Federal Circuit Report

• Jurisdiction: United States,Federal
• Citation: Vol. 46 No. 2
• Publication year: 2021
• topic: Patent law,Intellectual Property,Federal,Civil Procedure

Federal Circuit Report

Rex Hwang

Skiermont Derby LLP

WILL THE DOCTRINE OF ASSIGNOR ESTOPPEL SURVIVE SCRUTINY FROM THE SUPREME COURT?

The doctrine of assignor estoppel is an equitable, judge-made doctrine that prevents a party who assigned a patent to another from later challenging the validity of the assigned patent. The longstanding reasoning behind the doctrine is that "an assignor should not be permitted to sell something and later to assert that what was sold is worthless, all to the detriment of the assignee."¹ "In other words, it is the implicit representation by the assignor that the patent rights that he is assigning (presumably for value) are not worthless that sets the assignor apart from the rest of the world and can deprive him of the ability to challenge later the validity of the patent. To allow the assignor to make that representation at the time of the assignment (to his advantage) and later to repudiate it (again to his advantage) could work an injustice against the assignee."²

Last April in Hologic, Inc. v. Minerva Surgical, Inc., the Federal Circuit upheld the doctrine of assignor estoppel as applied to district court proceedings.³ Yet, the Federal Circuit has concluded on other occasions that the doctrine of assignor estoppel does not apply to patent validity attacks at the Patent Office.⁴ Thus, a loophole currently exists where assignor estoppel can be avoided by simply attacking an assigned patent's validity at the Patent Office as opposed to a district court lawsuit.

The United States Supreme Court is scheduled to review the Hologic decision in the coming months. This article reviews the Hologic decision in anticipation of the Supreme Court's upcoming review.

Background Facts⁵

In 1993, Csaba Truckai co-founded a company called NovaCept, Inc. In the late 1990s, Mr. Truckai and his design team at NovaCept developed a medical device called the NovaSure system. The Nova-Sure system generally involves a treatment for menorrhagia, or abnormally heavy menstrual bleeding. The NovaSure system is covered by U.S. Patent Nos. 6,872,183 ("'183 patent") and 9,095,348 ("'348 patent") (collectively, "NovaSure Patents"). Both of the NovaSure Patents list Mr. Truckai as an inventor.

By 2001, all of Mr. Truckai's interests in the NovaSure Patents were assigned to NovaCept. In 2004, Cytye Corporation acquired NovaCept. In 2007, Hologic acquired Cytye. Hologic is the current assignee of the NovaSure Patents and markets and sells the NovaSure system in the United States.

At some point during that time period Mr. Truckai left NovaCept and, in 2008, founded Minerva. He served as Minerva's President, its Chief Executive Officer, and a member of its Board of Directors. Mr. Truckai and others at Minerva developed the Endometrial Ablation System ("EAS"), which also treats menorrhagia. Minerva began commercial distribution of the EAS in August 2015.

In November 2015, Hologic sued Minerva in the U.S. District Court for the District of Delaware, alleging that the EAS infringed the NovaSure Patents. Minerva asserted various invalidity defenses in the Delaware case, and also filed IPR petitions in the Patent Office arguing that the NovaSure Patents were invalid in view of the prior art. The Board instituted review of the '183 patent, but denied review of the '348...