by Dennis Crouch
In his 1967 Ruschig decision, Judge Rich applied a colorful woodsman metaphor to the written description requirement:
It is an old custom in the woods to mark trails by making blaze marks on the trees. It is no help in finding a trail or in finding one’s way through the woods where the trails have disappeared—or have not yet been made, which is more like the case here—to be confronted simply by a large number of unmarked trees. Appellants are pointing to trees. We are looking for blaze marks which single out particular trees. We see none.
In Biogen Int’l GMBH v. Mylan Pharma Inc. (Fed. Cir. November 30, 2021), the Federal Circuit has extended that metaphor and found Biogen’s patents invalid for lack of written description. In the case, Judge Keeley (N.D.W.Va.) held a bench trial and concluded that the asserted claims Biogen’s MS treatment-method patent invalid for lack of written description. On appeal, a divided Federal Circuit then affirmed, with Judge Reyna penning the majority opinion joined by Judge Hughes, and Judge O’Malley writing in dissent.
Biogen’s U.S. Patent 8,399,514 covers a method of treating multiple sclerosis using the drug dimethyl fumarate (DMF). The claimed method has one step: administering about 480 mg of DMF per day along with an excipient. Claim 1 is reprinted below:
1. A method of treating a subject in need of treatment for multiple sclerosis comprising orally administering to the subject in need thereof a pharmaceutical composition consisting essentially of (a) a therapeutically effective amount of dimethyl fumarate, monomethyl fumarate, or a combination thereof, and (b) one or more pharmaceutically acceptable excipients, wherein the therapeutically effective amount of dimethyl fumarate, monomethyl fumarate, or a combination thereof is about 480 mg per day.
The question in the case is whether the dosage requirement (~480 mg/day) was sufficiently disclosed in the original specification so that it can be specifically claimed. For this type of analysis, the courts look to the Written Description requirement as one way to ensure that a patent’s exclusive rights are commensurate with what was actually invented. The doctrine requires that the patent application show “possession of the invention” as judged from the perspective of a person of skill in the art considering the entire original specification, including “words, structures, figures, diagrams, formulas, etc.” Lockwood v. Am. Airlines, Inc., 107 F.3d 1565, 1572 (Fed. Cir. 1997). Originally filed claims are seen as part of the specification, and so most often it is sufficient to show that claim limitations were found in the original application. But see, Ariad Pharm., Inc. v. Eli Lilly & Co., 598 F.3d 1336 (Fed. Cir. 2010) (en banc) (original claims can still fail). Despite Ariad, we most often see the power of written description in situations where the claims have been amended to add some limitation that is not clearly expressed in the original specification.
Here, for prior art purposes, the patentee needs to claim priority back to its original provisional application filed back in 2007. That original application is focused on use of DMF for a variety of neurological conditions, including MS and did not include the ~480 mg/day limitation within any of the included claims.
The ~480 mg/day dosage is listed once in the original specification, describing an effective dose of DMF without particularly specifying that the dosage is for MS.
For example, an effective dose of DMF … can be from about 0.1 g to 1 g per pay, 200 mg to about 800 mg per day (e.g., from about 240 mg to about 720 mg per day; or from about 480 mg to about 720 mg per day; or about 720 mg per day). For example, the 720 mg per day may be administered in separate administrations of 2, 3, 4, or 6 equal doses.
On appeal, the majority classified the disclosure of 480 mg/day as a “sole reference . . appear[ing] at the end of one range among a series of ranges.” The court contrasted the 480 mg/day disclosure with the specification’s disclosure of 720 mg/day that was specifically identified and elsewhere in the patent shown to be effective. The inventor also provided testimony that those ranges in the specification could not be extrapolated to a clinical dose. Based upon all of this, the court affirmed that “a skilled artisan would not have recognized, based on the single passing reference to a DMF480 dose in the disclosure, that DMF480 would have been efficacious in the treatment of MS, particularly because the specification’s only reference to DMF480 was part of a wide DMF dosage range and not listed as an independent therapeutically efficacious dose.”
Biogen later established that the 480 mg/day was effective, but by then prior art was already available and so a new application would have been ineffective.
In a recent decision, the Federal Circuit ruled that written description failed for a claim covering a range of values since the specification only disclosed several points within the range. Indivior UK v. Dr. Reddy’s Labs (Fed. Cir. 2021). This case is a flip-side — the specification discloses a range, and the court rules that, without more, written description also fails for a claim directed to an endpoint of the disclosed range.
Writing in dissent, Judge O’Malley focused on a separate district court error that, she concludes, tainted its written description analysis. In particular, the district court applied the doctrine of judicial estoppel to bar the patentee from distinguishing from clinical efficacy (required for FDA approval) and therapeutic effect (as claimed in the patent). O’Malley concludes that the district court’s analysis erroneously focused on requiring a showing that 480 mg/day was clinically effective and that improperly resulted in invalidity.