Navigating the Patentability of Diagnostic Methods at the EPO

Diagnostic Methods at the EPO: Key Insights

This article is for those seeking insights into diagnostic methods at the EPO and strategies for securing patent protection in this critical business area.

Diagnostic methods have long posed challenges regarding patentability under Article 53(c) EPC. A cornerstone in this area is decision G 1/04 from the Enlarged Board of Appeal, which outlines key criteria for determining whether method claims are excluded from patent protection.

Key Criteria from G 1/04

To assess if a claim qualifies as a diagnostic method under Article 53(c) EPC, it must encompass all four of the following phases:

i) Examination Phase: Collection of data (technical in nature).
ii) Data Comparison: Comparing collected data with standard values (non-technical).
iii) Identification of Deviations: Recognizing significant deviations or symptoms (non-technical).
iv) Diagnostic Conclusion: Attributing deviations to a specific clinical picture (diagnosis for curative purposes).

Importantly, the diagnostic phase (step iv) does not need to specify the exact disease. Even if not explicitly claimed, this step may be considered implicit based on dependent claims or the specification itself.

The Criterion of “Practiced on the Human Body”

According to G 1/04, only steps of a technical nature—primarily data collection—are relevant to determining if the method is “practiced on the human or animal body.” Notably, this step does not need to be invasive; interaction with the body requiring the patient’s presence suffices.

A Diverging Perspective: Decision T 1920/21

In January 2024, decision T 1920/21 offered an interesting interpretation of G 1/04. The Board ruled that a method claim was not excluded from patentability under Art. 53(c) EPC because it included an in vitro technical step: “measuring the content of ¹³C in CO₂ samples and determining the ¹³C/¹²C ratio by spectroscopy.” Since this step was performed in vitro – not performed on the body, the exclusion did not apply, even though other steps involved the body.

Contradiction with the EPO Guidelines

This decision appears to conflict with the EPO Guidelines for Examination (G II, 4.2.1.3), which state that only steps directly related to the diagnostic process (steps i–iv) matter for exclusion assessment. Preparatory or intermediate technical steps, like data processing, are deemed irrelevant under the Guidelines. This being said, EPO guidelines do not apply to Appeal proceedings.

Strategic Takeaways

Claim Amendments: Introducing an in vitro technical step may help avoid exclusion under Article 53(c) EPC.
System Claims: Even if method claims face hurdles, system or equipment claims offer robust protection, covering unauthorized activities like manufacturing, use, and distribution.

Would like to discuss this in more details? Feel free to contact Helene Fiorucci
Helene.fiorucci@alatis.com, US Patent Agent.