In Eagle Pharms., Inc. v. Slayback Pharma LLC, 2022 U.S. Dist. LEXIS 193941 (D. Del. Oct. 25, 2022), the District of Delaware held that Plaintiff failed to meet its burden to establish infringement by Defendants’ New Drug Application (NDA) filings. Id. at *20.


Eagle is the owner of NDA Nos. 205580 and 208194, pursuant to which it sells two liquid bendamustine-containing compositions: BELRAPZO® and BENDEKA®. Eagle is the assignee of the asserted patent, U.S. Patent No. 11,103,483 (“the ’483 patent”), which is listed in connection with BELRAPZO® in the FDA’s Orange Book.

Defendants Slayback and Apotex both applied for approval of NDAs to market a generic version of BELRAPZO® and notified Eagle pursuant to 21 C.F.R. § 314.52(c)(2). The FDA tentatively approved Defendants’ NDAs. Eagle sued the Defendants under the Hatch-Waxman Act 35 U.S.C. § 271(e)(2)(A), alleging that the Defendants’ NDA submissions constituted infringement of claims 2 and 4 of the 4‘83 patent. Defendants argued that their proposed products did not infringe the ’483 patent and alleged that the ’483 patent was invalid.

District Court

The asserted composition claims (claims 2 and 4) of the ’483 patent teach a “ready to use liquid bendamustine‑containing composition” for use in treating certain cancers. The parties did not dispute that Defendants’ products practiced every limitation of the asserted claims except for the “ready to use” limitation. Id. at *7. Thus, at trial, “[t]he only disputed infringement issue was whether Defendants’ proposed products [were] ‘ready to use.’” Id. at *3. “The parties stipulated that ‘ready to use’ means ‘able to be dispensed with minimal if any effort or preparation; prepackaged.’” Id.

The court found that the Defendants’ proposed products were not “ready to use” under the parties’ stipulated construction of the term. First, the court noted that the experts agreed that “the dispensing of a liquid concentrate bendamustine drug consists of the safe and effective preparation and provision of the drug in accordance with the applicable prescription to a healthcare provider for administration to the patient.” Id. at *10. Bendamustine is “highly toxic” and could harm (1) the drug’s dispenser if any unprotected physical contact with the drug occurs, and (2) the cancer patient if there is “even the slightest error in dosage amount or quality.” Id. at *10–12. Accordingly, the court found that dispensing a liquid concentrate form of bendamustine involves at least thirteen steps. Id. at *12–13.

Second, emphasizing the credibility and “compelling testimony” of the Defendants’ expert, the court found “as a matter of fact, that none of the undisputed steps in the dispensing process require[d] minimal effort or preparation.” Id. at *14. As Defendants’ expert testified, each step, “if done incorrectly, can cause harm to the patient because of the small difference between an effective and a lethal dose.” Id. The court also found, “based on [the Defendants’ expert]’s testimony, that the aggregate of the undisputed dispensing steps involves more than minimal effort and preparation.” Id.

Moreover, the court agreed with the Defendants’ expert that Plaintiff’s expert’s “characterization of the dispensing process [was] a ‘gross simplification of a very complex and serious process.’” Id. (quoting Tr. at 258:9-10). Again, credibility mattered. The court emphasized that Plaintiff’s expert did “not have experience in dispensing bendamustine drugs” whereas Defendants’ expert had “dispensed BENDEKA® hundreds of times.” Id. at *7–8, 14.

In line with Defendants’ expert’s testimony, the court also found that “the dosing steps required for Defendants’ proposed products are part of the dispensing process” because the products are packaged in multi‑dose vials and the dose amount varies for each patient. Id. at *15–16. Furthermore, based on an admission by Plaintiff’s expert, the court found that the Defendants’ products are not “prepackaged” as would be required to meet the “ready to use” limitation. Id. at *16–17.

Lastly, the court found that Defendants’ use of the phrase “ready to use” in FDA filings—including their NDAs—did not establish that the proposed products could be dispensed with minimal if any effort or preparation as required by the asserted claims. Id. at *17. Although Defendants used that phrase, “[n]one of th[e] documents . . . provide[d] a definition of ‘ready to use’ or shed sufficient light on the meaning of the term such that it could be dispensed with minimal if any effort or preparation.” Id.

Eagle failed to establish by a preponderance of the evidence that Defendants’ proposed products can be dispensed with only minimal if any effort or preparation and therefore met the only limitation at issue, “ready to use.” Therefore, Eagle failed to establish that Defendants’ filing of their NDAs constituted infringement of the asserted claims. Id. at *20.

Practical Takeaways

A patent drafter would do well to understand and set forth just what a phrase like “ready-to-use” means. Here, the court found that the phrase meant requiring only minimal effort or preparation. Defendant’s expert established that more than minimal effort or preparation was required to avoid harm to both the dispenser and the patient. Were it possible, the claims would have done well to avoid the phrase.

Judges may rely heavily on extrinsic evidence—including expert testimony—in determining whether an accused/proposed product infringes asserted claims. During trial and in his findings of fact, Judge Connolly lauded the Defendants’ expert witness for his credibility and preparedness, stating, “I’ve had more than a dozen trials in the past year. And I think he was one of the most credible witnesses I’ve had testify. He was very measured. He was direct in his answer to all the questions. I [also] found his testimony to be inherently consistent.” Id. at *8. Judge Connolly additionally noted the heightened credibility afforded to Defendants’ expert given his significant experience dispensing the drug at issue, whereas Plaintiff’s expert had no experience with the drug. It was not surprising then, that Judge Connolly expressly based many of his findings of fact on Defendants’ expert’s testimony. E.g.¸id. at *14 (“I also find, based on Dr. Brandt’s testimony, . . . .”); id. (“Dr. Brandt testified, and I agree, that . . . .”).

Thus, a litigant should try to enhance the ethos of their testifying expert witness by retaining a person that is not only a person of ordinary skill in the art, but a person with actual experience, particularly where an error in administration of a drug could harm a patient. Likewise, a litigant should take utmost care in preparing their testifying expert witness for trial.

One final note, the seeming inconsistency between Defendants’ FDA filings about “ready-to-use” and its position in litigation, although it did not hurt the Defendants in this case, reminds patent practitioners that coordinating with regulatory attorneys early and often can help minimize potential issues.