MPEP § 2144 — MPEP § 2144
Current through: 2022-07-01

2144-Supporting a Rejection Under 35 U.S.C. 103 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Manual of Patent Examining Procedure 

 Chapter 2100 

 Section 2144 
 

 
 
 
 
 
 2144 Supporting a Rejection Under 35 U.S.C. 103 [R-01.2024]

 When considering obviousness, Office personnel are cautioned
 against treating any line of reasoning as a per se rule. This section
 discusses supporting a rejection under 35 U.S.C. 103 by reliance on scientific
 theory and legal precedent. In keeping with the flexible approach to obviousness under
 KSR, as well as the requirement for explanation, Office personnel may
 invoke legal precedent as a source of supporting rationale when warranted and appropriately
 supported. See MPEP §
 2144.04 . So, for example, automating a manual activity, making
 portable, making separable, reversing or duplicating parts, or purifying an old product may
 form the basis of a rejection. However, such rationales should not be treated as
 per se rules, but rather must be explained and shown to apply to the
 facts at hand. A similar caveat applies to any obviousness analysis. Simply stating the
 principle (e.g., “art recognized equivalent,” “structural similarity”) without providing an
 explanation of its applicability to the facts of the case at hand is generally not
 sufficient to establish a prima facie case of obviousness. 
 

 I. 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). 
 

 II. 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). See also
 Dystar Textilfarben GmbH & Co. Deutschland KG v. C.H. Patrick, 464 F.3d 1356, 1368, 80 USPQ2d 1641, 1651 (Fed.
 Cir. 2006) (“Indeed, we have repeatedly held that an implicit motivation to combine
 exists not only when a suggestion may be gleaned from the prior art as a whole, but when
 the ‘improvement’ is technology-independent and the combination of references results in
 a product or process that is more desirable, for example because it is stronger,
 cheaper, cleaner, faster, lighter, smaller, more durable, or more efficient. Because the
 desire to enhance commercial opportunities by improving a product or process is
 universal—and even common-sensical—we have held that there exists in these situations a
 motivation to combine prior art references even absent any hint of suggestion in the
 references themselves.”).
 

 III. LEGAL PRECEDENT CAN PROVIDE THE RATIONALE SUPPORTING OBVIOUSNESS ONLY 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. In this context, “sufficiently similar” does not
 necessarily require that the facts of the prior legal decision and those of the
 application under examination come from the same technological area. Rather, facts are
 sufficiently similar when they can be analogized to each other such that they present
 the same legal issue. For example, the combining prior art elements rationale was
 applied to a claimed vehicle pedal assembly in KSR Int’l Co. v. Teleflex
 Inc., 550 U.S. 398, 417, 82 USPQ2d 1385, 1396 (2007), but that rationale
 applies broadly across a wide range of technologies; see, for example, the cases
 discussed in MPEP §
 2143 , subsection I.A. See also MPEP § 2145 ,
 subsection X.E. If the applicant has demonstrated the criticality of a specific
 limitation, it would not be appropriate to rely solely on the
 rationale used by the court 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).
 

 IV. 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
 Lintner, 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).
 

 In In re Lintner, 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 , subsection II, for case law pertaining to the presence
 of additional advantages or latent properties not recognized in the prior art.
 

 
 2144.01 Implicit Disclosure [R-10.2019]

 “[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 [R-08.2012]

 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.). 
 

 

 
 2144.03 Reliance on Common Knowledge in the Art or “Well Known” Prior
 Art [R-01.2024]
 

 In certain circumstances where appropriate, an examiner may take
 official notice of facts not in the record or 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), 5
 U.S.C. 500 et seq. 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. Determining 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. It is always
 preferable, when reasonably possible, for the examiner to cite a prior art
 reference rather than to rely on official notice. When an application is under
 final rejection or action under 37 CFR 1.113 , official notice
 should be rarely used. 
 

 Official notice unsupported by documentary
 evidence may be taken by the examiner where the facts asserted to be well-known,
 or to be common knowledge in the art, are “capable of such instant and
 unquestionable demonstration as to defy dispute.” In re Ahlert, 
 424 F.2d 1088, 1091, 165 USPQ 418, 420 (CCPA 1970) (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.” Note that in this case the noticed fact was beyond dispute, so the
 court affirmed even though no evidence had been presented as to any prior art
 disclosure providing “instant and unquestionable demonstration” of that fact. 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 be
 reasonable 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 be reasonable 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 beyond dispute, or are not
 capable of instant and unquestionable demonstration as being well-known. See
 Ahlert, 424 F.2d at 1091, 165 USPQ at 420. Even if the
 examiner appropriately believes such fact may be of beyond dispute, it is not
 advisable to rely on official notice when an examiner can find a prior art
 disclosure to support the fact at issue. 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. 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) (“When 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
 Arendi v. Apple, 832 F.3d 1355, 119 USPQ2d 1822 (Fed. Cir.
 2016) (finding that the Board had not provided a reasoned analysis, supported by
 the evidence of record, for why “common sense” taught the missing process step).
 See also In re Van Os , 844 F.3d 1359, 1361, 121 USPQ2d 1209,
 1211 (Fed. Cir. 2017) (“Absent some articulated rationale, a finding that a
 combination of prior art would have been ‘common sense’ or ‘intuitive’ is no
 different than merely stating the combination ‘would have been obvious.’ ... Here,
 neither the Board nor the examiner provided any reasoning or analysis to support
 finding a motivation to add Gillespie's disclosure to Hawkins beyond stating it
 would have been an ‘intuitive way’ to initiate Hawkins’ editing mode.”).
 

 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 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 the 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 so as to allow the applicant an opportunity
 to adequately traverse the rejection in the next reply after the Office action in
 which the "common knowledge" statement was made.
 

 C. If Applicant Traverses 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 a finding based on official notice, 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. A mere request by the applicant that
 the examiner provide documentary evidence in support of an officially-noticed fact
 is not a proper traversal. See 37 CFR 1.111(b) . See also
 Chevenard, 139 F.2d at 713, 60 USPQ at 241. 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. 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. See Ahlert, 424 F.2d at 1091, 165 USPQ
 at 420. 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 or 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. Also, official notice should be rarely used when an application is under
 final rejection or action under 37 CFR 1.113 .
 

 

 
 2144.04 Legal Precedent as Source of Supporting Rationale [R-07.2022]

 As discussed in MPEP § 2144 , an examiner may utilize
 legal precedent as a source of supporting rationale when warranted and appropriately
 supported. In formulating any rejection invoking legal precedent, the examiner must take
 care to ensure that the rationale is explained and shown to apply to the facts at hand.
 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 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
 Indicium of Nonobviousness Note that the omission of an element and
 retention of its function is an indicium of
 nonobviousness. In re Edge, 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 nonobvious over the prior art because 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” were 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 Syst., 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 facie obvious 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
 modification.).
 

 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). 
 

 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 nonobvious 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 nonobvious. 
 

 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 nonobvious 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.). However, in the case of product-by-process claims, if a first prior art
 process is improved to enhance the purity of the product produced by the process, and
 if the purified product has no structural or functional difference from the products
 produced by other prior art processes, then the improvement in the first process that
 improves the purity of the product does not give rise to patentability. See
 Purdue Pharma v. Epic Pharma, 811 F.3d 1345, 117 USPQ2d 1733
 (Fed. Cir. 2016). See also MPEP § 2113 . 
 

 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). 
 

 

 
 2144.05 Obviousness of Similar and Overlapping Ranges, Amounts, and
 Proportions [R-01.2024]
 

 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. OVERLAPPING, APPROACHING, AND SIMILAR RANGES, AMOUNTS, AND PROPORTIONS In the case where the claimed ranges “overlap or lie inside ranges
 disclosed by the prior art” a prima facie case 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.”). See also
 In re Bergen, 120 F.2d 329, 332, 49 USPQ 749, 751-52 (CCPA
 1941) (The court found that the overlapping endpoint of the prior art and claimed
 range was sufficient to support an obviousness rejection, particularly when there was
 no showing of criticality of the claimed range).
 

 Similarly, a prima facie case of
 obviousness exists where the claimed ranges or amounts do not overlap with the prior
 art but are merely close. Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (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. “The proportions are so close that
 prima facie one skilled in the art would have expected them to have the same
 properties.”). See also Warner-Jenkinson Co., Inc. v. Hilton Davis Chemical
 Co., 520 U.S. 17, 41 USPQ2d 1865 (1997) (under the doctrine of
 equivalents, a purification process using a pH of 5.0 could infringe a patented
 purification process requiring a pH of 6.0-9.0); 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%); In re
 Scherl, 156 F.2d 72, 74-75, 70 USPQ 204, 205-206 (CCPA 1946) (prior art
 showed an angle in a groove of up to 90° and an applicant claimed an angle of no less
 than 120°); In re Becket, 88 F.2d 684 (CCPA 1937) (“Where the
 component elements of alloys are the same, and where they approach so closely the
 same range of quantities as is here the case, it seems that there ought to be some
 noticeable difference in the qualities of the respective alloys.”); In re
 Dreyfus, 73 F.2d 931, 934, 24 USPQ 52, 55 (CCPA 1934)(the prior art,
 which taught about 0.7:1 of alkali to water, renders unpatentable a claim that
 increased the proportion to at least 1:1 because there was no showing that the
 claimed proportions were critical); In re Lilienfeld, 67 F.2d 920,
 924, 20 USPQ 53, 57 (CCPA 1933)(the prior art teaching an alkali cellulose containing
 minimal amounts of water, found by the Examiner to be in the 5-8% range, the claims
 sought to be patented were to an alkali cellulose with varying higher ranges of water
 (e.g., “not substantially less than 13%,” “not substantially below 17%,” and “between
 about 13[%] and 20%”); K-Swiss Inc. v. Glide N Lock GmbH, 567 Fed.
 App'x 906 (Fed. Cir. 2014)(reversing the Board's decision, in an appeal of an
 inter partes reexamination proceeding, that certain claims were
 not prima facie obvious due to non-overlapping ranges);
 In re Brandt, 886 F.3d 1171, 1177, 126 USPQ2d 1079, 1082 (Fed.
 Cir. 2018)(the court found a prima facie case of obviousness had
 been made in a predictable art wherein the claimed range of “less than 6 pounds per
 cubic feet” and the prior art range of “between 6 lbs./ft 3 
 and 25 lbs./ft 3 ” were so mathematically close that the
 difference between the claimed ranges was virtually negligible absent any showing of
 unexpected results or criticality.). 
 

 "[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, 383, 29 USPQ2d 1550, 1552 (Fed. Cir. 1994) (“[a] disclosure of millions of
 compounds does not render obvious a claim to three compounds, particularly when that
 disclosure indicates a preference leading away from the claimed compounds.”);
 MPEP §
 2144.08 ; and subsection III.D below for an additional
 discussion on consideration of prior art disclosures of a broad range.
 

 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. ROUTINE OPTIMIZATION 
 

 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 Lab. Inc., 874 F.2d 804, 809, 10 USPQ2d 1843, 1848
 (Fed. Cir. 1989), cert. denied, 493 U.S. 975 (1989)(Claimed
 ratios were obvious as being reached by routine procedures and producing
 predictable results); In re Kulling, 897 F.2d 1147, 1149, 14 USPQ2d 1056, 1058 (Fed. Cir.
 1990)(Claimed amount of wash solution was found to be unpatentable as a matter of
 routine optimization in the pertinent art, further supported by the prior art
 disclosure of the need to avoid undue amounts of wash solution); and In
 re Geisler, 116 F.3d 1465, 1470, 43 USPQ2d 1362, 1366 (Fed. Cir.
 1997)(Claims were unpatentable because appellants failed to submit evidence of
 criticality to demonstrate that that the wear resistance of the protective layer
 in the claimed thickness range of 50-100 Angstroms was “unexpectedly good”);
 Smith v. Nichols, 88 U.S. 112, 118-19 (1874) (a change in
 form, proportions, or degree “will not sustain a patent”); In re
 Williams, 36 F.2d 436, 438, 4 USPQ 237 (CCPA 1929) (“It is a settled
 principle of law that a mere carrying forward of an original patented conception
 involving only change of form, proportions, or degree, or the substitution of
 equivalents doing the same thing as the original invention, by substantially the
 same means, is not such an invention as will sustain a patent, even though the
 changes of the kind may produce better results than prior inventions.”). See also
 KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416, 82 USPQ2d
 1385, 1395 (2007) (identifying “the need for caution in granting a patent based on
 the combination of elements found in the prior art.”).
 

 B. There Must Be an Articulated Rationale Supporting the
 Rejection In order to properly support a rejection on the
 basis that an invention is the result of “routine optimization”, the examiner must
 make findings of relevant facts, and present the underpinning reasoning in
 sufficient detail. The articulated rationale must include an explanation of why it
 would have been routine optimization to arrive at the claimed invention and why a
 person of ordinary skill in the art would have had a reasonable expectation of
 success to formulate the claimed range. See In re Stepan , 868
 F.3d 1342, 1346, 123 USPQ2d 1838, 1841 (Fed. Cir. 2017). See also In re
 Van Os , 844 F.3d 1359,1361,121 USPQ2d 1209, 1211 (Fed. Cir. 2017)
 (“Absent some articulated rationale, a finding that a combination of prior art
 would have been ‘common sense’ or ‘intuitive’ is no different than merely stating
 the combination ‘would have been obvious.’”); Arendi S.A.R.L. v. Apple
 Inc. , 832 F.3d 1355, 1362, 119 USPQ2d 1822 (Fed. Cir. 2016)
 (“[R]eferences to ‘common sense’ … cannot be used as a wholesale substitute for
 reasoned analysis and evidentiary support … .”). 
 

 The Supreme Court has clarified that an "obvious to try" line of
 reasoning may properly support an obviousness rejection. In In re
 Antonie, 559 F.2d 618, 195 USPQ 6 (CCPA 1977), the CCPA held that 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, because “obvious to try” is not a valid rationale for an
 obviousness finding. However, in KSR International Co. v. Teleflex
 Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007), the Supreme Court held
 that “obvious to try” was a valid rationale for an obviousness finding, for
 example, when there is a “design need” or “market demand” and there are a “finite
 number” of solutions. 550 U.S. at 421, 82 USPQ2d at 1397 (“The same constricted
 analysis led the Court of Appeals to conclude, in error, that a patent claim
 cannot be proved obvious merely by showing that the combination of elements was
 ‘[o]bvious to try.’ ... When there is a design need or market pressure to solve a
 problem and there are a finite number of identified, predictable solutions, a
 person of ordinary skill has good reason to pursue the known options within his or
 her technical grasp. If this leads to the anticipated success, it is likely the
 product not of innovation but of ordinary skill and common sense. In that instance
 the fact that a combination was obvious to try might show that it was obvious
 under §103 .”). Thus, after KSR, the presence
 of a known result-effective variable would be one, but not the only, motivation
 for a person of ordinary skill in the art to experiment to reach another workable
 product or process. 
 

 III. REBUTTAL OF PRIMA FACIE CASE OF OBVIOUSNESS 
 

 A. Showing That the Range Is Critical Applicants can rebut a prima facie case of
 obviousness by showing the criticality of the 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
 also Minerals Separation, Ltd. v. Hyde, 242 U.S. 261, 271
 (1916) (a patent based on a change in the proportions of a prior product or
 process (changing from 4-10% oil to 1% oil) must be confined to the proportions
 that were shown to be critical (1%)); In re Scherl, 156 F.2d
 72, 74-75, 70 USPQ 204, 205 (CCPA 1946) (“Where the issue of criticality is
 involved, the applicant has the burden of establishing his position by a proper
 showing of the facts upon which he relies.”); In re Becket, 88
 F.2d 684 (CCPA 1937) (“Where the component elements of alloys are the same, and
 where they approach so closely the same range of quantities as is here the case,
 it seems that there ought to be some noticeable difference in the qualities of the
 respective alloys.”); In re Lilienfeld, 67 F.2d 920, 924 (CCPA
 1933) (“It is well established that, while a change in the proportions of a
 combination shown to be old, such as is here involved, may be inventive, such
 changes must be critical as compared with the proportions used in the prior
 processes, producing a difference in kind rather than degree.”); In re
 Wells, 56 F.2d 674, 675, 12 USPQ 430 (CCPA 1932) (“Changes in
 proportions of agents used in combinations . . . in order to be patentable, must
 be critical as compared with the proportions of the prior processes.”);
 E.I. DuPont de Nemours & Company v. Synvina C.V., 904
 F.3d 996, 1006, 128 USPQ2d 1193, 1201 (Fed. Cir. 2018.)(“[A] modification of a
 process parameter may be patentable if it ‘produce[s] a new and unexpected result
 which is different in kind and not merely in degree from the results of the prior
 art.” (citing Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA
 1955); UCB, Inc. v. Actavis Labs, UT, Inc., 65 F.4th 679, 693,
 2023 USPQ2d 448 (Fed. Cir. 2023) (“A difference of degree is not as persuasive as
 a difference in kind – i.e., if the range produces ‘a new property dissimilar to
 the known property,’ rather than producing a predictable result but to an
 unexpected extent.”).
 

 See MPEP § 716.02 -
 § 716.02(g) for a discussion of criticality and
 unexpected results. 
 

 B. Showing That the Prior Art Teaches Away 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. U.S. v. Adams, 383 U.S. 39, 51-2 (1966). See
 also Depuy Spine, Inc. v. Medtronic Sofamor Danek, Inc., 567
 F.3d 1314, 1326, 90 USPQ2d 1865, 1873 (Fed. Cir. 2009) (“An inference of
 nonobviousness is especially strong where the prior art’s teachings undermine the
 very reason being proffered as to why a person of ordinary skill would have
 combined the known elements.”) and Allergan, Inc. v. Sandoz
 Inc., 796 F.3d 1293, 1305, 115 USPQ2d 2012, 2019 (Fed. Cir. 2015)
 (The prior art taught away from use of 200 ppm benzalkonium chloride (“BAK”), as
 claimed, teaching “that BAK should be minimized in ophthalmic formulations to
 avoid safety problems”.).
 

 Teaching away was not established in 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 , subsection 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 three elongated handle openings. 392 F.3d
 at 1323, 73 USPQ2d at 1229. The court then turned to the patentee’s secondary
 considerations evidence of nonobviousness, such as commercial success,
 satisfaction of a long-felt need, and copying by others and found that Iron Grip
 had failed to establish: (A) a nexus between the licensing of its patent to three
 competitors and the “merits of the invention”; (B) that a competitor copied the
 claimed three-hole grip plate because “[n]ot every competing product that falls
 within the scope of a patent is evidence of copying” and “[o]therwise every
 infringement suit would automatically confirm the nonobviousness of the patent”;
 and (C) a long-felt but unmet need for the claimed three-hole grip plate prior to
 its patent because “[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. See also In
 re Brandt, 886 F.3d 1171, 1178, 126 USPQ2d 1079, 1083-1084 (Fed. Cir.
 2018) (The court determined the prior art did not teach away from the claimed
 invention because it only suggested that a denser coverboard could serve to
 protect a less dense insulation board and did not require a coverboard denser than
 6 lbs./ft 3 ).
 

 C. Showing That the Claimed
 Parameter Was Not Recognized as
 “Result-Effective” Applicants may rebut a prima facie 
 case of obviousness based on optimization of a variable disclosed in a range in the
 prior art by showing that the claimed variable was not recognized in the prior art to
 be a result-effective variable. E.I. Dupont de Nemours & Company v.
 Synvina C.V., 904 F.3d 996, 1008, 128 USPQ2d 1193, 1202 (Fed. Cir.
 2018). (“The idea behind the ‘result-effective variable’ analysis is straightforward.
 Our predecessor court reasoned that a person of ordinary skill would not always be
 motivated to optimize a parameter ‘if there is no evidence in the record that the
 prior art recognized that [that] particular parameter affected the result.’
 Antonie, 559 F.2d at 620.) For example, in
 Antonie the claimed device was characterized by a certain
 ratio, and the prior art did not disclose that ratio and was silent regarding one of
 the variables in the ratio. Id. at 619. Our predecessor court thus
 reversed the Board’s conclusion of obviousness. Id. at 620.
 Antonie described the situation where a ‘parameter optimized
 was not recognized to be a result-effective variable’ as an ‘exception' to the
 general principle in Aller that 'the discovery of an optimum value
 of a variable in a known process is normally obvious.’ Id. at 620.
 Our subsequent cases have confirmed that this exception is a narrow one. … In
 summarizing the relevant precedent from our predecessor court, we observed in
 Applied Materials that ‘[i]n cases in which the disclosure in
 the prior art was insufficient to find a variable result-effective, there was
 essentially no disclosure of the relationship between the variable and the result in
 the prior art.' 692 F.3d at 1297. Likewise, if the prior art does recognize that the
 variable affects the relevant property or result, then the variable is
 result-effective. Id. (‘A recognition in the prior art that a
 property is affected by the variable is sufficient to find the variable
 result-effective.’)”). Applicants must articulate why the variable at issue would not
 have been recognized in the prior art as result-effective. However, it should be
 noted that after KSR, the presence of a known result-effective
 variable would be one, but not the only, motivation for a person of ordinary skill in
 the art to experiment to reach another workable product or process. KSR
 International Co. v. Teleflex Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007).
 See subsection II.B above for additional information about consideration of
 result-effective variables within an obviousness analysis.
 

 D. Showing That a Claimed
 Parameter is Disclosed in a Very Broad Range in Prior Art One factor that may weigh against maintaining an
 obviousness rejection based on optimization of a variable disclosed in a range in the
 prior art is where an applicant establishes that the prior art disclosure of the
 variable is within a range that is so broad in light of the dissimilar
 characteristics of the members of the range as to not invite optimization by one of
 skill in the art. Genetics Inst., LLC v. Novartis Vaccines &
 Diagnostics, Inc., 655 F.3d 1291, 1306, 99 USPQ2d 1713, 1725 (Fed. Cir.
 2011) (holding that ordinary motivation to optimize did not apply where disclosure
 was 68,000 protein variants including 2,332 amino acids where one of skill in the art
 would appreciate that the claimed truncated proteins vary enormously in structure).
 See MPEP §§
 2131.02 , 2131.03 , and 2144.08 for
 additional discussion on consideration of range limitations.
 

 

 
 2144.06 Art Recognized Equivalence for the Same Purpose [R-01.2024]
 I. 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 re Crockett, 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.); Ex parte Quadranti, 25 USPQ2d 1071 (Bd.
 Pat. App. & Inter. 1992) (mixture of two known herbicides held prima
 facie obvious); and In re Couvaras, 70 F.4th 1374,
 1378-79, 2023 USPQ2d 697 (Fed. Cir. 2023) (That the two claimed types of active
 agents, GABA-a agonists and ARBs, were known to be useful for the same
 purpose—alleviating hypertension—alone can serve as a motivation to combine). 
 

 II. 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.); Smith v. 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).
 

 

 
 2144.07 Art Recognized Suitability for an Intended Purpose [R-01.2024]

 The selection of a known material based on its suitability for its
 intended use supported a prima facie obviousness 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.)
 

 See also In re Leshin, 277 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.). 
 

 

 
 2144.08 Obviousness of Species When Prior Art Teaches Genus [R-01.2024]

 [Editor Note: This MPEP section is applicable regardless of whether an
 application is examined under the AIA or under pre-AIA law. For applications subject
 to the first inventor to file (FITF) provisions of the AIA, the relevant time is
 "before the effective filing date of the claimed invention". For applications subject
 to pre-AIA 35
 U.S.C. 102 , the relevant time is "at the time of the
 invention". See MPEP § 2150 et seq. Many of the
 court decisions discussed in this section involved applications or patents subject to
 pre-AIA 35
 U.S.C. 102 . These court decisions may be applicable to
 applications and patents subject to AIA 35 U.S.C. 102 but the
 relevant time is before the effective filing date of the claimed invention and not at
 the time of the invention.] 

 I. EXAMINATION OF CLAIMS DIRECTED TO SPECIES BASED UPON A SINGLE PRIOR ART
 REFERENCE When a single prior art reference which discloses a genus
 encompassing the claimed species or subgenus but does not expressly disclose the
 particular claimed species or subgenus, Office personnel should attempt to find
 additional prior art to show that the differences between the prior art primary
 reference and the claimed invention as a whole would have been obvious. Where such
 additional prior art is not found, Office personnel should consider the factors
 discussed below to determine whether a single reference 35 U.S.C. 103 
 rejection would be appropriate. 
 

 II. DETERMINE WHETHER THE CLAIMED SPECIES OR SUBGENUS WOULD HAVE BEEN OBVIOUS TO
 ONE OF ORDINARY SKILL IN THE PERTINENT ART AT THE RELEVANT TIME The patentability of a claim to a specific compound, species, or
 subgenus embraced by a prior art genus should be analyzed no differently than any
 other claim for purposes of 35 U.S.C. 103 . “The section 103
 requirement of unobviousness is no different in chemical cases than with respect to
 other categories of patentable inventions.” 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)
 (en 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.”). 
 

 A. Establishing a Prima Facie Case of Obviousness Office personnel must consider the factors set out by the Supreme
 Court in Graham v. John Deere, 383 U.S. 1, 148 USPQ 459 (1966)
 in order to establish a prima facie case of obviousness. 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
 facie obviousness.”); 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 at 17-18, 148 USPQ at 467 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 ordinary 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. 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. Office
 personnel should evaluate, when appropriate, 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
 relevant time. See Graham, at 17-18, 148 USPQ at 467. See,
 e.g., MPEP §§
 714.12 , 714.13 , and 715.09 for
 guidance when rebuttal evidence or argument may not be considered.
 

 1. Determine the Scope and Content of the Prior Art After construing the claims, Office personnel should determine
 the scope and content of the relevant prior art. Each reference to be applied
 as the basis for an obviousness rejection 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 must also be analogous art to the claimed
 invention. See MPEP § 2141.01(a) .
 

 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, 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 and a discussion of the level of ordinary skill will not be needed.
 See MPEP §
 2141.03 , subsection II. However, any additional
 evidence presented by applicant should be evaluated. See MPEP §§
 2141 , subsection II, and 2141.03 ,
 subsection III.
 

 4. Determine Whether One of Ordinary Skill in the Art Would Have Had a
 Reason To Select the Claimed Species or Subgenus In light of the findings made relating to the
 Graham factors, Office personnel should determine whether
 it would have been obvious to one of ordinary skill in the relevant art to make
 the claimed invention as a whole, i.e., to select the claimed species or
 subgenus from the disclosed prior art genus. To address this key issue, Office
 personnel should consider all relevant prior art teachings, focusing on the
 following, where present. 
 

 (a) Consider the Size of the Genus Consider the size of the prior art genus, bearing in mind
 that size alone cannot support an obviousness rejection. There is no
 absolute correlation between the size of the prior art genus and a
 conclusion of obviousness. See, e.g., Baird, 16 F.3d at
 383, 29 USPQ2d at 1552. Thus, the mere fact that a prior art genus contains
 a small number of members does not create a per se rule
 of obviousness. Even where the genus contains a small number of members, the
 disclosed genus may not possess a recognizable class of compounds with
 common properties. This is a distinction between an obviousness rejection
 and an anticipation rejection. Contrast the obviousness consideration with
 an anticipation rejection where it is clear that each member of the small
 genus contains common properties. 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, as well as properties possessed by the claimed
 compound constituted description of claimed compound for purposes of
 pre-AIA
 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 and explain why it would have been obvious
 to one of ordinary skill in the art to select the claimed invention. An
 express teaching may be based on a statement in the prior art reference such
 as an art recognized equivalence. 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 it would have been obvious 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 disclosed genus. If such a prior
 art species or subgenus is structurally similar to that claimed, its
 disclosure may provide a reason for one of ordinary skill in the art to
 choose the claimed species or subgenus from the genus, based on the
 reasonable expectation that structurally similar species usually have
 similar properties. See, e.g., Dillon, 919 F.2d at 693,
 696, 16 USPQ2d at 1901, 1904. See also In re Deuel, 51
 F.3d 1552, 1558, 34 USPQ2d 1210, 1214 (Fed. Cir. 1995) (“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.”). 
 

 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 (W. H. Freeman & Co., 2d
 ed. 1990). 
 

 The closer the physical and/or chemical similarities
 between the claimed species or subgenus and any exemplary species or
 subgenus disclosed in the prior art, the greater the expectation that the
 claimed subject matter will function in an equivalent manner to the genus.
 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 facie obvious). 
 

 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 tricyclic dibenzo compounds and differed structurally only in the
 replacement of the unsaturated carbon atom in the center ring of
 amitriptyline with a nitrogen atom in imipramine. 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 Lintner, 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 facie obviousness 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 any
 teachings or suggestions in the prior art that 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). The fact-findings should state
 a rationale, as required by KSR, that supports a conclusion
 that the claimed invention would have been obvious. Thereafter, it should be
 determined whether these findings, considered as a whole, establish a
 prima facie case that the claimed invention would have
 been obvious to one of ordinary skill in the relevant art at the relevant time.
 
 

 

 
 2144.09 Close Structural Similarity Between Chemical Compounds
 (Homologs, Analogues, Isomers) [R-01.2024]
 

 [Editor Note: This MPEP section is applicable regardless of whether an
 application is examined under the AIA or under pre-AIA law. For applications subject
 to the first inventor to file (FITF) provisions of the AIA, the relevant time is
 "before the effective filing date of the claimed invention". For applications subject
 to pre-AIA 35
 U.S.C. 102 , the relevant time is "at the time of the
 invention". See MPEP § 2150 et seq. Many of the
 court decisions discussed in this section involved applications or patents subject to
 pre-AIA 35
 U.S.C. 102 . These court decisions may be applicable to
 applications and patents subject to AIA 35 U.S.C. 102 but the
 relevant time is before the effective filing date of the claimed invention and not at
 the time of the invention.] 

 I. 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. 1990) (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 , subsection II.A.4.(c).
 

 II. 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 -CH 2 - groups) are generally of sufficiently close
 structural similarity that there is a presumed expectation that such compounds
 possess similar properties. In re Wilder, 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); Aventis Pharma Deutschland v.
 Lupin Ltd., 499 F.3d 1293, 84 USPQ2d 1197 (Fed. Cir. 2007) (5(S)
 stereoisomer of ramipril obvious over prior art mixture of stereoisomers of
 ramipril.).
 

 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 parte Mowry, 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, 221 126 USPQ 513, 516 (CCPA 1960) (in the
 absence of “some way to bridge the factual gap between” them, prior art disclosure of
 C(8) to C(12) alkyl sulfates was not sufficient to render prima
 facie obvious claimed C(1) 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 nonobvious 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.).
 
 

 III. PRESENCE OF A TRUE HOMOLOGOUS OR ISOMERIC RELATIONSHIP IS NOT
 CONTROLLING 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 and functional similarity
 of the amino acids leucine and isoleucine); 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); In re Dillon, 919 F.2d 688, 16 USPQ2d 1897 (Fed. Cir. 1990) (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.). 
 

 IV. 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. 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).
 

 V. 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 re Schechter, 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.). 
 

 VI. 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 unlikely to
 render structurally similar claims prima facie obvious in the
 absence of any reason for one of ordinary skill in the art to make the reference
 compounds or any structurally related compounds. In re Stemniski, 444 F.2d 581, 170 USPQ 343 (CCPA 1971). 
 

 See also 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 ordinarily 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). 
 

 VII. PRIMA FACIE CASE REBUTTABLE BY EVIDENCE OF 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,
 693, 16 USPQ2d 1897, 1901 (Fed. Cir. 1990) ( en banc ).
 

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

 

 [top] 

 

 

 
 

 
 

 

 

 

 
 
 
 2101-2102-[Reserved] 

 2103-Patent Examination Process 

 2104-Requirements of 35 U.S.C. 101 
 2104.01-Barred by Atomic Energy Act 

 
 

 2105-Patent Eligible Subject Matter — Living Subject Matter 

 2106-Patent Subject Matter Eligibility 
 2106.01-[Reserved] 

 2106.02-[Reserved] 

 2106.03-Eligibility Step 1: The Four Categories of Statutory Subject Matter 

 2106.04-Eligibility Step 2A: Whether a Claim is Directed to a Judicial Exception 
 2106.04(a)-Abstract Ideas 
 2106.04(a)(1)-Examples of Claims That Do Not Recite Abstract Ideas 

 2106.04(a)(2)-Abstract Idea Groupings 

 2106.04(a)(3)-Tentative Abstract Ideas 

 
 

 2106.04(b)-Laws of Nature, Natural Phenomena & Products of Nature 

 2106.04(c)-The Markedly Different Characteristics Analysis 

 2106.04(d)-Integration of a Judicial Exception Into A Practical Application 
 2106.04(d)(1)-Evaluating Improvements in the Functioning of a Computer, or an Improvement to Any Other Technology or Technical Field in
 Step 2A Prong Two 

 2106.04(d)(2)-Particular Treatment and Prophylaxis in Step 2A Prong Two 

 
 

 
 

 2106.05-Eligibility Step 2B: Whether a Claim Amounts to Significantly More 
 2106.05(a)-Improvements to the Functioning of a Computer or To Any Other Technology or Technical Field 

 2106.05(b)-Particular Machine 

 2106.05(c)-Particular Transformation 

 2106.05(d)-Well-Understood, Routine, Conventional Activity 

 2106.05(e)-Other Meaningful Limitations 

 2106.05(f)-Mere Instructions To Apply An Exception 

 2106.05(g)-Insignificant Extra-Solution Activity 

 2106.05(h)-Field of Use and Technological Environment 

 
 

 2106.06-Streamlined Analysis 
 2106.06(a)-Eligibility is Self Evident 

 2106.06(b)-Clear Improvement to a Technology or to Computer Functionality 

 
 

 2106.07-Formulating and Supporting Rejections For Lack Of Subject Matter Eligibility 
 2106.07(a)-Formulating a Rejection For Lack of Subject Matter Eligibility 
 2106.07(a)(1)-Form Paragraphs for use in Lack of Subject Matter Eligibility Rejections 

 
 

 2106.07(b)-Evaluating Applicant’s Response 

 2106.07(c)-Clarifying the Record 

 
 

 
 

 2107-Guidelines for Examination of Applications for Compliance with the Utility Requirement 
 2107.01-General Principles Governing Utility Rejections 

 2107.02-Procedural Considerations Related to Rejections for Lack of Utility 

 2107.03-Special Considerations for Asserted Therapeutic or Pharmacological Utilities 

 
 

 2108-[Reserved] 

 2109-Inventorship 

 2109.01-Joint Inventorship 

 2110-[Reserved] 

 2111-Claim Interpretation; Broadest Reasonable Interpretation 
 2111.01-Plain Meaning 

 2111.02-Effect of Preamble 

 2111.03-Transitional Phrases 

 2111.04-“Adapted to,” “Adapted for,” “Wherein,” “Whereby,” and Contingent Clauses 

 2111.05-Functional and Nonfunctional Descriptive Material 

 
 

 2112-Requirements of Rejection Based on Inherency; Burden of Proof 
 2112.01-Composition, Product, and Apparatus Claims 

 2112.02-Process Claims 

 
 

 2113-Product-by-Process Claims 

 2114-Apparatus and Article Claims — Functional Language 

 2115-Material or Article Worked Upon by Apparatus 

 2116-Novel, Nonobvious Starting Material or End Product 
 2116.01-Novel, Nonobvious Starting Material or End Product 

 
 

 2117-Markush Claims 

 2118-2119-[Reserved] 

 2120-Rejection on Prior Art 
 2120.01-Rejections Under 35 U.S.C. 102(a)(1) and (a)(2) and Pre-AIA 35 U.S.C. 102(a), (b), or (e): Printed Publication or Patent 

 2120.02-Rejections Under 35 U.S.C. 102(a)(1) or Pre-AIA 35 U.S.C. 102(a) or (b): Knowledge by Others, or Public Use, or On Sale 

 
 

 2121-Prior Art; General Level of Operability Required to Make a Prima Facie Case 
 2121.01-Use of Prior Art in Rejections Where Operability is in Question 

 2121.02-Compounds and Compositions — What Constitutes Enabling Prior Art 

 2121.03-Plant Genetics — What Constitutes Enabling Prior Art 

 2121.04-Apparatus and Articles — What Constitutes Enabling Prior Art 

 
 

 2122-Discussion of Utility in the Prior Art 

 2123-Rejection Over Prior Art’s Broad Disclosure Instead of Preferred Embodiments 

 2124-Exception to the Rule That the Reference Must be Prior Art 
 2124.01-Tax Strategies Deemed Within the Prior Art 

 
 

 2125-Drawings as Prior Art 

 2126-Availability of a Document as a “Patent” for Purposes of Rejection Under 35 U.S.C. 102(a) or Pre-AIA 35 U.S.C. 102(a), (b),
 and (d) 
 2126.01-Date of Availability of a Patent as a Reference 

 2126.02-Scope of Reference’s Disclosure Which Can Be Used to Reject Claims When the Reference Is a “Patent” but Not a “Publication” 

 
 

 2127-Domestic and Foreign Patent Applications as Prior Art 

 2128-“Printed Publications” as Prior Art 
 2128.01-Level of Public Accessibility Required 

 2128.02-Date Publication Is Available as a Reference 

 
 

 2129-Admissions as Prior Art 

 2130-[Reserved] 

 2131-Anticipation — Application of 35 U.S.C. 102 
 2131.01-Multiple Reference 35 U.S.C. 102 Rejections 

 2131.02-Genus-Species Situations 

 2131.03-Anticipation of Ranges 

 2131.04-Secondary Considerations 

 2131.05-Nonanalogous or Disparaging Prior Art 

 
 

 2132-Pre-AIA 35 U.S.C. 102(a) 
 2132.01-Overcoming a Pre-AIA 35 U.S.C. 102(a) Rejection based on a Printed Publication or Patent 

 
 

 2133-Pre-AIA 35 U.S.C. 102(b) 
 2133.01-Rejections of Continuation-In-Part (CIP) Applications 

 2133.02-Rejections Based on Publications and Patents 
 2133.02(a)-Overcoming a Pre-AIA 35 U.S.C. 102(b) Rejection Based on a Printed Publication or Patent 

 
 

 2133.03-Rejections Based on “Public Use” or “On Sale” 
 2133.03(a)-“Public Use” 

 2133.03(b)-“On Sale” 

 2133.03(c)-The “Invention” 

 2133.03(d)-“In This Country” 

 2133.03(e)-Permitted Activity; Experimental Use 
 2133.03(e)(1)-Commercial Exploitation 

 2133.03(e)(2)-Intent 

 2133.03(e)(3)-“Completeness” of the Invention 

 2133.03(e)(4)-Factors Indicative of an Experimental Purpose 

 2133.03(e)(5)-Experimentation and Degree of Supervision and Control 

 2133.03(e)(6)-Permitted Experimental Activity and Testing 

 2133.03(e)(7)-Activity of an Independent Third Party Inventor 

 
 

 
 

 
 

 2134-Pre-AIA 35 U.S.C. 102(c) 

 2135-Pre-AIA 35 U.S.C. 102(d) 
 2135.01-The Four Requirements of Pre-AIA 35 U.S.C. 102(d) 

 
 

 2136-Pre-AIA 35 U.S.C. 102(e) 
 2136.01-Status of Unpublished or Published as Redacted U.S. Application as a Reference Under Pre-AIA 35 U.S.C. 102(e) 

 2136.02-Content of the Prior Art Available Against the Claims 

 2136.03-Critical Reference Date 

 2136.04-Different Inventive Entity; Meaning of “By Another” 

 2136.05-Overcoming a Rejection Under Pre-AIA 35 U.S.C. 102(e) 
 2136.05(a)-Antedating a Pre-AIA 35 U.S.C. 102(e) Reference 

 2136.05(b)-Showing The Reference Is Describing An Inventor's Or At Least One Joint Inventor's Own Work 

 
 

 
 

 2137-Pre-AIA 35 U.S.C. 102(f) 
 2137.01-[Reserved] 

 2137.02-[Reserved] 

 
 

 2138-Pre-AIA 35 U.S.C. 102(g) 
 2138.01-Interference Practice 

 2138.02-“The Invention Was Made in This Country” 

 2138.03-“By Another Who Has Not Abandoned, Suppressed, or Concealed It” 

 2138.04-“Conception” 

 2138.05-“Reduction to Practice” 

 2138.06-“Reasonable Diligence” 

 
 

 2139-Rejections Under Pre-AIA 35 U.S.C. 102 
 2139.01-Effective Filing Date of a Claimed Invention Under Pre-AIA 35 U.S.C. 102 

 2139.02-Determining Whether To Apply Pre-AIA 35 U.S.C. 102(a), (b), or (e) 

 2139.03-Form Paragraphs for Use in Rejections Under Pre-AIA 35 U.S.C. 102 

 
 

 2140-[Reserved] 

 2141-Examination Guidelines for Determining Obviousness Under 35 U.S.C. 103 
 2141.01-Scope and Content of the Prior Art 
 2141.01(a)-Analogous and Nonanalogous Art 

 
 

 2141.02-Differences Between Prior Art and Claimed Invention 

 2141.03-Level of Ordinary Skill in the Art 

 
 

 2142-Legal Concept of Prima Facie Obviousness 

 2143-Examples of Basic Requirements of a Prima Facie Case of Obviousness 
 2143.01-Suggestion or Motivation To Modify the References 

 2143.02-Reasonable Expectation of Success Is Required 

 2143.03-All Claim Limitations Must Be Considered 

 
 

 2144-Supporting a Rejection Under 35 U.S.C. 103 
 2144.01-Implicit Disclosure 

 2144.02-Reliance on Scientific Theory 

 2144.03-Reliance on Common Knowledge in the Art or “Well Known” Prior Art 

 2144.04-Legal Precedent as Source of Supporting Rationale 

 2144.05-Obviousness of Similar and Overlapping Ranges, Amounts, and Proportions 

 2144.06-Art Recognized Equivalence for the Same Purpose 

 2144.07-Art Recognized Suitability for an Intended Purpose 

 2144.08-Obviousness of Species When Prior Art Teaches Genus 

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

 
 

 2145-Consideration of Applicant’s Rebuttal Arguments and Evidence 

 2146-Pre-AIA 35 U.S.C. 103(c) 
 2146.01-Prior Art Disqualification Under Pre-AIA 35 U.S.C. 103(c) 

 2146.02-Establishing Common Ownership or Joint Research Agreement Under Pre-AIA 35 U.S.C. 103(c) 

 2146.03-Examination Procedure With Respect to Pre-AIA 35 U.S.C. 103(c) 
 2146.03(a)-Provisional Rejection (Obviousness) Under 35 U.S.C. 103(a) Using Provisional Prior Art Under Pre-AIA 35 U.S.C. 102(e) 

 
 

 
 

 2147-Biotechnology Process Applications; Pre-AIA 35 U.S.C. 103(b) 

 2148-Form Paragraphs for Use in Rejections Under Pre-AIA 35 U.S.C. 103 

 2149-[Reserved] 

 2150-Examination Guidelines for 35 U.S.C. 102 and 103 as Amended by the First Inventor To File Provisions of the Leahy-Smith America
 Invents Act 

 2151-Overview of the Changes to 35 U.S.C. 102 and 103 in the AIA 

 2152-Detailed Discussion of AIA 35 U.S.C. 102(a) and (b) 
 2152.01-Effective Filing Date of the Claimed Invention 

 2152.02-Prior Art Under AIA 35 U.S.C. 102(a)(1) (Patented, Described in a Printed Publication, or in Public Use, on Sale, or Otherwise
 Available to the Public) 
 2152.02(a)-Patented 

 2152.02(b)-Described in a Printed Publication 

 2152.02(c)-In Public Use 

 2152.02(d)-On Sale 

 2152.02(e)-Otherwise Available to the Public 

 2152.02(f)-No Requirement of “By Others” 

 
 

 2152.03-Admissions 

 2152.04-The Meaning of “Disclosure” 

 2152.05-Determining Whether To Apply 35 U.S.C. 102(a)(1) or 102(a)(2) 

 2152.06-Overcoming a 35 U.S.C. 102(a)(1) or 102(a)(2) Rejection 

 2152.07-Form Paragraphs for Use in Rejections Under AIA 35 U.S.C. 102 

 
 

 2153-Prior Art Exceptions Under 35 U.S.C. 102(b)(1) to AIA 35 U.S.C. 102(a)(1) 
 2153.01-Prior Art Exception Under AIA 35 U.S.C. 102(b)(1)(A) To AIA 35 U.S.C. 102(a)(1) (Grace Period Inventor-Originated Disclosure
 Exception) 
 2153.01(a)-Grace Period Inventor-Originated Disclosure Exception 

 2153.01(b)-[Reserved] 

 
 

 2153.02-Prior Art Exception Under AIA 35 U.S.C. 102(b)(1)(B) to AIA 35 U.S.C. 102(a)(1) (Inventor-Originated Prior Public Disclosure
 Exception) 

 
 

 2154-Provisions Pertaining to Subject Matter in a U.S. Patent or Application Effectively Filed Before the Effective Filing Date
 of the Claimed Invention 
 2154.01-Prior Art Under AIA 35 U.S.C. 102(a)(2) “U.S. Patent Documents” 
 2154.01(a)-WIPO Published Applications 

 2154.01(b)-Determining When Subject Matter Was Effectively Filed Under AIA 35 U.S.C. 102(d) 

 2154.01(c)-Requirement Of “Names Another Inventor” 

 2154.01(d)-Provisional Rejections Under 35 U.S.C. 102(a)(2); Reference Is a Copending U.S. Patent Application 

 
 

 2154.02-Prior Art Exceptions Under 35 U.S.C. 102(b)(2) to AIA 35 U.S.C. 102(a)(2) 
 2154.02(a)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(A) to AIA 35 U.S.C. 102(a)(2) (Inventor-Originated Disclosure Exception) 

 2154.02(b)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(B) to AIA 35 U.S.C. 102(a)(2) (Inventor-Originated Prior Public Disclosure
 Exception) 

 2154.02(c)-Prior Art Exception Under AIA 35 U.S.C. 102(b)(2)(C) to AIA 35 U.S.C. 102(a)(2) (Common Ownership or Obligation of Assignment) 

 
 

 
 

 2155-Use of Affidavits or Declarations Under 37 CFR 1.130 To Overcome Prior Art Rejections 
 2155.01-Showing That the Disclosure Was Made by the Inventor or a Joint Inventor 

 2155.02-Showing That the Subject Matter Disclosed Had Been Previously Publicly Disclosed by the Inventor or a Joint Inventor 

 2155.03-Showing That the Disclosure was Made, or That Subject Matter had Been Previously Publicly Disclosed, by Another Who Obtained
 the Subject Matter Disclosed Directly or Indirectly From the Inventor or a Joint Inventor 

 2155.04-Enablement 

 2155.05-Who May File an Affidavit or Declaration Under 37 CFR 1.130 

 2155.06-Situations in Which an Affidavit or Declaration Is Not Available 

 
 

 2156-Joint Research Agreements 

 2157-Improper Naming of Inventors 

 2158-AIA 35 U.S.C. 103 
 2158.01-Form Paragraphs for Use in Rejections Under AIA 35 U.S.C. 103 

 
 

 2159-Applicability Date Provisions and Determining Whether an Application Is Subject to the First Inventor To File Provisions of
 the AIA 
 2159.01-Applications Filed Before March 16, 2013 

 2159.02-Applications Filed on or After March 16, 2013 

 2159.03-Applications Subject to the AIA but Also Containing a Claimed Invention Having an Effective Filing Date Before March 16, 2013 

 2159.04-Applicant Statement in Transition Applications Containing a Claimed Invention Having an Effective Filing Date on or After
 March 16, 2013 

 
 

 2160-[Reserved] 

 2161-Three Separate Requirements for Specification Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 
 2161.01-Computer Programming, Computer Implemented Inventions, and 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 
 

 2162-Policy Underlying 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 2163-Guidelines for the Examination of Patent Applications Under the 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, first paragraph,
 “Written Description” Requirement 
 2163.01-Support for the Claimed Subject Matter in Disclosure 

 2163.02-Standard for Determining Compliance With the Written Description Requirement 

 2163.03-Typical Circumstances Where Adequate Written Description Issue Arises 

 2163.04-Burden on the Examiner with Regard to the Written Description Requirement 

 2163.05-Changes to the Scope of Claims 

 2163.06-Relationship of Written Description Requirement to New Matter 

 2163.07-Amendments to Application Which Are Supported in the Original Description 
 2163.07(a)-Inherent Function, Theory, or Advantage 

 2163.07(b)-Incorporation by Reference 

 
 

 
 

 2164-The Enablement Requirement 
 2164.01-Test of Enablement 
 2164.01(a)-Undue Experimentation Factors 

 2164.01(b)-How to Make the Claimed Invention 

 2164.01(c)-How to Use the Claimed Invention 

 
 

 2164.02-Working and Prophetic Examples 

 2164.03-Relationship of Predictability of the Art and the Enablement Requirement 

 2164.04-Burden on the Examiner Under the Enablement Requirement 

 2164.05-Determination of Enablement Based on Evidence as a Whole 
 2164.05(a)-Specification Must Be Enabling as of the Filing Date 

 2164.05(b)-Specification Must Be Enabling to Persons Skilled in the Art 

 
 

 2164.06-Quantity of Experimentation 
 2164.06(a)-Examples of Enablement Issues-Missing Information 

 2164.06(b)-Examples of Enablement Issues — Biological and Chemical Cases 

 2164.06(c)-Examples of Enablement Issues – Computer Programming Cases 

 
 

 2164.07-Relationship of Enablement Requirement to Utility Requirement of 35 U.S.C. 101 

 2164.08-Enablement Commensurate in Scope With the Claims 
 2164.08(a)-Single Means Claim 

 2164.08(b)-Inoperative Subject Matter 

 2164.08(c)-Critical Feature Not Claimed 

 
 

 
 

 2165-The Best Mode Requirement 
 2165.01-Considerations Relevant to Best Mode 

 2165.02-Best Mode Requirement Compared to Enablement Requirement 

 2165.03-Requirements for Rejection for Lack of Best Mode 

 2165.04-Examples of Evidence of Concealment 

 
 

 2166-Rejections Under 35 U.S.C. 112(a) or Pre-AIA 35 U.S.C. 112, First Paragraph 

 2167-2170-[Reserved] 

 2171-Two Separate Requirements for Claims Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 

 2172-Subject Matter Which the Inventor or a Joint Inventor Regards as The Invention 
 2172.01-Unclaimed Essential Subject Matter 

 
 

 2173-Claims Must Particularly Point Out and Distinctly Claim the Invention 
 2173.01-Interpreting the Claims 

 2173.02-Determining Whether Claim Language is Definite 

 2173.03-Correspondence Between Specification and Claims 

 2173.04-Breadth Is Not Indefiniteness 

 2173.05-Specific Topics Related to Issues Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 
 2173.05(a)-New Terminology 

 2173.05(b)-Relative Terminology 

 2173.05(c)-Numerical Ranges and Amounts Limitations 

 2173.05(d)-Exemplary Claim Language (“for example,” “such as”) 

 2173.05(e)-Lack of Antecedent Basis 

 2173.05(f)-Reference to Limitations in Another Claim 

 2173.05(g)-Functional Limitations 

 2173.05(h)-Alternative Limitations 

 2173.05(i)-Negative Limitations 

 2173.05(j)-Old Combination 

 2173.05(k)-Aggregation 

 2173.05(l)-[Reserved] 

 2173.05(m)-Prolix 

 2173.05(n)-Multiplicity 

 2173.05(o)-Double Inclusion 

 2173.05(p)-Claim Directed to Product-By- Process or Product and Process 

 2173.05(q)-“Use” Claims 

 2173.05(r)-Omnibus Claim 

 2173.05(s)-Reference to Figures or Tables 

 2173.05(t)-Chemical Formula 

 2173.05(u)-Trademarks or Trade Names in a Claim 

 2173.05(v)-Mere Function of Machine 

 
 

 2173.06-Practice Compact Prosecution 

 
 

 2174-Relationship Between the Requirements of 35 U.S.C. 112(a) and (b) or Pre-AIA 35 U.S.C. 112, First and Second Paragraphs 

 2175-Form Paragraphs for Use in Rejections Under 35 U.S.C. 112(b) or Pre-AIA 35 U.S.C. 112, Second Paragraph 

 2176-2180-[Reserved] 

 2181-Identifying and Interpreting a 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, Sixth Paragraph Limitation 

 2182-Search and Identification of the Prior Art 

 2183-Making a Prima Facie Case of Equivalence 

 2184-Determining Whether an Applicant Has Met the Burden of Proving Nonequivalence After a Prima Facie Case Is Made 

 2185-Related Issues Under 35 U.S.C. 112(a) or (b) and Pre-AIA 35 U.S.C. 112, First or Second Paragraphs 

 2186-Relationship to the Doctrine of Equivalents 

 2187-Form Paragraphs for Use Relating to 35 U.S.C. 112(f) or Pre-AIA 35 U.S.C. 112, Sixth Paragraph 

 2188-2189-[Reserved] 

 2190-Prosecution Laches and Res Judicata 

 

 

 
 

 
 
 

 
 

 

 
 
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 03/09/2026 20:50:41