When Will They Ever Learn? Subject Matter Disclosed in the Patent Specification But Never Claimed is Dedicated to the Public

Decision: Eagle Pharmaceuticals, Inc. v. Slayback Pharma LLC, Civil Action No. 18–1953–CFC (D. Del. May 9, 2019)

Holding: At the pleading stage, Judge Connolly in the District of Delaware granted Slayback Pharma’s (“Slayback”) motion for judgment of noninfringement of Eagle Pharmaceutical’s (“Eagle”) claims covering its biologic product BALRAPZO® by Slayback’s biosimilar. 

Background: Eagle sued Slayback alleging infringement under the doctrine of equivalents (“DOE”) of four patents: U.S. Patent Nos. 9,265,831 (“the ’831 patent”), 9,572,796 (“the ’796 patent”), 9,572,797 (“the ’797 patent”), and 10,010,533 (“the ’533 patent”). Slayback submitted New Drug Applications (“NDAs”) to the FDA to manufacture and sell a bendamustine drug bioequivalent to BALRAPZO® prior to the expiration of Eagle’s patents.

All four patents possess the same written description and similar claim limitations. Claim 1 of the ’796 patent is representative and reads:

1. A non-aqueous liquid composition comprising:

a. bendamustine, or a pharmaceutically acceptable salt thereof;

b. a pharmaceutically acceptable fluid comprising a mixture of polyethylene glycol and propylene glycol, wherein the ratio of polyethylene glycol to propylene glycol in the pharmaceutically acceptable fluid is from about 95:5 to about 50:50; and

c. a stabilizing amount of an antioxidant;

d.wherein the composition has less than about 5% total impurities after 15 months of storage at about 5° C…

In Slayback’s proposed bendamustine drug, the “pharmaceutically acceptable fluid” contains the same polyethylene glycol recited in claim 1 but utilizes ethanol as an alternative to the recited propylene glycol. Slayback argued that Eagle is barred from asserting infringement under the doctrine of equivalents in view of the disclosure-dedication doctrine because the written description discloses, but does not claim, ethanol as an alternative to polyethylene glycol:

In other aspects of the invention, the bendamustine-containing compositions include a) a pharmaceutically acceptable fluid which contains one or more of propylene glycol, ethanol, polyethylene glycol, benzyl alcohol and glycofurol . . .

’796 patent specification at col. 1, l. 60-64.

Eagle argued that, like claim construction, questions over the proper interpretation of a patent’s intrinsic record are not purely legal and are therefore prohibited at the Rule 12(c) stage. The court rejected this argument, holding that “the disclosure-dedication doctrine is a legal question appropriate for resolution at the Rule 12(c) stage of the proceedings.” Eagle, at *5:

The parties have not identified a claim construction dispute, and the written description of the asserted patents unambiguously and repeatedly identifies ethanol as an alternative to propylene glycol … Eagle attempts to manufacture a factual dispute concerning a POSITA’s [person of ordinary skill in the art] understanding of the disclosures in the written description of the asserted patents by relying on an expert.

Id. at *4–*5.

Eagle further argued that “a POSITA would understand from the written description of the asserted patents that ethanol can only be an alternative to propylene glycol in embodiments that include a stabilizing amount of a chloride salt and not embodiments that require, as the claims do, a stabilizing amount of an antioxidant.” Id. at *5. The court rejected this argument as well, explaining that the disclosure-dedication doctrine applies to unclaimed subject matter identified by the patentee as an alternative to a claim limitation, and not to the exact formulation of an alternative embodiment.

The court noted that Eagle’s argument ignored the Federal Circuit’s en banc decision on the disclosure-dedication doctrine found in Johnson & Johnston Assocs., Inc. v. R.E. Serv. Co., 285 F.3d 1046 (Fed. Cir. 2002), wherein the Federal Circuit overruled previous caselaw purporting to limit the disclosure-dedication doctrine to unclaimed alternative embodiments distinct from the invention. Id. at 1052. The district court in Eagle understood Johnson & Johnston to hold that “the disclosure-dedication doctrine is not restricted to disclosures of embodiments,” rather it “applies to claim limitations.” Eagle, at *7. Applying the doctrine, the district court found it would have been clear to a POSITA that the asserted patents disclosed ethanol as an alternative to propylene glycol:

In this case, the solvent limitation is the claim limitation at issue, and the written description of the asserted patents repeatedly identify ethanol as an alternative to one of the two solvents recited in that limitation.

Id. at *5–*6.

Consequently, Eagle was barred by the disclosure-dedication doctrine from alleging that Slayback’s bendamustine drug product infringed its asserted claims under the doctrine of equivalents.

Practical Takeaways:

This case highlights that, if history is not studied, or if precedential case law is not considered, the mistakes of history can and often will be repeated. As described above, en banc Federal Circuit authority establishes that disclosure-dedication can result from claiming more narrowly than the specification disclosure.

One objective in claim drafting is to capture a competitor under direct infringement, either through literal infringement or the doctrine of equivalents. It is true that it can be difficult to meet the burdens of 35 U.S.C. § 112 while ensuring your claims are broad enough to encompass the inventions of others. But that appears not to have been the case in Eagle, despite Eagle’s creative arguments that ethanol was not an alternative in the claimed formulation.

Here, Eagle disclosed multiple different solvents and embodiments in its patent specifications, then failed to include these alternatives in the scope of the granted claims. Thus, consistent with Johnson & Johnston, Eagle’s patent claims were caught by the disclosure-dedication doctrine.

To try and avoid this situation, patent drafters/prosecutors have at least two options: disclose less or claim more.

Disclosing less, especially if there is no intention to claim the alternatives in question may be easy. However, if the patent drafter chooses to disclose the alternatives in question, he/she should claim them. Presumably, Eagle could have avoided disclosure-dedication by drafting broad independent claims and incorporating all disclosed alternatives in more narrow dependent claims, e.g., ethanol in a dependent claim. As noted above, this option is only viable subject to whether the written description and enablement requirements of § 112 are satisfied. Possibly, the PTO could have rejected the claims as lacking § 112 written description “possession” support, but the fact that ethanol was presented in a claim, even if not accepted by the PTO, may well have avoided the disclosure-dedication doctrine. Of course, that situation may have raised the issue, beyond the scope of this article, of whether the doctrine of equivalents can apply if the patentee unsuccessfully tried to amend the claims to include ethanol. 

Drafters should consider first determining the desired claim scope and then making every effort to make sure all disclosed alternatives in the specification would literally infringe. If not, it may be time to weigh the benefits of extended claim scope vs. the risks of a more limited disclosure.