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.

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.

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.”).

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.

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.

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).

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.

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).).

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 reLarson, 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).

Note that the omission of an element and retention of its function is an indicium of nonobviousness. In reEdge, 359 F.2d 896, 149 USPQ 556 (CCPA 1966) (Claims at issue were directed to a printed sheet having a thin layer of erasable metal bonded directly to the sheet wherein said thin layer obscured the original print until removal by erasure. The prior art disclosed a similar printed sheet which further comprised an intermediate transparent and erasure-proof protecting layer which prevented erasure of the printing when the top layer was erased. The claims were found 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.).

In reVenner, 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.).

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 Gardnerv.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.

In reDailey, 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.).

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 reBurhans, 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 reGibson, 39 F.2d 975, 5 USPQ 230 (CCPA 1930) (Selection of any order of mixing ingredients is prima facie obvious.).

In reLindberg, 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.).

In reLarson, 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 Schenckv.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.).

In reDulberg, 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.”).

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.).

In reDilnot, 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.).

In reGazda, 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.).

In reHarza, 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.).

In reJapikse, 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).

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 reBergstrom, 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 reCofer, 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 parteStern, 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.

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 reWertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In reWoodruff, 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 Americav.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./ft³ and 25 lbs./ft³” 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.

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 reAller, 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 reHoeschele, 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 reKulling, 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.”).

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.

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 reWoodruff, 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.

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./ft³).

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.

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]

“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 reKerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980) (citations omitted) (Claims to a process of preparing a spray-dried detergent by mixing together two conventional spray-dried detergents were held to be prima facie obvious.). See also In reCrockett, 279 F.2d 274, 126 USPQ 186 (CCPA 1960) (Claims directed to a method and material for treating cast iron using a mixture comprising calcium carbide and magnesium oxide were held unpatentable over prior art disclosures that the aforementioned components individually promote the formation of a nodular structure in cast iron.); 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).

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 reRuff, 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.); Smithv.Hayashi, 209 USPQ 754 (Bd. of Pat. Inter. 1980) (The mere fact that phthalocyanine and selenium function as equivalent photoconductors in the claimed environment was not sufficient to establish that one would have been obvious over the other. However, there was evidence that both phthalocyanine and selenium were known photoconductors in the art of electrophotography. “This, in our view, presents strong evidence of obviousness in substituting one for the other in an electrophotographic environment as a photoconductor.” 209 USPQ at 759.).

An express suggestion to substitute one equivalent component or process for another is not necessary to render such substitution obvious. In reFout, 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 reLeshin, 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.]

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.

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.”).

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.

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.

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).

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.

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.

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.).

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).

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.

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).

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).

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.

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.]

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 rePayne, 606 F.2d 303, 313, 203 USPQ 245, 254 (CCPA 1979). See In rePapesch, 315 F.2d 381, 137 USPQ 43 (CCPA 1963) (discussed in more detail below) and In reDillon, 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).

Compounds which are position isomers (compounds having the same radicals in physically different positions on the same nucleus) or homologs (compounds differing regularly by the successive addition of the same chemical group, e.g., by -CH₂- groups) are generally of sufficiently close structural similarity that there is a presumed expectation that such compounds possess similar properties. In reWilder, 563 F.2d 457, 195 USPQ 426 (CCPA 1977). See also In reMay, 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 parteMowry, 91 USPQ 219 (Bd. App. 1950) (claimed cyclohexylstyrene not prima facie obvious over prior art isohexylstyrene). Similarly, homologs which are far removed from adjacent homologs may not be expected to have similar properties. In reMills, 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 reMills, 281 F.2d 218, 126 USPQ 513 (CCPA 1960); In reWiechert, 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.).

Prior art structures do not have to be true homologs or isomers to render structurally similar compounds prima facie obvious. In rePayne, 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 reDillon, 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 reGrabiak, 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 reBell, 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 reDeuel, 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.).

“[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 reHoeksema, 399 F.2d 269, 274-75, 158 USPQ 597, 601 (CCPA 1968).

See In rePayne, 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).

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 reMay, 574 F.2d 1082, 197 USPQ 601 (CCPA 1978) (appellant produced sufficient evidence to establish a substantial degree of unpredictability in the pertinent art area, and thereby rebutted the presumption that structurally similar compounds have similar properties); In reSchechter, 205 F.2d 185, 98 USPQ 144 (CCPA 1953). See also Ex parte Blattner, 2 USPQ2d 2047 (Bd. Pat. App. & Inter. 1987) (Claims directed to compounds containing a 7-membered ring were rejected as prima facie obvious over a reference which taught 5- and 6-membered ring homologs of the claimed compounds. The Board reversed the rejection because the prior art taught that the compounds containing a 5-membered ring possessed the opposite utility of the compounds containing the 6-membered ring, undermining the examiner’s asserted prima facie case arising from an expectation of similar results in the claimed compounds which contain a 7-membered ring.).

If 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 reStemniski, 444 F.2d 581, 170 USPQ 343 (CCPA 1971).

See alsoIn reAlbrecht, 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 reLalu, 747 F.2d 703, 223 USPQ 1257 (Fed. Cir. 1984).

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 rePapesch, 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 reWiechert, 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.