Judge Leonard Stark recently issued a claim construction opinion in patent infringement litigation related to the active ingredients in the drug Nuedexta and the use of those ingredients to treat neurological disorders. See Avanir Pharmaceuticals, Inc. v. Actavis South Atlantic LLC, C.A. No. 11-704-LPS, slip op. (D. Del. Dec. 3, 2012). Judge Stark construed the following terms of the patents-in-suit:
- “A method for treating pseudobulbar affect or emotional lability”
- “Dextromethorphan in combination with quinidine”
- “A unit dosage formulation for treatment of chronic or intractable pain”
- “A debrisoquin hydroxylase inhibitor”
- “A combined dosage which renders the dextromethorphan therapeutically effective in substantially reducing chronic or intractable pain without causing unacceptable side effects”
In construing the last of these claim terms, Judge Stark rejected the Defendants’ attempt to “limit the term to a numerical range that may appear in the written description or in other claims” when the “claim term is expressed in general descriptive words.” Id. at 9 (citing Conoco, Inc. v. Energy & Envtl. Int’l, L.C., 460 F.3d 1349, 1358 (Fed. Cir. 2006)). This was particularly incorrect because “adopting the Defendants’ proposed dosage of quinidine of between 50 mg/day to 300 mg/day would lead to the improper result of independent claim 18 having narrower claim scope than dependent claim 21, which depends from claim 18.” Id.