Seldom does an invention have only one facet. This is especially true in the biotech and pharmaceutical fields, in which a single scientific discovery can spawn a menagerie of molecules, compositions, methods, and devices. A newly discovered biochemical pathway might yield a host of new synthetic biomolecules that inhibit or enhance its effects, along with methods for making, formulating, and using these biomolecules. Similarly, a newfound nexus between a disease state and a biological marker might yield an array of new diagnostic and therapeutic methods.
Given this complexity, and as we saw in chapter 5, a patent application arising from a new scientific discovery usually claims what the Patent Office will deem to be several inventions. Protecting each invention requires obtaining a separate patent to each one. The Patent Office’s use of restriction requirements ensures this outcome.
Moreover, an application based on a new scientific discovery will invariably disclose facets of the invention in the specification that the claims do not encompass or do not fully encompass. For example, assume a patent application claiming a method for treating breast cancer using a new drug. Its specification may state that treating triple-negative breast cancer is the preferred embodiment, even though the claims might not encompass the method this narrowly.
As even a casual review of a biotech or pharmaceutical patent’s prosecution history makes clear, one bite at the apple is rarely enough to fully protect the patentable creations stemming from a single discovery. One patent, by itself, is usually insufficient to protect all commercially meaningful aspects of an invention, whether originally claimed or merely disclosed in the specification.
Fortunately, the U.S. patent system offers a virtually unlimited number of chances to protect key facets of an invention. Through continuing-application practice, an inventor pursues multiple facets of an inventive technology by filing a family of patent applications over time that claim priority of an initial parent patent application. This practice, which also exists in some other countries, has notable importance in the biotech and pharmaceutical industries for maximizing the commercial gain from inventions.
This chapter presents the main contours and advantages of continuing-application practice, and highlights some important limitations.
A continuing application is a nonprovisional application that claims priority to an earlier-filed parent application. This permits an applicant to obtain, among other things, patent protection for embodiments of a technology disclosed in the parent application, and/or originally claimed in it, but not covered by an allowed claim in that parent application.
A continuing application must be filed while its parent application is pending (i.e., neither issued as a patent nor abandoned). It must also have at least one inventor in common with its parent application.
There are three types of continuing applications: divisional applications, continuation applications, and continuation-in-part applications (CIPs).
As we know from chapter 5, a patent may not claim more than one invention. During prosecution, when a patent application does claim more than one invention, the examiner issues a restriction requirement, and the applicant must elect one invention for prosecution at that time. The nonelected inventions are then withdrawn.
To pursue claims to a nonelected invention, an applicant can file a divisional application for that invention. That is, each divisional application must claim an invention that the Patent Office deemed independent or distinct from the invention elected for prosecution in the parent application. The divisional application shares the identical specification and priority date with its parent application, differing only with regard to the claims.
EXAMPLE 7.1
Company X files a U.S. nonprovisional patent application (the parent application) having two claims. Claim 1 provides synthetic Peptide X useful for reducing the likelihood of restenosis in a human subject. Claim 2 provides a coronary stent coated with Peptide X in a manner permitting Peptide X to reduce the likelihood of restenosis in a human subject.
During prosecution, the examiner issues a restriction requirement asserting that the inventions of claims 1 and 2 are independent or distinct. The examiner requires Company X to elect one of the two inventions for prosecution in the parent application.
In response, Company X elects the invention of claim 1. Nonelected claim 2 is withdrawn, and the examiner proceeds to substantively examine claim 1. Ultimately, the examiner finds Peptide X patentable and allows claim 1.
Before the parent application issues as a patent (i.e., while it is still pending), Company X files a divisional application. This divisional application has a specification and priority date identical to those of the parent application. However, in the divisional application, Company X claims the coated stent encompassed by claim 2 of the parent application.
If Company X successfully prosecutes its divisional application so that it issues as a patent, Company X will have two U.S. patents: the one issuing from the parent application and claiming Peptide X and the one issuing from the divisional application and claiming the coated stent.
FIGURE 7.1 In example 7.1, Company X filed a parent patent application (PAR). When PAR was filed, it claimed Peptide X and a Peptide X–coated stent. In response to the restriction requirement, Company X elected the Peptide X claim and pursued it during prosecution. It did not elect the stent claim and hence did not pursue that claim during PAR’s prosecution. While PAR was still a pending application, though, Company X filed a divisional application (DIV) claiming the Peptide X–coated stent. By taking this step, Company X was able to protect both Peptide X and the coated stent, albeit via two separate patents.
In addition to nonelected inventions pursued via divisional applications, there may also be subject matter disclosed in the parent application that is either not claimed at all or not claimed in a way the applicant would like. This can occur, for example, when the claims are drafted either more narrowly or more broadly than the applicant would have liked.
In such a case, the applicant can file a continuation application to better claim this disclosed subject matter. Like a divisional application, a continuation application shares the identical specification and priority date with its parent application, differing only with regard to the claims.
EXAMPLE 7.2
Company X has a U.S. nonprovisional patent application (the parent application). Claim 1, the sole claim of this application, provides a coronary stent coated with synthetic Peptide X in a manner permitting Peptide X to reduce the likelihood of restenosis in a human subject.
Company X successfully prosecutes the parent application such that the examiner allows claim 1.
The application’s specification discloses an embodiment of the claimed coated stent wherein Peptide X is affixed to the stent using Linker 1. Although this embodiment falls within the broad scope of claim 1, Company X wishes to pursue patent protection specifically for that embodiment via one or more narrower claims.
Accordingly, while the parent application is still pending, Company X files a continuation application having a specification and priority date identical to those of the parent application. However, in the continuation application, Company X claims the coated stent wherein Peptide X is affixed to the stent using Linker 1.
If Company X successfully prosecutes its continuation application so that it issues as a patent, Company X will have two U.S. patents: the one issuing from the parent application and claiming a stent coated with Peptide X and the one issuing from the continuation application and claiming a stent coated with Peptide X using Linker 1. Here, the invention claimed in the continuation patent is encompassed by, and is a subset of, the invention claimed in the parent patent.
Even though claim 1 of the parent patent encompasses the coated stent of the continuation patent, there can still be tactical advantages to filing the continuation as Company X has done. For example, assume that (i) Company Y makes and sells a stent coated with Peptide X using Linker 1, (ii) Company X asserts the parent patent against Company Y in court, and (iii) Company Y defends itself by asserting that claim 1 is invalid as anticipated by a prior-art publication disclosing a stent coated with Peptide X using Linker 2. If this defense succeeds, claim 1 of the parent patent is held invalid, and Company Y prevails.
However, claim 1 of the continuation patent provides a coated stent wherein Peptide X is affixed to the stent using only Linker 1. If Company X were to sue Company Y for infringing the continuation patent, Company Y’s original, novelty-based invalidity defense would fail, because the prior-art publication does not disclose the claimed invention or any species of it. Thus, Company X could benefit from the continuation patent even though—and indeed because—it claims only a species of the invention claimed in the parent patent.
FIGURE 7.2 In example 7.2, Company X filed a parent patent application (PAR). PAR, which was allowed and has issued as patent, claims a Peptide X–coated stent. PAR discloses, but does not claim, a coated stent to which Peptide X is affixed via Linker 1. Although this Linker 1–containing stent is broadly encompassed by the PAR claims, Company X also wished to protect it more narrowly. So, while PAR was still pending as an application, Company X filed a continuation application (CON) claiming the coated stent to which Peptide X is affixed via Linker 1.
As we have seen, a divisional application shares the same specification and priority date with its parent, as does a continuation application. In their own ways, these applications permit an applicant to pursue aspects of an inventive technology that are already disclosed in a parent application.
What they do not do is permit adding new matter to a patent application, whether this new matter is added to the claims, the specification, or both. So, for example, neither a divisional application nor a continuation application permits claiming an aspect of an invention not disclosed in the parent application, expanding on a definition in the parent application’s specification, or adding new experimental data to a specification to show that the invention disclosed in a parent application works as intended.
A CIP application can do all of these things. A CIP application may be filed to pursue claims to subject matter that may or may not have been disclosed in the parent application. It may also be filed to add to or otherwise alter the specification (e.g., through the addition of new data) to demonstrate patentability of an invention already disclosed in the parent application. Regardless, a CIP application contains new matter with respect to its parent application.
Given this substantive difference between a CIP application and its parent, the CIP application has a split priority date. That is, it has a priority date that is the same as that of its parent application regarding common subject matter and a later priority date (i.e., the CIP application’s filing date) regarding the new subject matter.
EXAMPLE 7.3
Company X has a U.S. nonprovisional patent application (the parent application). Claim 1 provides a coronary stent coated with synthetic Peptide X in a manner permitting Peptide X to reduce the likelihood of restenosis in a human subject.
During prosecution of the parent application, scientists at Company X invent a new and effective species of the coated stent, namely a coated stent wherein Peptide X is affixed to the stent using Linker 1. Company X wishes to patent this species.
Since the parent application does not disclose this species, filing a continuation application is not an option for doing so. For the reasons discussed earlier in this chapter, neither is filing a divisional application.
So, while the parent application is still pending, Company X files a CIP application. The CIP application claims a coated stent wherein Peptide X is affixed to the stent using Linker 1 and includes supporting data in the specification.
If Company X successfully prosecutes both its parent and CIP applications, Company X will have two U.S. patents: the one issuing from the parent application and claiming a stent coated with Peptide X and the one issuing from the CIP application and claiming a stent coated with Peptide X using Linker 1. As with the scenario in example 7.2, the invention claimed in the CIP patent is encompassed by, and is a subset of, the invention claimed in the parent patent.
Although U.S. law permits filing CIP applications, these applications have certain disadvantages. By way of review first, a patent issuing from a CIP application (like a patent issuing from a continuation or divisional application) will expire twenty years from the earliest claimed priority date, which is the filing date of the parent application (or an earlier application as the case may be), not the filing date of the CIP application.
An important difference between a CIP application and other continuing applications is that, sometimes, one can also successfully pursue the claimed invention via a new (i.e., noncontinuing) application. The term of a patent issuing from a new application ends twenty years from the new application’s filing date. Yet, since a CIP is a continuing application, the term of a patent issuing from a CIP application will end earlier than it would if it had issued from a new noncontinuing application. This is an important drawback.
In addition, CIP application claims to inventions having new subject matter are not shielded from intervening prior art arising after the parent application’s filing date. Consequently, there may be intervening prior-art references that could invalidate claims in the CIP application even though they pose no threat to claims in the parent application. A CIP application’s priority claim, then, can be of questionable value.
These problems can diminish the value of filing a CIP application in the first place. So, depending on the facts, a new invention, such as the Linker 1–containing stent described in example 7.3, might be best protected via a new application rather than a CIP application.
Biotech and pharmaceutical patent practice frequently involves filing different types of continuing application to protect multiple aspects of a new technology, thus giving rise to large patent families. A patent family is typically understood to mean a group of patents and patent applications sharing a common priority application (e.g., a parent or grandparent application). Ideally, the claims of a patent family collectively cover all embodiments of the invention disclosed in the original specification that the applicant wanted to claim, was able to claim, or (if prosecution is ongoing) wanted to claim or was able to claim so far.
EXAMPLE 7.4
Company X files a U.S. nonprovisional patent application. As filed, the application claims (i) synthetic Peptide X useful for reducing the likelihood of restenosis in a human subject, (ii) a coronary stent coated with Peptide X in a manner permitting Peptide X to reduce the likelihood of restenosis in a human subject, (iii) a method for making the coated stent, and (iv) a method for treating a human subject using the stent.
Following restriction of the claims and a requirement to elect one of inventions (i) to (iv), Company X elects invention (i), Peptide X, and claims to the nonelected inventions are withdrawn.
Before issuance of the Peptide X patent, Company X files three divisional applications. These divisional applications claim the coated stent, the method for making the stent, and the therapeutic method for using the stent.
Before a patent issues from the coated-stent divisional application, Company X files a continuation of that divisional application to claim a coated stent wherein Peptide X is affixed to the stent using Linker 1. This species of coated stent was disclosed, but never claimed, in the parent (coated-stent) and grandparent (Peptide X) applications.
Company X successfully prosecutes the grandparent application, all three divisional applications, and the continuation application. Company X now has five patents having the same specification and priority date, and each claims a distinct facet of the inventive technology.
FIGURE 7.3 In example 7.4, Company X’s patent family arose from the five applications shown here. The parent application (PAR) claims Peptide X. Divisional applications 1, 2, and 3 (DIV-1, DIV-2, and DIV-3) claim inventions (ii), (iii), and (iv), respectively, which were not elected during PAR’s prosecution. Specifically, DIV-1 claims a Peptide X–coated stent, DIV-2 claims a method for making the coated stent, and DIV-3 claims a method for treating a human subject using the coated stent. Finally, the continuation application (CON) claims a coated stent wherein Peptide X is affixed to the stent via Linker 1.
A patent family is born of myriad tactical decisions, limitations, assumptions, and uncertainties. This is also true, of course, for an individual patent. Yet, building a patent family around a new technology through continuing-application practice demands greater skill at navigating the evolving scientific landscape, the rise and fall of companies promoting the technology, and the pressures that limitations on time and money can bring.
The strategies for building a patent family are countless and can differ in countless more ways depending on the facts at each point in time. Understanding and employing them is the province of attorneys and is beyond the scope of this book. What is important here is simply to understand what continuing applications are and how they can protect the many facets of an invention in cases in which one patent alone cannot.