Product-by-Process Claims

A product-by-process (PBP) claim defines a product not by its structural or chemical properties but by the method used to make it: DEFINITION: a patent claim that describes a product in terms of the process by which the product was made; example: 'A compound made by the process of reacting A with B at 200°C'; WHEN USED: PBP claims are used when the product itself cannot be adequately described in purely structural or compositional terms; this occurs when: (1) the product has novel properties that cannot be easily captured in structural terms; (2) the product's structure is not fully understood or difficult to characterize analytically; (3) the product is a complex biological or chemical mixture; COMMON IN BIOLOGICS AND CHEMISTRY: pharmaceutical companies and biotechnology companies frequently use PBP claims for biological molecules, protein formulations, and complex chemical compositions where complete structural characterization is impractical; ADVANTAGES: allows obtaining patent protection for novel products that cannot be fully characterized structurally; preserves patent protection even when structural characterization techniques cannot fully describe the product; DISADVANTAGES: narrow infringement scope (only the same product made by the same process); validity depends on product novelty, not process novelty — the product must be new even if the process is innovative; COMPARISON TO METHOD CLAIMS: a method claim covers the process of making; a PBP product claim covers the product made by that process (but is a PRODUCT claim, not a process claim); both can be asserted for the same invention.

The critical validity issue for product-by-process claims is whether the PRODUCT (not the process) is novel: PRODUCT NOVELTY DETERMINES VALIDITY: In re Thorpe (Fed. Cir. 1990): a product-by-process claim is not patentable if the product itself is known or obvious, even if the claimed process is new and non-obvious; the fact that the product is produced by a new process does not make an old product patentable; RATIONALE: a product claim covers the product regardless of how it is made; if the product already existed, no new product is being contributed to the public — only a new way to make an old product; the new process should be protected by a method claim, not a product-by-process claim; PRODUCT IDENTITY QUESTION: the key question is whether the product made by the claimed process is the SAME as the prior art product or is DIFFERENT (structurally, chemically, physically); if the process produces a product that differs from prior art in some meaningful way (e.g., different purity, different crystalline form, different secondary structure), the product may be novel; PRIORITY CLAIM INTERACTION: when a product-by-process claim is asserted to have an early priority date, the prior art must be evaluated against the PRODUCT, not the process; old prior art products that are structurally identical to the PBP-claimed product anticipate the claim even if they were made by different processes; OBVIOUSNESS: an obvious modification of a known product is not patentable as a PBP claim just because the claimed process is novel.

The Federal Circuit has issued conflicting guidance over the years, but the current rule is that infringement of a PBP claim requires making the same product by the same (or equivalent) process: ATLANTIC THERMOPLASTICS v. FAYTEX CORP. (Fed. Cir. 1992 en banc): the landmark case on PBP infringement; the en banc Federal Circuit held that a product-by-process claim is infringed ONLY when the accused product is made by the process in the claim (or its equivalent); a product that is identical in structure but made by a different process does NOT infringe a PBP claim; REASONING: by defining the product by its process, the patentee has limited the claim scope to products made by that process; PROCESS TERMS LIMIT PRODUCT SCOPE: the process limitations in a PBP claim narrow the product claim — they are not mere recitations of how to make the product; STRUCTURAL IDENTITY ALONE IS NOT ENOUGH: if the accused product is structurally identical to the PBP-claimed product but is made by a different process, there is no infringement; the competitor has designed around the claim by using a different manufacturing process; DOCTRINE OF EQUIVALENTS (DOE): a different process may still infringe under DOE if it is substantially equivalent — performing the same function, in the same way, to achieve the same result; PRACTICAL CONSEQUENCE: PBP claims often provide narrower protection than pure structural claims; a structural claim covers the product regardless of how it is made; a PBP claim requires both the product AND the process to be present or equivalent.

A significant doctrinal tension exists in product-by-process law between validity and infringement: THE ASYMMETRY: validity: the process terms are IGNORED for purposes of validity — a PBP claim is invalid if an old product was made by any process (including a different one); infringement: the process terms are ENFORCED for infringement — only products made by the claimed (or equivalent) process infringe; PRACTICAL EXAMPLE: Patentee claims 'Product A made by Process X'; Prior art discloses 'Product A made by Process Y'; For VALIDITY: the PBP claim may be invalid because Product A was known (process Y is irrelevant); if the patentee argues Product A is novel (made by Process X differs from Process Y's Product A), the claim is valid; For INFRINGEMENT: Defendant makes Product A (identical structure) using Process Z; No infringement because different process; LOGICAL TENSION: a claim that is invalidated by products made by different processes (validity = product-centered) is also not infringed by products made by different processes (infringement = process-centered); this can mean: the claim is only valid if Product A is novel; but if a competitor makes identical Product A by different Process Z, they don't infringe; the patentee is stuck — valid but unenforceable against certain products; DRAFTING SOLUTION: to avoid PBP asymmetry, patent attorneys draft BOTH: (1) structural/composition claims covering the product regardless of how made (to capture the full scope of the invention); (2) method claims on the process of making; (3) PBP claims as a fallback when structural characterization is impossible.

Product-by-process claims face specific examination and post-grant challenges: USPTO EXAMINATION: the USPTO examines PBP claims for product novelty; examiners look for prior art disclosing the same or an obvious product, regardless of the process used to make it; In re Thorpe standard applies: if the product was known, the claim is rejected even if made by a new process; APPLICANT RESPONSE STRATEGY: to overcome a § 102 or § 103 rejection, applicants must argue that: (a) the process produces a DIFFERENT product than the prior art — structurally, analytically, or functionally distinct; (b) expert declarations or comparative data showing the claimed product has unique characteristics; 37 C.F.R. § 1.132 declarations showing unexpected results of the product; CLAIM DIFFERENTIATION: if the applicant argues the process produces a structurally distinct product, those structural distinctions may limit the claim's scope through prosecution history; IPR PROCEEDINGS: IPR petitions challenging PBP claims must identify prior art disclosing the PRODUCT — not just the process; petitioner argues product structural identity; patent owner counters with evidence of structural differences; PTAB applies the same validity rule as district courts; CLAIM CONSTRUCTION IN IPR vs. DISTRICT COURT: the process terms in a PBP claim inform how the product is described; in claim construction, the process terms matter for determining what the product is — they can be used to distinguish from prior art that discloses a different product made by a different process.