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Targeting Indefinite Claims: Horizon Pharma, Inc. v. Dr. Reddy’s Laboratories, Inc.


Agreeing with the district court’s decision to invalidate two drug patents for indefiniteness, the Federal Circuit reasoned that two terms (“target” versus “produce”) used in the alternative in similar specification contexts were not implicitly interchangeable in meaning, affirmed a district court’s judgment that the claims were indefinite, and affirmed that conclusory, non-factual expert testimony was not persuasive either in construing the claims during a Markman hearing or in establishing an issue of fact to prevent summary judgment.


In one of its first decisions of 2021, the United States Court of Appeals for the Federal Circuit affirmed a district court decision invalidating two patents for Horizon Pharmaceutical’s pain relieving drug, Vimovo®. Earning Horizon over $52 million in 2019, Vimovo® is a combination drug of naproxen and esomeprazole indicated for treating arthritis-related pain. The patents at issue in the case—US Patent Numbers 9,220,698 (the ‘698 patent) and 9,393,208 (the ‘208 patent)—are set to expire in 2029. The patents are directed to methods of treating various arthritic conditions by administering a morning and afternoon dosage regimen of Vimovo®. Horizon sued Dr. Reddy’s for patent infringement. At issue in the case was whether the term “target”—appearing in two separate clauses in each of the sole independent claims of the patents-in-suit—was indefinite, and whether the standard that claims should be construed to sustain validity was properly applied.

The Patents at Issue

The claims at issue in the case are represented by claim 1 of the ‘698 patent, which reads in relevant part:

  1. A method for treating osteoarthritis, rheumatoid arthritis, or ankylosing spondylitis comprising orally administering to a patient in need thereof an AM unit dose form and, 10 hours (+-20%) later, a PM unit dose form, wherein:

the AM and PM unit dose forms each comprises:

naproxen, or a pharmaceutically acceptable salt thereof. . ., and

esomeprazole or a pharmaceutically acceptable salt thereof. . .;

said esomeprazole or a pharmaceutically acceptable salt thereof, is released from said AM and PM unit dose forms at a pH of 0 or greater,

the AM and PM unit dose forms target (emphasis in original):

 i) a pharmacokinetic (pk) profile for naproxen. . . and

 ii) a pharmacokinetic (pk) profile for esomeprazole. . . and

the AM and PM unit dose forms further target (emphasis in original) a mean % time at which intragastric pH remains at about 4.0 or greater for about a 24-hour period after reaching steady state that is at least about 60%.

District Court Decision

Before the United States District Court for the District of New Jersey, the parties argued over the meaning of the word “target.” Horizon contended that “target” meant “produce” and Dr. Reddy’s contended that ‘target’ is indefinite, and in the alternative, that it uses its ordinary meaning, which is ‘with the goal of obtaining.’ The district court agreed with Dr. Reddy’s, determining that ‘set a goal’ was what target ordinarily means, while at the same time declining to find the term “target” indefinite itself (although finding the claim indefinite in view of its construed meaning).

Horizon argued that the specification used the term “producing” in the context of achieving a pharmacokinetic profile as well as “targeting,” and that the alternate use of the terms implied interchangeability. The court disagreed, finding that the use of both terms did not mean that the words were interchangeable. Horizon further offered expert testimony about the meaning of “target” that the District Court deemed unsupported and conclusory.

The court held that “the target clauses are claim limitations, based primarily on [Horizon’s] reliance on the target clauses to distinguish the claimed invention from the prior art during patent prosecution.” According to the district court, the patent claims were indefinite because “while the goal itself was clearly defined, the act of targeting that goal was not.” Noting that “pills cannot be said to set goals,” the court concluded that the claim as written would require a treating physician to “avoid having a subjective intent to achieve the defined outcome.”

Federal Circuit Decision

The appeal involved three issues: whether the district properly construed the term “target” as meaning to “set a goal,” whether the claims were indefinite based on the construed meaning of “target,” and whether summary judgment was properly granted in favor of Dr. Reddy’s given there was a disagreement between the parties’ experts over the meaning of “target.”

On the first issue, the Federal Circuit agreed with the district court, noting that “words of a claim are generally given their ordinary and customary meaning,” and that in this case, the meaning of the word “target” was “readily apparent even to lay judges” as meaning “to set a goal.” In rejecting Horizon’s desired claim construction, the Federal Circuit added that the fact that the specification used both the terms “target” and “produce” actually suggested that the “the patent applicants [Horizon] were aware of their separate meanings and chose to use ‘target’ in the patent claims instead of ‘produce.’” Thus, the Federal Circuit agreed with the district court that “target” did not mean “produce.”

On the second issue on appeal, the Federal Circuit agreed with the district court that the claims were indefinite because, once construing “target” as “to set a goal,” the claims were nonsensical. After noting that a claim that is nonsensical is indefinite, the court stated that “reading the claim literally, a dose form, which is an inanimate object, cannot set a goal,” and therefore the “target” clauses in the ‘698 and ‘208 patents were nonsensical, thus rendering the claim indefinite. The court also rejected Horizon’s argument that precedent in Phillips compelled the court to construe the claims in a manner to “sustain their validity.” However, the court held that the relied upon principle did not apply in this situation, because it applies only when the claim is ambiguous. Here, since the court determined that the meaning of the claim term “target” was not ambiguous, Horizon’s asserted the Phillips principle did not apply.

On the third issue involving the opposing experts, the Federal Circuit found that Horizon’s expert “merely made conclusory statements about what a skilled artisan would understand about the meaning of the claim term “target” and quoted text from the patent’s specification that did not support this conclusion.” According to the court, since this “type of cursory conclusion” did not “create a genuine dispute of material fact,” the district court did not err in granting summary judgment of invalidity for indefiniteness.  

Key Takeaways

While nonprecedential, the Federal Circuit’s affirmation of the district court gives helpful guidance to patentees hoping to avoid invalidation by indefiniteness in the future:

  • The use of multiple overlapping or partly redundant terms in the specification does not mean a court will find that the terms are interchangeable. The district court and Federal Circuit both found the opposite here: the use of different terms in similar contexts implied that the patentee intended for the terms to be read with different meaning. Patent drafters should consider avoiding the presentation of alternate terms (e.g., target versus produce) in similar contexts to avoid introducing uncertainty about the meaning of such alternate terms. If alternate terms are presented in similar but distinct contexts, patent drafters should be cognizant of the distinctions in their meaning and provide appropriate support for claims using such alternate terms. In non-patent writing, word variety may be a virtue, but in patent drafting it can create headaches later.
  • The lack of a formal definition of a key claim-recited term (like “target”) in the specification can lead to trouble. Consider including definitions for key claim terms and/or phrases to reduce the chances of an unfavorable claim construction. In addition, strive for consistent use of terms to avoid ambiguity. As was the case in this dispute, while the term target can reasonably be understood to mean “to produce the specified effects” in the biotechnology arts, the difference between this understanding and the more common, layperson definition of “target”—particular when combined with the lack of intrinsic evidence and formal definition—added up to a loss for Horizon.
  • Conclusory or non-factual expert testimony can do harm during claim construction and beyond. Here, the district court was unpersuaded by Horizon’s conclusory expert, who, rather than cite new evidence of how a person of ordinary skill in the art might interpret the term “target,” pointed to the same specification passages that had also been deemed unpersuasive. Compounding the harm, the district court used the non-factual expert testimony to reach the finding that there was no genuine factual dispute and agreeing with Dr. Reddy’s that summary judgment was appropriate. Even an unpersuasive showing of additional facts in support of Horizon’s construction of “target” might have helped prevent summary judgment.