Unrivaled 2025: David Berl of Williams & Connolly

You successfully represented Regeneron Pharmaceuticals Inc. in Regeneron Pharmaceuticals Inc. v. Mylan Pharmaceuticals, Inc., in which the US District Court for the Northern District of West Virginia ruled in 2023 that a key patent covering diabetic retinopathy drug Eylea was valid and infringed. Can you tell us about your trial strategy?

The Eylea patent infringement case arose under a relatively new statute directed to resolving patent disputes regarding biosimilar products, the Biologics Price Competition and Innovation Act (BPCIA). Innovator companies have had limited success in BPCIA litigation. Accordingly, we devised a novel strategy involving narrowing the case early and accelerating the case schedule substantially to facilitate an early trial.

The accelerated timeline required deviation from the usual rules and strategies, focusing the case on the particular issues that were most likely to be tried rather than keeping all options open to maximize flexibility throughout the litigation. The strategy paid off at trial. We seized on the inconsistencies in Mylan’s case, advanced through multiple experts whose testimony was contradictory. By contrast, our witnesses were able to explain in a simple way that cohered with our narrowly focused strategy, why Regeneron’s invention was transformative, counter-intuitive, and ultimately advantageous for patients.

We did not shy away from the technical details—no matter how complex—that were important to understand the invention and Mylan’s infringement of it. Rather, we explained the details in an engaging manner that cohered with our themes, while making both interesting and comprehensible to a lay audience. Through our use of demonstratives and witness testimony, the court comprehended the crucial scientific issues. Had we avoided those issues out of concern for their complexity, the infringement and validity cases would have fallen flat, as the court would not have appreciated the true workings and value of Regeneron’s invention.

Can you describe a major hurdle that happened during the course of Regeneron. How did you overcome it?

The most important pre-trial ruling—the court’s decision interpreting the patent claims—was adverse to our client Regeneron in every respect. Our team did not hang its head, despite the disappointment; it was, in the Bill Belichick formulation I often repeat to my teams following a setback, “On to Cincinnati,” the next stage in the battle.

Thankfully, we had planned for every contingency, advancing alternative arguments under Mylan’s interpretation of the claims that were both forceful and consistent with our primary arguments. Our opponents had not done so, and the court’s decision—which they had urged—left Mylan and its experts flat-footed. We therefore turned the loss into an opportunity to develop new arguments that Mylan had not foreseen.

We looked forward to trial, which the adverse claim construction decision made more complex and challenging. Again, through creativity, a refusal to “dumb-down” the case, and the use of engaging demonstratives and analogies to more familiar concepts, we proved infringement even under an interpretation of our claims that we had disputed fiercely. Overcoming the adversity of a major, adverse pre-trial ruling enhanced the value of our ultimate trial victory. Per Thomas Paine, “what we obtain too cheap, we esteem too lightly.”

When did you first know you wanted to be a trial lawyer? What clicked for you?

From my early years, I have been addicted to competition. Whether it was getting out of bed quickly, winning a ping-pong game, or excelling academically, I competed constantly, against myself and others. A life without competition was as boring as it was unthinkable; I knew I needed a life of constant competition and adrenaline. Pure wins and losses are elusive in most careers, as shades of gray dominate. And unfortunately, the gene pool did not facilitate a career in competitive athletics. So, I gravitated to trial law—sports for unathletic people. Trials, with declared winners and losers, and innumerable strategic maneuvers that lead to those wins and losses, is the closest I’ll ever get to winning a Super Bowl. I cannot imagine doing anything else.

What are the major keys to winning over a jury or a judge?

Every case, no matter how complex, allows for a story. The judge or jury chooses whom it wants to win, not who should win. A patent is not a piece of paper—it can and should be brought to life, in a way a lay judge or jury can appreciate and admire. Showing that the patent is an invention in search of a patent, rather than a patent in search of an invention, makes all the difference. And don’t be afraid to take prudent, calculated risks—trials require wins, not avoided losses.

What is the best advice you give young trial lawyers?

“Take appropriate risks, even if they don’t always work out. Don’t confuse bad results with bad decisions, and don’t confuse good results with good decisions.”