​Patent Panic Button: Why CRISPR Titans are Revoking Their Own PatentsMarch 12, 2025

Gene editing technology has revolutionized molecular biology, offering unprecedented precision in genetic modifications and a lighter regulatory pathway compared to conventional transgenic approaches. However, the intellectual property landscape surrounding CRISPR has historically been overshadowed with disputes and unexpected developments. A recent and notable twist is the self-revocation of two seminal European patents by the team led by Nobel Laureates Emmanuelle Charpentier and Jennifer Doudna, and assigned to University of California, University of Vienna, and Emmanuelle Charpentier (collectively known as CVC). This move has introduced new uncertainties for companies navigating the complex CRISPR IP landscape.

The Unprecedented Self-Revocation

In an extraordinary decision, CVC requested the European Patent Office (EPO) to revoke two of its foundational patents: EP2800811 (EP ‘811) and EP3401400 (EP ‘400). These patents encompassed broad claims covering nearly all methods of modifying target DNA using the CRISPR-Cas9 system. The self-revocation appears to be a strategic response to unfavorable preliminary opinions from the EPO’s Opposition Division Board of Appeal, which questioned the sufficiency of the original patent disclosures. Specifically, the Board of Appeal indicated that CVC’s earliest patent filing lacked certain key features necessary for other scientists to effectively utilize the technology.​ This is akin to the U.S. written description requirement, which is referred to as sufficiency of disclosure with the EPO.

A critical point in the dispute centers on the protospacer adjacent motif (PAM) sequence, essential for CRISPR-Cas9 binding and cleavage. CVC’s initial provisional application, filed in May 2012, notably omitted the PAM sequence, which was later included in a subsequent provisional application in October 2012 after their groundbreaking publication in Science. Opponents argued, and the Board of Appeal concurred, that without the PAM sequence, the invention was not sufficiently disclosed, rendering the May 2012 application inadequate to support the later European patents. Consequently, EP ‘811 and EP ‘400 lost their priority date entitlement from May 2012, making the June 2012 Science publication invalidating prior art against their own patents. ​Here, the applicants failed to file a patent application containing the PAM sequences before their own publication in Science disclosing PAM sequences. This violates a basic cardinal rule in patent prosecution: file updated application(s) before publication of any new results that go beyond the priority application. This is also a good reminder of one of the many watchouts for “coversheet provisional” practice, where often a company wants a quick filing with minimal data, to support an upcoming disclosure or meeting with investors. The PAM sequence disclosure issue could have been averted if they sent their patent counsel the draft manuscript before submission, and filed an updated priority application.

Rather than relinquishing control over their CRISPR IP in Europe, CVC’s self-revocation aims to prevent a final adverse decision that could negatively impact the entire patent family and future patent prospects in Europe. In a submission accompanying the revocation request, CVC’s legal representatives stated: “The Patentees cannot be expected to expose the Nobel Prize-winning invention protected by the present patent to the repercussions of a decision handed down under such circumstances, when other members of this family… are still at a stage where the Patentees can procedurally ensure that they will ultimately be fully heard by the Board on all substantive issues.” ​

By revoking these patents, CVC seemingly seeks to shield other family members from an adverse final decision and to leverage pending applications within the same patent family to secure new patents. However, this self-revocation strategy does not rectify the foundational issue of the May 2012 application’s insufficiency. Future patents stemming from pending applications are likely to encounter similar challenges when faced with challenges to written description or sufficiency of disclosure. 

Broader Trends and Future Outlook

CVC’s self-revocation is not an isolated incident. Sigma-Aldrich just recently employed a similar tactic, revoking its own European CRISPR patents to avoid unfavorable rulings. 

In this twist nobody saw coming, less than two months after CVC revoked two of its foundational European CRISPR patents, Sigma-Aldrich has jumped on a similar “self-revocation” bandwagon approach.

Sigma-Aldrich’s move involves two significant patents, EP3138911 (EP ’911) and EP3360964 (EP ’964), which broadly cover methods and compositions for editing chromosomal sequences in eukaryotic cells using RNA-guided endonucleases like CRISPR/Cas proteins with nuclear localization signals.

Unlike CVC’s patents, Sigma’s patents had already faced setbacks: the EPO’s Opposition Division previously revoked them for lacking inventive step, citing the June 2012 Science publication by Nobel Laureates Emmanuelle Charpentier and Jennifer Doudna. Attempting to salvage their patents on appeal of the opposition decision, Sigma introduced new arguments and auxiliary requests, only to have them rejected by the Board of Appeal for being submitted too late. Sigma then moved to terminate the appeal proceedings, giving up its effort to overturn the Opposition Division’s revocation decisions of both EP ’911 and EP ’964 patents.

Strategic Implications

Why are major patent holders resorting to these tactics? Both Sigma and CVC seemingly aim to shield their other patent family members from the fallout of an unfavorable final decision and preserve their ability to secure future European patents. Yet, Sigma faces an uphill battle because its patents were already revoked once, complicating efforts to reposition future patent claims.

This growing trend of patent holders preemptively dropping pursuit of their claims before a final decision is generating a lot of questions within both scientific and legal communities – I have fielded a lot of questions in the past several months about the potential implications (with the biggest one being – “Why?”).

As the CRISPR IP landscape continues to evolve, companies should keep up to date and seek IP and regulatory guidance for their specific product development pathway, to bring products to market. In addition to the new patent applications published and issued patents granted for gene editing technology each week, ongoing opposition and litigation proceedings remain.

For companies and researchers in the gene-editing field looking to protect their innovations, these developments underscore the importance of meticulous patent drafting and comprehensive disclosure. Ensuring that all critical components of an invention are adequately described is paramount to secure a priority date that will withstand legal scrutiny. 

Cassie J. Edgar, Partner and Chair of the Regulatory Law practice group, advises clients in IP, regulatory law, and licensing including matters with USDA, FDA, and EPA. Cassie is also Co-Chair of the Data Privacy and Cybersecurity practice group. For additional information, please visit MVS or contact Cassie directly via e-mail at cassie.edgar@ipmvs.com.