Posted On: December 20, 2007 by Karen E. Keller

"Extended Release Formulation" and other terms defined in ANDA case

Recently, in the Wyeth v. Impax Laboratories, Inc. case, Judge Farnan construed three separate claim terms: (1) "extended release formulation"; (2) "diminished incidences of nausea and emesis"; and (3) "a method for eliminating the troughs and peaks of drug concentration in a patient's blood plasma." C.A. No. 06-222-JJF, Memo. Op. (D. Del. Dec. 13, 2007). The opinion itself was a straightforward application of the Phillips v. AWH Corp. case whereby the Court looked to the claims, the specification and the prosecution history and did not turn to any extrinsic evidence to aid in its construction. Id. at 3-4.

One interesting section of the opinion was in the construction of the terms "extended release formulation." The plaintiff, Wyeth, was seeking to apply a general definition using the words' ordinary meaning. The defendant, Impax, wanted to import specific ingredients that were listed in the specification as a requirement for it to be an "extended release formulation." Id. at 5-6. The Court found that in light of the patent and the specification the list of ingredients should not be included in the definition of the terms, particularly where in certain dependent claims that were not at issue, the language of the claims did in fact include a list of specific inactive ingredients. Where there was a particular limitation in a dependent claim there arises a presumption that the limitation should not be present in the independent claim. Id. at 6 (citing Phillips v. AWH Corp.).

As a side note - these parties had previously been involved in litigation in another district over the same patents. During that litigation a Markman ruling was issued on two of the same terms that were currently at issue in the new litigation. The earlier Markman ruling had been vacated by the judge in that case when the case settled before trial, however, the defendant directed the District of Delaware court to the approach taken by the earlier court in construing the terms. There is no mention in the opinion of how much weight, if any, this Court gave to the prior Markman ruling since it only needed to rely on the intrinsic record to decide the construction.