On 4 August 2026, Japan’s Intellectual Property High Court overturned the JPO’s earlier decision invalidating Broad Institute CRISPR-Cas9 patent claims. The dispute centred on whether priority from the underlying applications had been validly transferred before the PCT filing. The court held that status as a “successor in title” under Article 4A(1) of the Paris Convention does not invariably depend on objective written evidence such as a formal deed of assignment; a shared intention between transferor and transferee to transfer the priority right before the PCT filing can be sufficient.
The ruling is significant as the first high-court-level judgment addressing the validity of a CRISPR-Cas9 patent priority claim, but its practical reach is broader than biotechnology. It softens a rigid documentary approach without making priority transfers evidence-free: applicants should still preserve contemporaneous records showing who agreed to transfer the right, when the agreement was reached and what it covered. For multinational R&D collaborations and PCT filings involving multiple applicants, documenting the chain of title before filing remains the safer course, particularly because later validity proceedings may turn on factual proof of the parties’ agreement.
