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October 29, 2025
In Rex Medical, L.P., v. Intuitive Surgical, Inc. (“Rex”), the Federal Circuit affirmed the District Court’s reduction of a jury award from $10 million to $1.1 At trial, with no damages experts testifying, a jury awarded $10 million in damages finding that the defendant infringed U.S. Patent No. 9,439,650—a patent for a surgical stapling device (the “patent-in-suit” or “the ‘650 patent”).2 Following post-trial motions, the Court reduced defendant Intuitive’s damages to $1.3
After proving infringement, 35 U.S.C. § 284 provides that a successful patentee is entitled to damages which may be “in no event less than a reasonable royalty.” But Rex serves as a reminder that it is the patentee’s burden to prove their damages. Here, the exclusion of the patentee’s damages expert left the jury with no way to calculate a reasonable royalty.4 Patent damages may “not be determined by mere speculation or guess.”5 Patentees must prove how much they have been damaged.6 § 284 does not guarantee damages.7 “If none are proven that adequately tie a dollar amount to the infringing acts,” an award, if any, may be nothing or as little as $1.8
Before the District Court, Rex’s damages expert attempted to opine that a hypothetical negotiation for a license to the patent-in-suit would lead to a lump sum payment of $20 million.9 This opinion was based on a purportedly comparable license where a party in an earlier litigation agreed to pay $10 million for a portfolio of patents that included the ‘650 patent.10 Judge Noreika excluded this testimony because the damages expert failed to apportion the value of the patent-in-suit from the other licensed patents.11
This prior portfolio license covered all of the patentee’s surgical stapling patents, including ten U.S. patents, seven applications, and nineteen patents or applications from outside the United States.12 To rely on an earlier license that involved a patent portfolio, patentees must apportion the value of the asserted patent(s).13 “Expert testimony should be excluded when it fails to allocate license fees among the licensed patents covered by an agreement.”14 Without proof ascribing value to the patent-in-suit as part of a portfolio license, a court has “no basis upon which to conclude . . . a meaningful proxy for the royalty rate of the [asserted] patent.”15
Rex’s damages expert failed to address the apportioned value of the ‘650 patent from the entire portfolio of patents in the alleged comparable license.16 The Federal Circuit held that the District Court did not err in excluding the testimony and reducing the damages.17
Affirming the reduction in damages, the Federal Circuit noted that § 284 does not “require” an award of damages.18 Rather, patentees must prove their damages.19 When damages theories rely on comparable licenses that include multiple licensed patents, patentees have the burden of apportioning value to the patent-in-suit.20 A jury cannot speculate on the amount of damages (e.g., a reasonable royalty) when there is no admissible evidence in the record to support its findings.21 In Rex, the patentee failed to prove their damages.22 Since there was no evidence in the record with which to calculate a reasonable royalty rate, there was no way for the jury to support awarding a lump sum of $10 million as a reasonable royalty.23
The Federal Circuit did note that the outcome in Rex is fact-specific.24 If the parties submitted other evidence that could allow a jury to reasonably determine damages “without speculation,” the patentee’s motion for a new trial on damages might have been more appropriate, rather than granting defendant’s JMOL motion for no damages.25 Neither party presented admissible testimony apportioning the value of the patent-in-suit from the prior portfolio license.26 Without evidence in the record, a jury finding of a reasonable royalty for the infringed patent-in-suit would involve “improper guesswork.”27 Accordingly, the Federal Circuit affirmed the District Court’s grant of JMOL and an award of nominal damages.28
While the Federal Circuit has said that the outcome in Rex was fact-specific, the case highlights both pre-trial and trial—strategies and warnings—for practitioners regarding patent damages, royalties, and apportionment. If a party’s expert wants to rely on a comparable license where the patent-in-suit was part of a patent portfolio, the expert must apportion. Expert opinions can be excluded when they do not account for apportionment.29
Practitioners can avoid a failure to prove damages similar to the situation in Rex by addressing expected proofs to show damages early in the case. Anticipating and avoiding possible evidentiary issues at trial requires undertaking fact discovery and establishing a record to support later apportionment opinions. Having done the necessary pre-trial work to create such a record, experts will be in a better to position to defend their opinions during cross-examination and overcome motions attempting to exclude their testimony.
The Federal Circuit’s decision in Rex underscores the point that patentees carry the burden to prove their damages, and that infringement does not always guarantee damages.30 Practitioners should expect Daubert motions and motions in limine aimed at excluding damages experts, so anticipating these challenges and preparing accordingly will put both experts, and ultimately clients, in a better position to be successful at trial.