In their latest Law360 column on the Federal Circuit’s recent notable rulings, Knobbe Martens partners Jeremiah Helm and Sean Murray explore the court’s decision in Duke University v. Sandoz, a case focused on the written description requirement.
According to the authors, the ruling “addresses a fundamental question in patent law: can a patent applicant pick and choose from different pieces of the disclosure when crafting a claim to the invention?”
In answering this question, the Federal Circuit referenced the concept of “blaze marks” on multiple occasions, a long-held articulation of the written disclosure requirement that emphasized the need for a clear path between the patent’s disclosure and the claimed invention. Where a district court had found Sandoz unable to prove Duke University did not provide a clear written description in their patent for an eyelash growth serum, the Federal Circuit disagreed. Instead, the court emphasized that when a patent discloses a laundry list of possible elements, it must also provide clear “blaze marks” to guide a skilled artisan to the combination of elements ultimately claimed.
Helm and Murray note that Duke highlights “an important limit on retrospective claim drafting” and underscores that a patent’s specification must “provide a clear path to the specific claimed invention, and not just the individual claimed elements in isolation.”
“Moving forward, Duke will likely provide patent challengers with a potent tool to attack claims revised during prosecution to recite a subgenus not specifically disclosed in the patent,” they conclude.
Read the full article here.
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