In the high-stakes arena of patent litigation, claim breadth often seems like power. Patent holders, eager to stake wide intellectual territory protection, may pursue and obtain claims with broad scope. But this ambition can come at a steep cost. Broadly drafted patent claims, though appealing in the short term, can backfire. The backfire can result in in invalidity due to prior art, inadequate written description, or lack of enablement. In this article, we discuss some perils of broad patent claims from the initial drafting stage through enforcement lawsuits. These considerations are important because 99% of parties involved in patent law strive for certainty to manage business risk. Having wild fluctuations in patent law do not create this certainty.
Broad Claims During Patent Application Process
The peril begins at the patent drafting stage. Patent applicants often pursue broad claims to hopefully maximize post-issuance exclusivity and deter would-be competitors. But the broader the claim, the more susceptible it becomes to challenges. For example, a claim that purports to cover a wide range of embodiments might inadvertently overlap with the prior art. At its core, any invention claimed must satisfy the basic novelty and non-obviousness requirements. Broad claims are immediately susceptible to future rejections. And therefore, Examiners are quick to reject the claims in view of the prior art.
Worse yet, broad claims may attempt to cover embodiments the inventors didn't describe or teach, giving rise to 35 U.S.C. §112 doctrinal pitfalls for lack of written description or lack of enablement. A claim is not enabled if the patent does not teach a person of ordinary skill in the art (POSITA) how to make and use the invention across its full scope without undue experimentation. In 2023, the U.S. Supreme Court reiterated that the more broadly one claims, the more one must enable. Hence broad scope claims must be fully enabled. Amgen Inc. v. Sanofi, 598 US 594, 610-11 (2023). The broad scope can be supported by a sufficient number of examples, which means that the specific facts and circumstances can matter. Underlying the enablement doctrine is that the full scope must be enabled without undue experimentation. The Supreme Court in Amgen did not call out the traditional In Re Wands experimentation test, but it did reaffirm the aspect of enablement without undue experimentation.
Similarly, a claim lacks written description if the patent fails to convey that the inventors were in possession of the full claimed subject matter at the time of filing. See Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (en banc).
These requirements are not just formalities. In Liebel-Flarsheim Co. v. Medrad, Inc., 481 F.3d 1371 (Fed. Cir. 2007), the patentee pursued claims that covered injector systems both with and without pressure jackets even though the specification only disclosed systems with jackets. The Federal Circuit found that the broader claims were not enabled, leading to invalidation. The lesson: pushing claim scope beyond what's actually disclosed is a high-risk strategy.
As a consequence of broad claims during the application stage, the perils include a rejection of the claims, which perhaps cannot be rehabilitated. Claims can be amended but that can create prosecution history estoppel issues later on, that is, fodder for later defendants. Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U. S. 722 (2002). Furthermore, the back and forth with the Examiner over claim scope may generate a final office action, which now means an appeal to the Patent Board. These activities take time and cost clients money. The time taken also may eat into patent term restoration. See, 35 U.S.C. §154(b). In the pharmaceutical industry, much of a patent's value lies in the end of term, not the near term.
Perils of Broad Coverage In Litigation
These risks are compounded during litigation, when claim construction can make or break a case. Patent owners often advocate for broad interpretations of claim terms in order to capture the accused product. But in doing so, they may find themselves hoisted by their own petard. Broader interpretations often invite renewed scrutiny under Sections 102 (novelty), 103 (nonobviousness), and 112 (enablement and written description).
The Federal Circuit's decision in Trustees of Boston University v. Everlight Electronics Co., 896 F.3d 1357 (Fed. Cir. 2018), illustrates this danger vividly. BU advocated for a broad construction of a key claim term, "non-single crystalline buffer layer", to encompass amorphous, polycrystalline, and mixed forms. The resulting scope covered six permutations of device structure, one of which was undisputedly impossible to make using the methods taught in the patent.
That construction succeeded in capturing the accused infringer's product, but it created an enablement problem. The court held that because one embodiment within the claim's scope was physically impossible, and the patent did not enable it, the entire claim was invalid. The patentee's litigation strategy directly contributed to its downfall.
This result may seem harsh, particularly given that five of the six permutations were enabled. But the Federal Circuit reaffirmed a hard rule: a claim must be enabled for its entire scope. If even one embodiment is not enabled and cannot be achieved without undue experimentation, the claim falls. See Wyeth v. Abbott Labs., 720 F.3d 1380 (Fed. Cir. 2013).
The irony is not lost on seasoned practitioners. In their quest for litigation advantage, patent owners may stretch claim scope just far enough to capture the target and right into the jaws of invalidity. The very arguments used to broaden the claim for infringement purposes become the rope by which the claim is hanged under §112.
This dynamic creates a dilemma for patentees. Should they press for broader claim interpretations, risking invalidity, or settle for narrower constructions that may not cover the accused product? The strategic decision is fraught with trade-offs. But courts have signaled little sympathy for patentees who create their own enablement problems.
Courts have tried to strike a balance. In cases like Atlas Powder Co. v. E.I. du Pont De Nemours & Co., 750 F.2d 1569 (Fed. Cir. 1984) and In re Cook, 439 F.2d 730 (C.C.P.A. 1971), the Federal Circuit and its predecessor held that claims could still be valid despite including inoperative embodiments, so long as POSITAs could identify and avoid them without undue experimentation.
The distinction may lie in the difference between "inoperative" and "impossible." A formulation that doesn't perform as expected is one thing; a fabrication method that physics won't allow is another. The BU case shows that arguing your claim covers an impossible embodiment even by implication may doom the claim under modern enablement law.
Patent owners must also reckon with the Phillips framework for claim construction, which disfavors importing limitations from the specification. See Phillips v. AWH Corp., 415 F.3d 1303 (Fed. Cir. 2005) (en banc). This limits the ability to backpedal during litigation by arguing that certain embodiments are implicitly excluded. Courts may refuse to construe a claim narrowly just to preserve validity unless the language clearly supports such a reading. Furthermore, a district court may prohibit a party from amending any claim construction contentions because courts try to avoid the shifting sands approach to claim construction. A patentee could be stuck with its initial broad contentions. Genentech, Inc. v. Amgen, Inc., 289 F.3d 761, 774 (Fed. Cir. 2002).
As a result, patentees must consider litigation implications at the prosecution stage and vice versa. A claim that is drafted to be "just broad enough" might pass muster during examination but could collapse under judicial scrutiny when broader interpretations are pressed during enforcement. Consistency between what is claimed, what is disclosed, and how the claim is argued in court is critical.
And as described above, broad claim coverage asserted in litigation may be tempered by estoppel issues, either through prosecution history analysis during the claim construction process or via traditional estoppel principles.
In yet another area where asserted broad claim coverage can imperil a patent, the desire for breadth may impact the validity of a Reissue patent. Many times, patent holders within the 2-year window may apply for a broadening reissue patent. But later in court, the accused infringer may argue that the broadening reissued claims violate the "original patent" requirement under Section 251. This happened in Antares Pharma v. Medac Pharma, 771 F.3d 1354 (Fed. Cir. 2014).
And finally, arguing for broader claim coverage in litigation has the peril of uncertainty and cost. It might take years of litigation to finally determine infringement and validity. That creates uncertainty during the interim. Years of litigation also may cost the client millions of dollars.
Conclusion
In conclusion, broad patent claims are a double-edged sword. At the front end, their breadth may invite invalidity due to prior art or lack of support. At the back end, aggressive litigation positions may push claims into legally untenable territory. Patent applicants and litigators alike must tread carefully. The price of overreach may be not just losing a case but losing the patent entirely.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
