米国特許商標庁（USPTO）が、2024年2月13日に発行した「AI の支援を受けた発明の発明者適格に関するガイダンス」を全面的に撤回し、2025年11月28日付けで、改定されたガイダンスの内容を公表しました。
当初のガイダンスでは、AIの支援を受けた発明に関与する自然人の寄与について、共同発明者性を判断するPannu要件（共同発明者性に関する判例 Pannu v Iolab Corp., 155 F.3d 1344, 1351 (Fed. Cir. 1998)で明示されたPannu factorsとして知られる要件）を準用することとなっていましたが、今般の改定において、当該要件があくまで複数の自然人間の共同発明性を判断するものであり、法律上、AIは自然人ではないため、AIの支援を得た発明の開発に一人の自然人だけが関与する場合にはPannu要件を適用すべきではないと明言し、発明者はあくまで自然人に限られること、発明者認定の基準は着想（Conception）であることなどが明確化されました。
詳細は、2025年11月28日付けの通知（Revised Inventorship Guidance for AI-Assisted Inventions（A Notice by the Patent and Trademark Office on 11/28/2025））をご参照下さい。※以下は通知の抜粋。
I. Purpose
This notice provides further guidance on the proper legal standard for determining inventorship in patent applications for AI-assisted inventions.
II. Recission of Prior Guidance
The guidance issued on February 13, 2024, titled “Inventorship Guidance for AI-Assisted Inventions” is rescinded in its entirety. The approach set forth in that guidance, which relied on the application of the Pannu factors to AI-assisted inventions, is withdrawn. The Pannu factors only apply when determining whether multiple natural persons qualify as joint inventors.Pannu is inapplicable when only one natural person is involved in developing an invention with AI assistance because AI systems are not persons and therefore cannot be “joint inventors” so there is no joint inventorship question to analyze.
III. Governing Legal Standards
The same legal standard for determining inventorship applies to all inventions, regardless of whether AI systems were used in the inventive process. There is no separate or modified standard for AI-assisted inventions. The Federal Circuit has held that AI cannot be named as an inventor on a patent application (or issued patent) and that only natural persons can be inventors. Artificial intelligence systems, regardless of their sophistication, cannot be named as inventors or joint inventors on a patent application as they are not natural persons. The Federal Circuit has centered its inventorship inquiry around “conception,” characterizing conception as “the touchstone of inventorship.” Conception is “the formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.” Conception is complete when “the inventor has a specific, settled idea, a particular solution to the problem at hand, not just a general goal or research plan.”