By: Michael Shuster
The Hatch-Waxman Act, a federal law passed in 1984, was designed to streamline the process for bringing generic drugs to market. Under the law, generic drug manufacturers may file an abbreviated new drug application (ANDA) with the FDA toward approval for generic versions of already-approved drugs.
Such filings are founded on bioequivalence studies instead of clinical studies. In the filings, generic manufactures also must certify that the listed drug is not patented, that the patent has expired or that the patent is invalid or will not be infringed by the generic drug.
As evidenced by two recent decisions by the Eastern District of Texas, dismissing branded drugs’ patents may not prove a simple matter.
In the case of Allergan Inc. v. Sandoz, five generic drug makers sought approval to manufacture and market a generic version of Combigan. The Allergan product combines two approved glaucoma drugs for use in the treatment of glaucoma and ocular tension – an approach that the defendants asserted was obvious in light of the prior art. Based on that reasoning, the defendants contended that Allergan’s four associated patents were invalid or would not be infringed by their products.
On Aug. 22, 2011, U.S. District Judge T. John Ward ruled that the four Allergan patents were valid and that the four defendants in the consolidated case had infringed upon it. (The fifth defendant had settled prior to the trial, admitting that Allergan's patents were valid and that it had infringed.)
Near the end of his 101-page findings of fact and conclusions of law, Ward wrote that "the Court is not persuaded that Defendants have established by clear and convincing evidence that the patents-in-suit are obvious in light of the prior art. The Court finds that there are significant differences between the prior art and the claimed inventions, such that a person of ordinary skill in the art would not have been motivated to create a fixed combination composition of [the two glaucoma drugs in Combigan]."
Ward enjoined four defendants from making or selling the generic drugs until after the last of Allergan's patents in the suit expired. Allergan started developing Combigan in 1998 and won FDA approval for it in 2007. With this ruling, the company’s patent rights will hold through 2022. Had the decision favored the defendants, Allergan would have faced generic competition within three years.
In Pozen Inc. v. Par Pharmaceutical Inc., Pozen sued three generic drug makers that had filed ANDAs supporting the sale of a generic version of its Treximet. Also a combination product, Treximet comprises two approved migraine treatment agents in a single tablet. Pozen holds three patents on the product.
On Aug. 5, 2011, U.S. District Judge Leonard Davis ruled that the defendants infringed at least one of the Pozen patents. He enjoined the defendants in that case from making, using, selling or offering their infringing products in the United States. The ruling ensures Pozen of U.S. exclusivity until February 2025.
Although the Eastern District of Texas is known for patent litigation, it has not heard as many pharmaceutical cases as have the districts of Delaware or New Jersey. The Allergan and Pozen rulings may make Texas a more active venue for Hatch-Waxman case litigation.