Patent Claim Types

Product-by-Process Claims

Defining a product by how it's made — and the asymmetric scope that results.

Quick Answer

A product-by-process claim is valid only if the product is truly novel — prior art anticipates even if made by a different process (Atlantic Thermoplastics, 1992). Infringement requires the accused product to BE the same product, not just be made by a process that meets the claim language. The process language simultaneously narrows scope and opens validity to attack.

When to Use PBP Claims

Products That Resist Structural Description

Patent claims should ideally define products by their structural or functional characteristics. When that's impossible or insufficient, PBP claims are the fallback. MPEP § 2173.05(p) acknowledges their permissibility while emphasizing structural claiming is preferred.

Biological products

Proteins, antibodies, peptides produced by recombinant expression — structure is the sequence + post-translational modifications which may be fully defined, but the production process may create a distinctive product (glycosylation pattern, folding).

Complex polymers

Heterogeneous polymers, copolymers, or composites whose exact molecular structure varies batch-to-batch but whose properties (MW distribution, crystallinity) are defined by process conditions.

Extracts and mixtures

Natural product extracts, botanical compositions, or purified fractions where the exact active composition is uncertain but the extraction and purification process defines the product.

Novel materials

Carbon nanotubes, graphene variants, novel crystal forms (polymorphs), and advanced materials where morphology is determined by synthesis conditions.

Scope Asymmetry

Novelty vs. Infringement — The Asymmetric Rule

The most important concept in PBP claim law is the asymmetry between the validity and infringement analysis:

Validity (§§ 102/103)

Prior art anticipates a PBP claim if the PRODUCT is the same, regardless of the process used to make the prior art product.

Atlantic Thermoplastics Co. v. Faytex Corp. (Fed. Cir. 1992); In re Thorpe (Fed. Cir. 1985).

The process language in a PBP claim does NOT protect against prior art anticipation by a product made via a different process.

Infringement

A PBP claim is infringed only if the accused product IS the claimed product — structural identity. The accused party's process need not match the claim's process language.

Abbott Laboratories v. Sandoz, Inc. (Fed. Cir. 2009); Amgen v. F. Hoffmann-La Roche (Fed. Cir. 2009).

A competitor who makes the same product by a different process still infringes. But a different product made by the claimed process does NOT infringe.

FAQ

What is a product-by-process claim?

A product-by-process (PBP) claim defines a product by the process used to make it — e.g., 'A polymer obtained by polymerizing monomers A and B at 150°C.' PBP claims are proper when the product cannot be adequately characterized by its structural or physical properties alone, typically because the product's structure is not fully characterized or is difficult to describe with precision.

Are product-by-process claims limited to products made by the specific process?

For validity/novelty analysis: No — the Federal Circuit held in Atlantic Thermoplastics Co. v. Faytex Corp. (Fed. Cir. 1992) that prior art anticipates a PBP claim if it discloses the same product, even if made by a different process. For infringement: the same rule applies under In re Thorpe (Fed. Cir. 1985) and Abbott Laboratories v. Sandoz (Fed. Cir. 2009) — a PBP claim is infringed only if the accused product is the same product, regardless of process. The process language limits the product, not the method of making it.

When should a patent attorney use product-by-process claims?

PBP claims are most useful when: (1) the product's structure cannot be fully described in structural terms — typical for biological products (antibodies, proteins, complex natural-source extracts), polymers with heterogeneous structures, and novel materials whose crystal structure or morphology is only characterized by the process; (2) the product is novel but not clearly distinct from prior art by structural description alone; (3) the product achieves unexpected results compared to prior art products made by other processes.

How does infringement analysis work for product-by-process claims?

Under the Federal Circuit's current law (post-Abbott Laboratories v. Sandoz, 2009), infringement of a PBP claim requires that the accused product BE the claimed product — structural identity is the test. Simply making the product by a different process that meets the claim's process language is not sufficient for infringement if the resulting product differs structurally. The claimant must prove the accused product has the same structure/properties as the product defined by the claimed process.

Can a competitor avoid infringement by using a different manufacturing process?

Potentially yes — if the competitor's process produces a product with different structural or physical characteristics than the claimed product. But if the competitor's different process produces an identical product (same structure, same properties), infringement still applies. This is the key asymmetry: process language in a PBP claim narrows infringement (must be the same product) but doesn't protect from prior art (any prior art product anticipates regardless of process).