What is the significance of preferred embodiments in genus-species anticipation?

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.

Preferred embodiments play a crucial role in genus-species anticipation in patent law. They can help determine which compounds within a generic formula can be anticipated. The MPEP states:

“One may look to the preferred embodiments to determine which compounds can be anticipated.” (MPEP 2131.02)

When a prior art reference discloses a generic formula along with preferred substituents or specific examples, these preferred embodiments can limit the scope of the genus to a more manageable number of compounds. If your claimed compound falls within this limited set of preferred embodiments, it’s more likely to be anticipated by the prior art, even if the generic formula itself covers a vast number of possible compounds.