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Yoshihiro Fujikawa et al. v. Sompong Wattanasin

United States Court of Appeals, Federal Circuit
93 F.3d 1559 (1996)
ELI5:

Rule of Law:

In a patent priority dispute, reduction to practice of a pharmaceutical compound can be established through in vitro testing, provided there is a reasonable correlation showing the tests are indicative of a pharmacological response in vivo. A delay between reduction to practice and filing does not constitute suppression or concealment if the inventor engaged in continuous, albeit slow, activity towards filing the patent application.


Facts:

  • In 1984-1985, Sompong Wattanasin, a researcher for Sandoz, synthesized three cholesterol-inhibiting compounds that showed some activity in in vitro tests, but Sandoz then shelved the project for almost two years.
  • In January 1987, Sandoz revived the project, and Wattanasin synthesized four additional compounds.
  • Yoshihiro Fujikawa's effective patent filing date was August 20, 1987.
  • In October 1987, Wattanasin's new compounds showed positive results in in vitro (test tube) tests for cholesterol-inhibiting activity.
  • In December 1987, Sandoz conducted in vivo (live animal) tests on the most promising compounds, which confirmed their cholesterol-inhibiting activity in rats.
  • In January 1988, Sandoz's patent committee approved the invention for filing, and its legal department began collecting data to prepare the patent application.
  • Between May 1988 and March 1989, a patent application was drafted, revised, and ultimately filed for Wattanasin's invention.

Procedural Posture:

  • The U.S. Patent & Trademark Office (USPTO) initiated a three-party interference proceeding between inventors Wattanasin, Fujikawa, and Picard to determine priority for a cholesterol-inhibiting compound.
  • Picard withdrew from the interference, leaving a two-party dispute between Fujikawa (the senior party, with an earlier filing date) and Wattanasin (the junior party).
  • The single interference was divided into two separate proceedings: one for the compound count and one for the method count.
  • During the proceedings, Fujikawa's motion to add a sub-genus count to the interference was denied by the administrative patent judge.
  • The Board of Patent Appeals and Interferences (the Board), the tribunal of first instance in this matter, awarded priority of invention for both the compound and method counts to Wattanasin.
  • Fujikawa, as the losing party, appealed the Board's priority decisions and the denial of his motion to the U.S. Court of Appeals for the Federal Circuit.

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Issue:

In a patent priority dispute, does a junior party's 15-17 month delay in filing a patent application after reducing an invention to practice constitute suppression or concealment, thereby forfeiting priority to a senior party, when the delay was accompanied by ongoing preparatory activities for filing?


Opinions:

Majority - Clevenger, Circuit Judge.

No. A 15-17 month delay between reduction to practice and filing does not constitute suppression or concealment when the inventor's assignee engaged in continuous, though sometimes slow, activity toward filing the patent application. First, the court affirmed that Wattanasin was the de facto first inventor, finding that the October 1987 in vitro tests were sufficient to establish practical utility and reduce the compound to practice, as there was a 'reasonable correlation' between in vitro and in vivo results in this field. The December 1987 in vivo tests further confirmed utility for both the compound and method counts. Second, the court determined that the subsequent 15-17 month delay did not justify an inference of suppression or concealment. The court distinguished between intentional suppression, which requires specific intent to hide the invention and was not present here, and an inference of suppression from unreasonable delay. It found the delay reasonable given the 'total conduct' of Sandoz, which included further testing, patent committee approval, data gathering, and drafting the application. The court concluded that an unexplained three-month gap within this period was insufficient to infer suppression, considering the invention's complexity and the overall, inexorable movement toward disclosure.



Analysis:

This case clarifies the standards for 'reduction to practice' and 'suppression or concealment' in patent law. It confirms that for pharmaceutical inventions, well-correlated in vitro tests can suffice to establish practical utility, lowering the bar from requiring full in vivo or clinical data. The decision reinforces that the suppression or concealment analysis is not a rigid time-based test but a holistic review of the inventor's 'total conduct,' providing a safe harbor for inventors who demonstrate continuous, even if inefficient, progress toward filing. This approach encourages the revival of shelved projects by allowing inventors to rely on renewed activity for priority, thereby promoting a policy of continued innovation over penalizing initial delays.

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