Authored by Kaitlin Abrams Farrell and Austin J. Keith

On June 21, 2022, the Court of Appeals for the Federal Circuit (“CAFC”), in Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc., granted petition for panel rehearing, vacated its prior decision, and reversed the district court’s judgment that Novartis’s claims are not invalid for adequate written description.¹  HEC Pharm Co., Ltd. was granted a petition for rehearing of the CAFC’s prior decision in the same case in which the Court affirmed a final judgment of the United States District Court of Delaware.²

The district court determined that claims 1­–6 of U.S. Patent No. 9,187,405 (the “’405 Patent”) were not invalid and infringed by HEC.³  On rehearing, however, the panel found that the district court clearly erred in finding that a negative claim limitation satisfied the written description requirement of 35 U.S.C. § 112(a).  The negative claim limitation, “absent an immediately preceding loading dose”, was added during prosecution to overcome prior art.⁴

The ’405 Patent discloses methods of treating relapsing-remitting multiple sclerosis (“RMMS”) using the immunosuppressant fingolimod.  Each claim requires administering the fingolimod “at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen.”⁵  The Patent’s specification only describes administering fingolimod at regular intervals and does not mention “loading doses.”⁶

The ’405 Patent is owned by Novartis who markets the brand name drug Gilenya.  The ’405 Patent is listed in the Approved Drug Products with Therapeutic Equivalence Evaluations (the “Orange Book”) as covering Novartis’s Gilenya.⁷  HEC filed an abbreviated new drug application (“ANDA”) with the FDA seeking approval to market a generic version of Gilenya.  Novartis sued HEC in the District of Delaware, alleging that the ANDA infringed all claims of the ’405 Patent.⁸

The district court found that HEC’s ANDA infringes the ’405 Patent and that the claims were not invalid for, inter alia, inadequate written description of the no-loading-dose limitation or daily-dosage limitations.⁹  HEC appealed the district court’s decision as to written description.¹⁰

The original panel on appeal consisted of Chief Judge Moore, Judge Linn, and Judge O’Malley.  Judge O’Malley authored the opinion, with Judge Linn joining in the majority and Chief Judge Moore authoring the dissent.  The majority affirmed the district court finding that the Patent was valid and the competitor’s ANDA infringed.  However, following the retirement of Judge O’Malley, Judge Hughes was appointed to the panel.  On rehearing, Judge Hughes joined Chief Judge Moore’s opinion, which become the new majority opinion.¹¹

On rehearing, the majority explained that for negative claim limitations, there is adequate written description when “‘the specification describes a reason to exclude the relevant [element].’”¹²  The majority reasoned that “silence is generally not disclosure” because “[i]f it were, then every later-added negative limitation would be supported so long as the patent makes no mention of it.”¹³  The Court specifically noted that the negative limitation, however, does not need to be recited in the specification in haec verba, instead, there must be discussion in the specification about the disadvantages or alternatives of the negative limitation to convey that the inventor intended the exclusion of that particular element.¹⁴

In reversing the district court’s decision and its prior affirmance thereof, the Court disputed the district court’s conclusion that the specification’s silence adequately supported the negative limitation.  The district court had found that because (i) there is no recitation of a loading dose in the specification, and (ii) the specification disclosed that the “Prophetic Trial describes giving a ‘daily dosage’ of fingolimod, started initially,” the no-loading-dose limitation was supported.¹⁵  The panel on rehearing, however, found that the district court’s finding that specification discloses “initially” starting with a daily dose was clearly erroneous.¹⁶  Relying on Novartis’s expert’s testimony, the Court stated that “[t]his sentence speaks to the initial length of treatment, not the dosage with which treatment begins.”¹⁷  Writing for the majority, Chief Judge Moore emphasized that the “’405 specification discloses neither the presence nor absence of a loading dose” and that “[l]oading doses—whether to be used or not—are simply not discussed.”¹⁸

Relying on the prosecution history, the panel also found that the disclosure of a “daily dosage” could not amount to a disclosure that there can be no loading dose.¹⁹  The Court reasoned that if “reciting ‘daily dosage’ without mentioning a loading dose necessarily excluded a loading dose, there would have been no reason for the applicants to add the no-loading-dose limitation.”²⁰  The Court then reiterated that the question is not whether the patentee intended there to be a loading dose, but whether the patentee precluded the use of a loading dose.²¹  Additionally, the majority emphasized that there was “intrinsic evidence that a skilled artisan would not understand reciting a daily dosage regimen without mentioning a loading dose to exclude a loading dose.”²²

Contrary to Judge Linn’s dissent, discussed below, the panel rejected the premise that it was “creat[ing] a heightened standard for negative claim limitations.”  Rather, the majority stated that “as with positive limitations, the disclosure must only ‘reasonably convey[] to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.”²³  The Court also left open the possibility that silence could support a negative claim limitation in circumstances where “it can be established that a skilled artisan would understand a negative limitation to necessarily be present in a disclosure.”²⁴

Despite the majority emphasizing it did not heighten the standard for written description with respect to negative limitations, Judge Linn argues that the standard was heightened because the majority’s reasoning requires “not only a ‘reason to exclude’ but a showing that the negative limitation in question was ‘necessarily excluded.’”²⁵  Judge Linn further argued the majority “misstated” the question posed by its opinion:

I submit that the question posed by the majority is misstated.  The question is not whether the patentee precluded the use of a loading dose but whether the claim language that precludes the administration of a loading dose is supported by the written description passages that disclose the effective administration of nothing more than a “daily dose.”²⁶

Unlike the majority, Judge Linn understands Federal Circuit precedent concerning negative claim limitations, specifically Santarus, Inc. v. Par. Pharm., Inc., to  hold only that “[n]egative claim limitations are adequately supported when the specification describes a reason to exclude the relevant information” and not that “a specification “must describe a reason to exclude a negative limitation.”²⁷  He explained that “[a] specification that describes a reason to exclude the relevant negative limitation is but one way which the written description may be met” and should not be a requirement in every case.²⁸  Judge Linn argues that the critical question in assessing written description support for a negative limitation should be the same as for any other limitation: Does the written description reasonably convey to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date?²⁹  According to Judge Linn’s dissent, how that question is resolved should depend on the facts of each case and should be assessed through the eyes of the skilled artisan.³⁰

Although the majority denied implementing a “heightened standard” for written description to support negative limitations, patent owners should be aware that patent challengers will turn to Novartis v. Accord as a basis for invalidating patent claims containing negative limitations on written description grounds.  Therefore, patent prosecutors should ensure that the written description requirement for any negative limitation is met by making a showing that the negative limitation is “necessarily excluded.”  At the same time, the dissent and vacated order expose discord among Federal Circuit Judges on the written description standard, creating uncertainty for patent owners and practitioners.