2144.08 Obviousness of Species When Prior Art Teaches Genus
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This MPEP section is applicable to applications subject to the first inventor to file (FITF) provisions of the AIA except that the relevant date is the "effective filing date" of the claimed invention instead of the "time the invention was made," which is only applicable to applications subject to pre-AIA 35 U.S.C. 102.
I. EXAMINATION OF CLAIMS DIRECTED TO SPECIES BASED UPON A SINGLE PRIOR ART REFERENCE
When a single prior art reference which discloses a genus encompassing the claimed species or subgenus but does not expressly disclose the particular claimed species or subgenus, Office personnel should attempt to find additional prior art to show that the differences between the prior art primary reference and the claimed invention as a whole would have been obvious.
- Where such additional prior art is not found, Office personnel should consider the factors discussed below to determine whether a single reference 35 U.S.C. 103 rejection would be appropriate.
II. DETERMINE WHETHER THE CLAIMED SPECIES OR SUBGENUS WOULD HAVE BEEN OBVIOUS TO ONE OF ORDINARY SKILL IN THE PERTINENT ART AT THE TIME THE INVENTION WAS MADE
The patentability of a claim to a specific compound, species, or subgenus embraced by a prior art genus should be analyzed no differently than any other claim for purposes of 35 U.S.C. 103.
- “The section 103 requirement of unobviousness is no different in chemical cases than with respect to other categories of patentable inventions.”
A determination of patentability under 35 U.S.C. 103 should be made upon the facts of the particular case in view of the totality of the circumstances.
Use of per se rules by Office personnel is improper for determining whether claimed subject matter would have been obvious under 35 U.S.C. 103.
The fact that a claimed species or subgenus is encompassed by a prior art genus is not sufficient by itself to establish a prima facie case of obviousness.
A. Establishing a Prima Facie Case of Obviousness
Office personnel should establish a prima facie case of unpatentability considering the factors set out by the Supreme Court in Graham v. John Deere.
Graham requires that to make out a case of obviousness, one must:
- determine the scope and contents of the prior art;
- ascertain the differences between the prior art and the claims in issue;
- determine the level of ordinary skill in the pertinent art; and
- evaluate any evidence of secondary considerations.
If a prima facie case is established, the burden shifts to applicant to come forward with rebuttal evidence or argument to overcome the prima facie case.
- Finally, Office personnel should evaluate the totality of the facts and all of the evidence to determine whether they still support a conclusion that the claimed invention would have been obvious to one of ordinary skill in the art at the time the invention was made.
1. Determine the Scope and Content of the Prior Art
After construing the claims, Office personnel must also determine the scope and content of the relevant prior art. Each reference must qualify as prior art under 35 U.S.C. 102.
In the case of a prior art reference disclosing a genus, Office personnel should make findings as to:
- the structure of the disclosed prior art genus and that of any expressly described species or subgenus within the genus;
- any physical or chemical properties and utilities disclosed for the genus, as well as any suggested limitations on the usefulness of the genus, and any problems alleged to be addressed by the genus;
- the predictability of the technology; and
- the number of species encompassed by the genus taking into consideration all of the variables possible.
2. Ascertain the Differences Between the Closest Disclosed Prior Art Species or Subgenus of Record and the Claimed Species or Subgenus
Once the structure of the disclosed prior art genus and that of any expressly described species or subgenus within the genus are identified, Office personnel should compare it to the claimed species or subgenus to determine the differences.
- Through this comparison, the closest disclosed species or subgenus in the prior art reference should be identified and compared to that claimed.
- Office personnel should make explicit findings on the similarities and differences between the closest disclosed prior art species or subgenus of record and the claimed species or subgenus including findings relating to similarity of structure, properties and utilities.
“The question under 35 U.S.C. § 103 is not whether the differences [between the claimed invention and the prior art] would have been obvious” but “whether the claimed invention as a whole would have been obvious.”
3. Determine the Level of Skill in the Art
Office personnel should evaluate the prior art from the standpoint of the hypothetical person having ordinary skill in the art at the time the claimed invention was made.
In most cases, the only facts of record pertaining to the level of skill in the art will be found within the prior art reference and a discussion of the level of ordinary skill will not be needed.
- However, any additional evidence presented by applicant should be evaluated.
4. Determine Whether One of Ordinary Skill in the Art Would Have Been Motivated To Select the Claimed Species or Subgenus
In light of the findings made relating to the Graham factors, Office personnel should determine whether it would have been obvious to one of ordinary skill in the relevant art to make the claimed invention as a whole, i.e., to select the claimed species or subgenus from the disclosed prior art genus.
- To address this key issue, Office personnel should consider all relevant prior art teachings, focusing on the following, where present.
(a) Consider the Size of the Genus
Consider the size of the prior art genus, bearing in mind that size alone cannot support an obviousness rejection.
There is no absolute correlation between the size of the prior art genus and a conclusion of obviousness.
- Thus, the mere fact that a prior art genus contains a small number of members does not create a per se rule of obviousness.
- However, a genus may be so small that, when considered in light of the totality of the circumstances, it would anticipate the claimed species or subgenus.
- For example, it has been held that a prior art genus containing only 20 compounds and a limited number of variations in the generic chemical formula inherently anticipated a claimed species within the genus because “one skilled in [the] art would... envisage each member” of the genus. More specifically, the court in Petering stated:
A simple calculation will show that, excluding isomerism within certain of the R groups, the limited class we find in Karrer contains only 20 compounds.
- However, we wish to point out that it is not the mere number of compounds in this limited class which is significant here but, rather, the total circumstances involved, including such factors as the limited number of variations for R, only two alternatives for Y and Z, no alternatives for the other ring positions, and a large unchanging parent structural nucleus.
- With these circumstances in mind, it is our opinion that Karrer has described to those with ordinary skill in this art each of the various permutations here involved as fully as if he had drawn each structural formula or had written each name.
(b) Consider the Express Teachings
If the prior art reference expressly teaches a particular reason to select the claimed species or subgenus, Office personnel should point out the express disclosure and explain why it would have been obvious to one of ordinary skill in the art to select the claimed invention.
- An express teaching may be based on a statement in the prior art reference such as an art recognized equivalence.
(c) Consider the Teachings of Structural Similarity
Consider any teachings of a “typical,” “preferred,” or “optimum” species or subgenus within the disclosed genus.
- 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.
In making an obviousness determination, Office personnel should consider the number of variables which must be selected or modified, and the nature and significance of the differences between the prior art and the claimed invention.
The effect of a conservative substitution on protein function depends on the nature of the substitution and its location in the chain.
- Although at some locations a conservative substitution may be benign, in some proteins only one amino acid is allowed at a given position.
- For example, the gain or loss of even one methyl group can destabilize the structure if close packing is required in the interior of domains.
The closer the physical and/or chemical similarities between the claimed species or subgenus and any exemplary species or subgenus disclosed in the prior art, the greater the expectation that the claimed subject matter will function in an equivalent manner to the genus.
- Similarly, consider any teaching or suggestion in the reference of a preferred species or subgenus that is significantly different in structure from the claimed species or subgenus. Such a teaching may weigh against selecting the claimed species or subgenus and thus against a determination of obviousness.
Concepts used to analyze the structural similarity of chemical compounds in other types of chemical cases are equally useful in analyzing genus-species cases.
- For example, a claimed tetra-orthoester fuel composition was held to be obvious in light of a prior art tri-orthoester fuel composition based on their structural and chemical similarity and similar use as fuel additives.
- Likewise, claims to amitriptyline used as an antidepressant were held obvious in light of the structural similarity to imipramine, a known antidepressant prior art compound, where both compounds were tricyclic dibenzo compounds and differed structurally only in the replacement of the unsaturated carbon atom in the center ring of amitriptyline with a nitrogen atom in imipramine. Other structural similarities have been found to support a prima facie case of obviousness.
Generally, some teaching of a structural similarity will be necessary to suggest selection of the claimed species or subgenus.
(d) Consider the Teachings of Similar Properties or Uses
Consider the properties and utilities of the structurally similar prior art species or subgenus.
- It is the properties and utilities that provide real world motivation for a person of ordinary skill to make species structurally similar to those in the prior art.
Conversely, lack of any known useful properties weighs against a finding of motivation to make or select a species or subgenus.
If the claimed invention and the structurally similar prior art species share any useful property, that will generally be sufficient to motivate an artisan of ordinary skill to make the claimed species, e.g., id.
- For example, based on a finding that a tri-orthoester and a tetra-orthoester behave similarly in certain chemical reactions, it has been held that one of ordinary skill in the relevant art would have been motivated to select either structure.
- In fact, similar properties may normally be presumed when compounds are very close in structure.
Thus, evidence of similar properties or evidence of any useful properties disclosed in the prior art that would be expected to be shared by the claimed invention weighs in favor of a conclusion that the claimed invention would have been obvious.
(e) Consider the Predictability of the Technology
Consider the predictability of the technology.
If the technology is unpredictable, it is less likely that structurally similar species will render a claimed species obvious because it may not be reasonable to infer that they would share similar properties.
(f) Consider Any Other Teaching To Support the Selection of the Species or Subgenus
The categories of relevant teachings enumerated above are those most frequently encountered in a genus-species case, but they are not exclusive.
- Office personnel should consider the totality of the evidence in each case.
- In unusual cases, there may be other relevant teachings sufficient to support the selection of the species or subgenus and, therefore, a conclusion of obviousness.
5. Make Express Fact-Findings and Determine Whether They Support a Prima Facie Case of Obviousness
Based on the evidence as a whole, Office personnel should make express fact-findings relating to the Graham factors, focusing primarily on the prior art teachings discussed above.
- The fact-findings should specifically articulate what teachings or suggestions in the prior art would have motivated one of ordinary skill in the art to select the claimed species or subgenus.
- Thereafter, it should be determined whether these findings, considered as a whole, support a prima facie case that the claimed invention would have been obvious to one of ordinary skill in the relevant art at the time the invention was made.
» 2144.09 Close Structural Similarity Between Chemical Compounds (Homologs, Analogues, Isomers)
