## Facts

- An interference proceeding was declared between Owen W. Griffith’s pending patent application (assigned to Cornell Research Foundation, Inc.) and Tsuneo Kanamaru’s issued U.S. patent (assigned to Takeda Chemical Industries, Ltd.) covering aminocarnitine compounds used to treat diabetes.
- Griffith proved conception by June 30, 1981, and reduction to practice on January 11, 1984.
- Kanamaru filed a U.S. patent application on November 17, 1982.
- To obtain priority as the prior inventor under 35 U.S.C. § 102(g), Griffith had to show reasonable diligence from just before November 17, 1982 until his January 11, 1984 reduction to practice.
- The Board of Patent Appeals and Interferences found Griffith failed to establish a prima facie case of reasonable diligence, focusing on inactivity between June 15, 1983 and September 13, 1983.
- Griffith attributed delay to Cornell’s need for outside funding and to waiting for a particular graduate student to begin work; he also worked on other projects during the period.
- After additional submissions, the Board concluded the explanations did not legally excuse the inactivity and entered judgment awarding priority to Kanamaru.
- Griffith appealed, challenging the Board’s diligence determination and resulting award of priority.

## Issues

1. Whether Griffith proved “reasonable diligence” in reducing the invention to practice during the critical period required by 35 U.S.C. § 102(g) to antedate Kanamaru’s filing date.
2. Whether delays tied to institutional funding arrangements and waiting for preferred personnel can constitute legally sufficient excuses for a substantial gap in activity.

## Decision

- The Federal Circuit affirmed the Board’s judgment awarding priority to Kanamaru.
- The court held Griffith failed to establish a prima facie case of continuous reasonable diligence throughout the critical period.
- The court agreed that the June 15 to September 13, 1983 inactivity was not adequately excused by the asserted funding and graduate-student reasons.
- Because Griffith did not carry his burden on diligence, he was not entitled to priority over Kanamaru’s earlier filing date.

## Legal Principles

- Under 35 U.S.C. § 102(g) (interference priority), an inventor who relies on an earlier conception must prove continuous reasonable diligence in reducing the invention to practice during the critical period (from just before the opponent’s effective date through the inventor’s reduction to practice).
- A substantial, inadequately explained gap in activity can defeat a claim of reasonable diligence and thus priority.
- Factfinders may consider ordinary practical constraints faced by inventors, but delays driven by efforts to secure optimal funding arrangements or to improve marketability are generally not sufficient excuses for inactivity.
- Preferences for particular personnel do not excuse inactivity absent a showing that the work could not reasonably proceed with available resources.

## Conclusion

The Federal Circuit upheld the priority award to Kanamaru because Griffith, despite earlier conception, did not prove continuous reasonable diligence through the critical period; institutional choices to wait for funding or preferred staffing did not legally justify a significant inactivity gap.


Griffith v. Kanamaru, 816 F.2d 624 (Fed. Cir. 1987)