On January 3, 2021, The Federal Circuit held in a 2-1 decision in Novartis Pharmaceuticals Corp. v. Accord Healthcare, Inc. (Fed. Cir. 2022) that the claims of Novartis’ U.S. Pat. No. 9,187,405 (“the ’405 patent”) met the written description requirement under 35 U.S.C. § 112(a). Defendant HEC Pharm Co. Ltd. was the only remaining defendant at trial.

The ’405 patent covers a method for treating recurring remitting multiple sclerosis with the drug fingolimod marketed by Novartis as Gilenya®.  Representative claim 1 recites:

  1. A method for reducing or preventing or alleviating relapses in Relapsing-Remitting multiple sclerosis in a subject in need thereof, comprising orally administering to said subject 2-amino-2-[2-(4-octylphenyl)ethyl]propane-1,3-diol, in free form or in a pharmaceutically acceptable salt form, at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen.

This case was appealed from an ANDA litigation in which the generics alleged invalidity because of lack of written description for two elements in claim 1: (1) the daily dosage of 0.5 mg; and (2) the negative limitation of no immediately preceding loading dose.

Regarding the first element, the court affirmed that the daily dosage of 0.5 mg met the written description requirement because it was explicitly disclosed in a prophetic clinical trial example.  Also, the specification disclosed an animal study that used a 0.3 mg/kg/week dose for treating the rats.  The court found this dose equivalent to the 0.5 mg dose recited in claim 1.

The court’s discussion about the second element has attracted more interest and was discussed in Judge Moore’s dissent.  The negative claim limitation of “absent an immediately preceding loading dose” is not explicitly disclosed in the specification.  Novartis asserted that this limitation is implicitly disclosed in the animal study and the prophetic clinical trial example.  Accord argued that silence in the specification cannot support this negative claim element.

The court agreed with Novartis and held that a negative element may be supported by a specification that is silent on the element.  The majority opinion acknowledged that the Manual of Patent Examining Procedure (MPEP) states that “the ‘mere absence of a positive recitation’ is not enough and ‘silence alone is insufficient.’”  However, the majority argued that what matters in this case is “how a skilled artisan reads a disclosure”, and “[w]ritten description may take any form, so long as a skilled artisan would read the disclosure as describing the claimed invention.”

The majority rejected what it characterized as HEC’s “attempts to create a new heightened written description standard for negative limitations” contrary to the “central tenet of [the Court’s] written description jurisprudence—that the disclosure must be read from the perspective of a person of skill in the art.” Citing precedential cases, the majority argued that a negative limitation is sufficiently supported if the specification “describes a reason to exclude the relevant limitation.”  The majority asserted that the reasons to exclude need to be apparent to the person of ordinary skill in the art, but does not need to be expressly articulated in the specification.  Based on this proposition, the majority relied on expert testimony supporting that a person of ordinary skill in the art would have recognized that the silence about the loading dose in the prophetic clinical trial example and the animal study example would convey that no loading dose should be used in the treatment regimen.  Further, the majority found that the prophetic clinical trial example only describes a daily dose of 0.5 mg and stated that initially patients receive treatment for 2 to 6 months.  The court then asserted that these descriptions teach that no loading dose was used because, if a loading dose was needed, the specification would have stated so.

In dissent, Chief Judge Moore warned that, “[i]f silence were sufficient then every later-added negative limitation would be supported as long as the patent makes no mention of it.  This is a fundamental error of law.”

The Chief Judge argued that sufficient support for a negative limitation requires the specification to provide some reason to exclude the element, e.g., by listing the disadvantages or reciting alternative features.  Focusing on the specification itself, the Chief Judge found that “nowhere in the patent does it say a loading dose should not be administered.  Nowhere does it discuss alternatives…  Nowhere does it give advantages or disadvantages… Indeed, it provides no reason to exclude a loading dose.”

The Chief Judge argued that although the knowledge of a person of ordinary skill in the art may be used to inform what is disclosed in the specification, it cannot be used to teach a limitation that is not in the specification, even if it would have been obvious to a person skilled in the art to exclude an element in view of the disclosure.  The Chief Judge asserted that the majority’s reading of the specification is rewriting the specification with expert testimony to arrive at their conclusion regarding the adequacy of the written description.

The majority’s decision and Judge Moore’s dissent highlight how the Federal Circuit’s decisions can be difficult to reconcile, e.g., the recently decided Biogen v. Mylan case in a 2-1 decision held the claims invalid for lack of written description for a dosage of “about 480 mg per day” where the specification disclosed “480 mg per day” whereas the Novartis decision found that the phrase “absent an immediately preceding loading dose regimen,” which was nowhere disclosed in the specification, satisfied the written description requirement.  Thus, where silence can be construed as disclosure and actual disclosure can be disregarded as insufficient disclosure to uphold or invalidate patents, patent drafters would be well-advised to include as many different positive and negative limitations as possible, and the importance of the strength of expert testimony during district court litigation cannot be understated.