Explicit Disclosure of Negative Claim Limitation is Required

In a relatively rare panel rehearing, the Federal Circuit vacated its prior decision and reversed the District Court’s decision that the patent at issue was not invalid for inadequate written description.[1]

Novartis, the owner of U.S. Patent No. 9,187,405 (the ‘405 patent) directed to the use of Gilenya®, a drug for treating multiple sclerosis, sued HEC Pharm in the District of Delaware for patent infringement. HEC had filed an abbreviated new drug application (ANDA) with the Food and Drug Administration seeking approval to market a generic version of Gilenya®. The District Court found that HEC’s ANDA infringes the ‘405 patent and that the claims of the ‘405 patent are not invalid, which the Federal Circuit affirmed. HEC then appealed as to written description and petitioned for a panel rehearing.

The core issue of the appeal was whether the “negative claim limitation” recited in the claims of the ‘405 patent satisfied the written description requirement when the specification was silent on such a negative claim limitation. Specifically, the relevant claims of the ‘405 patent recited “at a daily dosage of 0.5 mg, absent an immediately preceding loading dose regimen,” which Novartis argued is a negative claim limitation that excluded the use of a loading dose, even though the specification did not explicitly disclose such negative limitation. The Federal Circuit did not agree.

Here, the Federal Circuit found that the specification of the ‘405 patent was silent on excluding the use of a loading dose and that the District Court’s reading of “initially” administering a daily dosage to indicate exclusion of a loading dose was erroneous. The Federal Circuit noted that “initially” as used in the specification was to indicate the initial length of the treatment, not the dosage with which the treatment begins, and pointed to Novartis’ own physician expert’s testimony as support.[2] Additionally, the Federal Circuit found that the disclosure of a daily dosage cannot amount to a disclosure that there can be no loading dose because it is at odds with the prosecution history, noting 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.[3]

In vacating its prior decision and reversing the District Court’s decision, the Federal Circuit held that for negative claim limitations, there is adequate written description when “the specification describes a reason to exclude the relevant [element],” and such a reason could be found in statements in the specification expressly listing the disadvantages of using that element. Another reason to exclude could be that the specification “distinguishes among” the element and alternatives to it.[4]

The Federal Circuit held that the common denominator in these examples is the disclosure of the element, and while a negative limitation need not be recited in the specification in haec verba, “there generally must be something in the specification that conveys to a skilled artisan that the inventor intended the exclusion, such as a discussion of disadvantages or alternatives.”[5]

The Federal Circuit noted that silence is generally not a disclosure but may satisfy the written description requirement if a skilled artisan would understand the specification as inherently disclosing the negative limitation, for example, if a skilled artisan would recognize that the absence of mention of a limitation necessarily excluded that limitation.[6] The Federal Circuit further noted that testimony from a skilled artisan as to possibilities or probabilities that the element would be excluded is not enough and that the patent owner needs to establish that the limitation would always be understood by a skilled artisan as being necessarily excluded if that limitation not mentioned.[7]

The Federal Circuit went on to specifically point out that they are not creating a heightened standard for negative claim limitations, but simply noting that as with positive limitations, disclosure is essential, and such 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.”[8]

A major takeaway from the Novartis decision is that, unless patent practitioners can establish that a skilled artisan would always understand such limitation to be necessarily excluded, a specific disclosure of negative limitations in some form, such as disadvantages of using an element or as alternatives, should be considered.

[1] Novartis Pharmaceuticals v. Accord Healthcare Inc., No. 2021-1070 (Fed. Cir. June 21, 2022).
[2] Id. at page 7, 8.
[3] Id. at page 10.
[4] Id. at page 5, first quoting Santarus, Inc. v. Par Pharm., Inc., 694 F.3d 1344, 1351 (Fed. Cir. 2012) and then quoting Inphi Corp. v. Netlist, Inc., 805 F.3d 1350, 1357 (Fed. Cir. 2015).
[5] Id. at page 5.
[6] Id. at page 6.
[7] Id. at page 7.
[8] Id. at page 12.