Bloomberg Law
March 8, 2023, 10:10 AM

Invoking Yogi Berra, Gilead Ruling Requires Clear Patent Steps

Kelcee Griffis
Kelcee Griffis

Gilead Sciences Inc.'s high-profile Federal Circuit win reinforces the need for drug companies to clearly connect their years of research and development to a later patent if they wish to ensure the backward reach of their invention’s IP protections.

A three-judge panel on March 6 ruled that the University of Minnesota didn’t lay out all the choices it made between broad provisional patent applications and its narrower, later-granted patent for a Hepatitis C treatment. That meant a patent application introduced by Gilead in the interim could invalidate the university’s patent.

Patent owners must not apply former New York Yankees catcher Yogi Berra’s advice that “when one comes to a fork in the road, take it” to IP practice, Judge Alan D. Lourie wrote in the precedential opinion, saying that patent claims can’t spell out a number of “optional choices” if owners want them to withstand scrutiny.

According to Michelman & Robinson LLP partner Ashley Moore, the decision should recommend a poet’s strategy instead: Robert Frost’s “Two roads diverged in a wood, and I—I took the one less traveled by.” Patents must clearly disclose which path the inventors selected and how they arrived at the claimed invention, she said.

“Just like Yogi Berra, they didn’t tell you which is the right one,” she said of UM’s tossed application. “They didn’t choose.”

If appealed to the US Supreme Court, the case could offer another opportunity for the justices to weigh patent-law specifics in the pharmaceutical realm. The high court is slated to hear a dispute this month between Amgen Inc. and Sanofi Inc. that explores another aspect of how a valid patent must be written.

Missing Blaze Marks

The Gilead decision turned on whether UM should have been able to backdate its work by years based on some of the school’s related patent applications going back to 2004. The patent applications first captured a broad genus of compounds and were later narrowed to cover a subgenus that included Gilead’s drug compound.

Once the Patent Trial and Appeal Board examined the validity of UM’s later-granted US Patent No. 8,815,830, it found there was no clear nexus to connect UM’s earlier patent applications to the ‘830 patent.

That rendered the ‘830 patent invalid in light of Gilead’s Hepatitis C treatment, which it documented in a patent application that predated UM’s finalized application leading to the ‘830 patent, according to the US Court of Appeals for the Federal Circuit decision.

To extend a patent’s reach backward in time, the owner must typically show a pattern of “blaze marks,” similar to tagged trees along a forest trail, that draw a straight line between a provisional patent application and the finalized version. If the applications fail to claim the same thing, as the PTAB and Federal Circuit ultimately agreed UM’s did, the invention’s effectiveness date can only be pegged to the later application.

“They didn’t really provide that trail from this very large genus that they initially disclosed” to the later filed and granted patent, said Chris Holman, a University of Missouri-Kansas City law professor who studies intellectual property and biotechnology.

The Federal Circuit decision can be seen as “reassuring for innovators like Gilead,” he said, because it indicates the courts are “basically policing and preventing someone like the University of Minnesota from filing a really broad disclosure early on and then narrowing it down” to cover a competing invention.

Breaking the Chain

The decision in favor of Gilead could have another effect: sending other drug companies into research mode. It might spur drug makers to examine their competitors’ patent applications and try to knock years off of those patents’ priority dates, Shashank Upadhye, an attorney specializing in drug development at Upadhye Tang LLP, wrote in an email.

“Many pharma companies have later issued patents that do chain back to many earlier applications. Though it may be tedious to do, patent challengers may follow Gilead’s example and compare the written descriptions in each preceding application to see if the chain can be broken and intervening prior art can apply,” he said.

Patent practitioners can guard against this scenario by being specific and outlining as much as is known about a discovery in their earliest applications, “to provide so-called blaze marks for later description support,” Upadhye said.

High Court Nexus

The Gilead case touches on hot-button issues of patent validity—specifically, a patent’s written description—that parallel questions the Supreme Court is set to mull later this month.

Section 112(a) of the Patent Act requires that patent claims “must set forth the subject matter that an inventor or a joint inventor regards as the invention.” From there, more specific provisions call for a “a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable” a person skilled in the art to make and use the invention.

Upadhye likened the written description to a dossier on a chocolate chip cookie that outlines its size, how it tastes, and how many chips you can expect per cookie. In this scenario, the cookie is then enabled by its recipe, which tells a baker how to create the described treat.

The Federal Circuit typically treats this language as two separate questions—a written description requirement, and an enablement standard—but some attorneys say the court has gone too far in distinguishing the two.

Amgen Inc. and Sanofi will argue at the Supreme Court on March 27 over whether drug patents have to specify all potential antibodies that could have the same effect or only spell out some of them to protect the entire category.

The justices’ decision to hear the case over canceled patents for Amgen’s Repatha cholesterol drug delves into the enablement standard but skirts the written description requirement, said Robin Feldman, director of the Center for Innovation at the University of California College of the Law, San Francisco. That could make the Gilead case another attractive target for the justices to consider, she wrote in an email.

In taking up Amgen-Sanofi while turning down other cases, “the justices carefully avoided the issue of written description. At some point, I would suspect, they will turn to it,” Feldman said.

The university and its counsel didn’t immediately respond to requests for comment. Gilead’s counsel declined to comment, and its representatives couldn’t be immediately reached.

The case is Regents of the University of Minnesota v. Gilead Sciences, Fed. Cir., No. 21-02168, affirmed 3/6/23.

To contact the reporter on this story: Kelcee Griffis in Washington at

To contact the editors responsible for this story: Adam M. Taylor at; Jay-Anne B. Casuga at