How should applicants establish a nexus between an intermediate and an end product’s unexpected properties?

When claiming patentability of an intermediate based on an end product’s properties, MPEP 716.02(b) provides specific guidance:

“In order to establish that the claimed intermediate is a ‘contributing cause’ of the unexpectedly superior activity or property of an end product, an applicant must identify the cause of the unexpectedly superior activity or property (compared to the prior art) in the end product and establish a nexus for that cause between the intermediate and the end product.”

This means applicants must:

• Identify the specific unexpected superior property in the end product
• Explain how this property is superior to what would be expected based on prior art
• Demonstrate a clear causal link between the intermediate and the end product’s superior property

Establishing this nexus is crucial for successfully arguing the patentability of the intermediate based on the end product’s characteristics.

To learn more:

• Intermediate compounds
• End product properties
• Nexus in patent law