Johnson & Johnson did not infringe patents held by Decision Diagnostics’ Pharma Tech Solutions unit when it made its own glucose monitors, according to a precedential decision by the U.S. Court of Appeals for the Federal Circuit.
The Federal Circuit on Nov. 22 upheld a decision by the U.S. District Court for the District of Nevada and granted summary judgment to J&J’s LifeScan, Inc. unit, which makes the OneTouch Ultra system for monitoring blood glucose levels at home.
Lawyers for Pharma Tech argued that LifeScan had infringed two of its patents, which also cover blood glucose monitoring systems that diabetes patients can use at home.
The two Pharma Tech patents claim inventions that improved upon prior monitoring systems by eliminating potential for user error that can diminish the accuracy of blood glucose readings.
LifeScan similarly has a product that uses a different method to minimize user error.
“Pharma Tech agrees that the accused products therefore do not literally infringe the claim,” but the company asserts that the Pharma Tech system could take measurements in an equivalent way to the LifeScan method--and “thus, the accused device infringes under the doctrine of equivalents,” according to the opinion.
The doctrine of equivalents is a legal rule under U.S. patent law in which a party can be held liable for patent infringement even when the invention in question doesn’t fall within the literal scope of a patent claim. Instead, it’s considered “equivalent.”
For example: If an inventor patents a four-legged table but doesn’t explicitly define the number of legs in their patent, when another person creates a three-legged table, the second table could be vulnerable under the doctrine of equivalents.
LifeScan asserted that estoppel applied in the case because Pharma Tech had narrowed its patent claims to be more specific in its glucose test methodology during the process of applying for the patents.
Estoppel is a principle in which a court may prevent a party from making assertions that contradict its prior statements.
The Federal Circuit agreed with the district court and LifeScan, finding that estoppel bars Pharma Tech from succeeding on its infringement claims under the doctrine of equivalents.
“This case is affirming that the [patent] prosecution history estoppel argument is still alive and well,” said Joe Edell, an intellectual property attorney with Fisch Sigler LLP in Washington, D.C.
“It shows that the Federal Circuit still appreciates that when an inventor amends their [patent] claims to limit the scope of their claim, then those amendments are going to prevent them from asserting the doctrine of equivalents to recapture what they gave up,” Edell added.
The case is: Pharma Tech Solutions, Inc. v. LifeScan, Inc., Fed. Cir., No. 19-01163, Decision 11/22/19