On June 21, 2022, Novartis Pharmaceuticals Corp.'s patent for a method of treating multiple sclerosis with fingolimod (Gilenya®) was held invalid for lack of written description under 35 U.S.C. § 112(a).1 Gilenya® was Novartis' third bestselling pharmaceutical drug in 2021, and represented a total revenue for the company of about $2.8B globally.2 The decision is a win for the generic drug makers engaged in the instant Hatch-Waxman litigation with Novartis, and will likely result in hundreds of millions of dollars in lost revenue for Novartis when the other patents listed in the Orange Book for this product expire in 2026.
U.S. patent 9,187,405 was directed to methods of treating multiple sclerosis with fingolimod "at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen." '405 Patent, claim 1 (emphasis added). During prosecution of the patent, the feature of "absent an immediately preceding loading dose regimen" was added to the claim to overcome prior art. However, the '405 Patent does not mention loading doses at all; the specification merely describes a clinical trial protocol in which 20 patients were administered 0.5 to 30 mg doses of fingolimod at regular intervals.
A patent is not presumed complete such that things not mentioned are necessarily excluded, and silence will not generally suffice to support a negative claim limitation.3 While there may be circumstances in which it a skilled artisan would understand a negative limitation to necessarily be present in a disclosure based on silence, such a finding cannot be "at odds with the prosecution history."4
In prosecution of the '405 patent, Novartis amended the claims to recite the feature of "absent an immediately preceding loading dose regimen" to overcome rejections based on prior art. Because the patented method was allowed only after this feature was included in the claim, the Federal Circuit reasoned that "neither the applicants nor the examiner understood the words 'daily dosage' without the words 'no loading dose' to convey the absence of a loading dose."5 Further, the testimony of Novartis' experts to the contrary was found unpersuasive because it was "inconsistent with unambiguous intrinsic evidence" (e.g., the prosecution history of patent).6 In other words, the description of Novartis' '405 patent was deficient, and no amount of money spent on expert testimony could overcome the intrinsic evidence of the specification and prosecution history.7
This case highlights the importance of drafting a full and complete patent application, especially for technical areas benefiting from negative claim limitations, such as therapeutics. Had the specification in this case had even a single line stating that there was no loading dose, or something to similar effect, Novartis would likely not have lost its patent for lack of written description (at least for purposes of ensuring patent protection in the United States). Because it is difficult to predict what rejections and references will be applied in prosecution, it is important to invest in a full and complete disclosure when preparing a patent application to provide support for various claim features that may be required, including negative claim features. In addition, the strength of a company's patent should be evaluated not just on the breadth of the claims, but also the extent to which those claims are limited by the prosecution history. Indeed, special care must be taken when considering which claim amendments and statements to make throughout the patent prosecution process.
 Novartis Pharmaceuticals v Accord Healthcare Inc., No. 2021-1070, slip op. at 2–3 (Fed. Cir. 2022).
 Matej Mikulic, Novatris AG’s Top 10 Drugs Based on Revenue in 2021, Statista (Feb. 2, 2022).
 See Novartis, at 10, 12.
 See id. at 10.
 Id. at 9.
 See id.