[co-author: Cassie George]
The dispute over who invented CRISPR-Cas9 (CRISPR), a gene-editing technology awarded the 2020 Nobel Prize in Chemistry, has been one of the most closely watched legal battles in the world of biotechnology. For more than a decade, researchers at the Regents of the University of California (Regents) and the Broad Institute (Broad) have each claimed that they were the first to conceive of CRISPR.
In 2022, the Patent Trial and Appeals Board (PTAB) instituted an “interference proceeding” to resolve the dispute. The PTAB held that researchers at Broad were the first to conceive CRISPR technology, rejecting Regents’ asserted earlier conception date. The PTAB cited expressions of experimental uncertainties after the alleged earlier conception date from researchers at Regents in support of its decision for Broad.
However, on May 12, 2025, the Federal Circuit vacated and remanded the PTAB decision, holding that the PTAB erred by conflating the legal standards for conception and reduction to practice.
Conception
CRISPR is a technology used for gene editing and has the capability to treat genetic diseases. It works by targeting changes to a specific genome base pair with high accuracy, and in a less costly and more efficient way than preexisting genetic engineering techniques.
The CRISPR patents at issue are subject to the Patent Act of 1952, which operates under a first-to-invent regime, that is, patents are awarded to those who first conceived of the idea [1]. The three stages for invention according to the Federal Circuit are: (1) conception, (2) reasonable diligence, and (3) reduction to practice.
Conception is achieved when there is formation of an idea in the mind of the inventor that is definite and permanent and of the complete and operative invention as it would be applied to practice. Moreover, conception is complete when the idea is so clearly defined that only ordinary skill in the art would be necessary to reduce the invention to practice, without extensive research or experimentation.
Critically, however, at the stage of the conception, the inventor does not need to know with scientific certainty that the invention will work. An inventor can determine if the invention works during the reduction to practice stage, which comes later.
The PTAB’s flawed conception analysis
The PTAB erred by requiring that researchers at Regents know that the CRISPR invention would work at the time of conception. The PTAB held that Regents’ scientists had not conceived the invention because Regents’ researchers discussed difficulties and doubts regarding experiments conducted after the alleged conception.
According to the Federal Circuit, knowledge that an invention will work is not necessary to prove earlier conception and can be established by subsequent reduction to practice. Thus, the PTAB legally erred by requiring that researchers at Regents know that its CRISPR invention was going to work at the time of conception.
The Federal Circuit also held that the PTAB should have considered whether a person of ordinary skill in the art (including those outside of Regents) could have reduced to practice the invention conceived by Regents’ researchers and whether Regents described routine methods known to one skilled in the art in its alleged conception date disclosure.
The Federal Circuit reiterated that the proper test for conception is whether the inventor formed the idea in sufficiently final form so that only the exercise of ordinary skill remained to reduce the invention to practice, that is, something beyond a “general hope,” but less than a scientific certainty.
Key takeaways
The Federal Circuit’s actions underscore that conception does not require proving that the invention actually works. Instead, conception only requires the formulation of a definite and permanent idea that a person of ordinary skill in the art could reduce to practice. The saga of the invention of CRISPR will continue as the PTAB takes up the case on remand in view of the Federal Circuit’s guidance on conception and reduction to practice.
The case summarized is Regents of the Univ. of Cal. v. Broad Inst., Inc., 136 F.4th 1367 (Fed. Cir. 2025).
[1] Inventorship for patent applications filed after March 16, 2013, under the America Invents Act (AIA), is accorded on a first-to-file framework. The inventor must be the first to file a patent application with the US Patent and Trademark Office and it does not matter under the AIA whether the inventor was the first to conceive of the invention.
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