Medtronic v. Mirowski — In a Licensee’s Declaratory Judgment Action, the Patentee Bears the Burden of Proving Infringement

Background

Mirowski Family Ventures holds patents on implantable cardiac devices — technology related to the automatic implantable cardioverter-defibrillator (AICD), which detects dangerous heart arrhythmias and delivers corrective electrical shocks. Medtronic, Inc. — a leading manufacturer of cardiac devices — operated under a license from Mirowski and paid royalties under that agreement.

When Mirowski notified Medtronic that several of its products infringed the licensed patents, Medtronic disagreed but could not terminate the license without exposing itself to an infringement lawsuit. Instead, Medtronic invoked a contractual clause allowing it to continue paying royalties into escrow while bringing a declaratory judgment action asking a federal court to declare its products did not infringe. The dispute then focused on a procedural but consequential question: in this DJ action, who bears the burden of proving infringement — Medtronic (the DJ plaintiff) or Mirowski (the patent owner)?

The Court’s Holding

Justice Breyer, writing for a unanimous Court, held that the burden of proving infringement remains with the patent owner — here, Mirowski — even when a licensee is the plaintiff in a declaratory judgment action. The ordinary rule in patent infringement suits is that the patentee must prove infringement. That allocation of the burden of persuasion does not shift simply because the licensee happens to file first as a declaratory judgment plaintiff.

The Court rejected the Federal Circuit’s reasoning that a licensee-plaintiff in a DJ action must bear the burden of proving non-infringement. The Court noted that this would create an anomaly: a party’s access to court via the Declaratory Judgment Act should not alter the substantive allocation of burdens that governs the underlying dispute. The patent owner always bears the burden of proving infringement, regardless of who initiates the litigation.

Key Takeaways

• In a licensee’s declaratory judgment action for non-infringement, the patentee bears the burden of proving infringement — the same as in an ordinary infringement suit.
• The Declaratory Judgment Act is a procedural vehicle and does not alter substantive burden-of-proof allocations.
• Licensees who disagree with a patentee’s infringement allegations can challenge them in a DJ action without losing the procedural advantages ordinarily available to a defendant.
• Patent owners cannot use the DJ posture to shift the evidentiary burden onto a licensee who disputes coverage.

Why It Matters

Medtronic v. Mirowski resolved a split in authority on who must prove what in a peculiar but common licensing scenario: a licensee who suspects it is over-paying royalties — or that certain products aren’t actually covered — files for declaratory relief rather than simply stopping payments and waiting to be sued. The Federal Circuit had placed the burden on the licensee, which made DJ actions riskier and effectively allowed patentees to assert broad infringement claims with little evidentiary obligation.

The unanimous Supreme Court ruling levels the playing field. Companies operating under patent licenses — in any industry — can now challenge coverage assertions in court without bearing a heavier evidentiary burden than the patent owner would bear in a direct infringement suit. This encourages accurate licensing negotiations and reduces the leverage that overbroad infringement allegations might otherwise generate.