What role do structural similarities play in determining obviousness of species claims?

Structural similarities between the prior art genus or species and the claimed species play a significant role in obviousness determinations. As stated in MPEP 2144.08:

“If such a prior art species or subgenus is structurally similar to that claimed, its disclosure may provide a reason for one of ordinary skill in the art to choose the claimed species or subgenus from the genus, based on the reasonable expectation that structurally similar species usually have similar properties.“

This means that when there are close structural similarities, examiners may find a prima facie case of obviousness. However, it’s important to note that:

• The degree of structural similarity is considered along with other factors
• Unexpected properties or results can overcome a prima facie case based on structural similarity
• Teaching away in the prior art can negate an obviousness rejection based on structural similarity

Examiners must carefully evaluate the totality of the evidence when considering structural similarities in obviousness determinations.

To learn more:

• obviousness
• structural similarities
• species claims
• prior art
• patent examination