Takeda Pharma. v. Doll (Fed. Cir. 2009)
For several decades, Hal Wegner has been the shepherd of Takeda's family of Cepham patents claiming priority back to 1974. The question on appeal in this case involves double patenting and whether post-filing developments in the art can be used to inform the question of whether two claims are "patentably distinct." Takeda's evidence that its claims were distinct was generated in this decade, but the PTO argued that double patenting must be determined based on evidence pre-dating the priority application. Takeda could file a terminal disclaimer, but that would destroy the valuable pre-GATT patent term.
Obviousness Type Double Patenting is also known as non-statutory double patenting because ... the theory is not based on any statute. Rather the doctrine is a judicially created mechanism designed to prevent a patentee from unfairly extending the term of patent rights through consecutive patents. To the extent this problem existed, much of it was eliminated in the 1995 changes that linked the patent term with the filing date rather than the issue date. Under the doctrine, separate claims with different patent terms will not both be patentable unless their subject matter is "patentably distinct." Today the double patenting issues may arise most frequently when family-member patent terms differ due to patent term adjustments based on PTO delay during prosecution.
Product and Process: Takeda's case involves a change in claim form. The PTO argued that the company's latter manufacturing process claims are not patentably distinct from its earlier product claims. Generally, a product and its manufacturing process are deemed patentably distinct when “the product as claimed can be made by another materially different process.” MPEP § 806.05. Here, the "materially different process" was not known until well-after the applications were filed.
Holding: In its holding, the Federal Circuit compromised: Evidence of distinctiveness can be post-filing, but must be prior to the filing of the secondary application because that filing "actually triggers the potential of an unjustified extension of patent term." The case is then remanded for a determination of whether Takeda can prove distinctiveness using evidence that predates the second application (which was filed in 1990).
Judge Schall concurred in the judgment of remand, but disagreed with the rule of law that post-filing information should be available to prove distinctiveness. "I believe that tying the inquiry to the invention date is most commensurate with patent law as a whole and the policy goals relating to obviousness-type double patenting." Judge Schall noted that the double patenting doctrine is one of patentability - and thus should be judged based on the date of invention.
Comments: I do not pretend to know the correct rule. However, Judge Rader's decision looks to be incorrect. His judgment was based on the filing date of the second application as being the triggering date for the potential of an unjustified extension of patent term. Of course, the potential having double patenting problems was at least implicitly created in the original filing. If you are looking for an explicit trigger, that might not even be found in the second application as filed since claims are usually amended during prosecution. If selecting a triggering date - I would have chosen the date that the second patent issues. Until that point, there is no double patenting.
Note:
- Judge Moore joined Judge Rader's majority opinion.



