Federal Circuit Confirms Silence Does Not Support Negative Claim Limitations

By: Caldwell

Federal Circuit Ruling

On June 21, 2022, the Federal Circuit ruled in generic drugmakers’ favor against Novartis Pharmaceuticals Corp., finding a patent invalid under Section 112 for lack of written description because a claim’s negative limitation was not disclosed in the patent.

Appellants HEC Pharm Co., Ltd. and HEC Pharm USA Inc. (collectively, “HEC”) filed an abbreviated new drug application (ANDA) with the Food and Drug Administration (FDA) seeking approval for a generic version of Novartis’s “Gilenya” drug, which is used to treat relapsing-remitting multiple sclerosis. Novartis sued HEC, alleging that the ANDA infringes all claims of Novartis’s patent. HEC countered by arguing that the patent was invalid for inadequate written description based on a negative claim limitation of “absent an immediately preceding loading dose,” which was added during prosecution to overcome prior art. Novartis Pharm. Corp. v. Accord Helathcare, Inc., — F.4th —, 2022 WL 2204163, at *1 (Fed. Cir. June 21, 2022). After a bench trial, the district court ruled that the ANDA infringes the patent and that the patent was valid. HEC appealed the validity finding.

Disclosing Negative Limitations

On appeal, the Federal Circuit addressed whether the patent’s written description sufficiently discloses a negative claim limitation relating to “loading doses.” A loading dose is a first dose of medication that is higher than the following daily doses. Id. Each of the patent’s claims “requires administering fingolimod ‘at a daily dosage of 0.5mg, absent an immediately preceding loading dose regimen.’” Id. (quoting the record on appeal). The language “absent an immediately preceding loading dose regimen” is a negative limitation because it demands the absence of a loading dose regimen.

The Federal Circuit explained that a patent satisfies Section 112’s written description requirement when the specification “’reasonably convey[s] to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.’” Id. at *2 (quoting Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc)). It then went on to reiterate that, when it comes to showing possession, “[d]isclosure is essential; it is ‘the quid pro quo of the right to exclude.’” Id. (quoting Kewanee Oil Co. v. Bicron Corp., 416 U.S. 470, 484 (1974)). The court further explained the following regarding disclosing a negative limitation (like the one at issue here):

· “[T]he hallmark of written description” under Section 112 “is disclosure,” and “[s]ilence is generally not disclosure.” Id. (quotation omitted).

· If silence were disclosure, “then every later-added negative limitation would be supported so long as the patent makes no mention of it.” Id.

· A negative limitation need not be recited in the specification verbatim, but “there generally must be something in the specification that conveys to a skilled artisan that the inventor intended the exclusion . . . .” Id.

· A negative limitation may be disclosed where the specification “provides a reason to exclude the relevant element,” such as where the specification lists disadvantages of using the excluded element or distinguishes among the excluded element and alternatives to it. Id.

· It is possible for a specification to inherently disclose a negative limitation—for example, “if the record established that in a particular field, the absence of mention of a limitation necessarily excluded that limitation . . . .” Id.

Silence is not Golden

Turning to the record, the Federal Circuit found that the patent’s specification “does not mention loading doses, much less the absence of a loading dose. Instead, it describes administering fingolimod at regular intervals (e.g., once daily, multiple times per day, or every other day).” Id. The district court had combined the daily fingolimod dosage disclosure with the patent’s silence on loading doses to conclude that it would tell a person of skill that loading doses are excluded from the disclosed invention. The Federal Circuit disagreed, holding that the specification’s disclosure of a daily dosage could not amount to a disclosure of no loading dose, and silence as to the loading dose also was not effective disclosure.

Although the Federal Circuit’s decision is probably not novel, it may invigorate efforts to assail negative limitations for want of written description—particularly in the generic pharmaceutical market. The decision is available here: Novartis Pharm. Corp. v. Accord Healthcare, Inc., Case No. 2021-1070 (June 21, 2022). Whether Novartis seeks the High Court’s intervention is yet to be determined. The decision does highlight that innovators working in the biotech space should work with patent counsel to create robust patent applications that contain patent claims adequately supported throughout the specification.