AstraZeneca's delayed-release formulation patents for its gastric ulcer drug Prilosec will be the focus of patent infringement litigation after a federal court dismissed as invalid one of the company's "method of treatment" patents.

The Manhattan federal court granted Genpharm's motion for summary judgment dismissing AstraZeneca patent No. 5,599,794 claiming a combination of clarithromycin and omeprazole for the treatment of gastritis and peptic ulcer.

"Every element of the claims of the '794 patent" is "disclosed in...prior art and the patent is invalid," Judge Barbara Jones said in the decision.

However, Jones denied Genpharm's motion to invalidate another patent (5,093,342) that claims the use of omeprazole as an antimicrobial agent "for the treatment of" H. pylori infections.

Genpharm's interpretation of the term "treatment" is "too broad in light of the invention claimed by the patent," the judge said.

Genpharm argued that the term "'treatment' means an antimicrobial effect resulting from the administration of omeprazole to an H. pylori-infected person" while AstraZeneca contended that "treatment" required "that the omeprazole be administered for the purpose of having some antimicrobial effect on H. pylori."

The court ruled that Genpharm did not show that the '342 patent was anticipated by prior art. The judge said that it was not clear whether an abstract of a study by Unge et al. cited by Genpharm as prior art was disseminated or presented at symposia.

"Because the court...cannot say that the Unge article qualifies as anticipating prior art...[Genpharm's] motion for summary judgment of invalidity of the '342 patent is denied," the judge said.

The court also dismissed two AstraZeneca claims in another method of treatment patent (5,629,305) since they were contained in prior art.

However, the court denied Genpharm's motion to dismiss three more claims of the '305 patent. "Because the sequence of administration [of the drug] is an element of [the three claims]...and is not revealed in the prior art, those claims are not anticipated."

The court's decision not to dismiss two of the method of treatment patents completely could delay a final decision in the case.

The case is also expected to be postponed due to issues related to consolidation of the lawsuits under multidistrict jurisdiction. Andrx, Schwarz Pharma and Cheminor are among other companies affected by the consolidation process.

The decision means that the two method of treatment patents may be taken up at trial along with the two delayed-release formulation patents. Andrx said the defendants have not yet filed motions for summary judgment in the case of the formulation patents.

The court also denied Genpharm's motion for summary judgment on AstraZeneca's claim that Genpharm's generic omeprazole will induce infringement of the method of treatment.

Genpharm argued that since its generic omeprazole is not on the market "there can be no claim for inducement of infringement."

Judge Jones noted that "an infringement case brought in response to an ANDA filing is properly directed not to what has happened, but rather to what will happen." While "Astra has presented circumstantial evidence that Genpharm's generic omeprazole will be used to infringe the method of treatment patents....Genpharm has offered little in opposition except simple details," the court said.

"Genpharm has not established on the present record that no reasonable juror could conclude that Genpharm intends to induce its customers to infringe Astra's patents," the court said.

On May 29, the court rejected AstraZeneca's claim that Genpharm and Dr. Reddy's Cheminor subsidiary infringe a patent for active metabolites of omeprazole called sulphenamides (¹ Also see "AstraZeneca Loses One Prilosec Patent: Three Others To Be Decided By Aug." - Pink Sheet, 4 June, 2001.).

The '342 patent expires in 2010 while the '794 and '305 patent expire in 2014. The basic compound patent (4,255,431) expires Oct. 5, following a six-month pediatric exclusivity extension.

Prilosec Summary Judgment Narrows Scope Of Patent Infringement Case

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