Academic journal article William and Mary Law Review

Indefiniteness as an Invalidity Defense

Academic journal article William and Mary Law Review

Indefiniteness as an Invalidity Defense

Article excerpt

TABLE OF CONTENTS  INTRODUCTION I. THE MECHANICS OF PATENT LITIGATION    A. Claim Construction    B. Assessing Patent Validity       1. Enablement       2. Anticipation       3. Written Description       4. Definiteness II. LESSONS FROM TEVA V. SANDOZ    A. Teva on Remand    B. Teva's "Good"Patents III. THE FUTURE OF INDEFINITENESS    A. Claim Construction Is Not the Problem    B. "Consequentially Ambiguous" CONCLUSION 


Should a good patent be deemed invalid because it is not perfect? (1) Assume the good patent satisfies all the important elements of patentability: it claims novel, (2) nonobvious, (3) and patent-eligible (4) subject matter; sufficiently discloses the claimed invention at the time of application; (5) contains embodiments that enable a skilled artisan to practice the invention; (6) and discloses the best version of the invention. (7) The good patent's only imperfection resides in a slightly imprecise term. (8) But the imprecision does not cause demonstrable confusion about the scope or content of the invention claimed. (9) The perceived defect appears entirely without real-world consequence. (10)

Invalidating such a good patent for inconsequential imperfection seems unadvisable. (11) No deterrence rationale justifies allowing such insubstantial error to be fatal. (12) Nonetheless, in the course of infringement litigation, such a minor defect might lead a court to invalidate the good patent as indefinite. (13)

Providing the statutory hook for definiteness jurisprudence, the law requires a valid patent to contain "one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention." (14) When invoking indefiniteness as an invalidity defense, an accused infringer may escape liability by arguing that the claim language appears ambiguous and by convincing the court to invalidate the patent at issue. (15)

Historically, courts tended to invalidate a patent as indefinite only if a claim term proved insusceptible to construction--meaning the evidence in the record failed to enable the court to discern how a person of ordinary skill in the art (POSA) would interpret the disputed claim language. (16) As claim construction jurisprudence tolerates some imprecision, the good patent would not be felled by indefiniteness that operates to invalidate a patent when claim terms cannot be construed. (17)

The true threat to the good patent arises when alleged infringers invoke indefiniteness as an invalidity defense after a court has carefully construed a given claim term. (18) This iteration of indefiniteness as an invalidity defense proves problematic because--when no longer tethered to claim construction, which places great emphasis on reading the patent from the perspective of POSA--the definiteness assessment may result in the invalidation of a patent on the basis of imprecision that causes no actual confusion. (19)

A recent case reveals the hazards posed by permitting defendants to raise indefiniteness as an invalidity defense following claim construction. In Teva Pharmaceuticals USA, Inc. v. Sandoz, Inc. (Teva V), the Federal Circuit, (20) on remand from the Supreme Court, invalidated a fully functional and generally unambiguous group of related patents because of a small, inconsequential defect. (21) Although the district court did not lend legal significance to the alleged indefiniteness given the absence of practical effect, the Federal Circuit assessed definiteness separate from claim construction, without discrete reference to the consequences of any error discovered. (22) Even after the Supreme Court demanded greater deference to the district court's subsidiary fact-finding related to claim construction in Teva IV, (23) the Federal Circuit found Teva's patents invalid without identifying clear error in the district court's fact-finding. (24)

Such dissonance between the Federal Circuit and district courts is not new. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed


An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.