Structural Similarity of Molecule in the Prior Art Did Not Lead to Obviousness for Anti-Diabetes Drug

Case: Takeda Chem. Indus., Ltd. v. Alphapharm Pty., Ltd., No. 06-1329 (Fed. Cir. 6/28/07)

The One Sentence Summary: An anti-diabetes drug patent was not obvious even though it was structurally similar to a molecule in the prior art.


What They Were Fighting About: Defendant argued that a patented anti-diabetes compound was obvious because it was similar in structure to a compound in the prior art.

Federal Circuit Holdings:

• The district court did not err in finding that there was no reason for a researcher to pick the prior art compound relied upon by defendant as a lead compound for structural changes. The prior art taught away from the proposed lead compound because it associated it with negative side effects. Thus, it was not "obvious to try" homologation and ring walking under the Supreme Court's recent obviousness analysis in KSR.
  
• Ring walking and homologation were not obvious techniques at the time of the patent.
• Prosecution histories of prior art are considered accessible to the public and part of the knowledge of one of skill in the art, but the district court gave proper weight to it.