Amgen Inc., Plaintiff-Cross v. Hoechst Marion Roussel, Inc. (Now Known as Aventis Pharmaceuticals, Inc.) and Transkaryotic Therapies, Inc.

I join my colleagues’ thorough opinion in all respects save one, albeit significant, exception. Because the claims lack meaningful limitations on the structure of the erythropoietin-producing cells, I cannot *1359agree that the district court should have abstained from inquiring fully whether the claims were suspect under the enablement and written description provisions of 35 U.S.C. § 112, ¶ 1.

As described by the specifications of the patents in suit, Amgen in 1984 cloned and sequenced the DNA encoding human er-ythropoietin (EPO). Amgen then showed that by introducing the cloned EPO DNA (linked…