by Eviatar Aron, Israel & US Patent Attorney
Applicants from non-US jurisdictions face a unique set of challenges when navigating the US patent system. With its complex rules, procedural nuances, and shifting legal standards, the United States Patent and Trademark Office (USPTO) presents hurdles that often differ significantly from those of other national or regional systems such as the European Patent Office (EPO) or the Chinese National Intellectual Property Administration (CNIPA). This already challenging situation has been further exacerbated by recent developments, which require increased diligence and adaptation to secure robust patent protection in the US. This article provides a broad overview of some of these challenges and how they can be handled by non-US applicants when filing a US patent application based on a corresponding non-US patent application, including certain matters that should be considered during the initial drafting of a patent application.
Patent Eligibility
A major challenge faced by non-US applicants is an understanding of patent eligibility as per US law. Patent eligibility (35 USC. § 101) is defined more narrowly in the US than in some other jurisdictions, especially since the Alice and Mayo decisions, following which a significant number of applications, particularly in the sectors of software, biotech, and diagnostic methods, have been rejected as lacking eligibility. While foreign applicants may assume that an invention patentable in their home country would be similarly eligible in the US, this is often not the case.
Written Description
Furthermore, US written description and enablement requirements are typically more stringent than in other jurisdictions. Recent Federal Circuit rulings—such as Amgen Inc. v. Sanofi (2023)—have reaffirmed the need for detailed disclosure, especially for broad genus claims. These heightened standards create a mismatch for foreign-originating applications, which may have been drafted under more lenient requirements, leading to increased rejections during prosecution.
Claims Interpretation
Another significant challenge lies in how the USPTO interprets claims during examination. The USPTO applies the Broadest Reasonable Interpretation (BRI) standard when construing claims, in contrast to the more applicant-friendly approaches used in many foreign jurisdictions. Under BRI, examiners interpret claim terms as broadly as reasonably possible in light of the specification. This often results in broader readings of claim scope than intended by the applicant, which can more easily encompass prior art, even if such art would not be considered anticipatory or obvious under other systems. Consequently, applications that are allowed abroad may face unexpected novelty or obviousness rejections in the US.
Novelty and Non-Obviousness
Regarding novelty and non-obviousness (35 USC. §§ 102 and 103), the US law tends to apply a stricter evidentiary burden than other jurisdictions. For example, US examiners frequently combine multiple references in §103 rejections using a flexible “motivation to combine” analysis, as articulated in KSR v. Teleflex. This differs from the more structured problem-solution approach used in the EPO or the inventive step analyses in other jurisdictions. Furthermore, the US does not require the same level of explicit technical problem identification to support an obviousness combination, which can catch foreign applicants off guard.
These differences emphasize the importance of adapting foreign claim sets when filing a corresponding US patent application. Claim language that is sufficiently patentable in other jurisdictions may be too broad, vague, or susceptible to interpretation under BRI. Strategically tailoring claims to withstand US scrutiny—while still aligning with global protection goals—is essential for success. Moreover, US examiners enjoy significant discretion in interpreting claims and applying prior art, which, in combination with BRI, allows the examiners considerable leeway when making a rejection.
Furthermore, in an effort to manage rising application volumes, the USPTO has increasingly employed automated tools to aid in classification, prior art search, and examination prioritization. (see USPTO Artificial Intelligence and Emerging Technologies Report (October 2020)). While efficiency gains are welcome, foreign applicants, especially those less familiar with US procedural nuances, may find themselves at a disadvantage if their applications are prematurely rejected due to reliance on AI-driven metrics that currently may not consider international drafting styles.
In Conclusion
For non-US applicants, successfully navigating the US patent prosecution landscape now requires more than mere technical merit; it demands proactive adaptation to a system that is becoming increasingly difficult to navigate without the benefit of adequate prior experience.
While this article lays out a broad overview of some of the main challenges that non-US applicants face when trying to successfully navigate the US patent prosecution landscape, it is highly recommended to get assistance from an experienced patent attorney to ensure that all of these challenges are successfully overcome. We therefore encourage applicants to consult with our US patent attorneys and agents when going through this process to ensure a higher likelihood of obtaining patent registration in the US.
