Court’s Drug Patent Prescription: Unclaimed Disclosure is Dedicated

By on May 19, 2020
Posted In Patents

Addressing the disclosure-dedication doctrine, the US Court of Appeals for the Federal Circuit concluded that the disclosure-dedication doctrine barred a patent owner’s claim of infringement under the doctrine of equivalents because the asserted patents disclose, but do not claim, the alleged equivalent. Eagle Pharmaceuticals Inc. v. Slayback Pharma LLC, Case No. 19-1924 (Fed. Cir. May 8, 2020) (Reyna, J.).

Eagle owns patents that cover its brand-name bendamustine product, BELRAPZO®, which is used to treat chronic lymphocytic leukemia and indolent B-cell non-Hodgkin lymphoma. Slayback filed an Abbreviated New Drug Application (ANDA) to market generic versions of BELRAPZO®. Eagle sued Slayback for patent infringement. Eagle asserted that Slayback’s product infringes the “pharmaceutically acceptable solvent” claim limitation under the doctrine of equivalents because ethanol in Slayback’s product is insubstantially different from the propylene glycol in the claimed “pharmaceutically acceptable solvent” composition. Slayback moved for judgment on the pleadings, arguing that the disclosure-dedication doctrine barred Eagle’s claim of infringement because Eagle’s patents dedicated ethanol to the public by disclosing it in the specification, but not claiming it. Eagle opposed, relying on an expert declaration to explain that the patent specification discloses three different categories of formulations, and a skilled artisan would not view ethanol as an appropriate substitute for the claimed pharmaceutical formulation claim element.

The district court agreed with Slayback, finding that the patent specification expressly and repeatedly identifies ethanol as an alternative to the claimed propylene glycol mixture. The district declined to consider Eagle’s expert declaration, rejecting it as an “attempt to manufacture a factual dispute” and explaining that it had sufficient information to decide the disclosure-dedication issue as a matter of law. Eagle appealed.

The Federal Circuit affirmed, rejecting Eagle’s argument that the disclosure-dedication doctrine did not apply because the patent specification disclosed ethanol as a substitute for unclaimed chloride salt formulations, not for the claimed propylene glycol formulations. The Court explained that the doctrine does not require the patent specification to disclose the unclaimed matter “in an embodiment that exactly matched the claimed embodiment.” Rather, the specification here only disclosed the unclaimed matter “as an alternative to the relevant claim limitation,” not as an equivalent to it. More specifically, the specification disclosed ethanol as an alternative to the claimed propylene glycol “pharmaceutically acceptable fluid” mixture. The Court distinguished the instant case from its 2005 decision in Pfizer v. Teva, explaining that unlike in Pfizer, the unclaimed subject matter here, ethanol, serves the purpose of the claim limitation, which is to be “pharmaceutically acceptable.”

The Federal Circuit also rejected Eagle’s procedural challenge that a fact dispute precluded judgment on the pleadings. The Court explained that while the district court had discretion to consider evidence outside the complaint, it did not abuse its discretion in setting aside Eagle’s expert declaration. The Court noted that the disclosure-dedication doctrine is a question of law and that expert testimony is not always necessary for a district court to determine how one skilled in the art would understand a patent disclosure and claimed invention. Here, there was nothing in the record that compelled a different inference from that made by the district court, i.e., that ethanol was disclosed as an alternative to the claimed formulation, and therefore there was no material disputed fact issue to resolve.

Practice Note: Be mindful when disclosing unclaimed matter, and evaluate whether it serves the purpose of the claim limitation.

Bhanu K. Sadasivan, PhD
Bhanu K. Sadasivan, PhD, focuses her practice on patent litigation, with an emphasis in the life sciences industry. She has experience litigating patent cases concerning recombinant DNA technology, pharmaceutical formulation, computer hardware and software. Read Bhanu K. Sadasivan's full bio.