July 1, 2025

On May 12, 2025, the Federal Circuit issued a decision in Regents of the Univ. of California v. Broad Inst., Inc.¹ concerning the ongoing priority dispute relating to competing inventor groups for the CRISPR-Cas9 eukaryotic gene editing system. The Regents of the University of California – Berkeley, the University of Vienna, and Emmanuelle Charpentier (collectively, “Regents”) appealed the PTAB’s determination that the Broad Institute, MIT, and Harvard University (collectively, “Broad”) had priority over Regents. In its decision, the court addressed the PTAB’s determinations by remanding with respect to its conclusions regarding conception and affirming with respect to its determination regarding written description. Specifically, the court explained that conception under the pre-AIA does not require knowledge of an invention’s operability and instead instructed that the inquiry should relate to the definiteness and permanence of the conceived idea such that only ordinary skill would be needed to reduce the idea to practice, as evidenced by the factual surroundings.

This case arises from the long-running interference proceeding before the PTAB between patent applications filed by Regents and Broad relating to the CRISPR-Cas9 system.² In response to a preliminary motion regarding Regents’ provisional filings, the PTAB determined that only their January 28, 2013, application satisfied the written description requirement.³ And, therefore, for the purposes of priority, Regents was not accorded the benefit of either of its two earlier provisional filings made on May 25, 2012, and October 29, 2012.⁴ As a result, the PTAB determined that Broad was the senior party over Regents and rejected Regents’ March 1, 2012, and June 28, 2012, asserted dates of conception.⁵ Regents then appealed these decisions by the PTAB to the Federal Circuit.⁶

On appeal, the court vacated and remanded the issue of conception under the pre-AIA regime after determining that the PTAB erred in its reasoning.⁷ Specifically, the court found that the PTAB erroneously conflated the legal standards for conception and reduction to practice by requiring that Regents’ scientists know whether their CRISPR-Cas9 system would produce effects on the genes in a eukaryotic cell.⁸ The court then clarified that the PTAB’s focus on statements made by Regents’ scientists which expressed their uncertainty in the experimentation was also in error because the PTAB did not consider whether substantive modifications which changed their original idea had occurred.⁹ The court then emphasized that, in determining conception, the inquiry should instead relate to whether the invention’s eventual reduction to practice required only the exercise of ordinary skill or instead required extensive research and skill.¹⁰

With respect to its emphasis on the exercise of ordinary skill in reducing a conception to practice, the court clarified that it was not necessary for an inventor to know with certainty that the invention would work.¹¹ However, the court also provided that more than the hope of achieving an otherwise never before achieved result was required.¹² Furthermore, the court clarified that neither evidence of experimental success nor whether routine methods or skills were used in these successful experiments should be overlooked in conducting this analysis.¹³ In reaching its conclusion that the PTAB erred by focusing on difficulties perceived by Regents’ scientists rather than considering whether their experimentation was of routine methodology and skill, the court also clarified that experimental difficulties do not per se indicate undue experimentation.¹⁴

The court then turned its review to the PTAB’s determination that Regents’ May 25, 2012, and October 29, 2012, provisional filings lacked written description support for the CRISPR-Cas9 system.¹⁵ In its affirmation of the PTAB’s holding regarding the written description requirement, the court clarified that the test for a disclosure’s sufficiency is whether the disclosure conveys to a person of ordinary skill in the art that the inventor had possession of the claimed subject matter at the time of filing.¹⁶ The court also clarified that the level of detail required for the written description requirement varies on the basis of the scope of the claims and the complexity and predictability of the relevant art.¹⁷ In reaching its holding that the PTAB correctly applied its written description analysis, the court clarified that Regents’ earlier provisional filings lacked the specificity required to establish possession of the claimed subject matter given the unpredictable and complex nature of the technology at issue.¹⁸

The case now returns to the PTAB to reevaluate whether Regents conceived of the invention prior to Broad’s reduction to practice. While the CRISPR priority dispute continues, this decision underscores the importance of distinguishing between conception and reduction to practice in the pre-AIA context and reaffirms the high bar required for demonstrating written description in unpredictable technologies. This ruling highlights the tension between filing early with less disclosure versus filing later with more experimentation and serves as a reminder of the importance of providing a robust and clear disclosure.