Richards Layton & Finger
 

Judge Sleet Holds Patent Not Invalid for Obviousness

March 7, 2017

Following a bench trial in AstraZenca AB v. Aurobindo Pharma Ltd., C.A. No. 14-664-GMS (D. Del. Feb. 2, 2017), Judge Sleet determined that the asserted claims of the patent-in-suit were not invalid for obviousness under 35 U.S.C. § 103. In light of the trial testimony, Defendant Aurobindo Pharma Ltd. (“Aurobindo”) argued that the asserted claims were obvious because a person of ordinary skill in the art (of medicinal chemistry) would have been motivated to select vildagliptin as a lead compound, move the hydroxyadmantyl group, and add a cyclopropyl ring. As to the argument that a person of ordinary skill in the art would have selected vildagliptin as a lead compound, Aurobindo pointed to vildagliptin’s “good potency, . . . favorable class history, and efficacy in biological data” as evidence that the compound was an obvious choice for lead compound. Nonetheless, plaintiff AstraZeneca AB (“AstraZeneca”) countered that in light of two more advanced compounds that had already entered the clinic, it was only with the use of hindsight that Aurobindo argued a person of ordinary skill in the art would have selected vildagliptin as a lead compound. The Court agreed with AstraZeneca, challenging Aurobindo’s expert’s narrow focus on potency. Furthermore, the Court held that Aurobindo’s expert failed to show a motivation for a person of ordinary skill in the art to move the hydroxyadmantyl group.

Aurobindo additionally argued that a person of ordinary skill in the art “would have expected to counteract the potential loss of stability that results from modifying vildagliptin to improve potency by creating a primary amine.” Although Aurobindo pointed to the addition of a cyclopropyl ring as the simplest modification to address the stability problem, the Court described this analysis as flawed. Specifically, if there was no reason to make the first modification of moving the hydroxyadmantyl group, then there was no obvious reason to make the second modification of adding a cyclopropyl ring. Accordingly, the Court concluded that the asserted claims of the patent-at-issue were not obvious. Finally, Judge Sleet denied AstraZeneca’s motion for attorneys’ fees, noting that the case did not qualify as exceptional.

Key Points:  This decision is a good example of the importance of expert testimony in ANDA cases. Judge Sleet recognized that the results of most ANDA cases hinge on the credibility of expert witnesses rather than a “substantively weak litigation position.”