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For Amgen’s PCSK9 patent case, is there any read-through from Court’s summary judgment order to the trial?

Zachary Silbersher

On January 18, the District Court in Delaware issued an opinion resolving multiple summary judgment motions filed by both parties.  The key takeaway from that decision is that the case is now teed-up for trial beginning on February 19. But the Court didi highlight some key issues likely to be the focus of the trial.

We have summarized this case, and related issues in detail in prior posts (here, here and here.)  Briefly, in 2016, Amgen ($AMGN) prevailed at trial against Regeneron ($REGN) and Sanofi by showing that Praluent® infringed two of Amgen’s anti-PCSK9 antibody patents.  The Court entered an injunction against Praluent®, but the Federal Circuit reversed before that injunction went into effect.  (Amgen recently lost its bid to the Supreme Court to reverse that decision from the Federal Circuit.)  The case was remanded back to the Delaware Court to hold a new trial.   

During the first trial, Regeneron attempted to show that Amgen’s patents cannot possibly be valid since the exemplary antibodies disclosed in Amgen’s patents look nothing like Regeneron’s Praluent® protein.  But the Court barred Regeneron from showing its own protein to the jury to demonstrate this.  Rather, the Court essentially barred any “post-priority date” evidence, which is evidence after the priority date of Amgen’s patents.  The Federal Circuit held this was error, and for the past year, while the case has been on remand, the parties have been conducting discovery into that post-priority date evidence.

The case is currently scheduled to begin trial on February 19, 2019.  Before that, both parties moved for summary judgment.  Regeneron essentially tried to win the case without going to trial, whereas Amgen attempted to bar Regeneron from making certain arguments at trial.  Both tactics came up short, and that, therefore, clears the path for the trial to begin in late February.

Those summary judgment motions nevertheless give us a preview of what the key issues in dispute will be at the upcoming trial.  Regeneron moved for summary judgment that Amgen’s patents are invalid for lack of written description and/or enablement. 

 Recall, there are two patents asserted in the case, U.S. Patent Nos. 8,829,165 and 8,859,741.  Both patents purport to cover anti-PCSK9 antibodies.  Yet, the patents primarily describe the antibodies by their function, i.e., where they bind on the PCSK9 protein, rather than by their structure, i.e., an enumerated string of amino acids.

Likewise, Regeneron argued that the patents are necessarily invalid because the Federal Circuit’s decision in this case held that a patent covering an antibody cannot be claimed based upon its function alone.  The Delaware court disagreed, and found this was an outstanding question, better suited for trial.  In other words, given that the experts on both sides dispute the extent to which an antigen’s structure can necessarily dictate a corresponding antibody’s structure, the Court viewed this question cannot be resolved on summary judgment. 

Regeneron also argued the patents are invalid because they describe antibodies that look nothing like Regeneron’s protein.  Thus, Amgen’s patents, according to Regeneron, simply did not adequately describe—and thus, did not adequately invent—Regeneron’s Praluent® protein.  The Delaware court again held this issue better resolved at trial through cross-examination of the experts.  The key inquiry is whether the handful of exemplary antibody embodiments disclosed in Amgen’s patents are “representative” of the millions of potential antibodies actually covered by patents.  In other words, are the exemplary species representative of the claimed genus.

 Regeneron also argued that Amgen’s patents are not “enabled.”  This theory of invalidity rings similar to that of written description, but is technically different.  A patent is not sufficiently “enabled” if reproducing the invention would require extensive experimentation and repeated trial-and-error.  The thrust of Regeneron’s argument is that it would not be a simple matter of routine experimentation for a scientist to go from the exemplary antibodies disclosed in Amgen’s patents to the full-breadth of antibodies covered by the claims.  Yet, again, the Delaware court held the experts disagree on this question, thus making it better suited for resolution at trial. 

Importantly, the Court highlighted that the post-priority is feeding this dispute.  Apparently, since the case was remanded to the Delaware court after the Federal Circuit’s decision, Regeneron collected discovery showing that Amgen purportedly attempted to make more antibodies within the claimed genus of its own patents, but failed to do so.  On the other hand, Amgen disputes that it could not do so.

Either way, this is very interesting nugget that will likely be fleshed out at the trial.  Evidence regarding Amgen’s efforts to make more antibodies encompassed by its patents was not before the jury in the prior trial in 2016.  That is because the Delaware court, at that time, excluded that evidence.  The Federal Circuit’s October 2017 decision identified that exclusion as error, and one of the reasons the case was remanded.  This underscores how and why—armed with new evidence—Regeneron could theoretically prevail at trial on invalidity in the upcoming trial even through it was defeated on the same arguments three years earlier.   

Meanwhile, Amgen also moved for summary judgment.  Amgen argued that Regeneron should be barred from making certain arguments to the jury about whether a patented antibody satisfies the written description or enablement requirements.  The thrust of Amgen’s argument is that Regeneron and/or Sanofi have themselves applied for patents covering antibodies, and in the course of doing so, characterized the law on patenting antibodies in ways that are inconsistent with what they are now arguing. 

In short, Amgen’s strategy was to mine the defendants own patent-filings related to antibodies, and to expose statements made therein that contradict positions taken by the defendants in this litigation.  On its face, it is a clever strategy.  But because many of the patents are unrelated to this case, it is not very compelling, and the Delaware Court summarily dismissed it. 

Importantly, certain estoppel arguments such as those put forward by Amgen apply primarily to misstatements of facts, not of law.  The Court found many of the purported inconsistencies identified by Amgen to be statements regarding the law, not statements regarding facts.  More to the point, Amgen relied upon allegedly inconsistent statements in patents and patent applications unrelated to this case.  Thus, they did not expose inconsistent statements of fact relevant to this case.

Jury selection is scheduled to begin in Delaware on February 19, and at this point, it is unlikely that date will be continued.