Bendamustine - USA

On May 08 2020, Federal Circuit affirmed district court’s judgment on pleadings that Slayback's NDA does not infringe Eagle’s patents under Doctrine of Equivalents (DOE).

Eagle is the holder of NDA for BALRAPZO® (bendamustine) that was approved by FDA to treat patients with chronic lymphocytic leukemia and indolent B-cell non-Hodgkin lymphoma. Eagle sued Slayback Pharma alleging infringement under the doctrine of equivalents of four patents: U.S. Patent Nos. 9,265,831, 9,572,796, 9,572,797 and 10,010,533 (all expiring on 01/28/2031). Eagle initiated lawsuit in response to Slayback's submission of NDA No. 212209 for approval to manufacture and sell before the four asserted patents expire. Eagle’s four asserted patents share essentially the same written description and all independent claims recite essentially the same limitations.

Claim 1 of U.S. Patent No. 9,572,796 is representative.

1. A non-aqueous liquid composition comprising: bendamustine, or a pharmaceutically acceptable salt thereof; 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 a stabilizing amount of an antioxidant…….;

Slayback conceded that its product literally infringes all claim limitations except for the “pharmaceutically acceptable fluid” limitation. Eagle asserted that Slayback’s product infringes the “pharmaceutically acceptable fluid” limitation under the doctrine of equivalents. Specifically, Eagle asserted that the “ethanol” in Slayback’s product is insubstantially different from the propylene glycol (“PG”) in the claimed composition. On January 4, 2019, Slayback moved for a judgment of non-infringement on the pleadings under Federal Rule of Civil Procedure 12(c). Slayback argued that the disclosure-dedication doctrine barred Eagle’s claim of infringement under the doctrine of equivalents because the asserted patents disclose, but do not claim, ethanol as an alternative solvent to PG. On May 9, 2019, the district court granted Slayback’s motion for judgment of non-infringement on the pleadings. You can read the summary “reported here” on this blog.

Eagle appealed.

During appeal, Eagle argued that the district court committed two errors. First, Eagle contended that the district court erred when it concluded that the asserted patents disclose, but do not claim, ethanol—and therefore dedicated ethanol to the public. Second, Eagle contended that the district court improperly applied the dedication-disclosure doctrine at the pleadings stage, in the presence of factual disputes and without drawing all inferences in Eagle’s favor.

With respect to first point, Eagle contended that the asserted patents disclose three distinct “categories” of bendamustine formulations: (i) chloride salt formulations; (ii) antioxidant formulations; and (iii) dimethyl sulfoxide (“DMSO”) formulations. Skilled artisan would recognize that the three separate categories “have separate ingredients and work in different ways.” Eagle asserted that the specification only discloses ethanol as an alternative to PG when discussing the unclaimed chloride salt formulations; it never discloses ethanol as an alternative to PG when discussing the claimed antioxidant formulations. Federal Circuit said that the disclosure-dedication doctrine does not require the specification to disclose the allegedly dedicated subject matter in an embodiment that exactly matches the claimed embodiment. Instead, the disclosure dedication doctrine requires only that the specification disclose the unclaimed matter “as an alternative to the relevant claim limitation.” [Pfizer, Inc. v. Teva Pharm. USA, Inc., 429 F.3d 1364, 1378 (Fed. Cir. 2005)]. The  asserted patents disclose ethanol as an alternative to PG in the “pharmaceutically acceptable fluid” claim limitation. The specification repeatedly identifies—without qualification—ethanol as an alternative pharmaceutically acceptable fluid. This is sufficient for the disclosure dedication doctrine here & thus ethanol is dedicated to public.

With respect to second point, Eagle argued that at the time the district court entered judgment of non-infringement on the pleadings, a factual dispute existed. District court erred by improperly ignoring Dr. Amiji’s declaration & resolving the factual dispute at the pleadings stage without drawing all reasonable inferences in Eagle’s favor. Specifically, Eagle argued that the district court was required to infer that a “skilled artisan would not have understood that ethanol was an alternative to PG in the claimed ‘PEG/PG/Antioxidant’ category of formulations.” Federal Circuit said that when ruling on a Rule 12(c) motion, district courts have discretion to consider evidence outside the complaint for purposes of deciding whether to accept that evidence and convert the motion into one for summary judgment. And district court here did not abuse its discretion when it set aside Dr. Amiji’s declaration. The district court reviewed Dr. Amiji’s declaration and determined that it was merely an “attempt to manufacture a factual dispute.” Moreover, patents themselves provided “sufficient context to decide” the legal issue at hand & therefore, there was no need to refer to the declaration. Only reasonable inference that can be made from the patent disclosures is that a skilled artisan would understand the patents to disclose ethanol as an alternative to the claimed PG. As a result, even when viewing the pleadings in the lightmost favorable to Eagle, there is no material issue of fact to resolve and Slayback is entitled to judgment in its favor as a matter of law.