What are some ways to demonstrate “possession” of an invention?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

MPEP 2163.02 outlines several ways to demonstrate “possession” of an invention:

• Description of an actual reduction to practice
• Showing that the invention was “ready for patenting”
• Disclosure of drawings or structural chemical formulas that show the invention was complete
• Describing distinguishing identifying characteristics sufficient to show possession

The MPEP cites several cases, including Pfaff v. Wells Elecs., Inc. and Regents of the Univ. of Cal. v. Eli Lilly, to support these methods. It’s important to note that, as stated in Amgen, Inc. v. Chugai Pharm., “one must define a compound by ‘whatever characteristics sufficiently distinguish it’.“