Cephalon, Inc. v. Slayback Pharma Ltd.

Case Name: Cephalon, Inc. v. Slayback Pharma Ltd., No. 17-1154-CFC, 2020 WL 1983730 (D. Del. April 27, 2020) (Connolly, J.) 

Drug Product and Patent(s)-in-Suit: Bendeka® (bendamustine hydrochloride); U.S. Patents 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”)

Nature of the Case and Issue(s) Presented: Bendeka is indicated for the treatment of chronic lymphocytic leukemia (CLL) and indolent B-cell non-Hodgkin lymphoma (NHL). Prior to trial, Defendants stipulated to infringement. The sole issue at trial concerned the validity of the claims of the patents-in-suit, which the court upheld.

Why Cephalon Prevailed: The court found that the formulation patents were not obvious. The asserted claims in those patents recited a non-aqueous liquid composition that contained: (i) bendamustine (or a pharmaceutically acceptable salt thereof); (ii) about 5% to about 10% by volume of the solvent propylene glycol (PG); (iii) the solvent polyethylene glycol (PEG); (iv) 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 (v) a stabilizing amount of an antioxidant. Defendants demonstrated that a POSITA was motivated to develop a non-aqueous liquid bendamustine formulation, but they could not establish that a POSITA would have: (i) used PEG and PG solvents; (ii) achieved the PEG:PG ratios; (iii) picked an antioxidant; (iv) implemented the claimed concentrations of bendamustine; (v) or achieved the PG ester stability limitations recited in the asserted claims. The court found that although the evidence of commercial success did not support a finding of non-obviousness, defendants had not shown by clear and convincing evidence that the prior art would have motivated a POSITA to reach the claimed formulations.

The court also found that the method-of-treatment patents were not obvious. The administration claims recited methods of treating CLL or NHL with a liquid bendamustine composition. The court explained that the prior art would have motivated a POSITA to reach the claimed formulation, dose, and dosing schedule, but that a POSITA would not have been motivated to reach the claimed administration times, volumes, and concentrations. The court further provided that plaintiffs’ secondary indicia of non-obviousness—commercial success, long-felt need, skepticism, and praise—did not support a finding of non-obviousness, but nevertheless found that the prior art would not have motivated a POSITA to arrive at the claimed administrations with a reasonable expectation of success.