By Lisa Seachrist

Washington Editor

WASHINGTON — The Supreme Court has decided on a patent law case that delineates the bounds of patent protections. And the unanimous decision has wide-ranging implications for the biotechnology industry.

The decision, which remanded a $3.5 million patent infringement case between two food dye manufacturers back to the U.S. Court of Appeals, reaffirmed the "Doctrine of Equivalents" — a premise in patent law that a product or process can infringe upon an existing patent if it differs in an insubstantial way from the literal claims written into the patent.

"The doctrine of equivalents is vital to the biotechnology industry," said Richard Burgoon, senior director and patent counsel for Cephalon Inc., of West Chester, Pa. "With technology like biotechnology, the limitations of words would work as an injustice against a patentee if an infringer knew that he could avoid infringement by making minor changes to the words in the patent claim. The doctrine protects the full rights of the patentee."

In upholding the doctrine, the court held that the tests for infringement aren't subject to rigid formula, that a patentee can't be expected to anticipate changes in technology that result in insubstantial alterations to their inventions, and that the intent of the accused infringer is irrelevant in determining patent infringement.

The court agreed to weigh the importance of the doctrine of equivalents when it heard a patent dispute between Hilton-Davis Chemical Co., of Cincinnati, and Warner-Jenkinson Co., of St. Louis. Hilton Davis sued Warner-Jenkinson over a dye separation process.

Both companies use ultrafiltration to separate impurities from dyes that they produce. In 1985, Hilton Davis patented its process which stipulates a pH between 6.0 and 9.0. A year later, citing the doctrine of equivalents, the company sued Warner-Jenkinson for patent infringement even though that process uses a pH of 5.

Both the Federal Court and the U.S. Circuit Court of Appeals ruled in favor of Hilton Davis. Warner-Jenkinson appealed to the U.S. Supreme Court requesting that the Court find the doctrine inconsistent with a 1952 revision of the Patent Act claiming the doctrine resulted in inventors having overly broad rights.

Writing the court's opinion, Justice Clarence Thomas noted that Warner-Jenkinson "invites us to speak to the death of [the doctrine of equivalents]. We decline that invitation."

Instead, the court emphasized the importance of the doctrine and maintained that the criteria for establishing equivalents was not a strict formula, but needed to be considered in light of the changing face of inventions.

"This is a very important point because the traditional tests for equivalents is easily applied to simple mechanical inventions," Burgoon said. "But, they are not as readily applied to biotechnology inventions."

The Biotechnology Industry Organization in its amicus * friend of the court * brief illustrated the problems with a literal interpretation of patent claims and the unique issues found in biotechnology. That brief highlighted the fact that there is redundancy in the genetic code: several three-base codons can code for the same amino acid. As a result, a literal interpretation of a patent claim would require that inventors list all possible sequences that could produce a single protein in order to protect claims to that protein.

"As a practical matter, the Patent and Trademark Office doesn't want to see patents that include all 50,000 sequences that code for that single protein," Burgoon said. "I think this example made an impression with the court. A couple of justices mentioned it during oral arguments in October."

In addition, the court held that proper time for evaluating equivalents is at the time of infringement, not at the time the patent is issued. In other words, technological advancements that change the way you make a product but don't substantially change the product itself can still infringe upon an existing patent.

As an example, Burgoon pointed to a hypothetical patent on a mouse monoclonal antibody to a particular antigen. Originally, that antibody was produced by inoculating and bleeding mice. Technological advancements now allow scientists to produce chimeric human-mouse monoclonal antibodies. In those chimeric antibodies, however, the mouse component recognizes the antigen. As a result, Burgoon noted the chimeric monoclonal may infringe upon the original patent.

"Technology is advancing so dramatically in biotechnology that you really can have situations where something developed at a later time may infringe upon your patent," Burgoon said.

In its oral and written arguments to the court, Warner-Jenkinson maintained that an infringer's intent should be weighed when determining if infringement has occurred. The court ruled instead that intent is irrelevant to that determination.

"Companies routinely try to design around existing patents," Burgoon said. "If they get too close they've infringed and intent plays no role. Intent necessarily plays a role in determining whether a company is assessed punitive damages."

While the court reaffirmed the doctrine of equivalents, the case is far from over for the litigants. The case goes back to the U.S. Court of Appeals to determine if the doctrine of equivalents holds for this patent. That court must decide why the lower limit of pH was set at 6.0. Hilton Davis maintains it was the decision of the patent office because the company had experienced technical difficulties at lower pH. However, if the Warner-Jenkinson can establish that the low pH was part of the prior art or common practice as was the case with pH higher than 9.0, the court would rule that there was no patent infringement. *