vchal /
3 August 2017Americas

Enzo and Yale lose Federal Circuit DNA patent appeal

Enzo Biochem and Yale University (collectively Enzo) have lost their appeal in a dispute centring on one of their DNA detection and identification patents.

Yesterday, August 2, the US Court of Appeals for the Federal Circuit affirmed the US District Court for the District of Connecticut’s entry of summary judgment in favour of biotech companies Applera (Applied Biosystems).

According to the Federal Circuit, the lower court had accurately interpreted a previous Federal Circuit decision regarding the proper construction of the claims in US patent number 5,449,767 and had correctly analysed Enzo’s doctrine of equivalents argument.

The litigation has run over 13 years, with the Federal Circuit’s most recent decision being the third time it has considered the infringement action.

Patent ‘767 deals with the use of nucleotide probes to detect the presence of a particular DNA or RNA sequence in a sample or to identify an otherwise unknown DNA sequence.

Yale University is the original assignee of the patent, while Enzo is the exclusive licensee.

In 2004, Enzo sued Applera, alleging infringement of six patents, including the ‘767 patent. The patents covered various techniques and processes for detecting the presence of a particular strand of DNA or RNA in a sample.

In 2006, the district court construed the claims of all six patents and, after years of litigation and an appeal to the Federal Circuit regarding invalidity issues decided on summary judgment, Enzo and Applera went to trial in October 2012.

The Federal Circuit said that Enzo had limited its infringement contentions during the jury trial to claims 1, 8, 67, 68, and 70 of the ‘767 patent. The jury found Applera infringed the claims and awarded $48.6 million in damages to Enzo.

Applera appealed, arguing that the district court had erred in its claim construction because the claims of the ‘767 patent only cover indirect detection.

The Federal Circuit agreed with Applera in Enzo II, reversing the district court’s claim construction and concluding that “the inventors were claiming only indirect detection”.

On remand, Enzo moved for entry of judgment on the jury verdict, and Applera moved for summary judgment of non-infringement.

The district court sided with Applera. It found that the Federal Court’s decision in Enzo II covered all claims of the ‘767 patent, not just claim 1 as argued by Enzo, and rejected Enzo’s doctrine of equivalents argument relating to claims 1 and 8.

Enzo’s motion for judgment on the jury verdict was denied, while Applera’s motion for summary judgment was granted.

Enzo appealed to the Federal Circuit, claiming that the district court had incorrectly interpreted Enzo II.

“We conclude that, after carefully parsing our decision, the district court correctly interpreted Enzo II,” said the court.

Enzo claimed that the district court should not have granted summary judgment of non-infringement because there was a genuine dispute of material fact regarding whether Applera’s products infringed under the doctrine.

It also argued that Applera didn’t “literally infringe” claims 1 and 8 of the patent (under the Enzo II construction), but that it infringed under the doctrine of equivalents.

“Enzo claims that the district court ‘misconstrued’ its expert declaration and improperly drew inferences in favour of Applera, rather than Enzo, when ruling on the motion for summary judgment,” said the court.

The Federal Circuit backed the district court, finding that it had correctly granted summary judgment.

“Indeed, Enzo’s attempt to reframe its infringement case under the doctrine of equivalents runs headfirst into our decision in Enzo II.”

Did you enjoy reading this story?  Sign up to our free newsletters and get stories like this sent straight to your inbox.

Already registered?

Login to your account

To request a FREE 2-week trial subscription, please signup.
NOTE - this can take up to 48hrs to be approved.

Two Weeks Free Trial

For multi-user price options, or to check if your company has an existing subscription that we can add you to for FREE, please email Adrian Tapping at