Product-by-Process Claims in The United States

By Elisabeth R. Healey, Ph.D. & Jeffrey Bergman

日本語   简体中文    繁體中文

U.S. patent practice concerning product-by-process claims has developed to allow an applicant to claim a patentable product that resists a definition other than the process by which it is made.

In Biogen MA, Inc. v. EMD Serono, Inc., [1] the U.S. Court of Appeals for the Federal Circuit (“CAFC”) recently evaluated patentability of a product-by-process limitation embedded within a method claim.  In this decision, the Federal Circuit reviewed Biogen’s U.S. Patent No. 7,588,755 directed to Rebif, a recombinant interferon-β product used in the treatment of multiple sclerosis. The main claim in Biogen’s patent recites a method for immunomodulation or treating a condition or disease “comprising the step of administering to a patient in need of such treatment a therapeutically effective amount of a composition comprising a recombinant polypeptide produced by non-human host transformed by a recombinant DNA molecule. . .”

The CAFC reconfirmed its own prior precedent that the “nesting of a product-by-process limitation within a method of treatment claim does not change the construction of the product-by-process limitation itself.”  The Court explained that there “is no logical reason why the nesting of a product-by-process limitation within a method claim should change how novelty of that limitation is evaluated.”  In this case, the polypeptide of Biogen’s method claim is a product-by-process produced by a non-human host transformed by a recombinant DNA molecule.  The novelty of the method of treatment rested wholly on the novelty of the composition administered – a product-by-process, which should be determined by comparing the recombinant product of the claim with the prior art product – not by comparing the processes of forming it. According to the CAFC, “the recombinant origin of the claimed polypeptide cannot alone confer novelty on that composition if the product itself is identical to the prior art non-recombinant product.”

Thus, while an old product is not patentable, even if made by a new process, a new product may be patented by reciting source or process limitations, so long as the product itself is new and unobvious. As such, claims including product-by-process limitations can be useful when there is no ability to adequately describe the physical attributes of a product, for example. Thus, for applicants guessing that their product is different but do not yet know how to describe it or compare it to the prior art, product-by-process claim limitations may allow these applicants to file patent applications sooner than otherwise would be possible, where more time would be required to sufficiently characterize the product. 

However, when choosing to draft product-by-process claims, a drafter must realize that the product itself is not covered generically, since all of the process steps must be performed to find infringement in the United States, unlike in many foreign jurisdictions. This is best illustrated with a simple hypothetical—the case of a chemical compound defined by process terms, where the inventor has not stated any structures or characteristics of the compound. The hypothetical claim of “Compound X, obtained by Process Y,” then, must be limited to Process Y, otherwise a court would be left with trying to determine whether Compound X, made by Process Z was, in fact, the same product. As a public policy argument, the view in the United States is that courts should not deny others the opportunity to practice Process Z, which may produce a better Compound X in a better way than is produced by Process Y. 

One of the significant aspects of this rationale in the United States is that a potential exists for claim limitations to be construed one way for validity purposes (as a product claim as seen in Biogen), and another way for infringement purposes (as a process claim). For the purposes of validity, a product must be shown to be novel (independent of the process), unless the process imparts characteristics that are not expected from the product.

The USPTO’s Manual of Patent Examining Procedure instructs examiners to consider the structure implied by process steps in the claims, stating that the “structure implied by the process steps should be considered when assessing the patentability of product-by-process claims over the prior art, especially where the product can only be defined by the process steps by which the product is made, or where the manufacturing process steps would be expected to impart distinctive structural characteristics to the final product.”[2]

However, as a practical matter, during prosecution, examiners search the prior art, and if the product exists, they will generally reject the claim as being anticipated. It is left to the applicant to argue why the process changes the product in some fashion. This most often needs to be accomplished through the use of Rule 132 declarations[3] or other evidence showing that the structure of the product is different as compared to the prior art reference. However, this can be extremely challenging, given that these types of claims are most often employed when it has already been determined that there is no meaningful way to describe the product itself.

In this context, the CAFC’s holding in Biogen that the claimed antiviral activity did not impart a limitation of a specific folded structure distinguishing the claimed polypeptide from that of the prior art, acts as a warning to patent drafters to ensure that product-by-process limitations are described as carefully and completely as possible from the outset.  In addition, when confronted with prior art during examination or in a post-issuance patentability or validity challenge, an applicant or patentee must be able to successfully distinguish the product without regard to the process by which the product is made. Thus, the use of a product-by-process claim permits a patent applicant to file earlier, but ultimately the patent applicant must do the analytic work necessary to distinguish the product itself over prior art. As noted, either an examiner or a third party challenger will simply allege “inherent anticipation” over any prior art disclosing an identical product.

Thus, a significant disadvantage to a product-by-process claim is that it will have a narrower scope of protection to stop infringers. It will only encompass products that are actually made by the recited process. Accordingly, and somewhat oddly, the product-by-process claim must be patentable over a broader range of subject matter than the protection it provides.

Ideally, if product-by-process claim limitations are used, a drafter should aim to explain a broad process with dependent claims that narrow the process down. Moreover, when prosecuting such a claim, care should be taken to avoid inadvertently disclaiming other processes which may achieve the same end product. 

Fortunately, the United States does offer some additional routes to choose from, if a patent applicant wants to take advantage of the early filing benefit of a product-by-process claim when analysis of the product is still unavailable. Specifically, in the United States, one may follow up the initial filing with a second filing once a method of analyzing the product becomes available. Depending on timing, the second filing might consist of a second provisional application or a continuation-in-part application. At that time, the application may be able to include conventional product claims, based on the new characterization.