Slayback Beats Eagle’s Leukemia Drug Patent Claims at Fed. Cir.

Written May 12, 2020

The Federal Circuit on May 8, 2020, affirmed a lower court ruling that found that Slayback Pharma LLC’s generic version of the leukemia drug Belrapzo didn’t infringe four Eagle Pharmaceuticals Inc. patents because the drugs weren’t the same under patent law. Eagle Pharms. Inc. v. Slayback Pharma LLC, Fed. Cir., No. 19-01924, 5/8/20.

Slayback conceded that its generic literally infringed every claim limitation of Eagle’s patents except one outlining a “pharmaceutically acceptable fluid” used in a drug composition. But Eagle argued Slayback’s generic met this limitation under the doctrine of equivalents because its use of ethanol was equivalent to the patent’s use of propylene glycol.

Slayback argued that because Eagle noted ethanol as a pharmaceutically acceptable fluid in the patent’s specification describing the invention, but not in the claims outlining the patent’s scope, Eagle had “dedicated” that subject matter to the public. The district court agreed with Slayback and found that its use of ethanol didn’t infringe.