Can post-filing date references be used to demonstrate lack of enablement?

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.

Generally, post-filing date references should not be used to demonstrate lack of enablement. MPEP 2164.05(a) states: “In general, the examiner should not use post-filing date references to demonstrate that a patent is not enabled.“

However, there are exceptions to this rule. The MPEP explains: “Exceptions to this rule could occur if a later-dated reference provides evidence of what one skilled in the art would have known on or before the effective filing date of the patent application.” This means that a post-filing date reference might be used if it sheds light on the state of knowledge at the time of filing.

The MPEP provides an example: “If a publication demonstrates that those of ordinary skill in the art would find that a particular invention was not enabled years after the filing date, the publication would be evidence that the claimed invention was not possible at the time of filing.” This illustrates how a later publication can sometimes be relevant to enablement considerations.