned that thus, although PHC hemihydrate is a synthetic compound, created by humans in a laboratory, never before existing in nature, it is nevertheless capable of “reproducing” itself through a natural process and items reproduced by a natural process, whether an inorganic structure or a life form, “must ipso facto be ineligible for patent protection under section 101.” Since the ‘723 Patent claimed PHC hemihydrate, and not “synthetic PHC hemihydrate,” Judge Gajarsa reasoned that it claimed unpatentable subject matter under section 101.
The litigation stems from SmithKline’s attempts to use the patent for Paxil’s active ingredient to block a generic drug manufacturer from producing a competing drug with an active ingredient that is not claimed in the Paxil patent. In the late 1970s a British company invented and patented a new class of compounds that became known as paroxetine. The patent (U.S. Patent No. 4,007,196) claimed paroxetine and its salts and disclosed their antidepressant properties. In 1980, SmithKline licensed the ‘196 Patent from the British company, as well as the technology for producing the crystalline hydrochloride salt of paroxetine, PHC anhydrate. In 1985, a SmithKline chemist discovered a new crystalline form of PHC, PHC hemihydrate, while attempting to produce PHC anhydrate according to the ‘196 patent. SmithKline filed a British patent application in October 1985, and subsequently obtained a United States patent (the ‘723 Patent”) that claimed the new compound. Claim 1 of the application reads, in its entirety, “Crystalline paroxetine hydrochloride hemihydrate”. PHC hemihydrate became the active ingredient in SmithKline’s wildly successful antidepressant Paxil, which SmithKline placed on the market in 1993.
In 1998, an affiliate of the defendant, Apotek, filed an Abbreviated New drug Application (ANDA) with the FDA, seeking approval to market its own PHC antidepressant, and identifying the active ingredient as PHC anhydrate. Apotek’s ANDA indicated Apotek’s intent to market the drug before the expiration of SmithKline’s ‘723 Patent on PHC hemihydrate and stated that it would not infringe the ‘723 Patent. Despite the fact that the ‘723 Patent does not cover Apotek’s active ingredient, PHC anhydrate, SmithKline sued Apotek for infringement of the ‘723 Patent’s claim for PHC hemihydrate.
SmithKline itself presented the evidence that the Federal Circuit used to invalidate SmithKline’s patent. SmithKline’s experts presented evidence to the district court that PHC anhydrate is an unstable compound, and that small quantities of PHC anhydrate originally produced by the method disclosed in the ‘196 patent at some point morphed into PHC hemihydrate. With this new form or polymorph in existence, the general environment became “seeded” with crystals of PHC hemihydrate, and in this seeded environment, PHC anhydrate converts to PHC hemihydrate upon its inevitable contact with seeds of PHC hemihydrate. Thus, according to SmithKline’s experts, creation of pure PHC anhydrate has now become extremely difficult, if not impossible, because of this phenomenon, which they dubbed the “seeding” or “disappearing polymorph” theory. Whenever PHC anhydrate is produced, a small quantity of PHC hemihydrate is also produced, and thus, SmithKline argued, production of PHC anhydrate according to the teachings of the ‘196 patent inevitable results in infringement of SmithKline’s ‘723 patent for PHC hemihydrate. The district court did not make findings of fact regarding precisely how or when PHC hemihydrate first came into existence, and on appeal, Apotek did not dispute that it was unable to prove precisely when PHC hemihydrate came into existence.
Both the majority and the concurring judge on the Federal Circuit panel were troubled by the prospect of SmithKline being able to use its patent on PHC hemihydrate to prevent a competitor from practicing the prior art to create PHC anhydrate, a compound that SmithKline’s patent did not claim. Judge Rader, writing for the panel majority, invalidated SmithKline’s patent on PHC hemihydrate, reasoning that the ‘196 patent for making PHC anhydrate inherently anticipated claim 1 of the ‘723 patent for PHC hemihydrate because of the evidence that producing PHC anhydrate now inevitably results in the production of at least trace amounts of PHC hemihydrate. The majority reiterated prior Federal Circuit authority holding that inherent anticipation does not require a person of ordinary skill in the art to recognize the inherent disclosure in the prior art at the time the prior art is created.
The district court had reasoned that Apotek failed to meet its burden of proving inherent anticipation because Apotek had been unable to prove by clear and convincing evidence that it was impossible to make pure PHC anhydrate in the United States before the critical date of the ‘723 patent. The Federal Circuit rejected the district court’s reasoning as contrary to precedent. Whether it was actually possible to make pure PHC anhydrate before the critical date of the ‘723 patent was irrelevant. Because the ‘196 patent disclosed a method of manufacturing PHC anhydrate that now naturally results in the production of PHC hemihydrate, the ‘196 patent is anticipating prior art that invalidates the ‘723 patent’s claim for PHC hemihydrate.
Judge Gajarsa, concurring in the result, reasoned that Claim 1 of the ‘723 Patent was unpatentable under 35 U.S.C. § 101. He seized on the evidence that PHC anhydrate could, under normal climactic conditions and with no human intervention, bond with water molecules and convert itself into PHC hemihydrate. He reasoned that thus, although PHC hemihydrate is a synthetic compound, created by humans in a laboratory, never before existing in nature, it is nevertheless capable of “reproducing” itself through a natural process and items reproduced by a natural process, whether an inorganic structure or a life form, “must ipso facto be ineligible for patent protection under section 101.” Since the ‘723 Patent claimed PHC hemihydrate, and not “synthetic PHC hemihydrate,” Judge Gajarsa reasoned that it claimed unpatentable subject matter under section 101.
posted by at 4/10/2005 09:40:00 PM
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