Editing MPEP 2144

<noinclude>{{MPEP Section|2143|2100|2145}}</noinclude>

==[[MPEP 2144|2144 Sources of Rationale Supporting a Rejection Under 35 U.S.C. 103]]==

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RATIONALE MAY BE IN A REFERENCE, OR 
REASONED FROM COMMON KNOWLEDGE 
IN THE ART, SCIENTIFIC PRINCIPLES, ART- 
RECOGNIZED EQUIVALENTS, OR LEGAL 
PRECEDENT

The rationale to modify or combine the prior art 
does not have to be expressly stated in the prior art; 
the rationale may be expressly or impliedly contained 
in the prior art or it may be reasoned from knowledge 
generally available to one of ordinary skill in the art, 
established scientific principles, or legal precedent 
established by prior case law. In re Fine, 837 F.2d 
1071, 5 USPQ2d 1596 (Fed. Cir. 1988); In re Jones, 
958 F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992). See 
also In re Kotzab, 217 F.3d 1365, 1370, 55 USPQ2d 
1313, 1317 (Fed. Cir. 2000) (setting forth test for 
implicit teachings); In re Eli Lilly & Co., 902 F.2d 
943, 14 USPQ2d 1741 (Fed. Cir. 1990) (discussion of 
reliance on legal precedent); In re Nilssen, 851 F.2d 
1401, 1403, 7 USPQ2d 1500, 1502 (Fed. Cir. 1988) 
(references do not have to explicitly suggest combining 
teachings); Ex parte Clapp, 227 USPQ 972 (Bd. 
Pat. App. & Inter. 1985) (examiner must present convincing 
line of reasoning supporting rejection); and 
Ex parte Levengood, 28 USPQ2d 1300 (Bd. Pat. App. 
& Inter. 1993) (reliance on logic and sound scientific 
reasoning). 

THE EXPECTATION OF SOME ADVANTAGE 
IS THE STRONGEST RATIONALE FOR COMBINING 
REFERENCES

The strongest rationale for combining references is 
a recognition, expressly or impliedly in the prior art or 
drawn from a convincing line of reasoning based on 
established scientific principles or legal precedent, 
that some advantage or expected beneficial result 
would have been produced by their combination. In re 
Sernaker, 702 F.2d 989, 994-95, 217 USPQ 1, 5-6 
(Fed. Cir. 1983).

LEGAL PRECEDENT CAN PROVIDE THE RATIONALE 
SUPPORTING OBVIOUSNESS ON- 
LY IF THE FACTS IN THE CASE ARE SUFFICIENTLY 
SIMILAR TO THOSE IN THE APPLICATION


The examiner must apply the law consistently to 
each application after considering all the relevant 
facts. If the facts in a prior legal decision are sufficiently 
similar to those in an application under examination, 
the examiner may use the rationale used by the 
court. If the applicant has demonstrated the criticality 
of a specific limitation, it would not be appropriate to 
rely solely on case law as the rationale to support an 
obviousness rejection. “The value of the exceedingly 
large body of precedent wherein our predecessor 
courts and this court have applied the law of obviousness 
to particular facts, is that there has been built a 
wide spectrum of illustrations and accompanying reasoning, 
that have been melded into a fairly consistent 
application of law to a great variety of facts.” In re Eli 
Lilly & Co., 902 F.2d 943, 14 USPQ2d 1741 (Fed. Cir. 
1990).

RATIONALE DIFFERENT FROM APPLICANT’S 
IS PERMISSIBLE

The reason or motivation to modify the reference 
may often suggest what the inventor has done, but for 
a different purpose or to solve a different problem. It 
is not necessary that the prior art suggest the combination 
to achieve the same advantage or result discovered 
by applicant. See, e.g., In re Kahn, 441 F.3d 
977, 987, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006) 
(motivation question arises in the context of the general 
problem confronting the inventor rather than the 
specific problem solved by the invention); Cross Med. 
Prods., Inc. v. Medtronic Sofamor Danek, Inc., 424 
F.3d 1293, 1323, 76 USPQ2d 1662, 1685 (Fed. Cir. 
2005) (“One of ordinary skill in the art need not see 
the identical problem addressed in a prior art reference 
to be motivated to apply its teachings.”); In re 
Linter, 458 F.2d 1013, 173 
USPQ 560 (CCPA 1972) 
(discussed below); In re Dillon, 919 F.2d 688, 16 
USPQ2d 1897 (Fed. Cir. 1990), cert. denied, 500 U.S. 
904 (1991) (discussed below). Although Ex parte 
Levengood, 28 USPQ2d 1300, 1302 (Bd. Pat. App. & 
Inter. 1993) states that obviousness cannot be established 
by combining references “without also providing 
evidence of the motivating force which would 
impel one skilled in the art to do what the patent 
applicant has done” (emphasis added), reading the 
quotation in context it is clear that while there must be 
motivation to make the claimed invention, there is no 
requirement that the prior art provide the same reason 
as the applicant to make the claimed invention.

In In re Linter the claimed invention was a laundry 
composition consisting essentially of a dispersant, 
cationic fabric softener, sugar, sequestering phosphate, 
and brightener in specified proportions. The 
claims were rejected over the combination of a primary 
reference which taught all the 
claim limitations 
except for the presence of sugar, and secondary references 
which taught the addition of sugar as a filler or 
weighting agent in compositions containing cationic 
fabric softeners. Appellant argued that in the claimed 
invention, the sugar is responsible for the compatibility 
of the cationic softener with the other detergent 
components. The court sustained the rejection, stating 
“The fact that appellant uses sugar for a different 
purpose does not alter the conclusion that its use in a 
prior art composition would be [sic, would have been] 
prima facie obvious from the purpose disclosed in the 
references.” 173 USPQ at 562.

In In re Dillon, applicant claimed a composition 
comprising a hydrocarbon fuel and a sufficient 
amount of a tetra-orthoester of a specified formula to 
reduce the particulate emissions from the combustion 
of the fuel. The claims were rejected as obvious over a 
reference which taught hydrocarbon fuel compositions 
containing tri-orthoesters for dewatering fuels, 
in combination with a reference teaching the equivalence 
of tri-orthoesters and tetra-orthoesters as water 
scavengers in hydraulic (nonhydrocarbon) fluids. The 
Board affirmed the rejection finding “there was a ‘reasonable 
expectation’ that the tri- and tetra-orthoester 
fuel compositions would have similar properties 
based on ‘close structural and chemical similarity’ 
between the tri- and tetra-orthoesters and the fact that 
both the prior art and Dillon use these compounds ‘as 
fuel additives’.” 919 F.2d at 692, 16 USPQ2d at 1900. 
The court held “it is not necessary in order to establish 
a prima facie case of obviousness . . . that there be a 
suggestion or expectation from the prior art that the 
claimed [invention] will have the same or a similar 
utility as one newly discovered by applicant,” and 
concluded that here a prima facie case was established 
because “[t]he art provided the motivation to 
make the claimed compositions in the expectation that 
they would have similar properties.” 919 F.2d at 693, 
16 USPQ2d at 1901 (emphasis in original).

See MPEP § 2145, paragraph II for case law pertaining 
to the presence of additional advantages or 
latent properties not recognized in the prior art.

===2144.01 Implicit Disclosure===

“[I]n considering the disclosure of a reference, it is 
proper to take into account not only specific teachings 
of the reference but also the inferences which one 
skilled in the art would reasonably be expected to 
draw therefrom.” In re Preda, 401 F.2d 825, 826, 
159 USPQ 342, 344 (CCPA 1968) (A process for catalytically 
producing carbon disulfide by reacting sulfur 
vapor and methane in the presence of charcoal at a 
temperature of “about 750-830°C” was found to be 
met by a reference which expressly taught the same 
process at 700°C because the reference recognized the 
possibility of using temperatures greater than 750°C. 
The reference disclosed that catalytic processes for 
converting methane with sulfur vapors into carbon 
disulfide at temperatures greater than 750°C (albeit 
without charcoal) was known, and that 700°C was 
“much lower than had previously proved feasible.”); 
In re Lamberti, 545 F.2d 747, 750, 192 USPQ 278, 
280 (CCPA 1976) (Reference disclosure of a compound 
where the R-S-R¢ portion has “at least one 
methylene group attached to the sulfur atom” implies 
that the other R group attached to the sulfur atom can 
be other than methylene and therefore suggests asymmetric 
dialkyl moieties.).

===2144.02 Reliance on Scientific Theory===

The rationale to support a rejection under 35 U.S.C. 
103 may rely on logic and sound scientific principle. 
In re Soli, 317 F.2d 941, 137 USPQ 797 (CCPA 
1963). However, when an examiner relies on a scientific 
theory, evidentiary support for the existence and 
meaning of that theory must be provided. In re Grose, 
592 F.2d 1161, 201 USPQ 57 (CCPA 1979) (Court 
held that different crystal forms of zeolites would not 
have been structurally obvious one from the other 
because there was no chemical theory supporting such 
a conclusion. The known chemical relationship 
between structurally similar compounds (homologs, 
analogs, isomers) did not support a finding of prima 
facie obviousness of claimed zeolite over the prior art 
because a zeolite is not a compound but a mixture of 
compounds related to each other by a particular crystal 
structure.). Although the theoretical mechanism of 
an invention may be explained by logic and sound scientific 
reasoning, this fact does not support an obviousness 
determination unless logic and scientific 
reasoning would have led one of ordinary skill in the 
art to make the claimed invention. Ex parte Levengood, 
28 USPQ2d 1300 (Bd. Pat. App. & Inter. 1993).

===2144.03 Reliance on Common Knowledge in the Art or "Well Known" Prior Art===

In limited circumstances, it is appropriate for an 
examiner to take official notice of facts not in the 
record or to rely on “common knowledge” in making 
a rejection, however such rejections should be judiciously 
applied.

PROCEDURE FOR RELYING ON COMMON 
KNOWLEDGE OR TAKING OFFICIAL NOTICE


The standard of review applied to findings of fact is 
the “substantial evidence” standard under the Administrative 
Procedure Act (APA). See In re Gartside, 
203 F.3d 1305, 1315, 53 USPQ2d 1769, 1775 (Fed. 
Cir. 2000). See also MPEP § 1216.01. In light of 
recent Federal Circuit decisions as discussed below 
and the substantial evidence standard of review now 
applied to USPTO Board decisions, the following 
guidance is provided in order to assist the examiners 
in determining when it is appropriate to take official 
notice of facts without supporting documentary evidence 
or to rely on common knowledge in the art in 
making a rejection, and if such official notice is taken, 
what evidence is necessary to support the examiner’s 
conclusion of common knowledge in the art.

A.Determine When It Is Appropriate To Take Official 
Notice Without Documentary Evidence 
To Support The Examiner’ s Conclusion

Official notice without documentary evidence to 
support an examiner’s conclusion is permissible only 
in some circumstances. While “official notice” may 
be relied on, these circumstances should be rare when 
an application is under final rejection or action under 
37 CFR 1.113. Official notice unsupported by documentary 
evidence should only be taken by the examiner 
where the facts asserted to be well-known, or to 
be common knowledge in the art are capable of 
instant and unquestionable demonstration as being 
well-known. As noted by the court in In re Ahlert, 424 
F.2d 1088, 1091, 165 USPQ 418, 420 (CCPA 1970), 
the notice of facts beyond the record which may be 
taken by the examiner must be “capable of such 
instant and unquestionable demonstration as to defy 
dispute” (citing In re Knapp Monarch Co., 296 F.2d 
230, 132 USPQ 6 (CCPA 1961)). In Ahlert, the court 
held that the Board properly took judicial notice that 
“it is old to adjust intensity of a flame in accordance 
with the heat requirement.” See also In re Fox, 471 
F.2d 1405, 1407, 176 USPQ 340, 341 (CCPA 1973) 
(the court took “judicial notice of the fact that tape 
recorders commonly erase tape automatically when 
new ‘audio information’ is recorded on a tape which 
already has a recording on it”). In appropriate circumstances, 
it might not be unreasonable to take official 
notice of the fact that it is desirable to make something 
faster, cheaper, better, or stronger without the 
specific support of documentary evidence. Furthermore, 
it might not be unreasonable for the examiner in 
a first Office action to take official notice of facts by 
asserting that certain limitations in a dependent claim 
are old and well known expedients in the art without 
the support of documentary evidence provided the 
facts so noticed are of notorious character and serve 
only to “fill in the gaps” which might exist in the evidentiary 
showing made by the examiner to support a 
particular ground of rejection. In re Zurko, 258 F.3d 
1379, 1385, 59 USPQ2d 1693, 1697 (Fed. Cir. 2001);
Ahlert, 424 F.2d at 1092, 165 USPQ at 421. 

It would not be appropriate for the examiner to take 
official notice of facts without citing a prior art reference 
where the facts asserted to be well known are 
not 
capable of instant and unquestionable demonstration 
as being well-known. For example, assertions of 
technical facts in the areas of esoteric technology or 
specific knowledge of the prior art must always be 
supported by citation to some reference work recognized 
as standard in the pertinent art. In re Ahlert, 424 
F.2d at 1091, 165 USPQ at 420-21. See also In re 
Grose, 592 F.2d 1161, 1167-68, 201 USPQ 57, 63 
(CCPA 1979) (“[W]hen the PTO seeks to rely upon a 
chemical theory, in establishing a prima facie case of 
obviousness, it must provide evidentiary support for 
the existence and meaning of that theory.”); In re 
Eynde, 480 F.2d 1364, 1370, 178 USPQ 470, 
474 
(CCPA 1973) (“[W]e reject the notion that judicial 
or administrative notice may be taken of the state 
of the art. The facts constituting the state of the art are 
normally subject to the possibility of rational disagreement 
among reasonable men and are not amenable 
to the taking of such notice.”).

It is never appropriate to rely solely on “common 
knowledge” in the art without evidentiary support in 
the record, as the principal evidence upon which a 
rejection was based. Zurko, 258 F.3d at 1385, 59 
USPQ2d at 1697 (“[T]he Board cannot simply reach 
conclusions based on its own understanding or experience—
or on its assessment of what would be basic 
knowledge or common sense. Rather, the Board must 
point to some concrete evidence in the record in support 
of these findings.”). While the court explained 
that, “as an administrative tribunal the Board 
clearly 
has expertise in the subject matter over which 




 

it exercises jurisdiction,” it made clear that such 
“expertise may provide sufficient support for conclusions 
[only] as to peripheral issues.” Id. at 1385-86, 
59 USPQ2d at 1697. As the court held in Zurko, an 
assessment of basic knowledge and common sense 
that is not based on any evidence in the record lacks 
substantial evidence support. Id. at 1385, 59 USPQ2d 
at 1697. See also In re Lee, 277 F.3d 1338, 1344-45, 
61 USPQ2d 1430, 1434-35 (Fed. Cir. 2002) (In 
reversing the Board’s decision, the court stated 
“‘common knowledge and common sense’ on which 
the Board relied in rejecting Lee’s application are not 
the specialized knowledge and expertise contemplated 
by the Administrative Procedure Act. Conclusory 
statements such as those here provided do not fulfill 
the agency’s obligation….The board cannot rely on 
conclusory statements when dealing with particular 
combinations of prior art and specific claims, but 
must set forth the rationale on which it relies.”). 

B.If Official Notice Is Taken of a Fact, 
Unsupported by Documentary Evidence, the 
Technical Line Of Reasoning Underlying a 
Decision To Take Such Notice Must Be Clear 
and Unmistakable 

Ordinarily, there must be some form of evidence in 
the record to support an assertion of common knowledge. 
See Lee, 277 F.3d at 1344-45, 61 USPQ2d at 
1434-35 (Fed. Cir. 2002); Zurko, 258 F.3d at 1386, 59 
USPQ2d at 1697 (holding that general conclusions 
concerning what is “basic knowledge” or “common 
sense” to one of ordinary skill in the art without specific 
factual findings and some concrete evidence in 
the record to support these findings will not support 
an obviousness rejection). In certain older cases, official 
notice has been taken of a fact that is asserted to 
be “common knowledge” without specific reliance on 
documentary evidence where the fact noticed was 
readily verifiable, such as when other references of 
record supported the noticed fact, or where there was 
nothing of record to contradict it. See In re Soli, 
317 
F.2d 941, 945-46, 137 USPQ 797, 800 (CCPA 
1963) (accepting the examiner’s assertion that the use 
of “a control is standard procedure throughout the 
entire field of bacteriology” because it was readily 
verifiable and disclosed in references of record not 
cited by the Office); In re Chevenard, 139 F.2d 711, 
713, 60 USPQ 239, 241 (CCPA 1943) (accepting the 
examiner’s finding that a brief heating at a higher 
temperature was the equivalent of a longer heating at 
a lower temperature where there was nothing in the 
record to indicate the contrary and where the applicant 
never demanded that the examiner produce evidence 
to support his statement). If such notice is 
taken, the basis for such reasoning must be set forth 
explicitly. The examiner must provide specific factual 
findings predicated on sound technical and scientific 
reasoning to support his or her conclusion of common 
knowledge. See Soli, 317 F.2d at 946, 37 USPQ at 
801; Chevenard, 139 F.2d at 713, 60 USPQ at 241. 
The applicant should be presented with the explicit 
basis on which the examiner regards the matter as 
subject to official notice and be allowed to challenge 
the assertion in the next reply after the Office action in 
which the common knowledge statement was made.

C.If Applicant Challenges a Factual Assertion 
as Not Properly Officially Noticed or not 
Properly Based Upon Common Knowledge, 
the Examiner Must Support the Finding With 
Adequate Evidence

To adequately traverse such a finding, an applicant 
must specifically point out the supposed errors in the 
examiner’s action, which would include stating why 
the noticed fact is not considered to be common 
knowledge or well-known in the art. See 37 CFR 
1.111(b). See also Chevenard, 139 F.2d at 713, 60 
USPQ at 241 (“[I]n the absence of any demand by 
appellant for the examiner to produce authority for his 
statement, we will not consider this contention.”). A 
general allegation that the claims define a patentable 
invention without any reference to the examiner’s 
assertion of official notice would be inadequate. If 
applicant adequately traverses the examiner’s assertion 
of official notice, the examiner must provide documentary 
evidence in the next Office action if the 
rejection is to be maintained. See 37 CFR 1.104(c)(2). 
See also Zurko, 258 F.3d at 1386, 59 USPQ2d at 1697 
(“[T]he Board [or examiner] must point to some concrete 
evidence in the record in support of these findings” 
to satisfy the substantial evidence test). If the 
examiner is relying on personal knowledge to support 
the finding of what is known in the art, the examiner 
must provide an affidavit or declaration setting forth 
specific factual statements and explanation to support 
the finding. See 37 CFR 1.104(d)(2).




 

If applicant does not traverse the examiner’s assertion 
of official notice or applicant’s traverse is not 
adequate, the examiner should clearly indicate in the 
next Office action that the common knowledge 
or 
well-known in the art statement is taken to be 
admitted prior art because applicant either failed to 
traverse the examiner’s assertion of official notice or 
that the traverse was inadequate. If the traverse was 
inadequate, the examiner should include an explanation 
as to why it was inadequate. 

D.Determine Whether the Next Office Action 
Should Be Made Final

If the examiner adds a reference in the next Office 
action after applicant’s rebuttal, and the newly added 
reference is added only as directly corresponding evidence 
to support the prior common knowledge finding, 
and it does not result in a new issue or constitute a 
new ground of rejection, the Office action may be 
made final. If no amendments are made to the claims, 
the examiner must not rely on any other teachings in 
the reference if the rejection is made final. If the 
newly cited reference is added for reasons other than 
to support the prior common knowledge statement 
and a new ground of rejection is introduced by the 
examiner that is not necessitated by applicant’s 
amendment of the claims, the rejection may not be 
made final. See MPEP § 706.07(a).

E.Summary

Any rejection based on assertions that a fact is well-
known or is common knowledge in the art without 
documentary evidence to support the examiner’s conclusion 
should be judiciously applied. Furthermore, as 
noted by the court in Ahlert, any facts so noticed 
should be of notorious character and serve only to 
“fill in the gaps” in an insubstantial manner which 
might exist in the evidentiary showing made by the 
examiner to support a particular ground for rejection. 
It is never appropriate to rely solely on common 
knowledge in the art without evidentiary support in 
the record as the principal evidence upon which a 
rejection was based. See Zurko, 258 F.3d at 1386, 59 
USPQ2d at 1697; Ahlert, 424 F.2d at 1092, 165 USPQ 
421. 

2144.04Legal Precedent as Source of Supporting 
Rationale [R-1]

As discussed in MPEP § 2144, if the facts in a prior 
legal decision are sufficiently similar to those in an 
application under examination, the examiner may use 
the rationale used by the court. Examples directed to 
various common practices which the court has held 
normally require only ordinary skill in the art and 
hence are considered routine expedients are discussed 
below. If the applicant has demonstrated the criticality 
of a specific limitation, it would not be appropriate to 
rely solely on case law as the rationale to support an 
obviousness rejection.

I.AESTHETIC DESIGN CHANGES

In re Seid, 161 F.2d 229, 73 USPQ 431 (CCPA 
1947) (Claim was directed to an advertising display 
device comprising a bottle and a hollow member in 
the shape of a human figure from the waist up which 
was adapted to fit over and cover the neck of the bottle, 
wherein the hollow member and the bottle 
together give the impression of a human body. Appellant 
argued that certain limitations in the upper part of 
the body, including the arrangement of the arms, were 
not taught by the prior art. The court found that matters 
relating to ornamentation only which have no 
mechanical function cannot be relied upon to patentably 
distinguish the claimed invention from the prior 
art.). But see In re Dembiczak, 175 F.3d 994, 
50 
USPQ2d 1614 (Fed. Cir. 1999) (The claims of a 
utility application, drawn to a generally round, orange 
plastic trash bag with a jack-o-lantern face, were 
rejected under 35 U.S.C. 103. However, the court 
reversed the rejection for lack of motivation to combine 
conventional trash bags with a reference showing 
a jack-o-lantern face on an orange paper bag stuffed 
with newspapers.); Ex parte Hilton, 148 
USPQ 356 
(Bd. App. 1965) (Claims were directed to fried potato 
chips with a specified moisture and fat content, 
whereas the prior art was directed to french fries having 
a higher moisture content. While recognizing that 
in some cases the particular shape of a product is of 
no patentable significance, the Board held in this case 
the shape (chips) is important because it results in a 
product which is distinct from the reference product 
(french fries).). 




 

II.ELIMINATION OF A STEP OR AN ELEMENT 
AND ITS FUNCTION

A.Omission of an Element and Its Function Is 
Obvious If the Function of the Element Is Not 
Desired

Ex parte Wu, 10 USPQ 2031 (Bd. Pat. App. & Inter. 
1989) (Claims at issue were directed to a 
method for 
inhibiting corrosion on metal surfaces using a composition 
consisting of epoxy resin, petroleum sulfonate, 
and hydrocarbon diluent. The claims were rejected 
over a primary reference which disclosed an anticorrosion 
composition of epoxy resin, hydrocarbon diluent, 
and polybasic acid salts wherein said salts were 
taught to be beneficial when employed in a freshwater 
environment, in view of secondary references which 
clearly suggested the addition of petroleum sulfonate 
to corrosion inhibiting compositions. The Board 
affirmed the rejection, holding that it would have been 
obvious to omit the polybasic acid salts of the primary 
reference where the function attributed to such salt is 
not desired or required, such as in compositions for 
providing corrosion resistance in environments which 
do not encounter fresh water.). See also In re Larson, 
340 F.2d 965, 144 USPQ 347 (CCPA 1965) (Omission 
of additional framework and axle which served 
to increase the cargo carrying capacity of prior art 
mobile fluid carrying unit would have been obvious if 
this feature was not desired.); and In re Kuhle, 
526 
F.2d 553, 188 USPQ 7 (CCPA 1975) (deleting a 
prior art switch member and thereby eliminating its 
function was an obvious expedient).

B.Omission of an Element with Retention of the 
Element's Function Is an Indicia of Unobviousness


Note that the omission of an element and retentionof its function is an indicia of unobviousness. In reEdge, 359 F.2d 896, 149 USPQ 556 (CCPA 1966) 
(Claims at issue were directed to a printed sheet having 
a thin layer of erasable metal bonded directly to 
the sheet wherein said thin layer obscured the original 
print until removal by erasure. The prior art disclosed 
a similar printed sheet which further comprised an 
intermediate transparent and erasure-proof protecting 
layer which prevented erasure of the printing when 
the top layer was erased. The claims were found 
unobvious over the prior art because the although the 
transparent layer of the prior art was eliminated, the 
function of the transparent layer was retained since 
appellant’s metal layer could be erased without erasing 
the printed indicia.).

III.AUTOMATING A MANUAL ACTIVITY 

In re Venner, 262 F.2d 91, 95, 120 USPQ 193, 194 
(CCPA 1958) (Appellant argued that claims to a permanent 
mold casting apparatus for molding trunk pistons 
were allowable over the prior art because the 
claimed invention combined “old permanent-mold 
structures together with a timer and solenoid which 
automatically actuates the known pressure valve system 
to release the inner core after a predetermined 
time has elapsed.” The court held that broadly providing 
an automatic or mechanical means to replace a 
manual activity which accomplished the same result 
is not sufficient to distinguish over the prior art.).

IV.CHANGES IN SIZE, SHAPE, OR SEQUENCE 
OF ADDING INGREDIENTS 

A.Changes in Size/Proportion

In re Rose, 220 F.2d 459, 105 USPQ 237 (CCPA 
1955) (Claims directed to a lumber package “of 
appreciable size and weight requiring handling by a 
lift truck” where held unpatentable over prior art lumber 
packages which could be lifted by hand because 
limitations relating to the size of the package were not 
sufficient to patentably distinguish over the prior art.); 
In re Rinehart, 531 F.2d 1048, 189 USPQ 143 (CCPA 
1976) (“mere scaling up of a prior art process capable 
of being scaled up, if such were the case, would not 
establish patentability in a claim to an old process so 
scaled.” 531 F.2d at 1053, 189 USPQ at 148.).

In Gardner v. TEC Systems, Inc., 725 F.2d 1338, 
220 USPQ 777 (Fed. Cir. 1984), cert. denied, 469 
U.S. 830, 225 USPQ 232 (1984), the Federal Circuit 
held that, where the only difference between the prior 
art and the claims was a recitation of relative dimensions 
of the claimed device and a device having the 
claimed relative dimensions would not perform differently 
than the prior art device, the claimed device was 
not patentably distinct from the prior art device.

B.Changes in Shape

In re Dailey, 357 F.2d 669, 149 USPQ 47 (CCPA 
1966) (The court held that the configuration of the 




 

claimed disposable plastic nursing container was a 
matter of choice which a person of ordinary skill in 
the art would have found obvious absent persuasive 
evidence that the particular configuration of the 
claimed container was significant.).

C.Changes in Sequence of Adding Ingredients

Ex parte Rubin, 128 USPQ 440 (Bd. App. 1959) 
(Prior art reference disclosing a process of making a 
laminated sheet wherein a base sheet is first coated 
with a metallic film and thereafter impregnated with a 
thermosetting material was held to render prima facieobvious claims directed to a process of making a laminated 
sheet by reversing the order of the prior art process 
steps.). See also In re Burhans, 154 F.2d 690, 69 
USPQ 330 (CCPA 1946) (selection of any order of 
performing process steps is prima facie obvious in the 
absence of new or unexpected results); In re Gibson, 
39 F.2d 975, 5 USPQ 230 (CCPA 1930) (Selection of 
any order of mixing ingredients is prima facie obvious.). 


V.MAKING PORTABLE, INTEGRAL, SEPARABLE, 
ADJUSTABLE, OR CONTINUOUS

A.Making Portable

In re Lindberg, 194 F.2d 732, 93 USPQ 23 (CCPA 
1952) (Fact that a claimed device is portable or movable 
is not sufficient by itself to patentably distinguish 
over an otherwise old device unless there are new or 
unexpected results.).

B.Making Integral

In re Larson, 340 F.2d 965, 968, 144 USPQ 347, 
349 (CCPA 1965) (A claim to a fluid transporting 
vehicle was rejected as obvious over a prior art reference 
which differed from the prior art in claiming a 
brake drum integral with a clamping means, whereas 
the brake disc and clamp of the prior art comprise several 
parts rigidly secured together as a single unit. The 
court affirmed the rejection holding, among other reasons, 
“that the use of a one piece construction instead 
of the structure disclosed in [the prior art] would be 
merely a matter of obvious engineering choice.”); but 
see Schenck v. Nortron Corp., 713 F.2d 782, 218 
USPQ 698 (Fed. Cir. 1983) (Claims were directed to a 
vibratory testing machine (a hard-bearing wheel balancer) 
comprising a holding structure, a base structure, 
and a supporting means which form “a single 
integral and gaplessly continuous piece.” Nortron 
argued that the invention is just making integral what 
had been made in four bolted pieces. The court found 
this argument unpersuasive and held that the claims 
were patentable because the prior art perceived a need 
for mechanisms to dampen resonance, whereas the 
inventor eliminated the need for dampening via the 
one-piece gapless support structure, showing insight 
that was contrary to the understandings and expectations 
of the art.).

C.Making Separable

In re Dulberg, 289 F.2d 522, 523, 129 USPQ 348, 
349 (CCPA 1961) (The claimed structure, a lipstick 
holder with a removable cap, was fully met by the 
prior art except that in the prior art the cap is “press 
fitted” and therefore not manually removable. The 
court held that “if it were considered desirable for any 
reason to obtain access to the end of [the prior art’s] 
holder to which the cap is applied, it would be obvious 
to make the cap removable for that purpose.”). 

D.Making Adjustable

In re Stevens, 212 F.2d 197, 101 USPQ 284 (CCPA 
1954) (Claims were directed to a handle for a fishing 
rod wherein the handle has a longitudinally adjustable 
finger hook, and the hand grip of the handle connects 
with the body portion by means of a universal joint. 
The court held that adjustability, where needed, is not 
a patentable advance, and because there was an art-
recognized need for adjustment in a fishing rod, the 
substitution of a universal joint for the single pivot of 
the prior art would have been obvious.).

E.Making Continuous 

In re Dilnot, 319 F.2d 188, 138 USPQ 248 (CCPA 
1963) (Claim directed to a method of producing a 
cementitious structure wherein a stable air foam is 
introduced into a slurry of cementitious material differed 
from the prior art only in requiring the addition 
of the foam to be continuous. The court held the 
claimed continuous operation would have been obvious 
in light of the batch process of the prior art.).




 

VI.REVERSAL, DUPLICATION, OR REARRANGEMENT 
OF PARTS 

A.Reversal of Parts

In re Gazda, 219 F.2d 449, 104 USPQ 400 (CCPA 
1955) (Prior art disclosed a clock fixed to the stationary 
steering wheel column of an automobile while the 
gear for winding the clock moves with steering wheel; 
mere reversal of such movement, so the clock moves 
with wheel, was held to be an obvious expedient.).

B.Duplication of Parts

In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 
1960) (Claims at issue were directed to a water-tight 
masonry structure wherein a water seal of flexible 
material fills the joints which form between adjacent 
pours of concrete. The claimed water seal has a “web” 
which lies  in the joint, and a plurality of “ribs” 
projecting outwardly from each side of the web into 
one of the adjacent concrete slabs. The prior art disclosed 
a flexible water stop for preventing passage of 
water between masses of concrete in the shape of a 
plus sign (+). Although the reference did not disclose 
a plurality of ribs, the court held that mere duplication 
of parts has no patentable significance unless a new 
and unexpected result is produced.).

C.Rearrangement of Parts

In re Japikse, 181 F.2d 1019, 86 USPQ 70 (CCPA 
1950) (Claims to a hydraulic power press which read 
on the prior art except with regard to the position of 
the starting switch were held unpatentable because 
shifting the position of the starting switch would not 
have modified the operation of the device.); In re 
Kuhle, 526 F.2d 553, 188 USPQ 7 (CCPA 1975) (the 
particular placement of a contact in a conductivity 
measuring device was held to be an obvious matter of 
design choice). However, “The mere fact that a 
worker in the art could rearrange the parts of the reference 
device to meet the terms of the claims on appeal 
is not by itself sufficient to support a finding of obviousness. 
The prior art must provide a motivation or 
reason for the worker in the art, without the benefit of 
appellant’s specification, to make the necessary 
changes in the reference device.” Ex parte Chicago 
Rawhide Mfg. Co., 223 USPQ 351, 353 (Bd. Pat. App. 
& Inter. 1984).

VII.PURIFYING AN OLD PRODUCT

Pure materials are novel vis-à-vis less pure or 
impure materials because there is a difference 
between pure and impure materials. Therefore, the 
issue is whether claims to a pure material are unobvious 
over the prior art. In re Bergstrom, 427 F.2d 1394, 
166 USPQ 256 (CCPA 1970). Purer forms of known 
products may be patentable, but the mere purity of a 
product, by itself, does not render the product unobvious. 
Ex parte Gray, 10 USPQ2d 1922 (Bd. Pat. App. 
& Inter. 1989).

Factors to be considered in determining whether a 
purified form of an old product is obvious over the 
prior art include whether the claimed chemical compound 
or composition has the same utility as closely 
related materials in the prior art, and whether the prior 
art suggests the particular form or structure of the 
claimed material or suitable methods of obtaining that 
form or structure. In re Cofer, 354 F.2d 664, 
148 
USPQ 268 (CCPA 1966) (Claims to the free-
flowing crystalline form of a compound were 
held 
unobvious over references disclosing the viscous 
liquid form of the same compound because the prior 
art of record did not suggest the claimed compound in 
crystalline form or how to obtain such crystals.). 

See also Ex parte Stern, 13 USPQ2d 1379 (Bd. Pat. 
App. & Inter. 1987) (Claims to interleukin 2 (a protein 
with a molecular weight of over 12,000) purified to 
homogeneity were held unpatentable over references 
which recognized the desirability of purifying interleukin 
2 to homogeneity in a view of a reference 
which taught a method of purifying proteins having 
molecular weights in excess of 12,000 to homogeneity 
wherein the prior art method was similar to the 
method disclosed by appellant for purifying interleukin 
2.). 

Compare Ex parte Gray, 10 USPQ2d 1922 (Bd. 
Pat. App. & Inter. 1989) (Claims were directed to 
human nerve growth factor b-NGF free from other 
proteins of human origin, and the specification disclosed 
making the claimed factor through the use of 
recombinant DNA technology. The claims were 
rejected as prima facie obvious in view of two references 
disclosing b-NGF isolated from human placental 
tissue. The Board applied case law pertinent to 
product-by-process claims, reasoning that the prior art 
factor appeared to differ from the claimed factor only 
in the method of obtaining the factor. The Board held 




 

that the burden of persuasion was on appellant to 
show that the claimed product exhibited unexpected 
properties compared with that of the prior art. The 
Board further noted that “no objective evidence has 
been provided establishing that no method was known 
to those skilled in this field whereby the claimed 
material might have been synthesized.” 10 USPQ2d at 
1926.).

2144.05Obviousness of Ranges [R-5]

See MPEP § 2131.03 for case law pertaining to 
rejections based on the anticipation of ranges under 
35 U.S.C. 102 and 35 U.S.C. 102/103.

I.OVERLAP OF RANGES

In the case where the claimed ranges “overlap or lie 
inside ranges disclosed by the prior art” a prima faciecase of obviousness exists. In re Wertheim, 541 F.2d 
257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 
F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990) (The 
prior art taught carbon monoxide concentrations of 
“about 1-5%” while the claim was limited to “more 
than 5%.” The court held that “about 1-5%” allowed 
for concentrations slightly above 5% thus the ranges 
overlapped.); In re Geisler, 116 F.3d 1465, 1469-71, 
43 USPQ2d 1362, 1365-66 (Fed. Cir. 1997) (Claim 
reciting thickness of a protective layer as falling 
within a range of “50 to 100 Angstroms” considered 
prima facie obvious in view of prior art reference 
teaching that “for suitable protection, the thickness of 
the protective layer should be not less than about 10 
nm [i.e., 100 Angstroms].” The court stated that “by 
stating that ‘suitable protection’ is provided if the protective 
layer is ‘about’ 100 Angstroms thick, [the 
prior art reference] directly teaches the use of a thickness 
within [applicant’s] claimed range.”). Similarly, 
a prima facie case of obviousness exists where the 
claimed ranges and prior art ranges do not overlap but 
are close enough that one skilled in the art would have 
expected them to have the same properties. Titanium 
Metals Corp. of America v. Banner, 778 F.2d 775, 
227 
USPQ 773 (Fed. Cir. 1985) (Court held as proper 
a rejection of a claim directed to an alloy of “having 
0.8% nickel, 0.3% molybdenum, up to 0.1% iron, balance 
titanium” as obvious over a reference disclosing 
alloys of 0.75% nickel, 0.25% molybdenum, balance 
titanium and 0.94% nickel, 0.31% molybdenum, balance 
titanium.). 

“[A] prior art reference that discloses a range 
encompassing a somewhat narrower claimed range is 
sufficient to establish a prima facie case of obviousness.” 
In re Peterson, 315 F.3d 1325, 1330, 
65 
USPQ2d 1379, 1382-83 (Fed. Cir. 2003). See 
also In re Harris, 409 F.3d 1339, 74 USPQ2d 1951 
(Fed. Cir. 2005)(claimed alloy held obvious over prior 
art alloy that taught ranges of weight percentages 
overlapping, and in most instances completely 
encompassing, claimed ranges; furthermore, narrower 
ranges taught by reference overlapped all but one 
range in claimed invention). However, if the reference’s 
disclosed range is so broad as to encompass a 
very large number of possible distinct compositions, 
this might present a situation analogous to the obviousness 
of a species when the prior art broadly discloses 
a genus. Id. See also In re Baird, 16 F.3d 380, 
29 USPQ2d 1550 (Fed. Cir. 1994); In re Jones, 958 
F.2d 347, 21 USPQ2d 1941 (Fed. Cir. 1992); MPEP 
§
 
2144.08.

A range can be disclosed in multiple prior art references 
instead of in a single prior art reference depending 
on the specific facts of the case. Iron Grip Barbell 
Co., Inc. v. USA Sports, Inc., 392 F.3d 1317, 1322, 73 
USPQ2d 1225, 1228 (Fed. Cir. 2004). The patent 
claim at issue was directed to a weight plate having 3 
elongated openings that served as handles for transporting 
the weight plate. Multiple prior art patents 
each disclosed weight plates having 1, 2 or 4 elongated 
openings. 392 F.3d at 1319, 73 USPQ2d at 
1226. The court stated that the claimed weight plate 
having 3 elongated openings fell within the “range” of 
the prior art and was thus presumed obvious. 392 F.3d 
at 1322, 73 USPQ2d at 1228. The court further stated 
that the “range” disclosed in multiple prior art patents 
is “a distinction without a difference” from previous 
range cases which involved a range disclosed in a single 
patent since the “prior art suggested that a larger 
number of elongated grips in the weight plates was 
beneficial… thus plainly suggesting that one skilled 
in the art look to the range appearing in the prior art.” 
Id.




 

II.OPTIMIZATION OF RANGES

A.Optimization Within Prior Art Conditions or 
Through Routine Experimentation

Generally, differences in concentration or temperature 
will not support the patentability of subject matter 
encompassed by the prior art unless there is 
evidence indicating such concentration or temperature 
is critical. “[W]here the general conditions of a claim 
are disclosed in the prior art, it is not inventive to discover 
the optimum or workable ranges by routine 
experimentation.” In re Aller, 220 F.2d 454, 456, 105 
USPQ 233, 235 (CCPA 1955) (Claimed process 
which was performed at a temperature between 40°C 
and 80°C and an acid concentration between 25% and 
70% was held to be prima facie obvious over a reference 
process which differed from the claims only in 
that the reference process was performed at a temperature 
of 100°C and an acid concentration of 10%.); 
see also Peterson, 315 F.3d at 1330, 65 USPQ2d at 
1382 (“The normal desire of scientists or artisans to 
improve upon what is already generally known provides 
the motivation to determine where in a disclosed 
set of percentage ranges is the optimum 
combination of percentages.”); In re Hoeschele, 406 
F.2d 1403, 160 USPQ 809 (CCPA 1969) (Claimed 
elastomeric polyurethanes which fell within the broad 
scope of the references were held to be unpatentable 
thereover because, among other reasons, there was no 
evidence of the criticality of the claimed ranges of 
molecular weight or molar proportions.). For more 
recent cases applying this principle, see Merck & Co. 
Inc. v. Biocraft Laboratories Inc., 874 F.2d 804, 10 
USPQ2d 1843 (Fed. Cir.), cert. denied, 493 U.S. 975 
(1989); In re Kulling, 897 F.2d 1147, 14 USPQ2d 
1056 (Fed. Cir. 1990); and In re Geisler, 116 F.3d 
1465, 43 USPQ2d 1362 (Fed. Cir. 1997).

B.Only Result-Effective Variables Can Be Optimized


A particular parameter must first be recognized as a 
result-effective variable, i.e., a variable which 
achieves a recognized result, before the determination 
of the optimum or workable ranges of said variable 
might be characterized as routine experimentation. In 
re Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977) 
(The claimed wastewater treatment device had a tank 
volume to contractor area of 0.12 gal./sq. ft. The prior 
art did not recognize that treatment capacity is a function 
of the tank volume to contractor ratio, and therefore 
the parameter optimized was not recognized in 
the art to be a result- effective variable.). See also In 
re Boesch, 617 F.2d 272, 205 USPQ 215 
(CCPA 
1980) (prior art suggested proportional balancing 
to achieve desired results in the formation of 
an alloy).

III.REBUTTAL OF PRIMA FACIE CASE OF 
OBVIOUSNESS

Applicants can rebut a prima facie case of obviousness 
based on overlapping ranges by showing the criticality 
of the claimed range. “The law is replete with 
cases in which the difference between the claimed 
invention and the prior art is some range or other variable 
within the claims. . . . In such a situation, the 
applicant must show that the particular range is critical, 
generally by showing that the claimed range 
achieves unexpected results relative to the prior art 
range.” In re Woodruff, 919 F.2d 1575, 16 USPQ2d 
1934 (Fed. Cir. 1990). See MPEP § 716.02 - 
§
 
716.02(g) for a discussion of criticality and unexpected 
results. 

A prima facie case of obviousness may also be 
rebutted by showing that the art, in any material 
respect, teaches away from the claimed invention. In 
re Geisler, 116 F.3d 1465, 1471, 43 USPQ2d 1362, 
1366 (Fed. Cir. 1997) (Applicant argued that the prior 
art taught away from use of a protective layer for a 
reflective article having a thickness within the 
claimed range of “50 to 100 Angstroms.” Specifically, 
a patent to Zehender, which was relied upon to reject 
applicant’s claim, included a statement that the thickness 
of the protective layer “should be not less than 
about [100 Angstroms].” The court held that the 
patent did not teach away from the claimed invention. 
“Zehender suggests that there are benefits to be 
derived from keeping the protective layer as thin as 
possible, consistent with achieving adequate protection. 
A thinner coating reduces light absorption and 
minimizes manufacturing time and expense. Thus, 
while Zehender expresses a preference for a thicker 
protective layer of 200-300 Angstroms, at the same 
time it provides the motivation for one of ordinary 
skill in the art to focus on thickness levels at the bottom 
of Zehender’s ‘suitable’ range- about 100 Angstroms- 
and to explore thickness levels below that 




 

range. The statement in Zehender that ‘[i]n general, 
the thickness of the protective layer should be not less 
than about [100 Angstroms]’ falls far short of the kind 
of teaching that would discourage one of skill in the 
art from fabricating a protective layer of 100 Angstroms 
or less. [W]e are therefore ‘not convinced that 
there was a sufficient teaching away in the art to overcome 
[the] strong case of obviousness’ made out by 
Zehender.”). See MPEP § 2145, paragraph X.D., for a 
discussion of “teaching away” references. 

Applicant can rebut a presumption of obviousness 
based on a claimed invention that falls within a prior 
art range by showing “(1) [t]hat the prior art taught 
away from the claimed invention...or (2) that there are 
new and unexpected results relative to the prior art.” 
Iron Grip Barbell Co., Inc. v. USA Sports, Inc., 392 
F.3d 1317, 1322, 73 USPQ2d 1225, 1228 (Fed. Cir. 
2004). The court found that patentee offered neither 
evidence of teaching away of the prior art nor new 
and unexpected results of the claimed invention 
drawn to a weight plate having 3 elongated handle 
openings. 392 F.3d at 1323, 73 USPQ2d at 1229. The 
court then turned to considering substantial evidence 
of pertinent secondary factors such as commercial 
success, satisfaction of a long-felt need, and copying 
by others may also support patentability. Id. Nevertheless, 
the court found that Iron Grip failed to show evidence 
of commercial success, copying by others, or 
satisfaction of a long felt need for the following reasons: 
(A) Iron Grip’s licensing of its patent to three 
competitors was insufficient to show nexus between 
the “merits of the invention and the licenses,” and 
thus did not establish secondary consideration of 
commercial success; (B) in response to Iron Grip’s 
argument that the competitor’s production of a three-
hole plate is evidence of copying, the court stated that 
“[n]ot every competing product that falls within the 
scope of a patent is evidence of copying” since 
“[o]therwise every infringement suit would automatically 
confirm the nonobviousness of the patent;” and 
(C) although Iron Grip offered as evidence that the 
absence of the three-grip plate on the market prior to 
its patent showed that the invention was nonobviousness, 
the court stated that “[a]bsent a showing of a 
long-felt need or the failure of others, the mere passage 
of time without the claimed invention is not evidence 
of nonobviousness.” 392 F.3d at 1324-25, 73 
USPQ2d at 1229-30.

2144.06Art Recognized Equivalence for 
the Same Purpose 

COMBINING EQUIVALENTS KNOWN FOR 
THE SAME PURPOSE

“It is prima facie obvious to combine two compositions 
each of which is taught by the prior art to be useful 
for the same purpose, in order to form a third 
composition to be used for the very same purpose.... 
[T]he idea of combining them flows logically from 
their having been individually taught in the prior art.” 
In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 
1072 (CCPA 1980) (citations omitted) (Claims to a 
process of preparing a spray-dried detergent by mixing 
together two conventional spray-dried detergents 
were held to be prima facie obvious.). See also In reCrockett, 279 F.2d 274, 126 USPQ 186 (CCPA 1960) 
(Claims directed to a method and material for treating 
cast iron using a mixture comprising calcium carbide 
and magnesium oxide were held unpatentable over 
prior art disclosures that the aforementioned components 
individually promote the formation of a nodular 
structure in cast iron.); and Ex parte Quadranti, 
25 
USPQ2d 1071 (Bd. Pat. App. & Inter. 1992) (mixture 
of two known herbicides held prima facie obvious). 
But see In re Geiger, 815 F.2d 686, 2 USPQ2d 
1276 (Fed. Cir. 1987) (“Based upon the prior art and 
the fact that each of the three components of the composition 
used in the claimed method is conventionally 
employed in the art for treating cooling water systems, 
the board held that it would have been prima 
facie obvious, within the meaning of 35 U.S.C. 103, 
to employ these components in combination for their 
known functions and to optimize the amount of each 
additive.... Appellant argues... hindsight reconstruction 
or at best,... ‘obvious to try’.... We agree with 
appellant.”).

SUBSTITUTING EQUIVALENTS KNOWN FOR 
THE SAME PURPOSE

In order to rely on equivalence as a rationale supporting 
an obviousness rejection, the equivalency 
must be recognized in the prior art, and cannot be 
based on applicant’s disclosure or the mere fact that 
the components at issue are functional or mechanical 
equivalents. In re Ruff, 256 F.2d 590, 118 USPQ 340 
(CCPA 1958) (The mere fact that components are 




 

claimed as members of a Markush group cannot be 
relied upon to establish the equivalency of these components. 
However, an applicant’s expressed recognition 
of an art-recognized or obvious equivalent may 
be used to refute an argument that such equivalency 
does not exist.); In re Scott, 323 F.2d 1016, 139 USPQ 
297 (CCPA 1963) (Claims were drawn to a hollow 
fiberglass shaft for archery and a process for the production 
thereof where the shaft differed from the prior 
art in the use of a paper tube as the core of the shaft as 
compared with the light wood or hardened foamed 
resin core of the prior art. The Board found the 
claimed invention would have been obvious, reasoning 
that the prior art foam core is the functional and 
mechanical equivalent of the claimed paper core. The 
court reversed, holding that components which are 
functionally or mechanically equivalent are not necessarily 
obvious in view of one another, and in this case, 
the use of a light wood or hardened foam resin core 
does not fairly suggest the use of a paper core.); Smithv. Hayashi, 209 USPQ 754 (Bd. of Pat. Inter. 1980) 
(The mere fact that phthalocyanine and selenium 
function as equivalent photoconductors in the claimed 
environment was not sufficient to establish that one 
would have been obvious over the other. However, 
there was evidence that both phthalocyanine and selenium 
were known photoconductors in the art of electrophotography. 
“This, in our view, presents strong 
evidence of obviousness in substituting one for the 
other in an electrophotographic environment as a photoconductor.” 
209 USPQ at 759.).

An express suggestion to substitute one equivalent 
component or process for another is not necessary to 
render such substitution obvious. In re Fout, 675 F.2d 
297, 213 USPQ 532 (CCPA 1982).

2144.07Art Recognized Suitability for anIntended Purpose 

The selection of a known material based on its suitability 
for its intended use supported a prima facieobviousness determination in Sinclair & Carroll Co. 
v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 
(1945) (Claims to a printing ink comprising a 
solvent 
having the vapor pressure characteristics of 
butyl carbitol so that the ink would not dry at room 
temperature but would dry quickly upon heating were 
held invalid over a reference teaching a printing ink 
made with a different solvent that was nonvolatile at 
room temperature but highly volatile when heated in 
view of an article which taught the desired boiling 
point and vapor pressure characteristics of a solvent 
for printing inks and a catalog teaching the boiling 
point and vapor pressure characteristics of butyl carbitol. 
“Reading a list and selecting a known compound 
to meet known requirements is no more ingenious 
than selecting the last piece to put in the last opening 
in a jig-saw puzzle.” 325 U.S. at 335, 65 USPQ at 
301.).

See also In re Leshin, 227 F.2d 197, 125 USPQ 416 
(CCPA 1960) (selection of a known plastic to make a 
container of a type made of plastics prior to the invention 
was held to be obvious); Ryco, Inc. v. Ag-Bag 
Corp., 857 F.2d 1418, 8 USPQ2d 1323 (Fed. Cir. 
1988) (Claimed agricultural bagging machine, which 
differed from a prior art machine only in that the 
brake means were hydraulically operated rather than 
mechanically operated, was held to be obvious over 
the prior art machine in view of references which disclosed 
hydraulic brakes for performing the same function, 
albeit in a different environment.).

2144.08Obviousness of Species When 
Prior Art Teaches Genus

I.GUIDELINES FOR THE EXAMINATION 
OF CLAIMS DIRECTED TO SPECIES OF 
CHEMICAL COMPOSITIONS BASED 
UPON A SINGLE PRIOR ART REFERENCE


These “Genus-Species Guidelines” are to assist 
Office personnel in the examination of applications 
which contain claims to species or a subgenus of 
chemical compositions for compliance with 35 U.S.C. 
103 based upon 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 follow these guidelines 
to determine whether a single reference 
35 
U.S.C. 103 rejection would be appropriate. 
The 
guidelines are based on the Office’s current 
understanding of the law and are believed to be fully 




 

consistent with binding precedent of the Supreme 
Court, the Federal Circuit, and the Federal Circuit’s 
predecessor courts.

The analysis of the guidelines begins at the point 
during examination after a single prior art reference is 
found disclosing a genus encompassing the claimed 
species or subgenus. Before reaching this point, 
Office personnel should follow appropriate antecedent 
examination procedures. Accordingly, Office personnel 
should first analyze the claims as a whole in 
light of and consistent with the written description, 
considering all claim limitations. When evaluating the 
scope of a claim, every limitation in the claim must be 
considered. See, e.g., In re Ochiai, 71 F.3d 1565, 
1572, 37 USPQ2d 1127, 1133 (Fed. Cir. 1995). However, 
the claimed invention may not be dissected into 
discrete elements to be analyzed in isolation, but must 
be considered as a whole. See, e.g., W.L. Gore & 
Assoc., Inc. v. Garlock, Inc., 721 F.2d 1540, 1548, 
220 
USPQ 303, 309 (Fed. Cir. 1983); Jones v. Hardy, 
727 F.2d 1524, 1530, 220 USPQ 1021, 1026 (Fed. Cir. 
1983) (“treating the advantage as the invention disregards 
the statutory requirement that the invention be 
viewed ‘as a whole’”). Next, Office personnel should 
conduct a thorough search of the prior art and identify 
all relevant references. Both claimed and unclaimed 
aspects of the invention should be searched if there is 
a reasonable expectation that the unclaimed aspects 
may be later claimed. If the most relevant prior art 
consists of a single prior art reference disclosing a 
genus encompassing the claimed species or subgenus, 
Office personnel should follow the guidelines set 
forth herein.

These guidelines do not constitute substantive rulemaking 
and hence do not have the force and effect of 
law. Rather, they are to assist Office personnel in analyzing 
claimed subject matter for compliance with 
substantive law. Thus, rejections must be based upon 
the substantive law, and it is these rejections which 
are appealable, not any failure by Office personnel to 
follow these guidelines.

Office personnel are to rely on these guidelines in 
the event of any inconsistent treatment of issues 
between these guidelines and any earlier provided 
guidance from the Office. 

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 
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.” In re Papesch, 315 F.2d 381, 385, 137 
USPQ 43, 47 (CCPA 1963). 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. See, e.g., In re Dillon, 919 F.2d 
688, 692-93, 16 USPQ2d 1897, 1901 (Fed. Cir. 1990) 
(in banc). 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. 
See, e.g., In re Brouwer, 77 F.3d 422, 425, 
37 
USPQ2d 1663, 1666 (Fed. Cir. 1996); In re Ochiai, 
71 F.3d 1565, 1572, 37 
USPQ2d 1127, 1133 (Fed. Cir. 
1995); In re Baird, 16 F.3d 380, 382, 29 USPQ2d 
1550, 1552 (Fed. Cir. 1994). 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. In re Baird, 16 F.3d 380, 
382, 29 USPQ2d 1550, 1552 (Fed. Cir. 1994) (“The 
fact that a claimed compound may be encompassed 
by a disclosed generic formula does not by itself render 
that compound obvious.”); In re Jones, 958 F.2d 
347, 350, 21 USPQ2d 1941, 1943 (Fed. Cir. 1992) 
(Federal Circuit has “decline[d] to extract from Merck[& Co. v. Biocraft Laboratories Inc., 874 F.2d 804, 10 
USPQ2d 1843 (Fed. Cir. 1989)] the rule that... regardless 
of how broad, a disclosure of a chemical genus 
renders obvious any species that happens to fall 
within it.”). See also In re Deuel, 51 F.3d 1552, 1559, 
34 USPQ2d 1210, 1215 (Fed. Cir. 1995). 

A proper obviousness analysis involves a three-step 
process. First, Office personnel should establish a 
prima facie case of unpatentability considering the 
factors set out by the Supreme Court in Graham v. 
John Deere. See, e.g., In re Bell, 991 F.2d 781, 783, 
26 USPQ2d 1529, 1531 (Fed. Cir. 1993) (“The PTO 
bears the burden of establishing a case of prima facieobviousness.”); In re Rijckaert, 9 F.3d 1531, 1532, 




 

28 USPQ2d 1955, 1956 (Fed. Cir. 1993); In re Oetiker, 
977 F.2d 1443, 1445, 24 USPQ2d 1443, 1444 
(Fed. Cir. 1992). Graham v. John Deere Co., 383 U.S. 
1, 17-18 (1966), requires that to make out a case of 
obviousness, one must: 

(A)determine the scope and contents of the prior 
art; 

(B)ascertain the differences between the prior art 
and the claims in issue; 

(C)determine the level of skill in the pertinent 
art; and 

(D)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. 

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. 
See, e.g., Bell, 991 F.2d at 783-84, 26 USPQ2d at 
1531; Rijckaert, 9 F.3d at 1532, 28 USPQ2d at 1956; 
Oetiker, 977 
F.2d at 1445, 24 USPQ2d at 1444.
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. Id. 

A.Establishing a Prima Facie Case of Obviousness


To establish a prima facie case of obviousness in a 
genus-species chemical composition situation, as in 
any other 35 U.S.C. 103 case, it is essential that Office 
personnel find some motivation or suggestion to make 
the claimed invention in light of the prior art teachings. 
See, e.g., In re Brouwer, 77 F.3d 422, 425, 
37 
USPQ2d 1663, 1666 (Fed. Cir. 1996) (“[T]he 
mere 
possibility that one of the esters or the active 
methylene group-containing compounds... could be 
modified or replaced such that its use would lead to 
the specific sulfoalkylated resin recited in claim 
8 
does not make the process recited in claim 8 obvious 
‘unless the prior art suggested the desirability of 
[such a] modification’ or replacement.”) (quoting In 
re Gordon, 733 F.2d 900, 902, 221 USPQ 1125, 1127 
(Fed. Cir. 1984)); In re Vaeck, 947 F.2d 488, 493, 
20 
USPQ2d 1438, 1442 (Fed. Cir. 1991) (“[A] 
proper 
analysis under § 103 requires, inter alia, consideration 
of... whether the prior art would have suggested 
to those of ordinary skill in the art that they 
should make the claimed composition or device, or 
carry out the claimed process.”). In order to find such 
motivation or suggestion there should be a reasonable 
likelihood that the claimed invention would have the 
properties disclosed by the prior art teachings. The 
prior art disclosure may be express, implicit, or inherent. 
Regardless of the type of disclosure, the prior art 
must provide some motivation to one of ordinary skill 
in the art to make the claimed invention in order to 
support a conclusion of obviousness. See, e.g., Vaeck, 
947 F.2d at 493, 20 USPQ2d at 1442 (A proper obviousness 
analysis requires consideration of “whether 
the prior art would also have revealed that in so making 
or carrying out [the claimed invention], those of 
ordinary skill would have a reasonable expectation of 
success.”); In re Dow Chemical Co., 837 F.2d 469, 
473, 5 USPQ2d 1529, 1531 (Fed. Cir. 1988) (“The 
consistent criterion for determination of obviousness 
is whether the prior art would have suggested to one 
of ordinary skill in the art that this process should be 
carried out and would have a reasonable likelihood of 
success, viewed in the light of the prior art.”); Hodosh 
v. Block Drug Co., 786 F.2d 1136, 1143 n.5, 
229 
USPQ 182, 187 n.5 (Fed. Cir. 1986). These disclosed 
findings should be made with a complete 
understanding of the first three “Graham factors.” 
When evidence of secondary considerations such as 
unexpected results is initially before the Office, for 
example in the specification, that evidence should be 
considered in deciding whether there is a prima faciecase of obviousness. The determination as to whether 
a prima facie case exists should be made on the full 
record before the Office at the time of the determination. 
Thus, Office personnel should: 

(A)determine the “scope and content of the prior 
art”; 

(B)ascertain the “differences between the prior 
art and the claims at issue”; and 

(C)determine “the level of ordinary skill in the 
pertinent art.” 

Graham v. John Deere, 383 U.S. 1, 17, 148 USPQ 
459, 467 (1966). Accord, e.g., In re Paulsen, 30 F.3d 
1475, 1482, 31 USPQ2d 1671, 1676 (Fed. Cir. 1994). 




 

1.Determine the Scope and Content of the 
Prior Art 

As an initial matter, Office personnel should determine 
the scope and content of the relevant prior art. 
Each reference must qualify as prior art under 35 
U.S.C. 102 (e.g., Panduit Corp. v. Dennison Mfg. Co., 
810 F.2d 1561, 1568, 1 USPQ2d 1593, 1597 (Fed. Cir. 
1987) (“Before answering Graham’s ‘content’ 
inquiry, it must be known whether a patent or publication 
is in the prior art under 35 U.S.C. §
 
102.”)) and 
should be in the field of applicant’s endeavor, or be 
reasonably pertinent to the particular problem with 
which the inventor was concerned. In re Oetiker, 977 
F.2d 1443, 1447, 24 USPQ2d 1443, 1445 (Fed. Cir. 
1992). Accord, e.g., In re Clay, 966 F.2d 656, 658-
59, 23 USPQ2d 1058, 1060 (Fed. Cir. 1992).

In the case of a prior art reference disclosing a 
genus, Office personnel should make findings as to: 

(A)the structure of the disclosed prior art genus 
and that of any expressly described species or subgenus 
within the genus; 

(B)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; 

(C)the predictability of the technology; and 

(D)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, chemical 
properties and utilities. In Stratoflex, Inc. v. Aeroquip 
Corp., 713 F.2d 1530, 1537, 218 USPQ 871, 877 
(Fed. Cir. 1983), the Court noted that “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.” 
(emphasis in original). 

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. See, Ryko Mfg. Co. v. Nu-Star Inc., 950 
F.2d 714, 718, 21 USPQ2d 1053, 1057 (Fed. Cir. 
1991) (“The importance of resolving the level of ordinary 
skill in the art lies in the necessity of maintaining 
objectivity in the obviousness inquiry.”); Uniroyal 
Inc. v. Rudkin-Wiley Corp., 837 F.2d 1044, 1050, 5 
USPQ2d 1434, 1438 (Fed. Cir. 1988) (evidence must 
be viewed from position of ordinary skill, not of an 
expert). 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. 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 three 
Graham factors, Office personnel should determine 
whether one of ordinary skill in the relevant art would 
have been motivated to make the claimed invention as 
a whole, i.e., to select the claimed species or subgenus 
from the disclosed prior art genus. See, e.g., Ochiai, 
71 F.3d at 1569-70, 37 
USPQ2d at 1131; Deuel, 
51 
F.3d at 1557, 34 USPQ2d at 1214 (“[A] prima 
facie case of unpatentability requires that the teachings 
of the prior art suggest the claimed compounds to 
a person of ordinary skill in the art.” (emphasis in 
original)); Jones, 958 F.2d at 351, 21 USPQ2d at 
1943-44 (Fed. Cir. 1992); Dillon, 919 F.2d at 692, 16 
USPQ2d at 1901; In re Lalu, 747 F.2d 703, 705, 
223 
USPQ 1257, 1258 (Fed. Cir. 1984) (“The prior art 
must provide one of ordinary skill in the art the motivation 
to make the proposed molecular modifications 
needed to arrive at the claimed compound.”). See also 
In re Kemps, 97 F.3d 1427, 1430, 40 USPQ2d 1309, 




 

1311 (Fed. Cir. 1996) (discussing motivation to combine). 
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. See, e.g., Baird, 16 F.3d at 383, 29 USPQ2d 
at 1552 (observing that “it is not the mere number of 
compounds in this limited class which is significant 
here but, rather, the total circumstances involved”). 
There is no absolute correlation between the size of 
the prior art genus and a conclusion of obviousness. 
Id. Thus, the mere fact that a prior art genus contains a 
small number of members does not create a per serule of obviousness. Some motivation to select the 
claimed species or subgenus must be taught by the 
prior art. See, e.g., Deuel, 51 F.3d at 1558-59, 34 
USPQ2d at 1215 (“No particular one of these DNAs 
can be obvious unless there is something in the prior 
art to lead to the particular DNA and indicate that it 
should be prepared.”); Baird, 16 F.3d at 382-83, 
29 
USPQ2d at 1552; Bell, 991 F.2d at 784, 
26 
USPQ2d at 1531 (“Absent anything in the cited 
prior art suggesting which of the 1036 possible 
sequences suggested by Rinderknecht corresponds to 
the IGF gene, the PTO has not met its burden of establishing 
that the prior art would have suggested the 
claimed sequences.”). 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. In 
re Petering, 301 F.2d 676, 681, 133 USPQ 275, 280 
(CCPA 1962) (emphasis in original). 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.

Id. (emphasis in original). Accord In re Schaumann, 
572 F.2d 312, 316, 197 USPQ 5, 9 (CCPA 1978) 
(prior art genus encompassing claimed species which 
disclosed preference for lower alkyl secondary amines 
and properties possessed by the claimed compound 
constituted description of claimed compound for purposes 
of 35 U.S.C. 102(b)). C.f., In re Ruschig, 
343 
F.2d 965, 974, 145 USPQ 274, 282 (CCPA 1965) 
(Rejection of claimed compound in light of prior art 
genus based on Petering is not appropriate where the 
prior art does not disclose a small recognizable class 
of compounds with common properties.).

(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 
which would have motivated 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. 
For example, see Merck & Co. v. Biocraft 
Labs., 874 F.2d 804, 807, 10 USPQ2d 1843, 1846 
(Fed. Cir. 1989) (holding claims directed to diuretic 
compositions comprising a specific mixture of 
amiloride and hydrochlorothiazide were obvious over 
a prior art reference expressly teaching that amiloride 
was a pyrazinoylguanidine which could be coadministered 
with potassium excreting diuretic agents, including 
hydrochlorothiazide which was a named example, 
to produce a diuretic with desirable sodium and potassium 
eliminating properties). See also, In re Kemps, 
97 F.3d 1427, 1430, 40 USPQ2d 1309, 1312 (Fed. Cir. 
1996) (holding there is sufficient motivation to combine 
teachings of prior art to achieve claimed invention 
where one reference specifically refers to the 
other). 

(c)Consider the Teachings of Structural Similarity


Consider any teachings of a “typical,” “preferred,” 
or “optimum” species or subgenus within the dis





 

closed genus. If such a species or subgenus is structurally 
similar to that claimed, its disclosure may 
motivate 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. See, e.g., Dillon, 
919 F.2d at 693, 696, 16 USPQ2d at 1901, 1904. 
See also Deuel, 51 F.3d at 1558, 34 USPQ2d at 1214 
(“Structural relationships may provide the requisite 
motivation or suggestion to modify known compounds 
to obtain new compounds. For example, a 
prior art compound may suggest its homologs because 
homologs often have similar properties and therefore 
chemists of ordinary skill would ordinarily contemplate 
making them to try to obtain compounds with 
improved properties.”). The utility of such properties 
will normally provide some motivation to make the 
claimed species or subgenus. Id.

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. See, e.g., In re Jones, 
958 F.2d 347, 350, 21 USPQ2d 1941, 1943 (Fed. Cir. 
1992) (reversing obviousness rejection of novel 
dicamba salt with acyclic structure over broad prior 
art genus encompassing claimed salt, where disclosed 
examples of genus were dissimilar in structure, lacking 
an ether linkage or being cyclic); In re Susi, 440 
F.2d 442, 445, 169 USPQ 423, 425 (CCPA 1971) (the 
difference from the particularly preferred subgenus of 
the prior art was a hydroxyl group, a difference conceded 
by applicant “to be of little importance”). In the 
area of biotechnology, an exemplified species may 
differ from a claimed species by a 
conservative substitution 
(“the replacement in a protein of 
one amino 
acid by another, chemically similar, amino acid... 
[which] is generally expected to lead to either no 
change or only a small change in the properties of the 
protein.” Dictionary of Biochemistry and Molecular 
Biology 97 (John Wiley & Sons, 2d ed. 1989)). 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. James Darnell et 
al., Molecular Cell Biology 51 (2d ed. 1990). 

The closer the physical and 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. See, e.g., Dillon, 919 F.2d at 696, 16 
USPQ2d at 1904 (and cases cited therein). Cf. Baird, 
16 F.3d at 382-83, 29 USPQ2d at 1552 (disclosure of 
dissimilar species can provide teaching away). 

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. Baird, 
16 
F.3d at 382-83, 29 USPQ2d at 1552 (reversing 
obviousness rejection of species in view of large size 
of genus and disclosed “optimum” species which differed 
greatly from and were more complex than the 
claimed species); Jones, 958 F.2d at 350, 21 USPQ2d 
at 1943 (reversing obviousness rejection of novel 
dicamba salt with acyclic structure over broad prior 
art genus encompassing claimed salt, where disclosed 
examples of genus were dissimilar in structure, lacking 
an ether linkage or being cyclic). For example, 
teachings of preferred species of a complex nature 
within a disclosed genus may motivate an artisan of 
ordinary skill to make similar complex species and 
thus teach away from making simple species within 
the genus. Baird, 16 F.3d at 382, 29 USPQ2d at 1552. 
See also Jones, 958 F.2d at 350, 21 USPQ2d at 1943 
(disclosed salts of genus held not sufficiently similar 
in structure to render claimed species prima facieobvious). 

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. 
Dillon, 919 F.2d at 692-93, 16 USPQ2d at 1900-
02. 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 tri





 

cyclic 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. In re Merck & Co., 800 F.2d 
1091, 1096-97, 231 USPQ 375, 378-79 (Fed. Cir. 
1986). Other structural similarities have been found 
to support a prima facie case of obviousness. See, 
e.g., In re May, 574 F.2d 1082, 1093-95, 197 USPQ 
601, 610-11 (CCPA 1978) (stereoisomers); In re 
Wilder, 563 F.2d 457, 460, 195 USPQ 426, 429 
(CCPA 1977) (adjacent homologs and structural isomers); 
In re Hoch, 428 F.2d 1341, 1344, 166 USPQ 
406, 409 (CCPA 1970) (acid and ethyl ester); In re 
Druey, 319 F.2d 237, 240, 138 USPQ 39, 41 (CCPA 
1963) (omission of methyl group from pyrazole ring). 
Generally, some teaching of a structural similarity 
will be necessary to suggest selection of the claimed 
species or subgenus. Id. 

(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. Dillon, 
919 F.2d at 697, 16 USPQ2d at 1905; In re Stemniski, 
444 F.2d 581, 586, 170 USPQ 343, 348 (CCPA 1971). 
Conversely, lack of any known useful properties 
weighs against a finding of motivation to make or 
select a species or subgenus. In re Albrecht, 514 F.2d 
1389, 1392, 1395-96, 185 USPQ 585, 587, 590 
(CCPA 1975) (The prior art compound so irritated the 
skin that it could not be regarded as useful for the disclosed 
anesthetic purpose, and therefore a person 
skilled in the art would not have been motivated to 
make related compounds.); Stemniski, 444 F.2d at 
586, 170 USPQ at 348 (close structural similarity 
alone is not sufficient to create a prima facie case of 
obviousness when the reference compounds lack utility, 
and thus there is no motivation to make related 
compounds.). However, the prior art need not disclose 
a newly discovered property in order for there to be a 
prima facie case of obviousness. Dillon, 919 F.2d at 
697, 16 USPQ2d at 1904-05 (and cases cited therein). 
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. 919 F.2d at 692, 16 
USPQ2d at 1900-01. In fact, similar properties may 
normally be presumed when compounds are very 
close in structure. Dillon, 919 F.2d at 693, 696, 16 
USPQ2d at 1901, 1904. See also In re Grabiak, 769 
F.2d 729, 731, 226 USPQ 870, 871 (Fed. Cir. 1985) 
(“When chemical compounds have ‘very close’ structural 
similarities and similar utilities, without more a 
prima facie case may be made.”). 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. Dillon, 919 F.2d at 697-98, 16 USPQ2d 
at 1905; In re Wilder, 563 F.2d 457, 461, 195 USPQ 
426, 430 
(CCPA 1977); In re Linter, 458 F.2d 1013, 
1016, 173 USPQ 560, 562 (CCPA 1972). 

(e)Consider the Predictability of the Technology


Consider the predictability of the technology. See, 
e.g., Dillon, 919 F.2d at 692-97, 16 USPQ2d at 1901-
05; In re Grabiak, 769 F.2d 729, 732-33, 226 USPQ 
870, 872 (Fed. Cir. 1985). 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. See, e.g., In re May, 574 F.2d 1082, 
1094, 197 USPQ 601, 611 (CCPA 1978) (prima facieobviousness of claimed analgesic compound based on 
structurally similar prior art isomer was rebutted with 
evidence demonstrating that analgesia and addiction 
properties could not be reliably predicted on the basis 
of chemical structure); In re Schechter, 205 F.2d 185, 
191, 98 USPQ 144, 150 (CCPA 1953) (unpredictability 
in the insecticide field, with homologs, isomers 
and analogs of known effective insecticides having 
proven ineffective as insecticides, was considered as a 
factor weighing against a conclusion of obviousness 
of the claimed compounds). However, obviousness 
does not require absolute predictability, only a reasonable 
expectation of success, i.e., a reasonable expectation 
of obtaining similar properties. See, e.g., In re 




 

O’Farrell, 853 F.2d 894, 903, 7 USPQ2d 1673, 1681 
(Fed. Cir. 1988). 

(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 (In re Bell, 991 
F.2d 781,784, 26 USPQ2d 1529, 1531 (Fed. Cir. 
1993); In re Kulling, 897 F.2d 1147, 1149, 
14 
USPQ2d 1056, 1057 (Fed. Cir. 1990)), 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. Kulling, 897 F.2d at 1149, 14 USPQ2d at 
1058; Panduit Corp. v. Dennison Mfg. Co., 810 F.2d 
1561, 1579 n.42, 1 USQP2d 1593, 1606 n.42 (Fed. 
Cir. 1987). 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. 

B.Determining Whether Rebuttal Evidence Is 
Sufficient To Overcome the Prima Facie Case 
of Obviousness

If a prima facie case of obviousness is established, 
the burden shifts to the applicant to come forward 
with arguments and/or evidence to rebut the prima 
facie case. See, e.g., Dillon, 919 F.2d at 692, 
16 
USPQ2d at 1901. Rebuttal evidence and arguments 
can be presented in the specification, In re Soni, 
54 F.3d 746, 750, 34 USPQ2d 1684, 1687 (Fed. Cir. 
1995), by counsel, In re Chu, 66 F.3d 292, 299, 36 
USPQ2d 1089, 1094-95 (Fed. Cir. 1995), or by way 
of an affidavit or declaration under 37 CFR 1.132, 
e.g., Soni, 54 F.3d at 750, 34 USPQ2d at 1687; In re 
Piasecki, 745 F.2d 1468, 1474, 223 USPQ 785, 789-
90 (Fed. Cir. 1984). However, arguments of counsel 
cannot take the place of factually supported objective 
evidence. See, e.g., In re Huang, 100 F.3d 135, 139-
40, 40 USPQ2d 1685, 1689 (Fed. Cir. 1996); In re De 
Blauwe, 736 F.2d 699, 705, 222 USPQ 191, 196 (Fed. 
Cir. 1984).

Office personnel should consider all rebuttal arguments 
and evidence presented by applicants. See, e.g., 
In re Soni, 54 F.3d 746, 750, 34 USPQ2d 1684, 1687 
(Fed. Cir. 1995) (error not to consider evidence presented 
in the specification). C.f., In re Alton, 76 F.3d 
1168, 37 USPQ2d 1578 (Fed. Cir. 1996) (error not to 
consider factual evidence submitted to counter a 35 
U.S.C. 112 rejection); In re Beattie, 974 F.2d 1309, 
1313, 24 USPQ2d 1040, 1042-43 (Fed. Cir. 1992) 
(Office personnel should consider declarations from 
those skilled in the art praising the claimed invention 
and opining that the art teaches away from the invention.); 
Piasecki, 745 F.2d at 1472, 223 USPQ at 788 
(“[Rebuttal evidence] may relate to any of the Graham 
factors including the so-called secondary considerations.”). 
Rebuttal evidence may include evidence 
of “secondary considerations,” such as “commercial 
success, long felt but unsolved needs, [and] failure of 
others.” Graham v. John Deere Co., 383 U.S. at 17, 
148 USPQ at 467. See also, e.g., In re Piasecki, 
745 
F.2d 1468, 1473, 223 USPQ 785, 788 (Fed. Cir. 
1984) (commercial success). Rebuttal evidence may 
also include evidence that the claimed invention 
yields unexpectedly improved properties or properties 
not present in the prior art. Rebuttal evidence may 
consist of a showing that the claimed compound possesses 
unexpected properties. Dillon, 919 F.2d at 692-
93, 16 USPQ2d at 1901. A showing of unexpected 
results must be based on evidence, not argument or 
speculation. In re Mayne, 104 F.3d 1339, 1343-44, 
41 
USPQ2d 1451, 1455-56 (Fed. Cir. 1997) (conclusory 
statements that claimed compound possesses 
unusually low immune response or unexpected biological 
activity that is unsupported by comparative 
data held insufficient to overcome prima facie case of 
obviousness). Rebuttal evidence may include evidence 
that the claimed invention was copied by others. 
See, e.g., In re GPAC, 57 F.3d 1573, 1580, 




 

35 
USPQ2d 1116, 1121 (Fed. Cir. 1995); Hybritech 
Inc. v. Monoclonal Antibodies, 802 F.2d 1367, 1380, 
231 USPQ 81, 90 (Fed. Cir. 1986). It may also include 
evidence of the state of the art, the level of skill in the 
art, and the beliefs of those skilled in the art. See, e.g., 
In re Oelrich, 579 F.2d 86, 91-92, 198 USPQ 210, 214 
(CCPA 1978) (Expert opinions regarding the level of 
skill in the art were probative of the Nonobviousness 
of the claimed invention.); Piasecki, 745 F.2d at 1471, 
1473-74, 223 USPQ at 790 (Evidence of nontechnological 
nature is pertinent to the conclusion of obviousness. 
The declarations of those skilled in the art 
regarding the need for the invention and its reception 
by the art were improperly discounted by the Board.); 
Beattie, 974 F.2d at 1313, 24 USPQ2d at 1042-43 
(Seven declarations provided by music teachers opining 
that the art teaches away from the claimed invention 
must be considered, but were not probative 
because they did not contain facts and did not deal 
with the specific prior art that was the subject of the 
rejection.). For example, rebuttal evidence may 
include a showing that the prior art fails to disclose or 
render obvious a method for making the compound, 
which would preclude a conclusion of obviousness of 
the compound. A conclusion of obviousness requires 
that the reference(s) relied upon be enabling in that it 
put the public in possession of the claimed invention. 
The court in In re Hoeksema, 399 F.2d 269, 274, 
158 
USPQ 596, 601 (CCPA 1968), stated: 

 Thus, upon careful reconsideration it is our view that 
if the prior art of record fails to disclose or render obvious 
a method for making a claimed compound, at the time the 
invention was made, it may not be legally concluded that 
the compound itself is in the possession of the public. 
[footnote omitted.] In this context, we say that the absence 
of a known or obvious process for making the claimed 
compounds overcomes a presumption that the compounds 
are obvious, based on close relationships between their 
structures and those of prior art compounds.

The Hoeksema court further noted that once a 
prima facie case of obviousness is made by the PTO 
through citation of references, the burden is on the 
applicant to produce contrary evidence establishing 
that the reference being relied on would not enable a 
skilled artisan to produce the different compounds 
claimed. Id. at 274-75, 158 USPQ at 601. See also 
Ashland Oil, Inc. v. Delta Resins & Refractories, Inc., 
776 F.2d 281, 295, 297, 227 USPQ 657, 666, 667 
(Fed. Cir. 1985) (citing Hoeksema for the proposition 
above); In re Grose, 592 F.2d 1161, 1168, 201 USPQ 
57, 63-64 (CCPA 1979) (“One of the assumptions 
underlying a prima facie obviousness rejection based 
upon a structural relationship between compounds, 
such as adjacent homologs, is that a method disclosed 
for producing one would provide those skilled in the 
art with a method for producing the other... Failure of 
the prior art to disclose or render obvious a method 
for making any composition of matter, whether a 
compound or a mixture of compounds like a zeolite, 
precludes a conclusion that the composition would 
have been obvious.”).

Consideration of rebuttal evidence and arguments 
requires Office personnel to weigh the proffered evidence 
and arguments. Office personnel should avoid 
giving evidence no weight, except in rare circumstances. 
Id. See also In re Alton, 76 F.3d 1168, 1174-
75, 37 USPQ2d 1578, 1582-83 (Fed. Cir. 1996). However, 
to be entitled to substantial weight, the applicant 
should establish a nexus between the rebuttal evidence 
and the claimed invention, i.e., objective evidence 
of nonobviousness must be attributable to the 
claimed invention. The Federal Circuit has acknowledged 
that applicant bears the burden of establishing 
nexus, stating:

In the ex parte process of examining a patent application, 
however, the PTO lacks the means or resources to gather 
evidence which supports or refutes the applicant’s assertion 
that the sales constitute commercial success. C.f. Ex 
parte Remark, 15 USPQ2d 1498, 1503 ([BPAI] 1990) 
(evidentiary routine of shifting burdens in civil proceedings 
inappropriate in ex parte prosecution proceedings 
because examiner has no available means for adducing 
evidence). Consequently, the PTO must rely upon the 
applicant to provide hard evidence of commercial success.

In re Huang, 100 F.3d 135, 139-40, 40 USPQ2d 1685, 
1689 (Fed. Cir. 1996). See also GPAC, 57 F.3d at 
1580, 35 USPQ2d at 1121; In re Paulsen, 30 F.3d 
1475, 1482, 31 USPQ2d 1671, 1676 (Fed. Cir. 1994) 
(Evidence of commercial success of articles not covered 
by the claims subject to the 35 U.S.C. 103 rejection 
was not probative of nonobviousness.). 
Additionally, the evidence must be reasonably commensurate 
in scope with the claimed invention. See, 
e.g., In re Kulling, 897 F.2d 1147, 1149, 14 USPQ2d 
1056, 1058 (Fed. Cir. 1990); In re Grasselli, 713 F.2d 
731, 743, 218 USPQ 769, 777 (Fed. Cir. 1983). In re 
Soni, 54 F.3d 746, 34 USPQ2d 1684 (Fed. Cir. 1995) 
does not change this analysis. In Soni, the Court 




 

declined to consider the Office’s argument that the 
evidence of nonobviousness was not commensurate in 
scope with the claim because it had not been raised by 
the examiner (54 F.3d at 751, 34 USPQ2d at 1688). 

When considering whether proffered evidence is 
commensurate in scope with the claimed invention, 
Office personnel should not require the applicant to 
show unexpected 
results over the entire range of properties 
possessed 
by 
a 
chemical compound or composition. 
See, e.g., In re Chupp, 816 F.2d 643, 646, 
2 
USPQ2d 1437, 1439 (Fed. Cir. 1987). Evidence that 
the compound or composition possesses superior and 
unexpected properties in one of a spectrum of common 
properties can be sufficient to rebut a prima faciecase of obviousness. Id. 

For example, a showing of unexpected results for a 
single member of a claimed subgenus, or a narrow 
portion of a claimed range would be sufficient to rebut 
a prima facie case of obviousness if a skilled artisan 
“could ascertain a trend in the exemplified data that 
would allow him to reasonably extend the probative 
value thereof.” In re Clemens, 622 F.2d 1029, 1036, 
206 USPQ 289, 296 (CCPA 1980) (Evidence of the 
unobviousness of a broad range can be proven by a 
narrower range when one skilled in the art could 
ascertain a trend that would allow him to reasonably 
extend the probative value thereof.). But see, Grasselli, 
713 F.2d at 743, 218 USPQ at 778 (evidence of 
superior properties for sodium containing composition 
insufficient to establish the non-obviousness of 
broad claims for a catalyst with “an alkali metal” 
where it was well known in the catalyst art that different 
alkali metals were not interchangeable and applicant 
had shown unexpected results only for sodium 
containing materials); In re Greenfield, 571 F.2d 
1185, 1189, 197 USPQ 227, 230 (CCPA 1978) (evidence 
of superior properties in one species insufficient 
to establish the nonobviousness of a subgenus 
containing hundreds of compounds); In re Lindner,
457 F.2d 506, 508, 173 USPQ 356, 358 (CCPA 1972) 
(one test not sufficient where there was no adequate 
basis for concluding the other claimed compounds 
would behave the same way). However, an exemplary 
showing may be sufficient to establish a reasonable 
correlation between the showing and the entire scope 
of the claim, when viewed by a skilled artisan. See, 
e.g., Chupp, 816 F.2d at 646, 2 USPQ2d at 1439; Clemens, 
622 F.2d at 1036, 206 USPQ at 296. On the 
other hand, evidence of an unexpected property may 
not be sufficient regardless of the scope of the showing. 
Usually, a showing of unexpected results is sufficient 
to overcome a prima facie case of obviousness. 
See, e.g., In re Albrecht, 514 F.2d 1389, 1396, 185 
USPQ 585, 590 (CCPA 1975). However, where the 
claims are not limited to a particular use, and where 
the prior art provides other motivation to select a particular 
species or subgenus, a showing of a new use 
may not be sufficient to confer patentability. See Dillon, 
919 F.2d at 692, 16 USPQ2d at 1900-01. Accordingly, 
each case should be evaluated individually 
based on the totality of the circumstances. 

Office personnel should not evaluate rebuttal evidence 
for its “knockdown” value against the prima 
facie case, Piasecki, 745 F.2d at 1473, 223 USPQ at 
788, or summarily dismiss it as not compelling or 
insufficient. If the evidence is deemed insufficient to 
rebut the prima facie case of obviousness, Office personnel 
should specifically set forth the facts and reasoning 
that justify this conclusion.

III.RECONSIDER ALL EVIDENCE AND 
CLEARLY COMMUNICATE FINDINGS 
AND CONCLUSIONS

A determination under 35 U.S.C. 103 should rest 
on all the evidence and should not be influenced by 
any earlier conclusion. See, e.g., Piasecki, 745 F.2d at 
1472-73, 223 USPQ at 788; In re Eli Lilly & Co., 902 
F.2d 943, 945, 14 USPQ2d 1741, 1743 (Fed. Cir. 
1990). Thus, once the applicant has presented rebuttal 
evidence, Office personnel should reconsider any initial 
obviousness determination in view of the entire 
record. See, e.g., Piasecki, 745 F.2d at 1472, 
223 
USPQ at 788; Eli Lilly, 902 F.2d at 945, 14 
USPQ2d at 1743. All the proposed rejections and 
their bases should be reviewed to confirm their correctness. 
Only then should any rejection be imposed 
in an Office action. The Office action should clearly 
communicate the Office’s findings and conclusions, 
articulating how the conclusions are supported by the 
findings. 

Where applicable, the findings should clearly articulate 
which portions of the reference support any 
rejection. Explicit findings on motivation or suggestion 
to select the claimed invention should also be 
articulated in order to support a 35 U.S.C. 103 ground 
of rejection. Dillon, 919 F.2d at 693, 16 USPQ2d at 




 

1901; In re Mills, 916 F.2d 680, 683, 16 USPQ2d 
1430, 1433 (Fed. Cir. 1990). Conclusory statements 
of similarity or motivation, without any articulated 
rationale or evidentiary support, do not constitute sufficient 
factual findings.




 

Flowchart





 

2144.09Close Structural Similarity Between 
Chemical Compounds (Homologs, 
Analogues, Isomers)

REJECTION BASED ON CLOSE STRUCTURAL 
SIMILARITY IS FOUNDED ON THE EXPECTATION 
THAT COMPOUNDS SIMILAR IN 
STRUCTURE WILL HAVE SIMILAR PROPERTIES 


A prima facie case of obviousness may be made 
when chemical compounds have very close structural 
similarities and similar utilities. “An obviousness 
rejection based on similarity in chemical structure and 
function entails the motivation of one skilled in the art 
to make a claimed compound, in the expectation that 
compounds similar in structure will have similar 
properties.” In re Payne, 606 F.2d 303, 313, 
203 
USPQ 245, 254 (CCPA 1979). See In re Papesch, 
315 F.2d 381, 137 USPQ 43 (CCPA 1963) (discussed 
in more detail below) and In re Dillon, 919 F.2d 688, 
16 USPQ2d 1897 (Fed. Cir. 1991) (discussed below 
and in MPEP § 2144) for an extensive review of the 
case law pertaining to obviousness based on close 
structural similarity of chemical compounds. See also 
MPEP §
 
2144.08, paragraph II.A.4.(c).

HOMOLOGY AND ISOMERISM ARE FACTS 
WHICH MUST BE CONSIDERED WITH ALL 
OTHER RELEVANT FACTS IN DETERMINING 
OBVIOUSNESS 

Compounds which are position isomers (compounds 
having the same radicals in physically different 
positions on the same nucleus) or homologs 
(compounds differing regularly by the successive 
addition of the same chemical group, e.g., by -CH2- 
groups) are generally of sufficiently close structural 
similarity that there is a presumed expectation that 
such compounds possess similar properties. In reWilder, 563 F.2d 457, 195 USPQ 426 (CCPA 1977). 
See also In re May, 574 F.2d 1082, 197 USPQ 601 
(CCPA 1978) (stereoisomers prima facie obvious).

Isomers having the same empirical formula but different 
structures are not necessarily considered equivalent 
by chemists skilled in the art and therefore are 
not necessarily suggestive of each other. Ex parteMowry, 91 USPQ 219 (Bd. App. 1950) (claimed 
cyclohexylstyrene not prima facie obvious over prior 
art isohexylstyrene). Similarly, homologs which are 
far removed from adjacent homologs may not be 
expected to have similar properties. In re Mills, 
281 
F.2d 218, 126 USPQ 513 (CCPA 1960) (prior art 
disclosure of C8 to C12 alkyl sulfates was not sufficient 
to render prima facie obvious claimed C1 alkyl 
sulfate).

Homology and isomerism involve close structural 
similarity which must be considered with all other relevant 
facts in determining the issue of obviousness. In 
re Mills, 281 F.2d 218, 126 USPQ 513 (CCPA 1960); 
In re Wiechert, 370 F.2d 927, 152 USPQ 247 (CCPA 
1967). Homology should not be automatically 
equated with prima facie obviousness because the 
claimed invention and the prior art must each be 
viewed “as a whole.” In re Langer, 465 F.2d 896, 
175 
USPQ 169 (CCPA 1972) (Claims to a polymerization 
process using a sterically hindered amine were 
held unobvious over a similar prior art process 
because the prior art disclosed a large number of 
unhindered amines and only one sterically hindered 
amine (which differed from a claimed amine by 3 carbon 
atoms), and therefore the reference as a whole did 
not apprise the ordinary artisan of the significance of 
hindered amines as a class.). 

PRESENCE OF A TRUE HOMOLOGOUS OR 
ISOMERIC RELATIONSHIP IS NOT CON-
TROLLING

Prior art structures do not have to be true homologs 
or isomers to render structurally similar compounds 
prima facie obvious. In re Payne, 606 F.2d 303, 203 
USPQ 245 (CCPA 1979) (Claimed and prior art compounds 
were both directed to heterocyclic carbamoyloximino 
compounds having pesticidal activity. The 
only structural difference between the claimed and 
prior art compounds was that the ring structures of the 
claimed compounds had two carbon atoms between 
two sulfur atoms whereas the prior art ring structures 
had either one or three carbon atoms between two sulfur 
atoms. The court held that although the prior art 
compounds were not true homologs or isomers of the 
claimed compounds, the similarity between the chemical 
structures and properties is sufficiently close that 
one of ordinary skill in the art would have been motivated 
to make the claimed compounds in searching 
for new pesticides.). 




 

See also In re Mayne, 104 F.3d 1339, 41 USPQ2d 
1451 (Fed. Cir. 1997) (claimed protein was held to be 
obvious in light of structural similarities to the prior 
art, including known structural similarity of Ile and 
Lev); In re Merck & Co., Inc., 800 F.2d 1091, 
231 
USPQ 375 (Fed. Cir. 1986) (claimed and prior art 
compounds used in a method of treating depression 
would have been expected to have similar activity 
because the structural difference between the compounds 
involved a known bioisosteric replacement) 
(see MPEP § 2144.08, paragraph II.A.4(c) for a more 
detailed discussion of the facts in the Mayne and 
Merck cases); In re Dillon, 919 F.2d 688, 16 USPQ2d 
1897 (Fed. Cir. 1991) (The tri-orthoester fuel compositions 
of the prior art and the claimed tetra-orthoester 
fuel compositions would have been expected to have 
similar properties based on close structural and chemical 
similarity between the orthoesters and the fact 
that both the prior art and applicant used the orthoesters 
as fuel additives.) (See MPEP § 2144 for a more 
detailed discussion of the facts in the Dillon case.).

Compare In re Grabiak, 769 F.2d 729, 226 USPQ 
871 (Fed. Cir. 1985) (substitution of a thioester group 
for an ester group in an herbicidal safener compound 
was not suggested by the prior art); In re Bell, 
991 
F.2d 781, 26 USPQ2d 1529 (Fed. Cir. 1993) (The 
established relationship between a nucleic acid and 
the protein it encodes in the genetic code does not render 
a gene prima facie obvious over its corresponding 
protein in the same way that closely related structures 
in chemistry may create a prima facie case because 
there are a vast number of nucleotide sequences that 
might encode for a specific protein as a result of 
degeneracy in the genetic code (i.e., the fact that most 
amino acids are specified by more than one nucleotide 
sequence or codon).); In re Deuel, 51 F.3d 1552, 
1558-59, 34 USPQ2d 1210, 1215 (Fed. Cir. 1995) (“A 
prior art disclosure of the amino acid sequence of a 
protein does not necessarily render particular DNA 
molecules encoding the protein obvious because the 
redundancy of the genetic code permits one to 
hypothesize an enormous number of DNA sequences 
coding for the protein.” The existence of a general 
method of gene cloning in the prior art is not sufficient, 
without more, to render obvious a particular 
cDNA molecule.). 

PRESENCE OR ABSENCE OF PRIOR ART SUGGESTION 
OF METHOD OF MAKING A 
CLAIMED COMPOUND MAY BE RELEVANT IN 
DETERMINING PRIMA FACIE OBVIOUSNESS

“[T]he presence—or absence—of a suitably operative, 
obvious process for making a composition of 
matter may have an ultimate bearing on whether that 
composition is obvious—or nonobvious—under 
35 
U.S.C. 103.” In re Maloney, 411 F.2d 1321, 1323, 
162 USPQ 98, 100 (CCPA 1969).

“[I]f the prior art of record fails to disclose or render 
obvious a method for making a claimed compound, 
at the time the invention was made, it may not 
be legally concluded that the compound itself is in the 
possession of the public. In this context, we say that 
the absence of a known or obvious process for making 
the claimed compounds overcomes a presumption that 
the compounds are obvious, based on the close relationships 
between their structures and those of prior 
art compounds.” In re Hoeksema, 399 F.2d 269, 274-
75, 158 USPQ 597, 601 (CCPA 1968). 

See In re Payne, 606 F.2d 303, 203 USPQ 245 
(CCPA 1979) for a general discussion of circumstances 
under which the prior art suggests methods for 
making novel compounds which are of close structural 
similarity to compounds known in the prior art. 
In the biotechnology arts, the existence of a general 
method of gene cloning in the prior art is not sufficient, 
without more, to render obvious a particular 
cDNA molecule. In re Deuel, 51 F.3d 1552, 1558, 34 
USPQ2d 1210, 1215 (Fed. Cir. 1995) (“[T]he existence 
of a general method of isolating cDNA or DNA 
molecules is essentially irrelevant to the question 
whether the specific molecules themselves would 
have been obvious, in the absence of other prior art 
that suggests the claimed DNAs.”); In re Bell, 991 
F.2d 781, 785, 26 USPQ2d 1529, 1532 (Fed. Cir. 
1993). However, it may be proper to apply “methodology 
in rejecting product claims under 35 U.S.C. 
103, depending on the particular facts of the case, the 
manner and context in which methodology applies, 
and the overall logic of the rejection.” Ex parte Goldgaber, 
41 USPQ2d 1172, 1176 (Bd. Pat. App. & Inter. 
1996).




 

PRESUMPTION OF OBVIOUSNESS BASED ON 
STRUCTURAL SIMILARITY IS OVERCOME 
WHERE THERE IS NO REASONABLE EXPECTATION 
OF SIMILAR PROPERTIES

The presumption of obviousness based on a reference 
disclosing structurally similar compounds may 
be overcome where there is evidence showing there is 
no reasonable expectation of similar properties in 
structurally similar compounds. In re May, 574 F.2d 
1082, 197 USPQ 601 (CCPA 1978) (appellant produced 
sufficient evidence to establish a substantial 
degree of unpredictability in the pertinent art area, and 
thereby rebutted the presumption that structurally 
similar compounds have similar properties); In reSchechter, 205 F.2d 185, 98 USPQ 144 (CCPA 1953). 
See also Ex parte Blattner, 2 USPQ2d 2047 (Bd. Pat. 
App. & Inter. 1987) (Claims directed to compounds 
containing a 7-membered ring were rejected as prima 
facie obvious over a reference which taught 5- and 6-
membered ring homologs of the claimed compounds. 
The Board reversed the rejection because the prior art 
taught that the compounds containing a 5-membered 
ring possessed the opposite utility of the compounds 
containing the 6-membered ring, undermining the 
examiner’s asserted prima facie case arising from an 
expectation of similar results in the claimed compounds 
which contain a 7-membered ring.). 

IF PRIOR ART COMPOUNDS HAVE NO UTILITY, 
OR UTILITY ONLY AS INTERMEDIATES, 
CLAIMED STRUCTURALLY SIMILAR COMPOUNDS 
MAY NOT BE PRIMA FACIE OBVIOUS 
OVER THE PRIOR ART 

If the prior art does not teach any specific or significant 
utility for the disclosed compounds, then the 
prior art is not sufficient to render structurally similar 
claims prima facie obvious because there is no motivation 
for one of ordinary skill in the art to make the 
reference compounds, much less any structurally 
related compounds. In re Stemniski, 444 F.2d 581, 
170 
USPQ 343 (CCPA 1971). 

Where structurally similar “prior art compounds 
‘cannot be regarded as useful’ for the sole use disclosed 
[by the reference],... a person having ordinary 
skill in the art would lack the ‘necessary impetus’ to 
make the claimed compounds.” In re Albrecht, 514 
F.2d 1389, 1396, 185 USPQ 585, 590 (CCPA 1975) 
(prior art reference studied the local anesthetic activity 
of various compounds, and taught that compounds 
structurally similar to those claimed were irritating to 
human skin and therefore “cannot be regarded as useful 
anesthetics.” 514 F.2d at 1393, 185 USPQ at 587).

Similarly, if the prior art merely discloses compounds 
as intermediates in the production of a final 
product, one of ordinary skill in the art would not 
have been motivated to stop the reference synthesis 
and investigate the intermediate compounds with an 
expectation of arriving at claimed compounds which 
have different uses. In re Lalu, 747 F.2d 703, 
223 
USPQ 1257 (Fed. Cir. 1984). 

PRIMA FACIE CASE REBUTTABLE BY EVIDENCE 
OF SUPERIOR OR UNEXPECTED RESULTS


A prima facie case of obviousness based on structural 
similarity is rebuttable by proof that the claimed 
compounds possess unexpectedly advantageous or 
superior properties. In re Papesch, 315 F.2d 381, 
137 
USPQ 43 (CCPA 1963) (Affidavit evidence 
which showed that claimed triethylated compounds 
possessed anti-inflammatory activity whereas prior art 
trimethylated compounds did not was sufficient to 
overcome obviousness rejection based on the homologous 
relationship between the prior art and claimed 
compounds.); In re Wiechert, 370 F.2d 927, 
152 
USPQ 247 (CCPA 1967) (a 7-fold improvement 
of activity over the prior art held sufficient to rebut 
prima facie obviousness based on close structural 
similarity). 

However, a claimed compound may be obvious 
because it was suggested by, or structurally similar to, 
a prior art compound even though a particular benefit 
of the claimed compound asserted by patentee is not 
expressly disclosed in the prior art. It is the differences 
in fact in their respective properties which are 
determinative of nonobviousness. If the prior art compound 
does in fact possess a particular benefit, even 
though the benefit is not recognized in the prior art, 
applicant’s recognition of the benefit is not in itself 
sufficient to distinguish the claimed compound from 
the prior art. In re Dillon, 919 F.2d 688, 16 USPQ2d 
1897 (Fed. Cir. 1991).

See MPEP § 716.02 - § 716.02(g) for a discussion 
of evidence alleging unexpectedly advantageous or 
superior results.