MPEP § 2143 — MPEP § 2143
Current through: 2022-07-01

2143-Examples of Basic Requirements of a Prima Facie Case of Obviousness 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

 Skip over navigation 
 
 
 
 
 
 
 
 search for patents | search for trademarks 

 
 
 
 
 
 
 
 
 
 
 
 Search 
 
 
 

 
 

 
 
 
 
 
 PATENTS 
 
 Patent Search 

 
 Patent Process 

 
 Patent Classification 

 
 Patent Forms 

 
 Statistics 

 
 Electronic Business Center 

 
 Patent Laws, Regulations, Policies & Procedures 

 
 Resources and Guidance 

 
 Office of Data Management 

 
 Announcements 

 
 Initiatives & Events 

 
 International Protection 

 
 Employee Locator 

 
 Contact Patents 

 

 

 
 TRADEMARKS 
 
 Trademark Search 

 
 Trademarks Process 

 
 News & Notices 

 
 Manuals, Guides, Official Gazette 

 
 Laws & Regulations 

 
 Online Filing 

 
 Contact Trademarks 

 

 

 
 IP LAW & POLICY 
 
 Rulemaking 

 
 IP Policy and Enforcement 

 
 Protecting IP Overseas 

 
 Training and Education 

 
 Training Programs & Conferences 

 
 Office of Governmental Affairs 

 
 Office of Chief Economist 

 
 Boards and Counsel 

 

 

 
 PRODUCTS & SERVICES 
 
 Electronic Data Products 

 
 XML Resources 

 
 XML Resources - Retrospective 

 
 USPTO Contact Center Order Form 

 
 Services 

 
 Locate Libraries 

 
 Training/Events 

 
 Online Services Hub 

 

 

 
 INVENTORS 
 
 Patents for Inventors 

 
 Trademarks for Inventors 

 
 Inventors Assistance 

 
 Education and Information 

 
 Scam Prevention 

 
 Pro Se and Pro Bono 

 
 Current Events 

 
 State Resources 

 
 InventorsEye Newsletter 

 

 

 
 NEWS & NOTICES 
 
 Subscription Center 

 
 Press Releases 

 
 Testimony and Speeches 

 
 Director's Forum 

 
 Systems Status 

 
 Emergency Notices 

 
 USPTO Videos 

 
 Official Gazette 

 
 Federal Register Notices 

 
 Event Calendar 

 

 

 
 FAQs 
 
 Patents FAQs 

 
 Trademarks FAQs 

 
 Assignments 

 
 Security 

 
 Musicians and Artists 

 
 Browser Plugins 

 
 Other Web Resources 

 

 

 
 ABOUT US 
 
 USPTO Leadership 

 
 USPTO Organization 

 
 USPTO Offices 

 
 Careers 

 
 Budget, Performance, and Planning 

 
 Statistics 

 
 Vendor Information 

 
 Public Advisory Committees 

 
 National Medal of Technology and Innovation 

 
 IP in Motion 

 
 Contact Us 

 

 

 
 
 

 

 
 

 
 
 
 
 Home Page 

 
 Patents 

 
 Patent Laws, Regulations, Policies & Procedures 

 
 Manual of Patent Examining Procedure 

 Chapter 2100 

 Section 2143 
 

 
 
 
 
 
 2143 Examples of Basic Requirements of a Prima Facie 
 Case of Obviousness [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.] 

 The Supreme Court in KSR Int'l Co. v. Teleflex Inc., 
 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007) identified a number of rationales to
 support a conclusion of obviousness which are consistent with the proper “functional
 approach” to the determination of obviousness as laid down in Graham .
 The key to supporting any rejection under 35 U.S.C. 103 is the clear articulation
 of the reason(s) why the claimed invention would have been obvious. The Supreme Court in
 KSR noted that the analysis supporting a rejection under
 35 U.S.C.
 103 should be made explicit. In Ball Aerosol v. Ltd.
 Brands, 555 F.3d 984, 89 USPQ2d 1870 (Fed. Cir. 2009), the Federal Circuit
 offered additional instruction as to the need for an explicit analysis. The Federal Circuit
 explained that the Supreme Court’s requirement for an explicit analysis does not require
 record evidence of an explicit teaching of a motivation to combine in the prior art.
 

 “[T]he analysis that “should be made explicit” refers not
 to the teachings in the prior art of a motivation to combine, but to the court’s analysis.
 . . . Under the flexible inquiry set forth by the Supreme Court, the district court
 therefore erred by failing to take account of ‘the inferences and creative steps,’ or even
 routine steps, that an inventor would employ and by failing to find a motivation to combine
 related pieces from the prior art.” Ball Aerosol, 555 F.3d at 993, 89
 USPQ2d at 1877. 
 

 The Federal Circuit’s directive in Ball
 Aerosol was addressed to a lower court, but it applies to Office personnel as
 well. When setting forth a rejection, Office personnel are to continue to make appropriate
 findings of fact as explained in MPEP § 2141 and § 2143 , and must provide
 a reasoned explanation as to why the invention as claimed would have been obvious to a
 person of ordinary skill in the art at the relevant time. This requirement for explanation
 remains even in situations in which Office personnel may properly rely on common sense or
 ordinary ingenuity. 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.’”).
 

 I. EXAMPLES OF RATIONALES Examples of rationales that may support a conclusion of obviousness
 include:
 

 
 (A) Combining prior art elements according to known methods to yield
 predictable results;
 

 (B) Simple substitution of one known element for another to obtain
 predictable results;
 

 (C) Use of known technique to improve similar devices (methods, or
 products) in the same way;
 

 (D) Applying a known technique to a known device (method, or product)
 ready for improvement to yield predictable results;
 

 (E) “Obvious to try” – choosing from a finite number of identified,
 predictable solutions, with a reasonable expectation of success;
 

 (F) Known work in one field of endeavor may prompt variations of it
 for use in either the same field or a different one based on design incentives or
 other market forces if the variations are predictable to one of ordinary skill in
 the art;
 

 (G) Some teaching, suggestion, or motivation in the prior art that
 would have led one of ordinary skill to modify the prior art reference or to
 combine prior art reference teachings to arrive at the claimed invention.
 

 
 Note that the list of rationales provided is not intended to be an
 all-inclusive list. Other rationales to support a conclusion of obviousness may be
 relied upon by Office personnel. Any rationale employed must provide a link between the
 factual findings and the legal conclusion of obviousness.
 

 It is important for Office personnel to recognize that
 when they do choose to formulate an obviousness rejection using one of the rationales
 suggested by the Supreme Court in KSR and discussed herein, they are
 to adhere to the guidance provided regarding the necessary factual findings. It remains
 Office policy that appropriate factual findings are required in order to apply the
 enumerated rationales properly. 
 

 The subsections below include discussions of each rationale along with
 examples illustrating how the cited rationales may be used to support a finding of
 obviousness. Some examples use the facts of pre- KSR cases to show how
 the rationales suggested by the Court in KSR may be used to support a
 finding of obviousness. The cases cited (from which the facts were derived) may not
 necessarily stand for the proposition that the particular rationale is the basis for the
 court’s holding of obviousness, but they do illustrate consistency of past decisions
 with the lines of reasoning laid out in KSR. Other examples are
 post- KSR decisions that show how the Federal Circuit has applied
 the principles of KSR. Cases are included that illustrate findings of
 obviousness as well as nonobviousness. Note that, in some instances, a single case is
 used in different subsections to illustrate the use of more than one rationale to
 support a finding of obviousness. It will often be the case that, once the
 Graham inquiries have been satisfactorily resolved, a conclusion
 of obviousness may be supported by more than one line of reasoning. 
 

 A. Combining Prior Art Elements According to Known Methods To Yield
 Predictable Results To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that the prior art included each element claimed,
 although not necessarily in a single prior art reference, with the only
 difference between the claimed invention and the prior art being the lack of
 actual combination of the elements in a single prior art reference;
 

 (2) a finding that one of ordinary skill in the art could have
 combined the elements as claimed by known methods, and that in combination,
 each element merely performs the same function as it does separately; 
 

 (3) a finding that one of ordinary skill in the art would have
 recognized that the results of the combination were predictable; and
 

 (4) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that all the claimed elements were known in the prior art and one
 skilled in the art could have combined the elements as claimed by known methods with
 no change in their respective functions, and the combination yielded nothing more
 than predictable results to one of ordinary skill in the art. KSR, 
 550 U.S. at 416, 82 USPQ2d at 1395; B/E Aerospace, Inc. v. C&D Zodiac,
 Inc., 962 F.3d 1373, 1379, 2020 USPQ2d 10706 (Fed. Cir. 2020);
 Sakraida v. AG Pro, Inc., 425 U.S. 273, 282, 189 USPQ 449, 453
 (1976); Anderson’s-Black Rock, Inc. v. Pavement Salvage Co., 396
 U.S. 57, 62-63, 163 USPQ 673, 675 (1969); Great Atl. & P. Tea Co. v.
 Supermarket Equip. Corp., 340 U.S. 147, 152, 87 USPQ 303, 306 (1950).
 “[I]t can be important to identify a reason that would have prompted a person of
 ordinary skill in the relevant field to combine the elements in the way the claimed
 new invention does.” KSR, 550 U.S. at 418, 82 USPQ2d at 1396. If
 any of these findings cannot be made, then this rationale cannot be used to support a
 conclusion that the claim would have been obvious to one of ordinary skill in the
 art.
 

 Example 1: The claimed invention in Anderson’s-Black Rock, Inc. v.
 Pavement Salvage Co., 396 U.S. 57, 163 USPQ 673 (1969) was a paving
 machine which combined several well-known elements onto a single chassis. Standard
 prior art paving machines typically combined equipment for spreading and shaping
 asphalt onto a single chassis. The patent claim included the well-known element of
 a radiant-heat burner attached to the side of the paver for the purpose of
 preventing cold joints during continuous strip paving. The prior art used radiant
 heat for softening the asphalt to make patches, but did not use radiant heat
 burners to achieve continuous strip paving. All of the component parts were known
 in the prior art. The only difference was the combination of the “old elements”
 into a single device by mounting them on a single chassis. The Court found that
 the operation of the heater was in no way dependent on the operation of the other
 equipment, and that a separate heater could also be used in conjunction with a
 standard paving machine to achieve the same results. The Court concluded that
 “[t]he convenience of putting the burner together with the other elements in one
 machine, though perhaps a matter of great convenience, did not produce a ‘new’ or
 ‘different function’” and that to those skilled in the art the use of the old
 elements in combination would have been obvious. Id. at 60, 163
 USPQ at 674. 
 

 Note that combining known prior art elements is not sufficient to
 render the claimed invention obvious if the results would not have been
 predictable to one of ordinary skill in the art. United States v.
 Adams, 383 U.S. 39, 51-52, 148 USPQ 479, 483-84 (1966). In
 Adams, the claimed invention was to a battery with one
 magnesium electrode and one cuprous chloride electrode that could be stored dry
 and activated by the addition of plain water or salt water. Although magnesium and
 cuprous chloride were individually known battery components, the Court concluded
 that the claimed battery was nonobvious. The Court stated that “[d]espite the fact
 that each of the elements of the Adams battery was well known in the prior art, to
 combine them as did Adams required that a person reasonably skilled in the prior
 art must ignore” the teaching away of the prior art that such batteries were
 impractical and that water-activated batteries were successful only when combined
 with electrolytes detrimental to the use of magnesium electrodes.
 Id. at 42-43, 50-52, 148 USPQ at 480, 483. “[W]hen the prior
 art teaches away from combining certain known elements, discovery of successful
 means of combining them is more likely to be nonobvious.” KSR, 
 550 U.S. at 416, 82 USPQ2d at 1395. 
 

 

 Example 2: The claimed invention in Ruiz v. A.B. Chance
 Co., 357 F.3d 1270, 69 USPQ2d 1686 (Fed. Cir. 2004) was directed to a
 system which employs a screw anchor for underpinning
 existing foundations and a metal bracket to transfer the
 building load onto the screw anchor. The prior art (Fuller) used screw anchors for
 underpinning existing structural foundations. Fuller used a concrete haunch to
 transfer the load of the foundation to the screw anchor. The prior art (Gregory)
 used a push pier for underpinning existing structural foundations. Gregory taught
 a method of transferring load using a bracket, wherein a metal bracket transfers
 the foundation load to the push pier. The pier is driven into the ground to
 support the load. Neither reference showed the two elements of the claimed
 invention – screw anchor and metal bracket – used together. The court found that
 “artisans knew that a foundation underpinning system requires a means of
 connecting the foundation to the load-bearing member.” Id. at
 1276, 69 USPQ2d at 1691.
 

 The nature of the problem to be solved – underpinning unstable
 foundations – as well as the need to connect the member to the foundation to
 accomplish this goal, would have led one of ordinary skill in the art to choose an
 appropriate load bearing member and a compatible attachment. Therefore, it would
 have been obvious to use a metal bracket (as shown in Gregory) in combination with
 the screw anchor (as shown in Fuller) to underpin unstable foundations.
 

 

 Example 3: The case of In re Omeprazole Patent
 Litigation, 536 F.3d 1361, 87 USPQ2d 1865 (Fed. Cir. 2008), is one in
 which the claims in question were found to be nonobvious in the context of an
 argument to combine prior art elements. The invention involved applying enteric
 coatings to a drug in pill form for the purpose of ensuring that the drug did not
 disintegrate before reaching its intended site of action. The drug at issue was
 omeprazole, the generic name for gastric acid inhibitor marketed as
 Prilosec ® . The claimed formulation included two
 layers of coatings over the active ingredient. 
 

 The district court found that Astra’s patent in
 suit was infringed by defendants Apotex and Impax. The district court rejected
 Apotex’s defense that the patents were invalid for obviousness. Apotex had argued
 that the claimed invention was obvious because coated omeprazole tablets were
 known from a prior art reference, and because secondary subcoatings in
 pharmaceutical preparations generally were also known. There was no evidence of
 unpredictability associated with applying two different enteric coatings to
 omeprazole. However, Astra’s reason for applying an intervening subcoating between
 the prior art coating and omeprazole had been that the prior art coating was
 actually interacting with omeprazole, thereby contributing to undesirable
 degradation of the active ingredient. This degradation of omeprazole by
 interaction with the prior art coating had not been recognized in the prior art.
 Therefore, the district court reasoned that based on the evidence available, a
 person of ordinary skill in the art would have had no reason to include a
 subcoating in an omeprazole pill formulation. 
 

 The Federal Circuit affirmed the district court’s
 decision that the claimed invention was not obvious. Even though subcoatings for
 enteric drug formulation were known, and there was no evidence of undue technical
 hurdles or lack of a reasonable expectation of success, the formulation was
 nevertheless not obvious because the flaws in the prior art formulation that had
 prompted the modification had not been recognized. Thus there would have been no
 reason to modify the initial formulation, even though the modification could have
 been done. Moreover, a person of ordinary skill in the art likely would have
 chosen a different modification even if they had recognized the problem.
 

 Office personnel should note that in this case the
 modification of the prior art that had been presented as an argument for
 obviousness was an extra process step that added an additional component to a
 known, successfully marketed formulation. The proposed modification thus amounted
 to extra work and greater expense for no apparent reason. This is not the same as
 combining known prior art elements A and B when each would have been expected to
 contribute its own known properties to the final product. In the
 Omeprazole case, in view of the expectations of those of
 ordinary skill in the art, adding the subcoating would not have been expected to
 confer any particular desirable property on the final product. Rather, the final
 product obtained according to the proposed modifications would merely have been
 expected to have the same functional properties as the prior art product. 
 

 The Omeprazole case can also be
 analyzed in view of the discovery of a previously unknown problem by the patentee.
 If the adverse interaction between active agent and coating had been known, it
 might well have been obvious to use a subcoating. However, since the problem had
 not been previously known, there would have been no reason to incur additional
 time and expense to add another layer, even though the addition would have been
 technologically possible. This is true because the prior art of record failed to
 mention any stability problem, despite the acknowledgment during testimony at
 trial that there was a known theoretical reason that omeprazole might be subject
 to degradation in the presence of the known coating material.
 

 

 Example 4: The case of Crocs, Inc. v. U.S. Int'l
 Trade Comm'n, 598 F.3d 1294, 93 USPQ 1777 (Fed. Cir. 2010), is a
 decision in which the claimed foam footwear was held by the Federal Circuit to be
 nonobvious over a combination of prior art references. 
 

 The claims involved in the obviousness issue were
 from Crocs’ U.S. Patent No. 6,993,858, and were drawn to footwear in which a
 one-piece molded foam base section formed the top of the shoe (the upper) and the
 sole. A strap also made of foam was attached to the foot opening of the upper,
 such that the strap could provide support to the Achilles portion of the wearer’s
 foot. The strap was attached via connectors that allowed it to be in contact with
 the base section, and to pivot relative to the base section. Because both the base
 portion and the strap were made of foam, friction between the strap and the base
 section allowed the strap to maintain its position after pivoting. In other words,
 the foam strap did not fall under the force of gravity to a position adjacent to
 the heel of the base section. 
 

 The International Trade Commission (ITC) determined
 that the claims were obvious over the combination of two pieces of prior art. The
 first was the Aqua Clog, which was a shoe that corresponded to the base section of
 the footwear of the ‘858 patent. The second was the Aguerre patent, which taught
 heel straps made of elastic or another flexible material. In the ITC’s view, the
 claimed invention was obvious because the prior art Aqua Clog differed from the
 claimed invention only as to the presence of the strap, and a suitable strap was
 taught by Aguerre. 
 

 The Federal Circuit disagreed. The Federal Circuit
 stated that the prior art did not teach foam heel straps, or that a foam heel
 strap should be placed in contact with a foam base. The Federal Circuit pointed
 out that the prior art actually counseled against using foam as a material for the
 heel strap of a shoe. 
 

 
 The record shows that the prior art would
 actually discourage and teach away from the use of foam straps. An ordinary
 artisan in this field would not add a foam strap to the foam Aqua Clog because
 foam was likely to stretch and deform, in addition to causing discomfort for a
 wearer. The prior art depicts foam as unsuitable for straps.
 

 
 Id. at 1309, 93 USPQ2d at 1787-88. 
 

 The Federal Circuit continued, stating that even if
 – contrary to fact – the claimed invention had been a combination of elements that
 were known in the prior art, the claims still would have been nonobvious. There
 was testimony in the record that the loose fit of the heel strap made the shoe
 more comfortable for the wearer than prior art shoes in which the heel strap was
 constantly in contact with the wearer’s foot. In the claimed footwear, the foam
 heel strap contacted the wearer’s foot only when needed to help reposition the
 foot properly in the shoe, thus reducing wearer discomfort that could arise from
 constant contact. This desirable feature was a result of the friction between the
 base section and the strap that kept the strap in place behind the Achilles
 portion of the wearer’s foot. The Federal Circuit pointed out that this
 combination “yielded more than predictable results.” Id. at
 1310, 93 USPQ2d at 1788. Aguerre had taught that friction between the base section
 and the strap was a problem rather than an advantage, and had suggested the use of
 nylon washers to reduce friction. Thus the Federal Circuit stated that even if all
 elements of the claimed invention had been taught by the prior art, the claims
 would not have been obvious because the combination yielded more than predictable
 results. 
 

 The Federal Circuit’s discussion in Crocs serves as
 a reminder to Office personnel that merely pointing to the presence of all claim
 elements in the prior art is not a complete statement of a rejection for
 obviousness. In accordance with MPEP § 2143 , subsection I.A.(3),
 a proper rejection based on the rationale that the claimed invention is a
 combination of prior art elements also includes a finding that results flowing
 from the combination would have been predictable to a person of ordinary skill in
 the art. MPEP §
 2143 , subsection I.A.(3). If results would not have been
 predictable, Office personnel should not enter an obviousness rejection using the
 combination of prior art elements rationale, and should withdraw such a rejection
 if it has been made. 
 

 

 Example 5: Sundance, Inc. v. DeMonte Fabricating Ltd., 550 F.3d 1356, 89
 USPQ2d 1535 (Fed. Cir. 2008), involved a segmented and mechanized cover for
 trucks, swimming pools, or other structures. The claim was found to be obvious
 over the prior art applied.
 

 A first prior art reference taught that a reason
 for making a segmented cover was ease of repair, in that a single damaged segment
 could be readily removed and replaced when necessary. A second prior art reference
 taught the advantages of a mechanized cover for ease of opening. The Federal
 Circuit noted that the segmentation aspect of the first reference and the
 mechanization function of the second perform in the same way after combination as
 they had before. The Federal Circuit further observed that a person of ordinary
 skill in the art would have expected that adding replaceable segments as taught by
 the first reference to the mechanized cover of the other would result in a cover
 that maintained the advantageous properties of both of the prior art covers. 
 

 Thus, the Sundance case points out that a hallmark
 of a proper obviousness rejection based on combining known prior art elements is
 that one of ordinary skill in the art would reasonably have expected the elements
 to maintain their respective properties or functions after they have been
 combined. 
 

 

 Example 6: In the case of Ecolab, Inc. v. FMC
 Corp., 569 F.3d 1335, 91 USPQ2d 1225 (Fed. Cir. 2009), an “apparent
 reason to combine” in conjunction with the technical ability to optimize led to
 the conclusion that the claimed invention would have been obvious. 
 

 The invention in question was a method of treating
 meat to reduce the incidence of pathogens, by spraying the meat with an
 antibacterial solution under specified conditions. The parties did not dispute
 that a single prior art reference had taught all of the elements of the claimed
 invention, except for the pressure limitation of “at least 50 psi.” 
 

 FMC had argued at the district court that the
 claimed invention would have been obvious in view of the first prior art reference
 mentioned above in view of a second reference that had taught the advantages of
 spray-treating at pressures of 20 to 150 psi when treating meat with a different
 antibacterial agent. The district court did not find FMC’s argument to be
 convincing, and denied the motion for judgment as a matter of law that the claim
 was obvious. 
 

 Disagreeing with the district court, the Federal
 Circuit stated that “there was an apparent reason to combine these known elements
 – namely to increase contact between the [antibacterial solution] and the bacteria
 on the meat surface and to use the pressure to wash additional bacteria off the
 meat surface.” Id. at 1350, 91 USPQ2d at 1234. The Federal
 Circuit explained that because the second reference had taught “using high
 pressure to improve the effectiveness of an antimicrobial solution when sprayed
 onto meat, and because an ordinarily skilled artisan would have recognized the
 reasons for applying [the claimed antibacterial solution] using high pressure and
 would have known how to do so, Ecolab’s claims combining high pressure with other
 limitations disclosed in FMC’s patent are invalid as obvious.”
 Id. 

 When considering the question of obviousness,
 Office personnel should keep in mind the capabilities of a person of ordinary
 skill. In Ecolab, the Federal Circuit stated: 
 

 
 Ecolab’s expert admitted that one skilled in the
 art would know how to adjust application parameters to determine the optimum
 parameters for a particular solution. The question then is whether it would
 have been obvious to combine the high pressure parameter disclosed in the
 Bender patent with the PAA methods disclosed in FMC’s ’676 patent. The answer
 is yes. Id. 

 
 If optimization of the application parameters had
 not been within the level of ordinary skill in the art, the outcome of the
 Ecolab case may well have been different. 
 

 

 Example 7: In the case of Wyers v. Master Lock
 Co., 616 F.3d 1231, 95 USPQ2d 1525 (Fed. Cir. 2010), the Federal
 Circuit held that the claimed barbell-shaped hitch pin locks used to secure
 trailers to vehicles were obvious. 
 

 The court discussed two different sets of claims in
 Wyers, both drawn to improvements over the prior art hitch
 pin locks. The first improvement was a removable sleeve that could be placed over
 the shank of the hitch pin lock so that the same lock could be used with towing
 apertures of varying sizes. The second improvement was an external flat flange
 seal adapted to protect the internal lock mechanism from contaminants. Wyers had
 admitted that each of several prior art references taught every element of the
 claimed inventions except for the removable sleeve and the external covering.
 Master Lock had argued that these references, in combination with additional
 references teaching the missing elements, would have rendered the claims obvious.
 The court first addressed the question of whether the additional references relied
 on by Master Lock were analogous prior art. As to the reference teaching the
 sleeve improvement, the court concluded that it dealt specifically with using a
 vehicle to tow a trailer, and was therefore in the same field of endeavor as
 Wyers’ sleeve improvement. The reference teaching the sealing improvement dealt
 with a padlock rather than a lock for a tow hitch. The court noted that Wyers’
 specification had characterized the claimed invention as being in the field of
 locking devices, thus at least suggesting that the sealed padlock reference was in
 the same field of endeavor. However, the court also observed that even if sealed
 padlocks were not in the same field of endeavor, they were nevertheless reasonably
 pertinent to the problem of avoiding contamination of a locking mechanism for tow
 hitches. The court explained that the Supreme Court’s decision in
 KSR “directs [it] to construe the scope of analogous art
 broadly.” Id. at 1238, 95 USPQ2d at 1530. For these reasons,
 the court found that Master Lock’s asserted references were analogous prior art,
 and therefore relevant to the obviousness inquiry. 
 

 The court then turned to the question of whether
 there would have been adequate motivation to combine the prior art elements as had
 been urged by Master Lock. The court recalled the Graham 
 inquiries, and also emphasized the “expansive and flexible” post-KSR approach to
 obviousness that must not “deny factfinders recourse to common sense.”
 Id. at 1238, 95 USPQ2d at 1530-31. (quoting
 KSR, 550 U.S. at 415, 421, 82 USPQ2d at 1395, 1397). The
 court stated: 
 

 
 KSR and our later cases establish that the legal
 determination of obviousness may include recourse to logic, judgment, and
 common sense, in lieu of expert testimony. . . . Thus, in appropriate cases,
 the ultimate inference as to the existence of a motivation to combine
 references may boil down to a question of “common sense,” appropriate for
 resolution on summary judgment or JMOL.
 

 
 Id. at 1240, 82 USPQ2d at 1531 (citing Perfect Web
 Techs., Inc. v. InfoUSA, Inc., 587 F.3d 1324, 1330, 92 USPQ2d, 1849,
 1854 (Fed. Cir. 2009); Ball Aerosol, 555 F.3d at 993, 89 USPQ2d
 1870, 1875 (Fed. Cir. 2009)). 
 

 After reviewing these principles, the court
 proceeded to explain why adequate motivation to combine had been established in
 this case. With regard to the sleeve improvement, it pointed out that the need for
 different sizes of hitch pins was well known in the art, and that this was a known
 source of inconvenience and expense for users. The court also mentioned the
 marketplace aspect of the issue, noting that space on store shelves was at a
 premium, and that removable sleeves addressed this economic concern. As to the
 sealing improvement, the court pointed out that both internal and external seals
 were well-known means to protect locks from contaminants. The court concluded that
 the constituent elements were being employed in accordance with their recognized
 functions, and would have predictably retained their respective functions when
 combined as suggested by Master Lock. The court cited In re
 O’Farrell, 853 F.2d 894, 904 (Fed. Cir. 1988) for the proposition
 that a reasonable expectation of success is a requirement for a proper
 determination of obviousness. 
 

 Office personnel should note that although the
 Federal Circuit invoked the idea of common sense in support of a conclusion of
 obviousness, it did not end its explanation there. Rather, the court explained why
 a person of ordinary skill in the art at the time of the invention, in view of the
 facts relevant to the case, would have found the claimed inventions to have been
 obvious. The key to supporting any rejection under 35 U.S.C.
 103 is the clear articulation of the reason(s) why the
 claimed invention would have been obvious. The Supreme Court in
 KSR noted that the analysis supporting a rejection under
 35 U.S.C.
 103 should be made explicit. The Court quoting In
 re Kahn, 441 F.3d 977, 988, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006),
 stated that “[R]ejections on obviousness cannot be sustained by mere conclusory
 statements; instead, there must be some articulated reasoning with some rational
 underpinning to support the legal conclusion of obviousness.” See
 MPEP §
 2141 , subsection III. Office personnel should continue
 to provide a reasoned explanation for every obviousness rejection. 
 

 

 Example 8: The claim in DePuy Spine, Inc. v.
 Medtronic Sofamor Danek, Inc., 567 F.3d 1314, 90 USPQ2d 1865 (Fed.
 Cir. 2009), was directed to a polyaxial pedicle screw used in spinal surgeries
 that included a compression member for pressing a screw head against a receiver
 member. A prior art reference (Puno) disclosed all of the elements of the claim
 except for the compression member. Instead, the screw head in Puno was separated
 from the receiver member to achieve a shock absorber effect, allowing some motion
 between receiver member and the vertebrae. The missing compression member was
 readily found in another prior art reference (Anderson), which disclosed an
 external fracture immobilization splint for immobilizing long bones with a swivel
 clamp capable of polyaxial movement until rigidly secured by a compression member.
 It was asserted during trial that a person of ordinary skill would have recognized
 that the addition of Anderson’s compression member to Puno’s device would have
 achieved a rigidly locked polyaxial pedicle screw covered by the claim. 
 

 In conducting its analysis, the Federal Circuit
 noted that the “predictable result” discussed in KSR refers not
 only to the expectation that prior art elements are capable of being physically
 combined, but also that the combination would have worked for its intended
 purpose. In this case, it was successfully argued that Puno “teaches away” from a
 rigid screw because Puno warned that rigidity increases the likelihood that the
 screw will fail within the human body, rendering the device inoperative for its
 intended purpose. In fact, the reference did not merely express a general
 preference for pedicle screws having a “shock absorber” effect, but rather
 expressed concern for failure and stated that the shock absorber feature
 “decrease[s] the chance of failure of the screw of the bone-screw interface”
 because “it prevent[s] direct transfer of load from the rod to the bone-screw
 interface.” Thus, the alleged reason to combine the prior art elements of Puno and
 Anderson—increasing the rigidity of the screw—ran contrary to the prior art that
 taught that increasing rigidity would result in a greater likelihood of failure.
 In view of this teaching and the backdrop of collective teachings of the prior
 art, the Federal Circuit determined that Puno teaches away from the proposed
 combination such that a person of ordinary skill would have been deterred from
 combining the references as proposed. Secondary considerations evaluated by the
 Federal Circuit relating to failure by others and copying also supported the view
 that the combination would not have been obvious at the time of the invention.
 
 

 
 B. Simple Substitution of One Known Element for Another To Obtain
 Predictable Results To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that the prior art contained a device (method,
 product, etc.) which differed from the claimed device by the substitution of
 some components (step, element, etc.) with other components;
 

 (2) a finding that the substituted components and their functions
 were known in the art;
 

 (3) a finding that one of ordinary skill in the art could have
 substituted one known element for another, and the results of the substitution
 would have been predictable; and 
 

 (4) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of
 obviousness.
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that the substitution of one known element for another yields
 predictable results to one of ordinary skill in the art. If any of these findings
 cannot be made, then this rationale cannot be used to support a conclusion that the
 claim would have been obvious to one of ordinary skill in the art. 
 

 Example 1: The claimed invention in In re Fout, 675 F.2d
 297, 213 USPQ 532 (CCPA 1982) was directed to a method for decaffeinating coffee
 or tea. The prior art (Pagliaro) method produced a decaffeinated vegetable
 material and trapped the caffeine in a fatty material (such as oil). The caffeine
 was then removed from the fatty material by an aqueous extraction process.
 Applicant (Fout) substituted an evaporative distillation step for the aqueous
 extraction step. The prior art (Waterman) suspended coffee in oil and then
 directly distilled the caffeine through the oil. The court found that “[b]ecause
 both Pagliaro and Waterman teach a method for separating caffeine from oil, it
 would have been prima facie obvious to substitute one method
 for the other. Express suggestion to substitute one equivalent for another need
 not be present to render such substitution obvious.” Id. at
 301, 213 USPQ at 536.
 

 

 Example 2: The claimed invention in In re O’Farrell, 853
 F.2d 894, 7 USPQ2d 1673 (Fed. Cir. 1988) was directed to a method for synthesizing
 a protein in a transformed bacterial host species by substituting a heterologous
 gene for a gene native to the host species. Generally speaking, protein synthesis
 in vivo follows a path from DNA to mRNA. Although the prior
 art Polisky article (authored by two of the three joint inventors of the
 application) had explicitly suggested employing the method described for protein
 synthesis, the inserted heterologous gene exemplified in the article was one that
 normally did not proceed all the way to the protein production step, but instead
 terminated with the mRNA. A second reference to Bahl had described a general
 method of inserting chemically synthesized DNA into a plasmid. Thus, it would have
 been obvious to one of ordinary skill in the art to replace the prior art gene
 with another gene known to lead to protein production, because one of ordinary
 skill in the art would have been able to carry out such a substitution, and the
 results were reasonably predictable. 
 

 In response to applicant’s argument that there had been
 significant unpredictability in the field of molecular biology at the time of the
 invention, the court stated that the level of skill was quite high and that the
 teachings of Polisky, even taken alone, contained detailed enabling methodology
 and included the suggestion that the modification would be successful for
 synthesis of proteins. 
 

 This is not a situation where the rejection is a statement that
 it would have been “obvious to try” without more. Here there was a reasonable
 expectation of success. “Obviousness does not require absolute predictability of
 success.” Id. at 903, 7 USPQ2d at 1681.
 

 

 Example 3: The fact pattern in Ruiz v. AB Chance Co., 357
 F.3d 1270, 69 USPQ2d 1686 (Fed. Cir. 2004) is set forth above in Example 2 in
 subsection I.A., above.
 

 The prior art showed differing load-bearing members and differing
 means of attaching the foundation to the member. Therefore, it would have been
 obvious to one of ordinary skill in the art to substitute the metal bracket taught
 in Gregory for Fuller’s concrete haunch for the predictable result of transferring
 the load.
 

 

 Example 4: The claimed invention in Ex parte Smith, 83
 USPQ2d 1509 (Bd. Pat. App. & Int. 2007), was a pocket insert for a bound book
 made by gluing a base sheet and a pocket sheet of paper together to form a
 continuous two-ply seam defining a closed pocket. The prior art (Wyant) disclosed
 at least one pocket formed by folding a single sheet and securing the folder
 portions along the inside margins using any convenient bonding method. The prior
 art (Wyant) did not disclose bonding the sheets to form a continuous two-ply seam.
 The prior art (Dick) disclosed a pocket that is made by stitching or otherwise
 securing two sheets along three of its four edges to define a closed pocket with
 an opening along its fourth edge.
 

 In considering the teachings of Wyant and Dick, the Board “found
 that (1) each of the claimed elements is found within the scope and content of the
 prior art; (2) one of ordinary skill in the art could have combined the elements
 as claimed by methods known at the time the invention was made; and (3) one of
 ordinary skill in the art would have recognized at the time the invention was made
 that the capabilities or functions of the combination were predictable.” Citing
 KSR, the Board concluded that “[t]he substitution of the
 continuous, two-ply seam of Dick for the folded seam of Wyant thus is no more than
 the simple substitution of one known element for another or the mere application
 of a known technique to a piece of prior art ready for improvement.
 

 

 Example 5: The claimed invention in In re ICON Health
 & Fitness, Inc., 496 F.3d 1374, 83 USPQ2d 1746 (Fed. Cir. 2007),
 was directed to a treadmill with a folding tread base that swivels into an upright
 storage position, including a gas spring connected between the tread base and the
 upright structure to assist in stably retaining the tread base in the storage
 position. On reexamination, the examiner rejected the claims as obvious based on a
 combination of references including an advertisement (Damark) for a folding
 treadmill demonstrating all of the claim elements other than the gas spring, and a
 patent (Teague) with a gas spring. Teague was directed to a bed that folds into a
 cabinet using a novel dual-action spring that reverses force as the mechanism
 passes a neutral position, rather than a single-action spring that would provide a
 force pushing the bed closed at all times. The dual-action spring reduced the
 force required to open the bed from the closed position, while reducing the force
 required to lift the bed from the open position. 
 

 The Federal Circuit addressed the propriety of
 making the combination since Teague was in a different field than the application.
 Teague was found to be reasonably pertinent to the problem addressed in the
 application because the folding mechanism did not require any particular focus on
 treadmills, but rather generally addressed problems of supporting the weight of
 such a mechanism and providing a stable resting position. 
 

 The court also considered whether one skilled in the
 art would have been led to combine the teachings of Damark and Teague. Appellant
 argued that Teague teaches away from the invention because it directs one skilled
 in the art not to use single-action springs and does not satisfy the claim
 limitations as the dual-action springs would render the invention inoperable. The
 Federal Circuit considered these arguments and found that, while Teague at most
 teaches away from using single-action springs to decrease the opening force, it
 actually instructed that single-action springs provide the result desired by the
 inventors, which was to increase the opening force provided by gravity. As to
 inoperability, the claims were not limited to single-action springs and were so
 broad as to encompass anything that assists in stably retaining the tread base,
 which is the function that Teague accomplished. Additionally, the fact that the
 counterweight mechanism from Teague used a large spring, which appellant argued
 would overpower the treadmill mechanism, ignores the modifications that one
 skilled in the art would make to a device borrowed from the prior art. One skilled
 in the art would size the components from Teague appropriately for the
 application.
 

 ICON is another useful example for understanding the scope of
 analogous art. The art applied concerned retaining mechanisms for folding beds,
 not treadmills. When determining whether a reference may properly be applied to an
 invention in a different field of endeavor, it is necessary to consider the
 problem to be solved. It is certainly possible that a reference may be drawn in
 such a way that its usefulness as a teaching is narrowly restricted. However,
 in ICON, the problem to be solved was not limited to the
 teaching of the “treadmill” concept. The Teague reference was analogous art
 because “Teague and the current application both address the need to stably retain
 a folding mechanism,” and because “nothing about ICON’s folding mechanism requires
 any particular focus on treadmills,” Id. at 1378, 1380, 83
 USPQ2d at 1749-50. 
 

 ICON is also informative as to the relationship between the
 problem to be solved and existence of a reason to combine. “Indeed, while perhaps
 not dispositive of the issue, the finding that Teague, by addressing a similar
 problem, provides analogous art to ICON’s application goes a long way towards
 demonstrating a reason to combine the two references. Because ICON’s broad claims
 read on embodiments addressing that problem as described by Teague, the prior art
 here indicates a reason to incorporate its teachings.” Id. at
 1380-81, 83 USPQ2d at 1751. 
 

 The Federal Circuit’s discussion in
 ICON also makes clear that if the reference does not teach
 that a combination is undesirable, then it cannot be said to teach away. An
 assessment of whether a combination would render the device inoperable must not
 “ignore the modifications that one skilled in the art would make to a device
 borrowed from the prior art.” Id. at 1382, 83 USPQ2d at
 1752.
 

 

 Example 6: Agrizap, Inc. v. Woodstream Corp., 520 F.3d 1337, 86 USPQ2d
 1110 (Fed. Cir. 2008), involved a stationary pest control device for electrocution
 of pests such as rats and gophers, in which the device is set in an area where the
 pest is likely to encounter it. The only difference between the claimed device and
 the prior art stationary pest control device was that the claimed device employed
 a resistive electrical switch, while the prior art device used a mechanical
 pressure switch. A resistive electrical switch was taught in two prior art
 patents, in the contexts of a hand-held pest control device and a cattle prod. 
 

 In determining that the claimed invention was
 obvious, the Federal Circuit noted that “[t]he asserted claims simply substitute a
 resistive electrical switch for the mechanical pressure switch” employed in the
 prior art device. Id. at 1344, 86 USPQ2d at 1115. In this case,
 the prior art concerning the hand-held devices revealed that the function of the
 substituted resistive electrical switch was well known and predictable, and that
 it could be used in a pest control device. According to the Federal Circuit, the
 references that taught the hand-held devices showed that “the use of an animal
 body as a resistive switch to complete a circuit for the generation of an electric
 charge was already well known in the prior art.” Id. Finally,
 the Federal Circuit noted that the problem solved by using the resistive
 electrical switch in the prior art hand-held devices – malfunction of mechanical
 switches due to dirt and dampness – also pertained to the prior art stationary
 pest control device. 
 

 The Federal Circuit recognized 
 Agrizap as “a textbook case of when the asserted claims involve a
 combination of familiar elements according to known methods that does no more than
 yield predictable results.” Id. Agrizap exemplifies a strong case of obviousness based on
 simple substitution that was not overcome by the objective evidence of
 nonobviousness offered. It also demonstrates that analogous art is not limited to
 the field of the inventor’s endeavor, in that one of the references that used an
 animal body as a resistive switch to complete a circuit for the generation of an
 electric charge was not in the field of pest control.
 

 

 Example 7: The invention at issue in Muniauction,
 Inc. v. Thomson Corp., 532 F.3d 1318, 87 USPQ2d1350 (Fed. Cir. 2008),
 was a method for auctioning municipal bonds over the Internet. A municipality
 could offer a package of bond instruments of varying principal amounts and
 maturity dates, and an interested buyer would then submit a bid comprising a price
 and interest rate for each maturity date. It was also possible for the interested
 buyer to bid on a portion of the offering. The claimed invention considered all of
 the noted parameters to determine the best bid. It operated on conventional Web
 browsers and allowed participants to monitor the course of the auction. 
 

 The only difference between the prior art bidding
 system and the claimed invention was the use of a conventional Web browser. At
 trial, the district court had determined that Muniauction’s claims were not
 obvious. Thomson argued that the claimed invention amounted to incorporating a Web
 browser into a prior art auction system, and was therefore obvious in light of
 KSR. Muniauction rebutted the argument by offering evidence
 of skepticism by experts, copying, praise, and commercial success. Although the
 district court found the evidence to be persuasive of nonobviousness, the Federal
 Circuit disagreed. It noted that a nexus between the claimed invention and the
 proffered evidence was lacking because the evidence was not coextensive with the
 claims at issue. For this reason, the Federal Circuit determined that
 Muniauction’s evidence of secondary considerations was not entitled to substantial
 weight. 
 

 The Federal Circuit analogized this case to
 Leapfrog Enters., Inc. v. Fisher-Price, Inc., 485 F.3d 1157,
 82 USPQ2d 1687 (Fed. Cir. 2007). The Leapfrog case involved a
 determination of obviousness based on application of modern electronics to a prior
 art mechanical children’s learning device. In Leapfrog, the
 court noted that market pressures would have prompted a person of ordinary skill
 to use modern electronics in the prior art device. Similarly in
 Muniauction, market pressures would have prompted a person
 of ordinary skill to use a conventional Web browser in a method of auctioning
 municipal bonds. 
 

 

 Example 8: In Aventis Pharma Deutschland v. Lupin
 Ltd., 499 F.3d 1293, 84 USPQ2d 1197 (Fed. Cir. 2007), the claims were
 drawn to the 5(S) stereoisomer of the blood pressure drug ramipril in
 stereochemically pure form, and to compositions and methods requiring 5(S)
 ramipril. The 5(S) stereoisomer is one in which all five stereocenters in the
 ramipril molecule are in the S rather than the R configuration. A mixture of
 various stereoisomers including 5(S) ramipril had been taught by the prior art.
 The question before the court was whether the purified single stereoisomer would
 have been obvious over the known mixture of stereoisomers. 
 

 The record showed that the presence of multiple S
 stereocenters in drugs similar to ramipril was known to be associated with
 enhanced therapeutic efficacy. For example, when all of the stereocenters were in
 the S form in the related drug enalapril (SSS enalapril) as compared with only two
 stereocenters in the S form (SSR enalapril), the therapeutic potency was 700 times
 as great. There was also evidence to indicate that conventional methods could be
 used to separate the various stereoisomers of ramipril. 
 

 The district court saw the issue as a close case,
 because, in its view, there was no clear motivation in the prior art to isolate
 5(S) ramipril. However, the Federal Circuit disagreed, and found that the claims
 would have been obvious. The Federal Circuit cautioned that requiring such a
 clearly stated motivation in the prior art to isolate 5(S) ramipril ran counter to
 the Supreme Court’s decision in KSR, and the court stated:
 

 
 Requiring an explicit teaching to purify the
 5(S) stereoisomer from a mixture in which it is the active ingredient is
 precisely the sort of rigid application of the TSM test that was criticized in
 KSR. 

 
 Id. at 1301, 84 USPQ2d at 1204. The Aventis 
 court also relied on the settled principle that in chemical cases, structural
 similarity can provide the necessary reason to modify prior art teachings. The
 Federal Circuit also addressed the kind of teaching that would be sufficient in
 the absence of an explicitly stated prior art-based motivation, explaining that an
 expectation of similar properties in light of the prior art can be sufficient,
 even without an explicit teaching that the compound will have a particular
 utility. 
 

 In the chemical arts, the cases involving so-called
 “lead compounds” form an important subgroup of the obviousness cases that are
 based on substitution. The Federal Circuit has had a number of opportunities since
 the KSR decision to discuss the circumstances under which it
 would have been obvious to modify a known compound to arrive at a claimed
 compound. The following cases explore the selection of a lead compound, the need
 to provide a reason for any proposed modification, and the predictability of the
 result. 
 

 

 Example 9: Eisai Co. Ltd. v. Dr. Reddy’s Labs., Ltd., 533 F.3d 1353, 87
 USPQ2d 1452 (Fed. Cir. 2008), concerns the pharmaceutical compound rabeprazole.
 Rabeprazole is a proton pump inhibitor for treating stomach ulcers and related
 disorders. The Federal Circuit affirmed the district court’s summary judgment of
 nonobviousness, stating that no reason had been advanced to modify the prior art
 compound in a way that would destroy an advantageous property. 
 

 Co-defendant Teva based its obviousness argument on
 the structural similarity between rabeprazole and lansoprazole. The compounds were
 recognized as sharing a common core, and the Federal Circuit characterized
 lansoprazole as a “lead compound.” The prior art compound lansoprazole was useful
 for the same indications as rabeprazole, and differed from rabeprazole only in
 that lansoprazole has a trifluoroethoxy substituent at the 4-position of the
 pyridine ring, while rabeprazole has a methoxypropoxy substituent. The trifluoro
 substituent of lansoprazole was known to be a beneficial feature because it
 conferred lipophilicity to the compound. The ability of a person of ordinary skill
 to carry out the modification to introduce the methoxypropoxy substituent, and the
 predictability of the result were not addressed. 
 

 Despite the significant similarity between the
 structures, the Federal Circuit did not find any reason to modify the lead
 compound. According to the Federal Circuit: 
 

 
 Obviousness based on structural similarity thus
 can be proved by identification of some motivation that would have led one of
 ordinary skill in the art to select and then modify a known compound (i.e. a
 lead compound) in a particular way to achieve the claimed compound. . . . In
 keeping with the flexible nature of the obviousness inquiry, the requisite
 motivation can come from any number of sources and need not necessarily be
 explicit in the art. Rather “it is sufficient to show that the claimed and
 prior art compounds possess a ‘sufficiently close relationship . . . to create
 an expectation,’ in light of the totality of the prior art, that the new
 compound will have ‘similar properties’ to the old.” Id. at
 1357, 87 USPQ2d at 1455. (citations omitted)
 

 
 The prior art taught that introducing a fluorinated
 substituent was known to increase lipophilicity, so a skilled artisan would have
 expected that replacing the trifluoroethoxy substituent with a methoxypropoxy
 substituent would have reduced the lipophilicity of the compound. Thus, the prior
 art created the expectation that rabeprazole would be less useful than
 lansoprazole as a drug for treating stomach ulcers and related disorders because
 the proposed modification would have destroyed an advantageous property of the
 prior art compound. The compound was not obvious as argued by Teva because, upon
 consideration of all of the facts of the case, a person of ordinary skill in the
 art at the time of the invention would not have had a reason to modify
 lansoprazole so as to form rabeprazole. 
 

 Office personnel are cautioned that the term “lead
 compound” in a particular opinion can have a contextual meaning that may vary from
 the way a pharmaceutical chemist might use the term. In the field of
 pharmaceutical chemistry, the term “lead compound” has been defined variously as
 “a chemical compound that has pharmacological or biological activity and whose
 chemical structure is used as a starting point for chemical modifications in order
 to improve potency, selectivity, or pharmacokinetic parameters;” “[a] compound
 that exhibits pharmacological properties which suggest its development;” and “a
 potential drug being tested for safety and efficacy.” See, e.g.,
 http://en.wikipedia.org/wiki/Lead_compound, accessed January 13, 2010;
 www.combichemistry.com/glossary_k.html, accessed January 13, 2010; and
 www.buildingbiotechnology.com/glossary4.php, accessed January 13, 2010. 
 

 The Federal Circuit in Eisai 
 makes it clear that from the perspective of the law of obviousness, any known
 compound might possibly serve as a lead compound: “Obviousness based on structural
 similarity thus can be proved by identification of some motivation that would have
 led one of ordinary skill in the art to select and then modify a known compound
 (i.e. a lead compound) in a particular way to achieve the claimed compound.”
 Eisai, 533 F.3d at 1357, 87 USPQ2d at 1455. Thus, Office
 personnel should recognize that a proper obviousness rejection of a claimed
 compound that is useful as a drug might be made beginning with an inactive
 compound, if, for example, the reasons for modifying a prior art compound to
 arrive at the claimed compound have nothing to do with pharmaceutical activity.
 The inactive compound would not be considered to be a lead compound by
 pharmaceutical chemists, but could potentially be used as such when considering
 obviousness. Office personnel might also base an obviousness rejection on a known
 compound that pharmaceutical chemists would not select as a lead compound due to
 expense, handling issues, or other business considerations. However, there must be
 some reason for starting with that particular lead compound other than the mere
 fact that the “lead compound” exists. See Altana Pharma AG v. Teva Pharm.
 USA, Inc., 566 F.3d 999, 1007, 91 USPQ2d 1018, 1024 (Fed. Cir. 2009)
 (holding that there must be some reason “to select and modify a known compound”);
 Ortho-McNeil Pharm., Inc. v. Mylan Labs, Inc., 520 F.3d
 1358, 1364, 86 USPQ2d 1196, 1201 (Fed. Cir. 2008). 
 

 

 Example 10: The claimed chemical compound was also found to be
 nonobvious in Procter & Gamble Co. v. Teva Pharm. USA,
 Inc., 566 F.3d 989, 90 USPQ2d 1947 (Fed. Cir. 2009). The compound at
 issue was risedronate – the active ingredient of Procter & Gamble’s
 osteoporosis drug Actonel ® . Risedronate is an example
 of a bisphosphonate, which is a class of compounds known to inhibit bone
 resorption. 
 

 When Procter & Gamble sued Teva for
 infringement, Teva defended by arguing invalidity for obviousness over one of
 Procter & Gamble’s earlier patents. The prior art patent did not teach
 risedronate, but instead taught thirty-six other similar compounds including 2-pyr
 EHDP that were potentially useful with regard to osteoporosis. Teva argued
 obviousness on the basis of structural similarity to 2-pyr EHDP, which is a
 positional isomer of risedronate. 
 

 The district court found no reason to select 2-pyr
 EHDP as a lead compound in light of the unpredictable nature of the art, and no
 reason to modify it so as to obtain risedronate. In addition, there were
 unexpected results as to potency and toxicity. Therefore the district court found
 that Teva had not made a prima facie case, and even if it had,
 it was rebutted by evidence of unexpected results. 
 

 The Federal Circuit affirmed the district court’s
 decision. The Federal Circuit did not deem it necessary in this case to consider
 the question of whether 2-pyr EHDP had been appropriately selected as a lead
 compound. Rather, the Federal Circuit reasoned that, if 2-pyr EHDP is presumed to
 be an appropriate lead compound, there must be both a reason to modify it so as to
 make risedronate and a reasonable expectation of success. Here, there was no
 evidence that the necessary modifications would have been routine, so there would
 have been no reasonable expectation of success. 
 

 Procter & Gamble is also informative in its discussion of
 the treatment of secondary considerations of non-obviousness. Although the court
 found that no prima facie case of obviousness had been
 presented, it proceeded to analyze Procter & Gamble’s proffered evidence
 countering the alleged prima facie case in some detail, thus
 shedding light on the proper treatment of such evidence. 
 

 The Federal Circuit noted in dicta that even if a
 prima facie case of obviousness had been established,
 sufficient evidence of unexpected results was introduced to rebut such a showing.
 At trial, the witnesses consistently testified that the properties of risedronate
 were not expected, offering evidence that researchers did not predict either the
 potency or the low dose at which the compound was effective. Tests comparing
 risedronate to a compound in the prior art reference showed that risedronate
 outperformed the other compound by a substantial margin, could be administered in
 a greater amount without an observable toxic effect, and was not lethal at the
 same levels as the other compound. The weight of the evidence and the credibility
 of the witnesses were sufficient to show unexpected results that would have
 rebutted an obviousness determination. Thus, nonobviousness can be shown when a
 claimed invention is shown to have unexpectedly superior properties when compared
 to the prior art. 
 

 The court then addressed the evidence of commercial
 success of risedronate and the evidence that risedronate met a long felt need. The
 court pointed out that little weight was to be afforded to the commercial success
 because the competing product was also assigned to Procter & Gamble. However,
 the Federal Circuit affirmed the district court’s conclusion that risedronate met
 a long-felt, but unsatisfied need. The court rejected Teva’s contention that
 because the competing drug was available before
 Actonel ® , there was no unmet need that the invention
 satisfied. The court emphasized that whether there was a long-felt but unsatisfied
 need is to be evaluated based on the circumstances as of the filing date of the
 challenged invention – not as of the date that the invention is brought to market. 
 

 It should be noted that the lead compound cases do
 not stand for the proposition that identification of a single lead compound is
 necessary in every obviousness rejection of a chemical compound. For example, one
 might envision a suggestion in the prior art to formulate a compound having
 certain structurally defined moieties, or moieties with certain properties. If a
 person of ordinary skill would have known how to synthesize such a compound, and
 the structural and/or functional result could reasonably have been predicted, then
 a prima facie case of obviousness of the claimed chemical
 compound might exist even without identification of a particular lead compound. As
 a second example, it could be possible to view a claimed compound as consisting of
 two known compounds attached via a chemical linker. The claimed compound might
 properly be found to have been obvious if there would have been a reason to link
 the two, if one of ordinary skill would have known how to do so, and if the
 resulting compound would have been the predictable result of the linkage
 procedure. Thus, Office personnel should recognize that in certain situations, it
 may be proper to reject a claimed chemical compound as obvious even without
 identifying a single lead compound. 
 

 

 Example 11: The decision reached by the Federal Circuit
 in Altana Pharma AG v. Teva Pharm. USA, Inc., 566 F.3d 999,
 91 USPQ2d 1018 (Fed. Cir. 2009), as discussed below, involved a motion for
 preliminary injunction and did not include a final determination of obviousness.
 However, the case is instructive as to the issue of selecting a lead compound. 
 

 The technology involved in
 Altana was the compound pantoprazole, which is the active
 ingredient in Altana’s antiulcer drug Protonix ® .
 Pantoprazole belongs to a class of compounds known as proton pump inhibitors that
 are used to treat gastric acid disorders in the stomach. 
 

 Altana accused Teva of infringement. The district
 court denied Altana’s motion for preliminary injunction for failure to establish a
 likelihood of success on the merits, determining that Teva had demonstrated a
 substantial question of invalidity for obviousness in light of one of Altana’s
 prior patents. Altana’s patent discussed a compound referred to as compound 12,
 which was one of eighteen compounds disclosed. The claimed compound pantoprazole
 was structurally similar to compound 12. The district court found that one of
 ordinary skill in the art would have selected compound 12 as a lead compound for
 modification, and the Federal Circuit affirmed. 
 

 Obviousness of a chemical compound in view of its
 structural similarity to a prior art compound may be shown by identifying some
 line of reasoning that would have led one of ordinary skill in the art to select
 and modify the prior art compound in a particular way to produce the claimed
 compound. The necessary line of reasoning can be drawn from any number of sources
 and need not necessarily be explicitly found in the prior art of record. The
 Federal Circuit determined that ample evidence supported the district court’s
 finding that compound 12 was a natural choice for further development. For
 example, Altana’s prior art patent claimed that its compounds, including compound
 12, were improvements over the prior art; compound 12 was disclosed as one of the
 more potent of the eighteen compounds disclosed; the patent examiner had
 considered the compounds of Altana’s prior art patent to be relevant during the
 prosecution of the patent in suit; and experts had opined that one of ordinary
 skill in the art would have selected the eighteen compounds to pursue further
 investigation into their potential as proton pump inhibitors. 
 

 In response to Altana’s argument that the prior art
 must point to only a single lead compound for further development, the Federal
 Circuit stated that a “restrictive view of the lead compound test would present a
 rigid test similar to the teaching-suggestion-motivation test that the Supreme
 Court explicitly rejected in KSR . . . . The district court in
 this case employed a flexible approach – one that was admittedly preliminary – and
 found that the defendants had raised a substantial question that one of skill in
 the art would have used the more potent compounds of [Altana’s prior art] patent,
 including compound 12, as a starting point from which to pursue further
 development efforts. That finding was not clearly erroneous.”
 Id. at 1008, 91 USPQ2d at 1025. 
 

 
 C. Use of Known Technique To Improve Similar Devices (Methods, or Products)
 in the Same Way To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that the prior art contained a “base” device
 (method, or product) upon which the claimed invention can be seen as an
 “improvement;”
 

 (2) a finding that the prior art contained a “comparable” device
 (method, or product that is not the same as the base device) that has been
 improved in the same way as the claimed invention; 
 

 (3) a finding that one of ordinary skill in the art could have
 applied the known “improvement” technique in the same way to the “base” device
 (method, or product) and the results would have been predictable to one of
 ordinary skill in the art; and 
 

 (4) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that a method of enhancing a particular class of devices (methods, or
 products) has been made part of the ordinary capabilities of one skilled in the art
 based upon the teaching of such improvement in other situations. One of ordinary
 skill in the art would have been capable of applying this known method of enhancement
 to a “base” device (method, or product) in the prior art and the results would have
 been predictable to one of ordinary skill in the art. “It's enough … to show that
 there was a known problem … in the art, that [another reference] … helped address
 that issue, and that combining the teachings of [the two references] wasn't beyond
 the skill of an ordinary artisan. Nothing more is required to show a motivation to
 combine under KSR. ” See Intel Corp. v. PACT XPP Schweiz
 AG, 61 F.4th 1373, 1380-81, 2023 USPQ2d 297 (Fed. Cir. 2023) (finding
 that both prior art references “address the same problem and that [the secondary
 reference’s] cache was a known way to address that problem is precisely the reason
 that there's a motivation to combine under KSR and our
 precedent.”). 
 

 The Supreme Court in KSR noted
 that if the actual application of the technique would have been beyond the skill of
 one of ordinary skill in the art, then using the technique would not have been
 obvious. KSR, 550 U.S. at 417, 82 USPQ2d at 1396. If any of these
 findings cannot be made, then this rationale cannot be used to support a conclusion
 that the claim would have been obvious to one of ordinary skill in the art. 
 

 Example 1: The claimed invention in In re Nilssen, 851
 F.2d 1401, 7 USPQ2d 1500 (Fed. Cir. 1988) was directed to a “means by which the
 self-oscillating inverter in a power-line-operated inverter-type fluorescent lamp
 ballast is disabled in case the output current from the inverter exceeds some
 pre-established threshold level for more than a very brief period.”
 Id. at 1402, 7 USPQ2d at 1501 That is, the current output
 was monitored, and if the current output exceeded some threshold for a specified
 short time, an actuation signal was sent and the inverter was disabled to protect
 it from damage.
 

 The prior art (a USSR certificate) described a device for
 protecting an inverter circuit in an undisclosed manner via a control means. The
 device indicated the high-load condition by way of the control means, but did not
 indicate the specific manner of overload protection. The prior art (Kammiller)
 disclosed disabling the inverter in the event of a high-load current condition in
 order to protect the inverter circuit. That is, the overload protection was
 achieved by disabling the inverter by means of a cutoff switch.
 

 The court found “it would have been obvious to one of ordinary
 skill in the art to use the threshold signal produced in the USSR device to
 actuate a cutoff switch to render the inverter inoperative as taught by
 Kammiller.” Id. at 1403, 7 USPQ2d at 1502. That is, using the
 known technique of a cutoff switch for protecting a circuit to provide the
 protection desired in the inverter circuit of the USSR document would have been
 obvious to one of ordinary skill.
 

 

 Example 2: The fact pattern in Ruiz v. AB Chance Co., 357
 F.3d 1270, 69 USPQ2d 1686 (Fed. Cir. 2004) is set forth above in Example 2 in
 subsection I.A.
 

 The nature of the problem to be solved may lead inventors to look
 at references relating to possible solutions to that problem.
 Id. at 1277, 69 USPQ2d at 1691. Therefore, it would have
 been obvious to use a metal bracket (as shown in Gregory) with the screw anchor
 (as shown in Fuller) to underpin unstable foundations.
 

 
 D. Applying a Known Technique to a Known Device (Method, or Product) Ready
 for Improvement To Yield Predictable Results To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that the prior art contained a “base” device
 (method, or product) upon which the claimed invention can be seen as an
 “improvement;”
 

 (2) a finding that the prior art contained a known technique that
 is applicable to the base device (method, or product); 
 

 (3) a finding that one of ordinary skill in the art would have
 recognized that applying the known technique would have yielded predictable
 results and resulted in an improved system; and 
 

 (4) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that a particular known technique was recognized as part of the
 ordinary capabilities of one skilled in the art. One of ordinary skill in the art
 would have been capable of applying this known technique to a known device (method,
 or product) that was ready for improvement and the results would have been
 predictable to one of ordinary skill in the art. If any of these findings cannot be
 made, then this rationale cannot be used to support a conclusion that the claim would
 have been obvious to one of ordinary skill in the art.
 

 Example 1: The claimed invention in Dann v. Johnston, 425
 U.S. 219, 189 USPQ 257 (1976) was directed towards a system (i.e., computer) for
 automatic record keeping of bank checks and deposits. In this system, a customer
 would put a numerical category code on each check or deposit slip. The check
 processing system would record these on the check in magnetic ink, just as it does
 for amount and account information. With this system in place, the bank can
 provide statements to customers that are broken down to give subtotals for each
 category. The claimed system also allowed the bank to print reports according to a
 style requested by the customer. As characterized by the Court, “[u]nder
 respondent’s invention, then, a general purpose computer is programmed to provide
 bank customers with an individualized and categorized breakdown of their
 transactions during the period in question.” Id. at 222, 189
 USPQ at 259. 
 

 BASE SYSTEM - The nature of the use of data processing equipment
 and computer software in the banking industry was that banks routinely did much of
 the record-keeping automatically. In routine check processing, the system read any
 magnetic ink characters identifying the account and routing. The system also read
 the amount of the check and then printed that value in a designated area of the
 check. The check was then sent through a further data processing step which used
 the magnetic ink information to generate the appropriate records for transactions
 and for posting to the appropriate accounts. These systems included generating
 periodic statements for each account, such as the monthly statement sent to
 checking account customers.
 

 IMPROVED SYSTEM - The claimed invention supplemented this system
 by recording a category code which could be used to track expenditures by
 category. Again, the category code will be a number recorded on the check (or
 deposit slip) which will be read, converted into a magnetic ink imprint, and then
 processed in the data system to include the category code. This enabled reporting
 of data by category as opposed to only allowing reporting by account number. 
 

 KNOWN TECHNIQUE - This is an application of a technique from the
 prior art – the use of account numbers (generally used to track an individual's
 total transactions) to solve the problem of how to track categories of
 expenditures to more finely account for a budget. That is, account numbers
 (identifying data capable of processing in the automatic data processing system)
 were used to distinguish between different customers. Furthermore, banks have long
 segregated debits attributable to service charges within any given separate
 account and have rendered their customers subtotals for those charges. Previously,
 one would have needed to set up separate accounts for each category and thus
 receive separate reports. Supplementing the account information with additional
 digits (the category codes) solved the problem by effectively creating a single
 account that can be treated as distinct accounts for tracking and reporting
 services. That is, the category code merely allowed what might previously have
 been separate accounts to be handled as a single account, but with a number of
 sub-accounts indicated in the report. 
 

 The basic technique of putting indicia on data to enable standard
 sorting, searching, and reporting yielded no more than the predictable outcome
 which one of ordinary skill would have expected to achieve with this common tool
 of the trade and was therefore an obvious expedient. The Court held that “[t]he
 gap between the prior art and respondent’s system is simply not so great as to
 render the system nonobvious to one reasonably skilled in the art.”
 Id. at 230, 189 USPQ at 261. 
 

 

 Example 2: The fact pattern in In re Nilssen, 851 F.2d
 1401, 7 USPQ2d 1500 (Fed. Cir. 1988) is set forth above in Example 1 in subsection
 C.
 

 The court found “it would have been obvious to one of ordinary
 skill in the art to use the threshold signal produced in the USSR device to
 actuate a cutoff switch to render the inverter inoperative as taught by
 Kammiller.” Id. at 1403, 7 USPQ2d at 1502. The known
 technique of using a cutoff switch would have predictably resulted in protecting
 the inverter circuit. Therefore, it would have been within the skill of the
 ordinary artisan to use a cutoff switch in response to the actuation signal to
 protect the inverter.
 

 

 Example 3: The claimed invention in In re
 Urbanski, 809 F.3d 1237, 1244, 117 USPQ2d 1499, 1504 (Fed. Cir. 2016)
 was directed to a method of enzymatic hydrolysis of soy fiber to reduce water
 holding capacity, requiring reacting the soy fiber and enzyme in water for about
 60-120 minutes. The claims were rejected over two references, wherein the primary
 reference, Gross, taught using a reaction time of 5 to 72 hours and the secondary
 reference, Wong, taught using a reaction time of 100 to 240 minutes, preferably
 120 minutes. The applicant argued that modifying the primary reference in the
 manner suggested by the secondary reference would forego the benefits taught by
 the primary reference, thereby teaching away from the combination. The court found
 there was sufficient motivation to combine because both references recognized
 reaction time and degree of hydrolysis as result-effective variables, which can be
 varied to have a predictable effect on the final product; and the primary
 reference does not contain an express teaching away from the proposed
 modification. “Substantial evidence thus supports the Board’s finding that a
 person of ordinary skill would have been motivated to modify the Gross process by
 using a shorter reaction time, in order to obtain the favorable properties
 disclosed in Wong.” 
 

 
 E. “Obvious To Try” – Choosing From a Finite Number of Identified,
 Predictable Solutions, With a Reasonable Expectation of Success To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that at the relevant time, there had been a
 recognized problem or need in the art, which may include a design need or
 market pressure to solve a problem;
 

 (2) a finding that there had been a finite number of identified,
 predictable potential solutions to the recognized need or problem; 
 

 (3) a finding that one of ordinary skill in the art could have
 pursued the known potential solutions with a reasonable expectation of success;
 and 
 

 (4) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that “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 that product [was] 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 .” KSR, 
 550 U.S. at 421, 82 USPQ2d at 1397. If any of these findings cannot be made, then
 this rationale cannot be used to support a conclusion that the claim would have been
 obvious to one of ordinary skill in the art.
 

 The question of whether a claimed invention can be
 shown to be obvious based on an “obvious to try” line of reasoning has been explored
 extensively by the Federal Circuit in several cases since the KSR 
 decision. The case law in this area is developing quickly in the chemical arts,
 although the rationale has been applied in other art areas as well. 
 

 Some commentators on the KSR 
 decision have expressed a concern that because inventive activities are always
 carried out in the context of what has come before and not in a vacuum, few
 inventions will survive scrutiny under an obvious to try standard. The cases decided
 since KSR have proved this fear to have been unfounded. Courts appear to be applying
 the KSR requirement for “a finite number of identified predictable solutions” in a
 manner that places particular emphasis on predictability and the reasonable
 expectations of those of ordinary skill in the art. 
 

 The Federal Circuit pointed out the challenging nature
 of the task faced by the courts – and likewise by Office personnel – when considering
 the viability of an obvious to try argument: “The evaluation of the choices made by a
 skilled scientist, when such choices lead to the desired result, is a challenge to
 judicial understanding of how technical advance is achieved in the particular field
 of science or technology.” Abbott Labs. v. Sandoz, Inc., 544 F.3d
 1341, 1352, 89 USPQ2d 1161, 1171 (Fed. Cir. 2008). The Federal Circuit cautioned that
 an obviousness inquiry based on an obvious to try rationale must always be undertaken
 in the context of the subject matter in question, “including the characteristics of
 the science or technology, its state of advance, the nature of the known choices, the
 specificity or generality of the prior art, and the predictability of results in the
 area of interest.” Id. 

 Example 1: The claimed invention in Pfizer, Inc. v. Apotex,
 Inc., 480 F.3d 1348, 82 USPQ2d 1321 (Fed. Cir. 2007), was directed to
 the amlodipine besylate drug product, which was sold in tablet form in the United
 States under the trademark Norvasc ® . Amlodipine and the
 use of besylate anions were both known at the time of the invention. Amlodipine
 was known to have the same therapeutic properties as were being claimed for the
 amlodipine besylate, but Pfizer discovered that the besylate form had better
 manufacturing properties (e.g., reduced “stickiness”).
 

 Pfizer argued that the results of forming amlodipine besylate
 would have been unpredictable and therefore nonobvious. The court rejected the
 notion that unpredictability could be equated with nonobviousness here, because
 there were only a finite number (53) of pharmaceutically acceptable salts to be tested for improved properties.
 

 The court found that one of ordinary skill in the art having
 problems with the machinability of amlodipine would have looked to forming a salt
 of the compound and would have been able to narrow the group of potential
 salt-formers to a group of 53 anions known to form pharmaceutically acceptable
 salts, which would be an acceptable number to form “a reasonable expectation of
 success.” 
 

 

 Example 2: The claimed invention in Alza Corp. v. Mylan Labs.,
 Inc., 464 F.3d 1286, 80 USPQ2d 1001 (Fed. Cir. 2006) was drawn to
 sustained-release formulations of the drug oxybutynin in which the drug is
 released at a specified rate over a 24-hour period. Oxybutynin was known to be
 highly water-soluble, and the specification had pointed out that development of
 sustained-release formulations of such drugs presented particular problems. 
 

 A prior art patent to Morella had taught sustained-release
 compositions of highly water-soluble drugs, as exemplified by a sustained-release
 formulation of morphine. Morella had also identified oxybutynin as belonging to
 the class of highly water-soluble drugs. The Baichwal prior art patent had taught
 a sustained-release formulation of oxybutynin that had a different release rate
 than the claimed invention. Finally, the Wong prior art patent had taught a
 generally applicable method for delivery of drugs over a 24-hour period. Although
 Wong mentioned applicability of the disclosed method to several categories of
 drugs to which oxybutynin belonged, Wong did not specifically mention its
 applicability to oxybutynin. 
 

 The court found that because the absorption properties of
 oxybutynin would have been reasonably predictable at the time of the invention,
 there would have been a reasonable expectation of successful development of a
 sustained-release formulation of oxybutynin as claimed. The prior art, as
 evidenced by the specification, had recognized the obstacles to be overcome in
 development of sustained-release formulations of highly water-soluble drugs, and
 had suggested a finite number of ways to overcome these obstacles. The claims were
 obvious because it would have been obvious to try the known methods for
 formulating sustained-release compositions, with a reasonable expectation of
 success. The court was not swayed by arguments of a lack of absolute
 predictability.
 

 

 Example 3: The Federal Circuit’s decision in In re
 Kubin, 561 F.3d 1351, 90 USPQ2d 1417 (Fed. Cir. 2009), affirmed the
 Office’s determination in Ex parte Kubin, 83 USPQ2d 1410 (Bd.
 Pat. App. & Int. 2007) that the claims in question, directed to an isolated
 nucleic acid molecule, would have been obvious over the prior art applied. The
 claim stated that the nucleic acid encoded a particular polypeptide. The encoded
 polypeptide was identified in the claim by its partially specified sequence, and
 by its ability to bind to a specified protein. 
 

 A prior art patent to Valiante taught the polypeptide encoded by
 the claimed nucleic acid, but did not disclose either the sequence of the
 polypeptide, or the claimed isolated nucleic acid molecule. However, Valiante did
 disclose that by employing conventional methods such as those disclosed by a prior
 art laboratory manual by Sambrook, the sequence of the polypeptide could be
 determined, and the nucleic acid molecule could be isolated. In view of Valiante’s
 disclosure of the polypeptide, and of routine prior art methods for sequencing the
 polypeptide and isolating the nucleic acid molecule, the Board found that a person
 of ordinary skill in the art would have had a reasonable expectation that a
 nucleic acid molecule within the claimed scope could have been successfully
 obtained. 
 

 Relying on In re Deuel, 51 F.3d 1552, 34
 USPQ2d 1210 (Fed. Cir. 1995), appellant argued that it was improper for the Office
 to use the polypeptide of the Valiante patent together with the methods described
 in Sambrook to reject a claim drawn to a specific nucleic acid molecule without
 providing a reference showing or suggesting a structurally similar nucleic acid
 molecule. Citing KSR, the Board stated that “when there is
 motivation 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 anticipated
 success, it is likely the product not of innovation but of ordinary skill and
 common sense.” KSR, 550 U.S. at 402-03, 82 USPQ2d at 1390. The
 Board noted that the problem facing those in the art was to isolate a specific
 nucleic acid, and there were a limited number of methods available to do so. The
 Board concluded that the skilled artisan would have had reason to try these
 methods with the reasonable expectation that at least one would be successful.
 Thus, isolating the specific nucleic acid molecule claimed was “the product not of
 innovation but of ordinary skill and common sense.” Id. 

 The Board’s reasoning was substantially adopted by
 the Federal Circuit. However, it is important to note that in the
 Kubin decision, the Federal Circuit held that “the Supreme
 Court in KSR unambiguously discredited” the Federal Circuit’s
 decision in Deuel, insofar as it “implies the obviousness
 inquiry cannot consider that the combination of the claim’s constituent elements
 was ‘obvious to try.’” Kubin, 561 F.3d at 1358, 90 USPQ2d at
 1422. Instead, Kubin stated that KSR 
 “resurrects” the Federal Circuit’s own wisdom in O’Farrell, in
 which “to differentiate between proper and improper applications of ‘obvious to
 try,’” the Federal Circuit “outlined two classes of situations where ‘obvious to
 try’ is erroneously equated with obviousness under § 103 .”
 Kubin, 561 F.3d at 1359, 90 USPQ2d at 1423. These two
 classes of situations are: (1) when what would have been “obvious to try” would
 have been to vary all parameters or try each of numerous possible choices until
 one possibly arrived at a successful result, where the prior art gave either no
 indication of which parameters were critical or no direction as to which of many
 possible choices is likely to be successful; and (2) when what was “obvious to
 try” was to explore a new technology or general approach that seemed to be a
 promising field of experimentation, where the prior art gave only general guidance
 as to the particular form of the claimed invention or how to achieve it.
 Id. (citing In re O’Farrell, 853 F.2d
 894, 903, 7 USPQ2d 1673, 1681 (Fed. Cir. 1988)). 
 

 

 Example 4: Takeda Chem. Indus., Ltd. v. Alphapharm Pty., Ltd., 492 F.3d
 1350, 83 USPQ2d 1169 (Fed. Cir. 2007), is an example of a chemical case in which
 the Federal Circuit found that the claimed invention was not obvious. The claimed
 compound was pioglitazone, a member of a class of drugs known as
 thiazolidinediones (TZDs) marketed by Takeda as a treatment for Type 2 diabetes.
 The Takeda case brings together the concept of a “lead
 compound” and the obvious-to-try argument. 
 

 Alphapharm had filed an Abbreviated New Drug
 Application with the Food and Drug Administration, which was a technical act of
 infringement of Takeda’s patent. When Takeda brought suit, Alphapharm’s defense
 was that Takeda’s patent was invalid due to obviousness. Alphapharm argued that a
 two-step modification – involving homologation and ring-walking – of a known
 compound identified as “compound b” would have produced pioglitazone, and that it
 was therefore obvious. 
 

 The district court found that there would have been
 no reason to select compound b as a lead compound. There were a large number of
 similar prior art TZD compounds; fifty-four were specifically identified in
 Takeda’s prior patent, and the district court observed that “hundreds of millions”
 were more generally disclosed. Although the parties agreed that compound b
 represented the closest prior art, one reference taught certain disadvantageous
 properties associated with compound b, which according to the district court would
 have taught the skilled artisan not to select that compound as a lead compound.
 The district court found no prima facie case of obviousness,
 and stated that even if a prima facie case had been
 established, it would have been overcome in this case in view of the unexpected
 lack of toxicity of pioglitazone. 
 

 The Federal Circuit affirmed the decision of the
 district court, citing the need for a reason to modify a prior art compound. The
 Federal Circuit quoted KSR, stating: 
 

 
 The KSR Court recognized that
 “[w]hen 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.” KSR, 550 U.S. at 421, 82 USPQ2d at 1397. In such
 circumstances, “the fact that a combination was obvious to try might show that
 it was obvious under § 103 .”
 Id. That is not the case here. Rather than identify
 predictable solutions for antidiabetic treatment, the prior art disclosed a
 broad selection of compounds any one of which could have been selected as a
 lead compound for further investigation. Significantly, the closest prior art
 compound (compound b, the 6-methyl) exhibited negative properties that would
 have directed one of ordinary skill in the art away from that compound. Thus,
 this case fails to present the type of situation contemplated by the Court when
 it stated that an invention may be deemed obvious if it was “obvious to try.”
 The evidence showed that it was not obvious to try.
 

 
 Takeda, 492 F.3d at 1359, 83 USPQ2d at 1176. 
 

 Accordingly, Office personnel should recognize that
 the obvious to try rationale does not apply when the appropriate factual findings
 cannot be made. In Takeda, there was a recognized need for
 treatment of diabetes. However, there was no finite number of identified,
 predictable solutions to the recognized need, and no reasonable expectation of
 success. There were numerous known TZD compounds, and although one clearly
 represented the closest prior art, its known disadvantages rendered it unsuitable
 as a starting point for further research, and taught the skilled artisan away from
 its use. Furthermore, even if there had been reason to select compound b, there
 had been no reasonable expectation of success associated with the particular
 modifications necessary to transform compound b into the claimed compound
 pioglitazone. Thus, an obviousness rejection based on an obvious to try rationale
 was not appropriate in this situation. 
 

 

 Example 5: The case of Ortho-McNeil Pharm., Inc. v.
 Mylan Labs, Inc., 520 F.3d 1358, 86 USPQ2d 1196 (Fed. Cir. 2008),
 provides another example in which a chemical compound was determined not to be
 obvious. The claimed subject matter was topiramate, which is used as an
 anti-convulsant. 
 

 In the course of working toward a new anti-diabetic
 drug, Ortho-McNeil’s scientist had unexpectedly discovered that a reaction
 intermediate had anti-convulsant properties. Mylan’s defense of invalidity due to
 obviousness rested on an obvious to try argument. However, Mylan did not explain
 why it would have been obvious to begin with an anti-diabetic drug precursor,
 especially the specific one that led to topiramate, if one had been seeking an
 anti-convulsant drug. The district court ruled on summary judgment that
 Ortho-McNeil’s patent was not invalid for obviousness. 
 

 The Federal Circuit affirmed. The Federal Circuit
 pointed out that there was no apparent reason a person of ordinary skill would
 have chosen the particular starting compound or the particular synthetic pathway
 that led to topiramate as an intermediate. Furthermore, there would have been no
 reason to test that intermediate for anticonvulsant properties if treating
 diabetes had been the goal. The Federal Circuit recognized an element of
 serendipity in this case, which runs counter to the requirement for
 predictability. Summarizing their conclusion with regard to Mylan’s obvious to try
 argument, the Federal Circuit stated: 
 

 
 [T]his invention, contrary to Mylan’s
 characterization, does not present a finite (and small in the context of the
 art) number of options easily traversed to show obviousness. . . .
 KSR posits a situation with a finite, and in the context
 of the art, small or easily traversed, number of options that would convince an
 ordinarily skilled artisan of obviousness. . . . [T]his clearly is not the
 easily traversed, small and finite number of alternatives that
 KSR suggested might support an inference of obviousness.
 Id. at 1364, 86 USPQ2d at 1201. 
 

 
 Thus, Ortho-McNeil helps to
 clarify the Supreme Court’s requirement in KSR for “a finite number” of
 predictable solutions when an obvious to try rationale is applied: under the
 Federal Circuit’s case law “finite” means “small or easily traversed” in the
 context of the art in question. As taught in Abbott, discussed
 above, it is essential that the inquiry be placed in the context of the subject
 matter at issue, and each case must be decided on its own facts. 
 

 

 Example 6: In Bayer Schering Pharma A.G. v. Barr
 Labs., Inc., 575 F.3d 1341, 91 USPQ2d 1569 (Fed. Cir. 2009), the
 claimed invention was an oral contraceptive containing micronized drospirenone
 marketed as Yasmin ® . The prior art compound
 drospirenone was known to be a poorly water-soluble, acid-sensitive compound with
 contraceptive effects. It was also known in the art that micronization improves
 the solubility of poorly water soluble drugs.
 

 Based on the known acid sensitivity, Bayer had
 studied how effectively an enteric-coated drospirenone tablet delivered a
 formulation as compared to an intravenous injection of the same formulation to
 measure the “absolute bioavailability” of the drug. Bayer added an unprotected
 (normal) drospirenone tablet and compared its bioavailability to that of the
 enteric-coated formulation and the intravenous delivery. Bayer expected to find
 that the enteric-coated tablet would produce a lower bioavailability than an
 intravenous injection, while the normal pill would produce an even lower
 bioavailability than the enteric-coated tablet. However, they found that despite
 observations that drospirenone would quickly isomerize in a highly acidic
 environment (supporting the belief that an enteric coating would be necessary to
 preserve bioavailability), the normal pill and the enteric-coated pill resulted in
 the same bioavailability. Following this study, Bayer developed micronized
 drospirenone in a normal pill, the basis for the disputed patent. 
 

 The district court found that a person having
 ordinary skill in the art would have considered the prior art result that a
 structurally related compound, spirorenone, though acid-sensitive, would
 nevertheless absorb in vivo, would have suggested the same
 result for drospirenone. It also found that while another reference taught that
 drospirenone isomerizes in vitro when exposed to acid
 simulating the human stomach, a person of ordinary skill would have been aware of
 the study’s shortcomings, and would have verified the findings as suggested by a
 treatise on the science of dosage form design, which would have then showed that
 no enteric coating was necessary. 
 

 The Federal Circuit held that the patent was invalid
 because the claimed formulation was obvious. The Federal Circuit reasoned that the
 prior art would have funneled the formulator toward two options. Thus, the
 formulator would not have been required to try all possibilities in a field
 unreduced by the prior art. The prior art was not vague in pointing toward a
 general approach or area of exploration, but rather guided the formulator
 precisely to the use of either a normal pill or an enteric-coated pill. 
 

 It is important for Office personnel to recognize
 that the mere existence of a large number of options does not in and of itself
 lead to a conclusion of nonobviousness. Where the prior art teachings lead one of
 ordinary skill in the art to a narrower set of options, then that reduced set is
 the appropriate one to consider when determining obviousness using an obvious to
 try rationale. 
 

 

 Example 7: The case of Sanofi-Synthelabo v. Apotex,
 Inc., 550 F.3d 1075, 89 USPQ2d 1370 (Fed. Cir. 2008), also sheds
 light on the obvious to try line of reasoning. The claimed compound was
 clopidogrel, which is the dextrorotatory isomer of methyl alpha-
 5(4,5,6,7-tetrahydro(3,2-c)thienopyridyl)(2-chlorophenyl)-acetate. Clopidogrel is
 an anti-thrombotic compound used to treat or prevent heart attack or stroke. The
 racemate, or mixture of dextrorotatory and levorotatory (D- and L-) isomers of the
 compound, was known in the prior art. The two forms had not previously been
 separated, and although the mixture was known to have anti-thrombotic properties,
 the extent to which each of the individual isomers contributed to the observed
 properties of the racemate was not known and was not predictable. 
 

 The district court assumed that in the absence of
 any additional information, the D-isomer would have been prima
 facie obvious over the known racemate. However, in view of the
 evidence of unpredicted therapeutic advantages of the D-isomer presented in the
 case, the district court found that any prima facie case of
 obviousness had been overcome. At trial, the experts for both parties testified
 that persons of ordinary skill in the art could not have predicted the degree to
 which the isomers would have exhibited different levels of therapeutic activity
 and toxicity. Both parties’ experts also agreed that the isomer with greater
 therapeutic activity would most likely have had greater toxicity. Sanofi witnesses
 testified that Sanofi’s own researchers had believed that the separation of the
 isomers was unlikely to have been productive, and experts for both parties agreed
 that it was difficult to separate isomers at the time of the invention.
 Nevertheless, when Sanofi ultimately undertook the task of separating the isomers,
 it found that they had the “rare characteristic of ‘absolute stereoselectivity,’”
 whereby the D-isomer provided all of the favorable therapeutic activity but no
 significant toxicity, while the L-isomer produced no therapeutic activity but
 virtually all of the toxicity. Based on this record, the district court concluded
 that Apotex had not met its burden of proving by clear and convincing evidence
 that Sanofi’s patent was invalid for obviousness. The Federal Circuit affirmed the
 district court’s conclusion. 
 

 Office personnel should recognize that even when
 only a small number of possible choices exist, the obvious to try line of
 reasoning is not appropriate when, upon consideration of all of the evidence, the
 outcome would not have been reasonably predictable and the inventor would not have
 had a reasonable expectation of success. In Bayer, there were
 art-based reasons to expect that both the normal pill and the enteric-coated pill
 would be therapeutically suitable, even though not all prior art studies were in
 complete agreement. Thus, the result obtained was not unexpected. In
 Sanofi, on the other hand, there was strong evidence that
 persons of ordinary skill in the art, prior to the separation of the isomers,
 would have had no reason to expect that the D-isomer would have such strong
 therapeutic advantages as compared with the L-isomer. In other words, the result
 in Sanofi was unexpected. 
 

 

 Example 8: In Rolls-Royce, PLC v. United Tech.
 Corp., 603 F.3d 1325, 95 USPQ2d 1097 (Fed. Cir. 2010), the Federal
 Circuit addressed the obvious to try rationale in the context of a fan blade for
 jet engines. The case had arisen out of an interference proceeding. Finding that
 the district court had correctly determined that there was no interference-in-fact
 because Rolls-Royce’s claims would not have been obvious in light of United’s
 application, the Federal Circuit affirmed. 
 

 The Federal Circuit described the fan blade of the
 count as follows: 
 

 
 Each fan blade has three regions – an inner, an
 intermediate, and an outer region. The area closest to the axis of rotation at
 the hub is the inner region. The area farthest from the center of the engine
 and closest to the casing surrounding the engine is the outer region. The
 intermediate region falls in between. The count defines a fan blade with a
 swept-forward inner region, a swept-rearward intermediate region, and
 forward-leaning outer region. 
 

 
 Id. at 1328, 95 USPQ2d at 1099. 
 

 United had argued that it would have been obvious
 for a person of ordinary skill in the art to try a fan blade design in which the
 sweep angle in the outer region was reversed as compared with prior art fan blades
 from rearward to forward sweep, in order to reduce endwall shock. The Federal
 Circuit disagreed with United’s assessment that the claimed fan blade would have
 been obvious based on an obvious to try rationale. The Federal Circuit pointed out
 that in a proper obvious to try approach to obviousness, the possible options for
 solving a problem must have been “known and finite.” Id. at
 1339, 95 USPQ2d at 1107 (citing Abbott, 544 F.3d at 1351, 89
 USPQ2d at 1171). In this case, nothing in the prior art would have suggested that
 changing the sweep angle as Rolls-Royce had done would have addressed the issue of
 endwall shock. Thus, the Federal Circuit concluded that changing the sweep angle
 “would not have presented itself as an option at all, let alone an option that
 would have been obvious to try.” Id. The decision in
 Rolls-Royce is a reminder to Office personnel that the
 obvious to try rationale can properly be used to support a conclusion of
 obviousness only when the claimed solution would have been selected from a finite
 number of potential solutions known to persons of ordinary skill in the art. 
 

 

 Example 9: The case of Perfect Web Tech., Inc. v.
 InfoUSA, Inc., 587 F.3d 1324, 1328-29, 92 USPQ2d 1849, 1854 (Fed.
 Cir. 2009), provides an example in which the Federal Circuit held that a claimed
 method for managing bulk email distribution was obvious on the basis of an obvious
 to try argument. In Perfect Web, the method required selecting
 the intended recipients, transmitting the emails, determining how many of the
 emails had been successfully received, and repeating the first three steps if a
 pre-determined minimum number of intended recipients had not received the email. 
 

 The Federal Circuit affirmed the district court’s
 determination on summary judgment that the claimed invention would have been
 obvious. Failure to meet a desired quota of email recipients was a recognized
 problem in the field of email marketing. The prior art had also recognized three
 potential solutions: increasing the size of the initial recipient list; resending
 emails to recipients who did not receive them on the first attempt; and selecting
 a new recipient list and sending emails to them. The last option corresponded to
 the fourth step of the invention as claimed. 
 

 The Federal Circuit noted that based on “simple
 logic,” selecting a new list of recipients was more likely to result in the
 desired outcome than resending to those who had not received the email on the
 first attempt. There had been no evidence of any unexpected result associated with
 selecting a new recipient list, and no evidence that the method would not have had
 a reasonable likelihood of success. Thus, the Federal Circuit concluded that, as
 required by KSR, there were a “finite number of identified,
 predictable solutions,” and that the obvious to try inquiry properly led to the
 legal conclusion of obviousness. 
 

 The Federal Circuit in Perfect
 Web also discussed the role of common sense in the determination of
 obviousness. The district court had cited KSR for the
 proposition that “[a] person of ordinary skill is also a person of ordinary
 creativity, not an automaton,” and found that “the final step [of the claimed
 invention] is merely the logical result of common sense application of the maxim
 ‘try, try again.’” In affirming the district court, the Federal Circuit undertook
 an extended discussion of common sense as it has been applied to the obviousness
 inquiry, both before and since the KSR decision. 
 

 The Federal Circuit pointed out that application of
 common sense is not really an innovation in the law of obviousness when it stated,
 “Common sense has long been recognized to inform the analysis of obviousness if
 explained with sufficient reasoning.” Perfect Web, 587 F.3d at
 1328, 92 USPQ2d at 1853 (emphasis added). The Federal Circuit then provided a
 review of a number of precedential cases that inform the understanding of common
 sense, including In re Bozek, 416 F.2d 1385, 1390, 163 USPQ
 545, 549 (CCPA 1969) (explaining that a patent examiner may rely on “common
 knowledge and common sense of the person of ordinary skill in the art without any
 specific hint or suggestion in a particular reference”) and In re
 Zurko, 258 F.3d 1379, 1383, 1385, 59 USPQ2d 1693 at 1695, 1697 (Fed.
 Cir. 2001) (clarifying that a factual foundation is needed in order for an
 examiner to invoke “good common sense” in a case in which “basic knowledge and
 common sense was not based on any evidence in the record”). The Federal Circuit
 implicitly acknowledged in Perfect Web that the kind of strict
 evidence-based teaching, suggestion, or motivation required in In re
 Lee, 277 F.3d 1338, 1344, 61 USPQ2d 1430, 1434 (Fed. Cir. 2002), is
 not an absolute requirement for an obviousness rejection in light of the teachings
 of KSR. The Federal Circuit explained that “[a]t the time [of
 the Lee decision], we required the PTO to identify record evidence of a teaching,
 suggestion, or motivation to combine references.” However, Perfect
 Web went on to state that even under Lee, common
 sense could properly be applied when analyzing evidence relevant to obviousness.
 Citing DyStar Textilfarben GmbH v. C.H. Patrick Co., 464 F.3d
 1356, 80 USPQ2d 1641 (Fed. Cir. 2006), and In re Kahn, 441 F.3d
 977, 78 USPQ2d 1329 (Fed. Cir. 2006), two cases decided shortly before the Supreme
 Court’s decision in KSR, the Federal Circuit noted that
 although “a reasoned explanation that avoids conclusory generalizations” is
 required to use common sense, identification of a “specific hint or suggestion in
 a particular reference” is not. See also B/E Aerospace, Inc. v. C&D
 Zodiac, Inc., 962 F.3d 1373, 1380-81, 2020 USPQ2d 10706 (Fed. Cir.
 2020) (stating that “the Board’s invocation of common sense was properly
 accompanied by reasoned analysis and evidentiary support” to show why it would be
 obvious to incorporate a second recess to receive an airplane seat support). But
 see 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).
 
 

 
 F. Known Work in One Field of Endeavor May Prompt Variations of It for Use
 in Either the Same Field or a Different One Based on Design Incentives or Other
 Market Forces if the Variations Are Predictable to One of Ordinary Skill in the
 Art To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that the scope and content of the prior art, whether
 in the same field of endeavor as that of the applicant’s invention or a
 different field of endeavor, included a similar or analogous device (method, or
 product);
 

 (2) a finding that there were design incentives or market forces
 which would have prompted adaptation of the known device (method, or product);
 
 

 (3) a finding that the differences between the claimed invention
 and the prior art were encompassed in known variations or in a principle known
 in the prior art;
 

 (4) a finding that one of ordinary skill in the art, in view of
 the identified design incentives or other market forces, could have implemented
 the claimed variation of the prior art, and the claimed variation would have
 been predictable to one of ordinary skill in the art; and 
 

 (5) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claimed invention
 would have been obvious is that design incentives or other market forces could have
 prompted one of ordinary skill in the art to vary the prior art in a predictable
 manner to result in the claimed invention. If any of these findings cannot be made,
 then this rationale cannot be used to support a conclusion that the claim would have
 been obvious to one of ordinary skill in the art.
 

 Example 1: The fact pattern in Dann v. Johnston, 425 U.S.
 219, 189 USPQ 257 (1976) is set forth above in Example 1 in subsection D. 
 

 The Court found that the problem addressed by applicant – the
 need to give more detailed breakdown by a category of transactions – was closely
 analogous to the task of keeping track of the transaction files of individual
 business units. Id. at 229, 189 USPQ at 261. Thus, an artisan
 in the data processing area would have recognized the similar class of problem and
 the known solutions of the prior art and it would have been well within the
 ordinary skill level to implement the system in the different environment. The
 Court held that “[t]he gap between the prior art and respondent’s system is simply
 not so great as to render the system nonobvious to one reasonably skilled in the
 art.” Id. at 230, 189 USPQ at 261.
 

 

 Example 2: The claimed invention in Leapfrog Enterprises, Inc. v.
 Fisher-Price, Inc., 485 F.3d 1157, 82 USPQ2d 1687 (Fed. Cir. 2007)
 was directed to a learning device to help young children read phonetically. The
 claim read as follows:
 

 An interactive learning device, comprising:

 a housing including a plurality of switches;

 a sound production device in communication with the switches and
 including a processor and a memory;
 

 at least one depiction of a sequence of letters, each letter
 being associable with a switch; and
 

 a reader configured to communicate the identity of the depiction
 to the processor,
 

 wherein selection of a depicted letter activates an associated
 switch to communicate with the processor, causing the sound production device to
 generate a signal corresponding to a sound associated with the selected letter,
 the sound being determined by a position of the letter in the sequence of
 letter.
 

 The court concluded that the claimed invention would have been
 obvious in view of the combination of two pieces of prior art, (1) Bevan (which
 showed an electro-mechanical toy for phonetic learning), (2) the Super Speak &
 Read device (SSR) (an electronic reading toy), and the knowledge of one of
 ordinary skill in the art. 
 

 The court made clear that there was no technological advance
 beyond the skill shown in the SSR device. The court stated that “one of ordinary
 skill in the art of children’s learning toys would have found it obvious to
 combine the Bevan device with the SSR to update it using modern electronic
 components in order to gain the commonly understood benefits of such adaptation,
 such as decreased size, increased reliability, simplified operation, and reduced
 cost. While the SSR only permits generation of a sound corresponding to the first
 letter of a word, it does so using electronic means. The combination is thus the
 adaptation of an old idea or invention (Bevan) using newer technology that is
 commonly available and understood in the art (the SSR).”
 

 The court found that the claimed invention was but a variation on
 already known children’s toys. This variation presented no nonobvious advance over
 other toys. The court made clear that there was no technological advance beyond
 the skill shown in the SSR device. The court found that “[a]ccommodating a prior
 art mechanical device that accomplishes that goal to modern electronics would have
 been reasonably obvious to one of ordinary skill in designing children’s learning
 devices. Applying modern electronics to older mechanical devices has been
 commonplace in recent years.” 
 

 

 Example 3: The claimed invention in KSR Int'l Co. v.
 Teleflex Inc., 550 U.S. 398, 82 USPQ2d 1385 (2007), was an adjustable
 pedal assembly with a fixed pivot point and an electronic pedal-position sensor
 attached to the assembly support. The fixed pivot point meant that the pivot was
 not changed as the pedal was adjusted. The placement of the sensor on the assembly
 support kept the sensor fixed while the pedal was adjusted. 
 

 Conventional gas pedals operated by a mechanical link which
 adjusted the throttle based on the travel of the pedal from a set position. The
 throttle controlled the combustion process and the available power generated by
 the engine. Newer cars used computer controlled throttles in which a sensor
 detected the motion of the pedal and sent signals to the engine to adjust the
 throttle accordingly. At the time of the invention, the marketplace provided a
 strong incentive to convert mechanical pedals to electronic pedals, and the prior
 art taught a number of methods for doing so. The prior art (Asano) taught an
 adjustable pedal with a fixed pivot point with mechanical throttle control. The
 prior art (‘936 patent to Byler) taught an electronic pedal sensor which was
 placed on a pivot point in the pedal assembly and that it was preferable to detect
 the pedal’s position in the pedal mechanism rather than in the engine. The prior
 art (Smith) taught that to prevent the wires connecting the sensor to the computer
 from chafing and wearing out, the sensor should be put on a fixed part of the
 pedal assembly rather than in or on the pedal’s footpad. The prior art (Rixon)
 taught an adjustable pedal assembly (sensor in the footpad) with an electronic
 sensor for throttle control. There was no prior art electronic throttle control
 that was combined with a pedal assembly which kept the pivot point fixed when
 adjusting the pedal.
 

 The Court stated that “[t]he proper question to have asked was
 whether a pedal designer of ordinary skill, facing the wide range of needs created
 by developments in the field of endeavor, would have seen a benefit to upgrading
 Asano with a sensor.” Id. at 424, 82 USPQ2d at 1399. The Court
 found that technological developments in the automotive design would have prompted
 a designer to upgrade Asano with an electronic sensor. The next question was where
 to attach the sensor. Based on the prior art, a designer would have known to place
 the sensor on a nonmoving part of the pedal structure and the most obvious
 nonmoving point on the structure from which a sensor can easily detect the pedal’s
 position was a pivot point. The Court concluded that it would have been obvious to
 upgrade Asano’s fixed pivot point adjustable pedal by replacing the mechanical
 assembly for throttle control with an electronic throttle control and to mount the
 electronic sensor on the pedal support structure.
 

 

 Example 4: The claimed invention in Ex parte Catan, 83
 USPQ2d 1569 (Bd. Pat. App. & Int. 2007), was a consumer electronics device
 using bioauthentication to authorize sub-users of an authorized credit account to
 place orders over a communication network up to a pre-set maximum sub-credit
 limit.
 

 The prior art (Nakano) disclosed a consumer electronics device
 like the claimed invention, except that security was provided by a password
 authentication device rather than a bioauthentication device. The prior art
 (Harada) disclosed that the use of a bioauthentication device (fingerprint sensor)
 on a consumer electronics device (remote control) to provide bioauthentication
 information (fingerprint) was known in the prior art at the time of the invention.
 The prior art (Dethloff) also disclosed that it was known in the art at the time
 of the invention to substitute bioauthentication for PIN authentication to enable
 a user to access credit via a consumer electronics device.
 

 The Board found that the prior art “shows that one of ordinary
 skill in the consumer electronic device art at the time of the invention would
 have been familiar with using bioauthentication information interchangeably with
 or in lieu of PINs to authenticate users.” The Board concluded that one of
 ordinary skill in the art of consumer electronic devices would have found it
 obvious to update the prior art password device with the modern bioauthentication
 component and thereby gain, predictably, the commonly understood benefits of such
 adaptation, that is, a secure and reliable authentication procedure.
 

 
 G. Some Teaching, Suggestion, or Motivation in the Prior Art That Would Have
 Led One of Ordinary Skill To Modify the Prior Art Reference or To Combine Prior
 Art Reference Teachings To Arrive at the Claimed Invention To reject a claim based on this rationale, Office personnel must
 resolve the Graham factual inquiries. Then, Office personnel must
 articulate the following:
 

 
 (1) a finding that there was some teaching, suggestion, or
 motivation, either in the references themselves or in the knowledge generally
 available to one of ordinary skill in the art, to modify the reference or to
 combine reference teachings; 
 

 (2) a finding that there was reasonable expectation of success;
 and 
 

 (3) whatever additional findings based on the
 Graham factual inquiries may be necessary, in view of the
 facts of the case under consideration, to explain a conclusion of obviousness.
 
 

 
 The rationale to support a conclusion that the claim would have
 been obvious is that "a person of ordinary skill in the art would have been motivated
 to combine the prior art to achieve the claimed invention and whether there would
 have been a reasonable expectation of success in doing so." DyStar
 Textilfarben GmbH & Co. Deutschland KG v. C.H. Patrick Co., 464 F.3d
 1356, 1360, 80 USPQ2d 1641, 1645 (Fed. Cir. 2006). If any of these findings cannot be
 made, then this rationale cannot be used to support a conclusion that the claim would
 have been obvious to one of ordinary skill in the art. 
 

 The courts have made clear that the teaching, suggestion, or
 motivation test is flexible and an explicit suggestion to combine the prior art is
 not necessary. The motivation to combine may be implicit and may be found in the
 knowledge of one of ordinary skill in the art, or, in some cases, from the nature of
 the problem to be solved. Id. at 1366, 80 USPQ2d at 1649. “[A]n
 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. In such situations,
 the proper question is whether the ordinary artisan possesses knowledge and skills
 rendering him capable of combining the prior art references.”
 Id. at 1368, 80 USPQ2d at 1651.
 

 
 2143.01 Suggestion or Motivation To Modify the References [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.] 

 Obviousness can be established by combining or modifying the teachings
 of the prior art to produce the claimed invention where there is some teaching,
 suggestion, or motivation to do so. In re Kahn, 441 F.3d 977, 986, 78
 USPQ2d 1329, 1335 (Fed. Cir. 2006) (discussing rationale underlying the
 motivation-suggestion-teaching test as a guard against using hindsight in an obviousness
 analysis). Axonics, Inc. v. Medtronic, Inc., 73 F.4th 950, 957-58,
 2023 USPQ2d 795 (Fed. Cir. 2023) (the court found an erroneous framing of the motivation
 inquiry led to an incorrect conclusion of nonobviousness). A “motivation to combine may
 be found explicitly or implicitly in market forces; design incentives; the ‘interrelated
 teachings of multiple patents’; ‘any need or problem known in the field of endeavor at
 the time of invention and addressed by the patent’; and the background knowledge,
 creativity, and common sense of the person of ordinary skill.” Zup v. Nash
 Mfg., 896 F.3d 1365, 1371, 127 USPQ2d 1423, 1427 (Fed. Cir. 2018) (quoting
 Plantronics, Inc. v. Aliph, Inc., 724 F.3d 1343, 1354 [107 USPQ2d
 1706] (Fed. Cir. 2013) (citing Perfect Web Techs., Inc. v. InfoUSA,
 Inc., 587 F.3d 1324, 1328 [92 USPQ2d 1849] (Fed. Cir. 2009) (quoting
 KSR, 550 U.S. at 418-21)). See MPEP § 2143 regarding
 the need to provide a reasoned explanation even in situations involving common sense or
 ordinary ingenuity. See also MPEP § 2144.05 , subsection II, B.
 

 I. PRIOR ART SUGGESTION OF THE CLAIMED INVENTION NOT NECESSARILY NEGATED BY
 DESIRABLE ALTERNATIVES The disclosure of desirable alternatives does not necessarily negate
 a suggestion for modifying the prior art to arrive at the claimed invention. In
 In re Fulton, 391 F.3d 1195, 73 USPQ2d 1141 (Fed. Cir. 2004),
 the claims of a utility patent application were directed to a shoe sole with
 increased traction having hexagonal projections in a “facing orientation.” 391 F.3d
 at 1196-97, 73 USPQ2d at 1142. The Board combined a design patent having hexagonal
 projections in a facing orientation with a utility patent having other limitations of
 the independent claim. 391 F.3d at 1199, 73 USPQ2d at 1144. Applicant argued that the
 combination was improper because (1) the prior art did not suggest having the
 hexagonal projections in a facing (as opposed to a “pointing”) orientation was the
 “most desirable” configuration for the projections, and (2) the prior art “taught
 away” by showing desirability of the “pointing orientation.” 391 F.3d at 1200-01, 73
 USPQ2d at 1145-46. The court stated that “the prior art’s mere disclosure of more
 than one alternative does not constitute a teaching away from any of these
 alternatives because such disclosure does not criticize, discredit, or otherwise
 discourage the solution claimed….” Id. In affirming the Board’s
 obviousness rejection, the court held that the prior art as a whole suggested the
 desirability of the combination of shoe sole limitations claimed, thus providing a
 motivation to combine, which need not be supported by a finding that the prior art
 suggested that the combination claimed by the applicant was the preferred, or most
 desirable combination over the other alternatives. Id. See also
 In re Urbanski, 809 F.3d 1237, 1244, 117 USPQ2d 1499, 1504
 (Fed. Cir. 2016). 
 

 In Ruiz v. A.B. Chance Co., 357 F.3d 1270,
 69 USPQ2d 1686 (Fed. Cir. 2004), the patent claimed underpinning a slumping building
 foundation using a screw anchor attached to the foundation by a metal bracket. One
 prior art reference taught a screw anchor with a concrete bracket, and a second prior
 art reference disclosed a pier anchor with a metal bracket. The court found
 motivation to combine the references to arrive at the claimed invention in the
 “nature of the problem to be solved” because each reference was directed “to
 precisely the same problem of underpinning slumping foundations.”
 Id. at 1276, 69 USPQ2d at 1690. The court also
 rejected the notion that “an express written motivation to
 combine must appear in prior art references….” Id. at 1276, 69
 USPQ2d at 1690.
 

 II. WHERE THE TEACHINGS OF THE PRIOR ART CONFLICT, THE EXAMINER MUST WEIGH THE
 SUGGESTIVE POWER OF EACH REFERENCE The test for obviousness is what the combined teachings of the
 references would have suggested to one of ordinary skill in the art, and all
 teachings in the prior art must be considered to the extent that they are in
 analogous arts. Where the teachings of two or more prior art references conflict, the
 examiner must weigh the power of each reference to suggest solutions to one of
 ordinary skill in the art, considering the degree to which one reference might
 accurately discredit another. In re Young, 927 F.2d 588, 18 USPQ2d
 1089 (Fed. Cir. 1991) (Prior art patent to Carlisle disclosed controlling and
 minimizing bubble oscillation for chemical explosives used in marine seismic
 exploration by spacing seismic sources close enough to allow the bubbles to intersect
 before reaching their maximum radius so the secondary pressure pulse was reduced. An
 article published several years later by Knudsen opined that the Carlisle technique
 did not yield appreciable improvement in bubble oscillation suppression. However, the
 article did not test the Carlisle technique under comparable conditions because
 Knudsen did not use Carlisle’s spacing or seismic source. Furthermore, where the
 Knudsen model most closely approximated the patent technique there was a 30%
 reduction of the secondary pressure pulse. On these facts, the court found that the
 Knudsen article would not have deterred one of ordinary skill in the art from using
 the Carlisle patent teachings.).
 

 III. FACT THAT REFERENCES CAN BE COMBINED OR MODIFIED MAY NOT BE SUFFICIENT TO
 ESTABLISH PRIMA FACIE OBVIOUSNESS The mere fact that references can be combined
 or modified does not render the resultant combination obvious unless the results
 would have been predictable to one of ordinary skill in the art. KSR Int'l
 Co. v. Teleflex Inc., 550 U.S. 398, 417, 82 USPQ2d 1385, 1396 (2007)
 (“If a person of ordinary skill can implement a predictable variation,
 §
 103 likely bars its patentability. For the same reason, if a
 technique has been used to improve one device, and a person of ordinary skill in the
 art would recognize that it would improve similar devices in the same way, using the
 technique is obvious unless its actual application is beyond his or her skill.”).
 

 IV. MERE STATEMENT THAT THE CLAIMED INVENTION IS WITHIN THE CAPABILITIES OF ONE OF
 ORDINARY SKILL IN THE ART IS NOT SUFFICIENT BY ITSELF TO ESTABLISH PRIMA
 FACIE OBVIOUSNESS A statement that modifications of the prior art to meet the claimed
 invention would have been “‘ well within the ordinary skill of the
 art at the time the claimed invention was made’” because the
 references relied upon teach that all aspects of the claimed invention were
 individually known in the art is not sufficient to establish a prima
 facie case of obviousness without some objective reason to combine the
 teachings of the references. Ex parte Levengood, 28 USPQ2d 1300
 (Bd. Pat. App. & Inter. 1993). ‘‘‘[R]ejections on obviousness cannot be sustained
 by mere conclusory statements; instead, there must be some articulated reasoning with
 some rational underpinning to support the legal conclusion of obviousness.’”
 KSR, 550 U.S. at 418, 82 USPQ2d at 1396 (quoting In re
 Kahn, 441 F.3d 977, 988, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006)).
 

 V. THE PROPOSED MODIFICATION CANNOT RENDER THE PRIOR ART UNSATISFACTORY FOR ITS
 INTENDED PURPOSE If a proposed modification would render the prior art invention
 being modified unsatisfactory for its intended purpose, there may be no suggestion or
 motivation to make the proposed modification. In re Gordon, 733
 F.2d 900, 221 USPQ 1125 (Fed. Cir. 1984) (Claimed device was a blood filter assembly
 for use during medical procedures wherein both the inlet and outlet for the blood
 were located at the bottom end of the filter assembly, and wherein a gas vent was
 present at the top of the filter assembly. The prior art reference taught a liquid
 strainer for removing dirt and water from gasoline and other light oils wherein the
 inlet and outlet were at the top of the device, and wherein a pet-cock (stopcock) was
 located at the bottom of the device for periodically removing the collected dirt and
 water. The reference further taught that the separation is assisted by gravity. The
 Board concluded the claims were prima facie obvious, reasoning
 that it would have been obvious to turn the reference device upside down. The court
 reversed, finding that if the prior art device were turned upside down it would be
 inoperable for its intended purpose because the gasoline to be filtered would be
 trapped at the top, the water and heavier oils sought to be separated would flow out
 of the outlet instead of the purified gasoline, and the screen would become
 clogged.). But see In re Urbanski, 809 F.3d 1237, 1244, 117 USPQ2d
 1499, 1504 (Fed. Cir. 2016) (The patent claims were directed to a method of enzymatic
 hydrolysis of soy fiber to reduce water holding capacity, requiring reacting the soy
 fiber and enzyme in water for about 60-120 minutes. The claims were rejected over two
 prior art references, wherein the primary reference taught using a longer reaction
 time of 5 to 72 hours and the secondary reference taught using a reaction time of 100
 to 240 minutes, preferably 120 minutes. The applicant argued that modifying the
 primary reference in the manner suggested by the secondary reference would forego the
 benefits taught by the primary reference, thereby teaching away from the combination.
 The court held that both prior art references “suggest[ed] that hydrolysis time may
 be adjusted to achieve different fiber properties. Nothing in the
 prior art teaches that the proposed modification would have resulted in an
 ‘inoperable’ process or a dietary fiber product with undesirable properties.”
 (emphasis in original)). 
 

 “Although statements limiting the function or capability of a prior
 art device require fair consideration, simplicity of the prior art is rarely a
 characteristic that weighs against obviousness of a more complicated device with
 added function.” In re Dance, 160 F.3d 1339, 1344, 48 USPQ2d 1635,
 1638 (Fed. Cir. 1998) (Court held that claimed catheter for removing obstruction in
 blood vessels would have been obvious in view of a first reference which taught all
 of the claimed elements except for a “means for recovering fluid and debris” in
 combination with a second reference describing a catheter including that means. The
 court agreed that the first reference, which stressed simplicity of structure and
 taught emulsification of the debris, did not teach away from the addition of a
 channel for the recovery of the debris.). Similarly, in Allied Erecting v.
 Genesis Attachments, 825 F.3d 1373, 1381, 119 USPQ2d 1132, 1138 (Fed.
 Cir. 2016), the court stated “[a]lthough modification of the movable blades may
 impede the quick change functionality disclosed by Caterpillar, ‘[a] given course of
 action often has simultaneous advantages and disadvantages, and this does not
 necessarily obviate motivation to combine’” (quoting Medichem, S.A. v.
 Rolabo, S.L., 437 F.3d 1157, 1165, 77 USPQ2d 1865, 1870 (Fed. Cir. 2006)
 (citation omitted)).
 

 VI. THE PROPOSED MODIFICATION CANNOT CHANGE THE PRINCIPLE OF OPERATION OF A
 REFERENCE If the proposed modification or combination of the prior art would
 change the principle of operation of the prior art invention being modified, then the
 teachings of the references are not sufficient to render the claims prima
 facie obvious. In re Ratti, 270 F.2d 810, 813, 123
 USPQ 349, 352 (CCPA 1959) (Claims were directed to an oil seal comprising a bore
 engaging portion with outwardly biased resilient spring fingers inserted in a
 resilient sealing member. The primary reference relied upon in a rejection based on a
 combination of references disclosed an oil seal wherein the bore engaging portion was
 reinforced by a cylindrical sheet metal casing. The seal construction taught in the
 primary reference required rigidity for operation, whereas the seal in the claimed
 invention required resiliency. The court reversed the rejection holding the
 “suggested combination of references would require a substantial reconstruction and
 redesign of the elements shown in [the primary reference] as well as a change in the
 basic principle under which the [primary reference] construction was designed to
 operate.”).
 

 

 
 2143.02 Reasonable Expectation of Success Is Required [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. OBVIOUSNESS REQUIRES A REASONABLE EXPECTATION OF SUCCESS Where there is a reason to modify or combine the prior art to
 achieve the claimed invention, the claims may be rejected as prima
 facie obvious provided there is also a reasonable expectation of
 success. The reasonable expectation of success requirement refers to “the likelihood
 of success” in combining or modifying prior art disclosures to meet the limitations
 of the claimed invention. See Elekta Ltd. v. ZAP Surgical Sys.,
 Inc., 81 F.4th 1368, 1375, 2023 USPQ2d 1100 (Fed. Cir. 2023) and
 Intelligent Bio-Sys., Inc. v. Illumina Cambridge Ltd., 821 F.3d
 1359, 1367, 119 USPQ2d 1171, 1176 (Fed. Cir. 2016). See MPEP § 2143 for
 guidance on rationales for modifying or combining the prior art. In In re
 Merck & Co., Inc., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986), the
 Board affirmed a rejection of claims directed to a method of treating depression with
 amitriptyline (or nontoxic salts thereof) as prima facie obvious.
 The prior art disclosed that amitriptyline is a compound known to possess
 psychotropic properties and that imipramine is a structurally similar psychotropic
 compound known to possess antidepressive properties. Additional prior art, suggested
 that these compounds would have been expected to have similar activity because the
 structural difference between them involved a known bioisosteric replacement, and
 because a research paper comparing the pharmacological properties of these two
 compounds suggested clinical testing of amitriptyline as an antidepressant. The court
 affirmed the Board’s determination, finding that the teachings of the prior art
 provided a sufficient basis for a reasonable expectation of success.) In Ex
 parte Blanc, 13 USPQ2d 1383 (Bd. Pat. App. & Inter. 1989) (the
 claims were directed to a process of sterilizing a polyolefinic composition with
 high-energy radiation in the presence of a phenolic polyester antioxidant to inhibit
 discoloration or degradation of the polyolefin. Appellant argued that it is
 unpredictable whether a particular antioxidant will solve the problem of
 discoloration or degradation. However, the Board found that because the prior art
 taught that appellant’s preferred antioxidant is very efficient and provides better
 results compared with other prior art antioxidants, there would have been a
 reasonable expectation of success.). 
 

 As discussed above, reasonable expectation of success
 can be implicitly shown via the prior art teachings or as part of the obviousness
 analysis. See Elekta Ltd. v. ZAP Surgical Sys., Inc., 81 F.4th
 1368, 1376-77, 2023 USPQ2d 1100 (Fed. Cir. 2023) (“[W]e can reasonably discern that
 the Board considered and implicitly addressed reasonable expectation of success based
 on the arguments and evidence presented to the Board on motivation to combine.”). In
 this decision, the court found the Board’s explanation on why the patent owner's
 arguments and evidence presented on motivation to combine were not persuasive
 implicitly addressed reasonable expectation of success and was supported by
 substantial evidence. On the other hand, depending on the situation (e.g., the
 technology, the prior art teachings and the obviousness analysis), reliance on an
 implicit showing of reasonable expectation of success may not be sufficient to
 establish a prima facie showing of obviousness. Eli Lilly
 & Co. v. Teva Pharms. Int’l GmbH, 8 F.4th 1331, 1344, 2021 USPQ2d
 862 (Fed. Cir. 2021) (A finding that a patent challenger in an inter
 partes review had demonstrated a motivation to combine references does
 not necessarily imply that the challenger had also met its burden of showing a
 reasonable expectation of success in achieving a claimed method of treatment.). In
 this case, the court found that the challenged method of treating claims “contain
 limitations related to their intended purpose for treating vasomotor symptoms [as
 stated in the preamble], and thus those limitations are undoubtedly relevant to the
 reasonable expectation of success.” Id. at 1345. In other words,
 the court found that the preamble was limiting and applicable to reasonable
 expectation of success. However, the limitations in the preamble were not addressed
 in the motivation to combine analysis. Any obviousness rejection should include,
 either explicitly or implicitly, an indication of a reasonable expectation of
 success.
 

 Conclusive proof of efficacy is not required to show
 a reasonable expectation of success. OSI Pharm., LLC v. Apotex
 Inc., 939 F.3d 1375, 1385, 2019 USPQ2d 379681 (Fed. Cir. 2019) (“To be
 clear, we do not hold today that efficacy data is always required for a reasonable
 expectation of success. Nor are we requiring ‘absolute predictability of success.’”);
 Acorda Therapeutics, Inc. v. Roxane Lab., Inc., 903 F.3d 1310,
 1333, 128 USPQ2d 1001, 1018 (Fed. Cir. 2018) (“This court has long rejected a
 requirement of ‘[c]onclusive proof of efficacy’ for obviousness.” (citing to
 Hoffmann-La Roche Inc. v. Apotex Inc., 748 F.3d 1326, 1331
 (Fed. Cir. 2014); PharmaStem Therapeutics, Inc. v. ViaCell, Inc., 
 491 F.3d 1342, 1364 (Fed. Cir. 2007); Pfizer, Inc. v. Apotex,
 Inc., 480 F.3d 1348, 1364, 1367–68 (Fed. Cir. 2007) (reasoning that “the
 expectation of success need only be reasonable, not absolute”)).
 

 II. AT LEAST SOME DEGREE OF PREDICTABILITY IS REQUIRED; APPLICANTS MAY PRESENT
 EVIDENCE SHOWING THERE WAS NO REASONABLE EXPECTATION OF SUCCESS Obviousness does not require absolute predictability, but at least
 some degree of predictability is required. Evidence showing there was no reasonable
 expectation of success may support a conclusion of nonobviousness. In re
 Rinehart, 531 F.2d 1048, 189 USPQ 143 (CCPA 1976) (Claims directed to a
 method for the commercial scale production of polyesters in the presence of a solvent
 at superatmospheric pressure were rejected as obvious over a reference which taught
 the claimed method at atmospheric pressure in view of a reference which taught the
 claimed process except for the presence of a solvent. The court reversed, finding
 there was no reasonable expectation that a process combining the prior art steps
 could be successfully scaled up in view of unchallenged evidence showing that the
 prior art processes individually could not be commercially scaled up successfully.).
 See also OSI Pharm., LLC v. Apotex Inc., 939 F.3d 1375, 1385, 2019
 USPQ2d 379681 (Fed. Cir. 2019) (“These references provide no more than hope—and hope
 that a potentially promising drug will treat a particular cancer is not enough to
 create a reasonable expectation of success in a highly unpredictable art such as
 this. Indeed, given a 99.5% failure rate and no efficacy data or any other reliable
 indicator of success, the only reasonable expectation at the time of the invention
 was failure, not success.”); Amgen, Inc. v. Chugai Pharm. Co., 927
 F.2d 1200, 1207-08, 18 USPQ2d 1016, 1022-23 (Fed. Cir. 1991), cert.
 denied, 502 U.S. 856 (1991) (In the context of a biotechnology case,
 testimony supported the conclusion that the references did not show that there was a
 reasonable expectation of success.); In re O’Farrell, 853 F.2d
 894, 903, 7 USPQ2d 1673, 1681 (Fed. Cir. 1988) (The court held the claimed method
 would have been obvious over the prior art relied upon because one reference
 contained a detailed enabling methodology, a suggestion to modify the prior art to
 produce the claimed invention, and evidence suggesting the modification would be
 successful.).
 

 III. PREDICTABILITY IS DETERMINED AT THE RELEVANT TIME Whether an art is predictable or whether the proposed modification
 or combination of the prior art has a reasonable expectation of success is determined
 at the time the invention was made for pre-AIA obviousness analysis. Ex
 parte Erlich, 3 USPQ2d 1011, 1016 (Bd. Pat. App. & Inter. 1986)
 (Although an earlier case reversed a rejection because of unpredictability in the
 field of monoclonal antibodies, the court found “ in this case 
 at the time this invention was made, one of ordinary skill in
 the art would have been motivated to produce monoclonal antibodies specific for human
 fibroplast interferon using the method of [the prior art] with a reasonable
 expectation of success.”) (emphasis in original). For obviousness analysis under the
 AIA, the relevant time is “before the effective filing date of the claimed
 invention.”
 

 

 
 2143.03 All Claim Limitations Must Be Considered [R-01.2024]

 “All words in a claim must be considered in judging the patentability
 of that claim against the prior art.” In re Wilson, 424 F.2d 1382,
 1385, 165 USPQ 494, 496 (CCPA 1970). 
 

 Examiners must consider all claim limitations when
 determining patentability of an invention over the prior art. In re
 Gulack, 703 F.2d 1381, 1385, 217 USPQ 401, 403-04 (Fed. Cir. 1983). The
 subject matter of a properly construed claim is defined by the terms that limit the
 scope of the claim when given their broadest reasonable interpretation. In
 Axonics, Inc. v. Medtronic, Inc., 73 F.4th 950, 958-59, 2023
 USPQ2d 795 (Fed. Cir. 2023), the court found the claims were improperly narrowed based
 on a preferred embodiment to sacral anatomy or sacral neuromodulation, whereas the
 patent claims made no reference to sacral anatomy or sacral neuromodulation. Thus, the
 relevant prior art was improperly limited to a narrow subset of claim scope. See also
 MPEP §
 2111 et seq. It is the subject matter of the properly construed claim that
 must be examined. The determination of whether particular language is a limitation in a
 claim depends on the specific facts of the case. See, e.g., Griffin v.
 Bertina, 285 F.3d 1029, 1034, 62 USPQ2d 1431 (Fed. Cir. 2002).
 

 As a general matter, the grammar and ordinary meaning of
 terms as understood by one having ordinary skill in the art used in a claim will dictate
 whether, and to what extent, the language limits the claim scope. Language that suggests
 or makes a feature or step optional but does not require that feature or step does not
 limit the scope of a claim under the broadest reasonable claim interpretation. In
 addition, when a claim requires selection of an element from a list of alternatives, the
 prior art teaches the element if one of the alternatives is taught by the prior art.
 See, e.g., Fresenius USA, Inc. v. Baxter Int’l, Inc., 582 F.3d 1288,
 1298, 92 USPQ2d 1163, 1171 (Fed. Cir. 2009). 
 

 The following types of claim language may raise a
 question as to its limiting effect (this list is not exhaustive): 
 

 
 • preamble ( MPEP § 2111.02 );
 

 • clauses such as “adapted to,” adapted for,”
 “wherein,” and “whereby” ( MPEP § 2111.04 , subsection I);
 
 

 • contingent limitations ( MPEP § 2111.04 ,
 subsection II);
 

 • printed matter ( MPEP §
 2111.05 ); and 
 

 • functional language associated with a claim term
 ( MPEP §
 2181 ). 
 

 
 If an independent claim is nonobvious under
 35 U.S.C.
 103 , then any claim depending therefrom is nonobvious. In
 re Fine, 837 F.2d 1071, 5 USPQ2d 1596 (Fed. Cir. 1988). However, this
 conclusion of the Fine court may not apply if a claim is not properly
 dependent or if the effective filing date of a dependent claim is later than the
 effective filing date of an independent claim from which the dependent claim depends.
 See MPEP §
 608.01(n) for a discussion of dependent claims and
 MPEP §
 2133.01 and §
 2152.01 for a discussion of effective filing date of a claimed
 invention determined on a claim-by-claim basis.
 

 I. INDEFINITE LIMITATIONS MUST BE CONSIDERED A claim limitation which is considered indefinite cannot be
 disregarded. If a claim is subject to more than one interpretation, at least one of
 which would render the claim unpatentable over the prior art, the examiner should
 reject the claim as indefinite under 35 U.S.C. 112(b) or
 pre-AIA 35
 U.S.C. 112 , second paragraph (see MPEP §
 2175 ) and should reject the claim
 over the prior art based on the interpretation of the claim that renders the prior
 art applicable. Ex parte Ionescu, 222 USPQ 537 (Bd. Pat. App.
 & Inter. 1984) (Claims on appeal were rejected on indefiniteness grounds only;
 the rejection was reversed and the case remanded to the examiner for consideration of
 pertinent prior art.). Making both rejections, when appropriate, avoids piecemeal
 appellate review. See Ionescu, 222 USPQ at 540 n.9 (citing CCPA
 and Federal Circuit cases.). See also In re Wilson, 424 F.2d 1382,
 165 USPQ 494 (CCPA 1970) (The Board erred because it ignored claim language that it
 considered to be indefinite, and reached a conclusion that the claim would have been
 obvious based only on the rest of the claim.). However, an examiner should not simply
 speculate about the meaning of the claim language and then enter an obviousness
 rejection in view of that speculative interpretation. In re
 Steele, 305 F.2d 859,134 USPQ 292 (CCPA 1962) (The “considerable
 speculation” by the examiner and the Board as to the scope of the claims did not
 provide a proper basis for an obviousness rejection.). A claim should not be rejected
 over prior art just because it is indefinite. Ionescu, 222 USPQ at
 540 (citing Steele ). Although a claim that is indefinite because
 it is susceptible to more than one interpretation may be rejected over prior art, an
 examiner should not base a prior art rejection on a claim interpretation that is not
 reasonable; see MPEP §
 2111 regarding proper claim interpretation. 
 

 II. LIMITATIONS WHICH DO NOT FIND SUPPORT IN THE ORIGINAL SPECIFICATION MUST BE
 CONSIDERED When evaluating claims for obviousness under 35 U.S.C. 103 ,
 all the limitations of the claims must be considered and given weight, including
 limitations which do not find support in the specification as originally filed (i.e.,
 new matter). Ex parte Grasselli, 231 USPQ 393 (Bd. App. 1983)
 aff’d mem. 738 F.2d 453 (Fed. Cir. 1984) (Claim to a catalyst
 expressly excluded the presence of sulfur, halogen, uranium, and a combination of
 vanadium and phosphorous. Although the negative limitations excluding these elements
 did not appear in the specification as filed, it was error to disregard these
 limitations when determining whether the claimed invention would have been obvious in
 view of the prior art.). “All words in a claim must be considered in judging the
 patentability of that claim against the prior art.” In re Miller, 
 441 F.2d 689, 694, 169 USPQ 597, 600 (CCPA 1971) (quoting In re
 Wilson, 424 F.2d 1382, 1385, 165 USPQ 494, 496 (CCPA 1970)). 
 

 

 [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 

 

 

 
 

 
 
 

 
 

 

 
 
 Accessibility 

 Privacy Policy 

 Terms of Use 

 Security 

 Emergencies/Security Alerts 

 Information Quality Guidelines 

 
 

 
 
 Federal Activities Inventory Reform (FAIR) Act 

 Notification and Federal Employee Antidiscrimination and Retaliation (NoFEAR) Act 

 Budget & Performance 

 Freedom of Information Act (FOIA) 

 
 

 
 
 Department of Commerce NoFEAR Act Report 

 Regulations.gov 

 STOP!Fakes.gov 

 Department of Commerce 

 USA.gov 

 
 

 
 
 Strategy Targeting Organized Piracy (STOP!) 

 Careers 

 Site Index 

 Contact Us 

 Submit Feedback 

 
 

 
 This page is owned by Patents.

 Last Modified: 
 
 03/09/2026 20:49:32