Holding
In Cephalon, Inc. v. Slayback Pharma Ltd. Liab. Co., the Federal Circuit summarily affirmed under Rule 36 the district court's decision that all asserted claims of the asserted patents are not invalid, and that Defendants infringed and induced infringement. Cephalon, Inc. v. Slayback Pharma Ltd. Liab. Co., 456 F. Supp. 3d 594 (D. Del. April 27, 2020), aff'd, 856 Fed. App'x. 309 (Fed. Cir. Aug. 13, 2021), reh'g denied (Fed. Cir. Oct. 15, 2021).1
Background
Teva Pharmaceuticals Int'l GmbH, Cephalon, and Eagle Pharmaceuticals sued Apotex, Fresenius Kabi USA, Mylan Labs., and Slayback Pharma under the Hatch-Waxman Act, 35 U.S.C. ' 271(e)(2)(A). Defendants had filed Abbreviated New Drug Applications ('ANDAs') to market generic versions of Bendeka'. Bendeka''s active ingredient is bendamustine hydrochloride (referred to by the parties as bendamustine). The patents at issue were U.S. Patent Nos. 9,265,831 ('the '831 patent'), 9,572,797 ('the '797 patent'), 9,144,568 ('the '568 patent'), 9,597,399 ('the '399 patent'), and 9,572,887 ('the '887 patent').
Defendants unsuccessfully argued that the asserted claims were invalid for obviousness, indefiniteness, lack of enablement, and lack of written description.
District Court Decision
Formulation Claims Not Shown to Have Been Obvious
The asserted formulation claims (claims 2, 3, and 5 of the '831 patent; claims 9 and 11 of the '797 patent) teach a non-aqueous liquid composition that contains:
- bendamustine (or a pharmaceutically acceptable salt thereof);
- about 5% to about 10% by volume of the solvent propylene glycol (PG);
- the solvent polyethylene glycol (PEG);
- one of the following ratios of PEG to PG: about 95:5, about 90:10, about 85:15, about 80:20, and about 75:25; and
- a stabilizing amount of an antioxidant.
Two claims also specify components and quantities: (1) claim 11 of the '797 patent requires that 'the antioxidant is thioglycerol or monothioglycerol,'2and (2) claim 5 of the '831 patent requires that 'the bendamustine concentration is from about 25 mg/mL to about 50 mg/mL.' Certain claims of the '831 and '797 patents also recite stability limitations such as 'less than or equal to 0.11% PG esters at about 1 month of storage at about 5'C.'
Although the district court agreed that 'a POSITA would have had reason to try to develop a non-aqueous liquid bendamustine formulation,' the district court was not persuaded that 'a POSITA would have used in that formulation the PEG and PG solvents, PEG:PG ratios, antioxidant, concentrations of bendamustine, or PG ester stability limitations recited in the asserted claims.' Id. at 605−06. In fact, the court found...
