Tag: Written Description
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Exelixis v. MSN Labs: Federal Circuit Upholds Crystalline Salt Genus Under § 112 Written Description
The Federal Circuit’s precedential decision in Exelixis, Inc. v. MSN Laboratories Private Ltd., Case No. 25-1236 (Fed. Cir. Aug. 31, 2026), affirmed a bench-trial finding that patents claiming crystalline cabozantinib (L)-malate satisfied the written-description requirement even though the specification expressly characterized only two crystalline polymorphs. The court concluded that the chemical name and formula of…
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Dental Monitoring v. Align: Federal Circuit Requires Written-Description Support for AIA Provisional Prior Art
The Federal Circuit’s decision in Dental Monitoring SAS v. Align Technology, Inc., Case No. 2025-1752 (Fed. Cir. Aug. 10, 2026), holds that a patent or published application cannot obtain the filing date of a provisional application for prior-art purposes under the America Invents Act merely because the provisional describes the subject matter being asserted as…
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Enanta v. Pfizer: Federal Circuit Rejects Provisional Priority Based on an Alleged Typographical Error
The Federal Circuit’s decision in Enanta Pharmaceuticals, Inc. v. Pfizer Inc., Case No. 2025-1427 (Fed. Cir. June 23, 2026), holds that a later patent cannot claim the filing date of a provisional application when the provisional expressly discloses a different chemical range, even if the applicant contends that the difference resulted from a typographical error.…
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Teva v. Lilly: Federal Circuit Limits Amgen by Distinguishing Method-of-Use Claims from Composition Claims
The Federal Circuit’s decision in Teva Pharmaceuticals International GmbH v. Eli Lilly and Company, Case No. 24-1094 (Fed. Cir. Apr. 16, 2026), marks one of the most important post-Amgen v. Sanofi patent decisions involving antibody claims and Section 112. In a unanimous opinion authored by Chief Judge Prost, the court reversed a district court judgment…
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Seagen v. Daiichi Sankyo: Federal Circuit Reverses $41M Verdict on Written Description
The Federal Circuit’s December 2, 2025 decision in Seagen Inc. v. Daiichi Sankyo Co., No. 23-2424, continues a noticeable and consequential trend: the court’s growing willingness to overturn jury verdicts on written description and enablement grounds as a matter of law. In reversing a $41 million verdict and vacating findings of willful infringement, the panel…
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Duke v. Sandoz: Federal Circuit Invalidates Genus Claim for Lack of Written Description
On November 18, 2025, the Federal Circuit issued a significant written description decision in Duke University v. Sandoz Inc., reversing a jury verdict and holding claim 30 of U.S. Patent No. 9,579,270 invalid for lack of adequate written description. The opinion is a textbook application of the court’s “blaze marks” jurisprudence and a reminder that…
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Brita v. ITC: Functional Genus Claims Fail Written Description and Enablement
The Federal Circuit’s October 15, 2025 decision in Brita LP v. International Trade Commission delivers a clear warning to patentees who rely on broad, functionally defined genus claims without commensurate disclosure. Affirming the ITC, the court held that claims covering any gravity-fed water filter media achieving a particular performance metric failed both the written description…
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Mondis v. LG: Federal Circuit Reverses Jury Verdict for Lack of Written Description
The Federal Circuit’s August 8, 2025 decision in Mondis Technology Ltd. v. LG Electronics Inc. is another reminder that even a hard-fought jury verdict—complete with a finding of willfulness and tens of millions of dollars in damages—can evaporate if the asserted claims cannot survive scrutiny under 35 U.S.C. § 112. Once again, the court reversed…
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Agilent v. Synthego: Federal Circuit Clarifies Written Description and Motivation to Combine
The Federal Circuit vacated and reversed key findings by the PTAB in a suite of post-grant challenges brought against Agilent Technologies’ patents on CRISPR-related RNA purification methods. The decision in Agilent Technologies, Inc. v. Synthego Corp., Nos. 23-1916, -1917, -1918, -1919, and -2043, addresses recurring issues in PTAB proceedings: how to properly assess written description…
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In re Xencor: Written Description and Preamble Limitations
On March 13, 2025, the United States Court of Appeals for the Federal Circuit issued a decision in In re Xencor, Inc., affirming the rejection of Xencor’s patent application for failing to meet the written description requirement under 35 U.S.C. § 112. This case raises important considerations regarding patent claim construction, particularly the treatment of…