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11 January 2021AmericasRory O'Neill

SCOTUS weighs future of assignor estoppel

The US Supreme Court will decide whether or not to maintain a legal doctrine which stops inventors who sell their patent rights from later claiming the patents are invalid.

The country’s top court granted certiorari in a dispute between medical devices company Minerva and Hologic. Minerva has urged the court to abandon the doctrine of assignor estoppel, which it says “allows worthless patents to stifle innovation and impede full and free competition”.

Hologic, a medical imaging company, sued Minerva for infringing features of a patent which lists Minerva founder Csaba Truckai as an inventor.

Truckai sold the patent to Cytyc Corporation in 2004, three years before Hologic purchased Cytyc and the IP.

In response to Hologic’s lawsuit, Minerva claimed the patent was invalid and that Hologic had broadened the scope of the patent beyond what was initially claimed by Truckai.

Specifically, Minerva alleged that Hologic broadened the scope of the patent after learning confidential information about Minerva’s technology.

Minerva’s defence was rejected at the US Court of Appeals for the Federal Circuit on the grounds of assignor estoppel, which it said barred Truckai from challenging the validity of the patent.

In its petition to the Supreme Court, Minerva argued that: “The rationale for the doctrine was to prevent assignors from later asserting that what they had assigned was worthless. But Minerva never asserted that what Truckai assigned was worthless. It was instead challenging the assignee’s (Hologic’s) later unsupported expansion of the scope of the patent claims.”

Minerva has received the support of a group of IP law academics, who filed an amicus  brief arguing that the Federal Circuit has over-extended assignor estoppel to the point of harming “important public policy interests in invalidating bad patents, ensuring free competition, and promoting efficient mobility of employees”.

Hologic, meanwhile, claims the dispute with Minerva is a “textbook example” of conduct which the doctrine was originally designed to prevent.

“Truckai assigned the rights to any future patent on his invention, including the patent rights Minerva seeks to invalidate. [The Supreme Court] and others have confirmed that this kind of situation warrants the application of assignor estoppel,” the company said in a court filing.

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