Inherency Doctrine

The Basic Rule

• A prior art reference anticipates a patent claim not only through its EXPLICIT disclosures but also through what is INHERENTLY DISCLOSED
• A characteristic or property that is necessarily present when the prior art is practiced is 'inherent' to the prior art even if it is not described

The Necessary Presence Requirement

• The critical word is 'NECESSARILY'
• Inherency requires that the claimed element MUST ALWAYS be present whenever the prior art is practiced
• It is NOT sufficient that the claimed element: sometimes appears
• Probably appears
• Or might appear under certain conditions
• The element must be an inevitable result of the prior art disclosure

The Recognition Question

• A key principle is that the inherent characteristic need NOT have been recognized by the prior art author
• If the prior art discloses a compound or process that necessarily produces a particular result, the result is prior art even if the authors were unaware of it

Example

• A prior art publication describes a method of making compound A
• Later, scientists discover that compound A metabolizes in the human body into compound B
• A patent is filed claiming compound B
• The prior art method of making compound A INHERENTLY produces compound B (it is an inevitable metabolic result of compound A)
• Even though the prior art authors didn't know about compound B, the disclosure of compound A anticipates a claim to compound B
• This is the core scenario in Schering Corp. v. Geneva Pharmaceuticals (Fed. Cir. 2003)

Why Inherency Exists

• Without inherency, a patent applicant could claim the natural consequence of a prior art disclosure simply because the prior art authors did not recognize the consequence
• This would allow obvious improvements or natural results to be patented, blocking use of the prior art
• Inherency prevents this by treating naturally resulting characteristics as prior art.

The Federal Circuit Standard

• The standard for inherent anticipation has been articulated in many cases
• The key articulation from In re Oelrich (Fed. Cir. 1983) and refined in subsequent cases: 'To establish inherency, the extrinsic evidence must make clear that the missing descriptive matter is necessarily present in the thing described in the reference, and that it would be so recognized by persons of ordinary skill in the art'

(1) Necessarily Present

• The claimed element must always be present when the prior art is practiced
• It cannot merely sometimes appear or probably appear

Extrinsic Evidence is Permitted

• When a prior art reference does not explicitly disclose a property, the party asserting inherency may present EXTRINSIC EVIDENCE (evidence from outside the reference itself) to show the property is necessarily present: experimental data showing that practicing the prior art necessarily produces the claimed result
• Declarations from experts
• Publications AFTER the prior art date that reveal the inherent property of the prior art

Critically

• The extrinsic evidence must establish that the property was INHERENT IN THE PRIOR ART AT THE TIME IT WAS CREATED
• New publications can be used to establish what was inherent in old prior art

Speculation is not Inherency

• 'might have' or 'could have' or 'would have' or 'probably would' are insufficient
• Inherency requires MUST HAVE

The Schering Example

• Schering held a patent on the compound desloratadine (Clarinex)
• The Federal Circuit found the patent anticipated because earlier patents disclosing loratadine (Claritin) inherently disclosed desloratadine — because desloratadine is the human metabolite of loratadine
• When patients take Claritin, they necessarily produce desloratadine in their bodies
• The inherent formation of the metabolite meant the earlier compound claim anticipated the later metabolite claim.

Inherency in Obviousness — the Legal Framework

• The Federal Circuit has recognized that inherency can apply in an obviousness analysis under § 103
• IN PAR PHARM. v. TEVA PHARM. (Fed. Cir. 2009) and similar cases establish the principle: if a combination of prior art references would have been obvious to try, and practicing that combination necessarily produces a claimed element, the element may be considered obvious

Lower Standard Than Anticipation

• Unlike anticipation inherency (which requires the element to be necessarily present in a SINGLE reference), obviousness inherency applies when: a COMBINATION of prior art references is made obvious by the ordinary skill in the art
• AND the claimed element is an INHERENT RESULT of that obvious combination

Example

• Prior art reference A discloses compound X
• Prior art reference B discloses that compound X can be combined with compound Y
• A person of ordinary skill would obviously try the combination of X + Y
• The combination of X + Y inherently produces the pharmaceutical effect claimed in the patent even though neither reference mentions this effect

Important Limitation

• Inherency in obviousness DOES NOT make an UNEXPECTED result obvious
• If the result of the combination is truly UNEXPECTED (not inherent in the normal sense), inherency doesn't apply
• The result must flow naturally and inevitably from the obvious combination

Recognition not Required (But Applies Differently)

• In anticipation, the prior art author's lack of recognition does not prevent inherency
• In obviousness, the fact that a result was unexpected can be evidence AGAINST obviousness (secondary consideration of unexpected results)
• Inherency in obviousness and unexpected results are thus somewhat in tension

Practical Application in IPR

• In IPR proceedings, petitioners often argue: 'the combination of references A and B would have been obvious
• The combination necessarily produces the claimed property even if not explicitly described'
• Patent owners counter with unexpected results evidence and expert declarations

Biotech and Pharmaceutical Focus

• Inherency in both anticipation and obviousness is most heavily litigated in pharmaceutical and biotechnology patents because: natural metabolites
• Reaction products
• And naturally resulting physical properties are common claimed features
• The question of whether these features 'necessarily' result from prior art is often a central dispute.

Inherency in IPR Petitions

• IPR proceedings under 35 U.S.C. § 311 are limited to grounds of anticipation (§ 102) and obviousness (§ 103) based on PATENTS and PRINTED PUBLICATIONS
• Inherency is available in IPR because it arises within the context of § 102 anticipation and § 103 obviousness (not as a separate ground)

Expert Declaration

• In IPR, most inherency arguments are supported by expert declarations under 37 C.F.R. § 1.132 equivalent
• The expert must explain WHY the element is necessarily present (mechanism; chemistry; physics)

Patent Owner Response

• The patent owner typically challenges inherency by: arguing the element is NOT necessarily present (sometimes or probably present is insufficient)
• Presenting experimental evidence that practicing the prior art does NOT always produce the claimed element
• Showing that unexpected results make inherency inapplicable
• Filing counter-declarations by experts

Inherency in District Court (Litigation)

• District court invalidity defenses include inherency
• The clear and convincing evidence standard applies (higher than IPR's preponderance standard)
• Summary judgment motions often raise inherency when the prior art is well-established and the claimed element is a well-known natural result of the prior art

Expert Testimony at Trial

• At trial, experts testify about whether a skilled artisan would know the claimed element is necessarily present in the prior art
• Laboratory testing is sometimes introduced to demonstrate (or refute) inherent presence.

Facts

• Schering held a patent on the antihistamine compound desloratadine (Clarinex)
• Generic manufacturers challenged the patent as anticipated by earlier patents on loratadine (Claritin)

Holding

• The earlier patents on loratadine anticipate the claim to desloratadine because desloratadine is the inevitable human metabolite of loratadine
• When patients take Claritin
• They necessarily produce desloratadine
• The prior art authors did not know about the metabolite, but the metabolite is inherent in the prior art

Significance

• Established that lack of recognition by the prior art author does not prevent inherency
• IN RE CRUCIFEROUS SPROUT LITIGATION (Fed. Cir. 2007):

Facts

• Patentee claimed a method of preparing broccoli sprout products with specific glucosinolate ratios
• Prior art disclosed cultivation of broccoli sprouts

Holding

• The specific glucosinolate ratios were inherent in the natural broccoli sprout cultivation described in the prior art
• The patentee couldn't claim a naturally occurring characteristic of broccoli sprouts as a novel invention

Significance

• Inherency applies to naturally occurring characteristics of naturally occurring materials
• IN PAR PHARM. v. TEVA PHARM. (Fed. Cir. 2009):

Facts

• Patent claimed a blood concentration profile for methylphenidate after transdermal delivery
• Prior art disclosed transdermal delivery but not the specific blood profile

Holding

• If a person of ordinary skill in the art would administer the drug transdermally (as suggested by prior art), the specific blood concentration profile might inherently result
• Further factual development needed

Significance

• Inherency in obviousness requires more than speculation — the result must follow necessarily from the obvious combination
• BETTCHER INDUSTRIES v. BUNZL USA (Fed. Cir. 2011):

Facts

• Patent claimed a rotary knife with specific ergonomic features
• Prior art disclosed knives with similar structural features