Silence Is Not Necessarily Golden For Negative Patent Claim Limitations

• Published date: 11 July 2022
• Subject Matter: Intellectual Property, Food, Drugs, Healthcare, Life Sciences, Patent, Food and Drugs Law
• Law Firm: Duane Morris LLP
• Author: Mr Thomas J. Kowalski, Vicki Norton, Ph.D., Deborah L. Lu, Ph.D. and Brandon A. Chan, Ph.D.

During the prosecution of a patent application before the U.S. Patent and Trademark Office, claim amendments that introduce a negative limitation―the exclusion of a particular element or feature from the scope of the claims―may be dispositive in distinguishing the instant application from the prior art and advance the application toward allowance. However, the introduction of negative limitations may raise questions and issues as to whether the claims satisfy the written description requirement under 35 USC '112(a). Recently, the U.S. Court of Appeals for the Federal Circuit in Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc., No. 2021-1070, 2022 WL 2204163 (Fed. Cir. June 21, 2022) elaborated upon what satisfies the written description requirement with respect to the recitation of negative claim limitations.

Novartis owns U.S. Patent No. 9,187,405 ('405 patent), which relates to methods for treating relapsing-remitting multiple sclerosis via the oral administration of fingolimod, an immunosuppressant marketed under the name Gilenya. Independent claim 1 recites the "a daily dosage of 0.5 mg [of fingolimod], absent an immediately preceding loading dose regimen." See '405 patent, claim 1 (noting claim language added by post-filing amendment in italics). HEC Pharm Co., Ltd. and HEC Pharm USA Inc. (HEC) filed an abbreviated new drug application with the Food and Drug Administration to seek approval for marketing a generic version of Gilenya. Novartis sued HEC, alleging that its generic drug infringes the '405 patent. In a bench trial, the district court held that HEC did infringe the '405 patent and found no invalidity with respect to, inter alia, an alleged inadequate written description for the recitation of the absence of a loading dose in the claimed methods of treatment, which was added during prosecution to distinguish it from the cited prior art and obtain allowance. HEC appealed and the Federal Circuit affirmed in a split decision, with Judge Kathleen M. O'Malley and Judge Richard Linn in the majority, and Chief Judge Kimberly A. Moore dissenting. See generally Novartis Pharms. Corp. v. Accord Healthcare, Inc., 21 F.4th 1362 (Fed. Cir. 2022). HEC petitioned for a rehearing. In the meantime, Judge O'Malley retired, and Judge Todd M. Hughes replaced her on the panel for the case, which granted a rehearing. Upon rehearing, Chief Judge Moore authored the majority decision (with Judge Linn dissenting) vacating the prior decision and reversing the...