Patents

Natera v. NeoGenomics: Causal Nexus and the Equity of a Two-Player Market

The Federal Circuit affirms a preliminary injunction barring a competing cancer-recurrence assay, sharpening how courts trace irreparable harm to the patented method through the causal-nexus requirement.

March 10, 2026
Laboratory technician analyzing genomic sequencing data on a monitor
Natera tied the demand for a rival cancer assay directly to the patented amplification method, satisfying the causal nexus. Shutterstock
Educational content, not legal advice. This article explains general legal concepts. It does not create an attorney–client relationship. For your specific situation, consult a licensed attorney.

In Natera, Inc. v. NeoGenomics Laboratories, Inc., Nos. 2024-1324, -1409 (Fed. Cir. July 12, 2024), the U.S. Court of Appeals for the Federal Circuit affirmed a preliminary injunction that barred a direct competitor from selling its tumor-informed cancer-recurrence test. The precedential opinion, authored by Chief Judge Moore for a panel that also included Judges Taranto and Chen, arose on interlocutory appeal from the U.S. District Court for the Middle District of North Carolina, which had granted the injunction in December 2023 and put it into effect on January 12, 2024. The decision is one of the more instructive recent applications of the equitable framework that governs patent injunctions, both because it involves a rare head-to-head market and because it shows the Federal Circuit policing the causal-nexus requirement that ties irreparable harm to the patented invention rather than to the infringer’s product writ large.

Natera owns U.S. Patent No. 11,519,035, directed to methods of amplifying targeted genetic material—such as circulating tumor DNA—while suppressing amplification of non-targeted material, and a companion patent, U.S. Patent No. 11,530,454, directed to detection. The injunction rested principally on the ‘035 patent. Natera markets Signatera, a tumor-informed assay used to monitor patients for molecular residual disease and cancer recurrence; NeoGenomics sells RaDaR, a competing tumor-informed test. The two products occupy what the district court described as a concentrated, essentially two-player market, a factual posture that shaped the entire equitable analysis.

At a glance

  • Case: Natera, Inc. v. NeoGenomics Laboratories, Inc., Nos. 2024-1324, -1409
  • Court: U.S. Court of Appeals for the Federal Circuit (precedential)
  • Decided: July 12, 2024
  • Panel: Moore, C.J. (author), Taranto and Chen, JJ.
  • Posture: Interlocutory appeal from the U.S. District Court for the Middle District of North Carolina; preliminary injunction affirmed
  • Patents: U.S. Patent No. 11,519,035 (amplification); U.S. Patent No. 11,530,454 (detection)
  • Products: Natera’s Signatera v. NeoGenomics’s RaDaR—competing tumor-informed cancer-recurrence assays
  • Holding: No abuse of discretion in finding likelihood of success, irreparable harm with an adequate causal nexus, and a balance of the equities and public interest favoring a carefully tailored injunction

The four-factor framework and where eBay fits

Although Natera concerns a preliminary rather than a permanent injunction, the equitable architecture is the same one the Supreme Court restored in eBay Inc. v. MercExchange, L.L.C., 547 U.S. 388 (2006). eBay rejected the Federal Circuit’s then-prevailing “general rule” that a permanent injunction follows almost automatically from a finding of infringement, and held instead that a patentee must satisfy the traditional four-factor test: (1) irreparable injury; (2) the inadequacy of remedies at law, such as money damages; (3) that the balance of hardships warrants an equitable remedy; and (4) that the public interest would not be disserved. The preliminary-injunction inquiry layers a likelihood-of-success requirement on top of those equitable considerations, but the irreparable-harm, balance-of-hardships, and public-interest factors are continuous with eBay.

That continuity matters because the hardest questions in modern injunction practice—who suffers irreparable harm, and whether damages can be calculated—do not turn on the procedural label. Natera is therefore a useful window into how the Federal Circuit thinks about eBay’s equitable factors even outside the permanent-injunction setting. On the merits, the panel found no legal error in the district court’s claim construction or infringement analysis and concluded that NeoGenomics had failed to raise a substantial question of invalidity, having not shown the asserted claims more likely than not obvious. With likelihood of success secured, the equitable factors did the decisive work.

Irreparable harm and the causal nexus

The center of gravity in Natera is the causal-nexus requirement. Since the Apple v. Samsung line of cases, a patentee seeking an injunction must show not merely that it will suffer harm and that the defendant infringes, but that the harm is attributable to the infringing feature—“some connection between the patented feature and demand for the infringing product.” The requirement guards against a patentee leveraging a minor patented component to enjoin a complex product whose sales are driven by unpatented attributes.

NeoGenomics argued that the district court had impermissibly grounded irreparable harm in tumor-informed testing generally, a capability that, in its telling, was not itself claimed by the ‘035 patent. The Federal Circuit rejected the framing. The district court had found that the “driver of demand” for RaDaR—highly sensitive, tumor-informed detection—could not be achieved without practicing the particular amplification methods the patent claims. On that record, the causal nexus was not a gap between a peripheral feature and overall demand; the patented method was the technological precondition for the very capability customers were buying. The panel declined to carve tumor-informed testing out of the analysis merely because the phrase did not appear verbatim in the claims, emphasizing that the nexus inquiry asks about the relationship between the patented technology and consumer demand, not about claim drafting.

The two-player market supplied the irreparable-harm narrative. Where the patentee and the infringer are direct competitors in a concentrated market, lost sales translate into lost customers, eroded business relationships, foregone clinical and research collaborations, and price effects that are difficult to reconstruct after the fact. The district court found—and the Federal Circuit accepted—that those losses were not readily quantifiable, satisfying both the irreparable-harm and the inadequacy-of-legal-remedies factors that eBay treats as distinct but related. This is the paradigm in which post-eBay injunctions remain most attainable: a practicing entity competing directly against the infringer, not a licensing patentee whose injury is, by its own business model, monetizable through a royalty.

Tailoring, the public interest, and the alternative of an ongoing royalty

The fourth eBay factor—public interest—carried unusual weight because the enjoined product is a medical test. The district court did not treat the public-health stakes as a categorical bar to relief; instead, it tailored the injunction. The court carved out patients already using RaDaR and exempted ongoing research projects, studies, and clinical trials, so that continuity of care and scientific work would not be sacrificed to enforce the patent against new commercial sales. The Federal Circuit found no error in that balancing, noting that the district court had carefully crafted and repeatedly clarified the injunction to mitigate adverse effects on cancer patients and clinical research. The lesson is that public-interest objections in the life sciences are often best answered by scope, not denial: a narrowly drawn injunction can neutralize the harm the public-interest factor is meant to protect.

It is worth situating that result against the principal alternative to an injunction. When a court denies an injunction under eBay—frequently because the patentee does not practice the invention and its harm is fully compensable in money—it may instead impose an ongoing royalty on continued infringement, the remedy the Federal Circuit blessed in Paice LLC v. Toyota Motor Corp. An ongoing royalty effectively converts the property right into a liability rule, allowing the infringer to continue at a court-set price. Natera sits at the opposite pole: because the harm to a direct competitor in a two-player market could not be captured by a royalty, the equitable remedy was the injunction itself. The two outcomes are the endpoints of the same eBay spectrum, and the causal-nexus and market-structure findings are what locate a given case along it.

Open questions

  • How tightly must the “driver of demand” map onto the literal claim language? Natera tolerates a functional capability that the claims enable without naming, but the boundary between an enabled capability and an unclaimed feature remains contestable.
  • Does the two-player-market reasoning translate to markets with three or four competitors, where a defendant can argue that customers would simply migrate to a non-infringing rival rather than to the patentee?
  • Will the tailoring approach—carve-outs for existing patients and research—become an expected feature of life-sciences injunctions, effectively raising the bar for defendants who resist any injunction rather than negotiating scope?
  • How will the analysis differ at the permanent-injunction stage, where likelihood of success is replaced by a final merits judgment and the equities are assessed on a fuller record?

Implications

  • Direct competition is still the surest path to an injunction. Practicing patentees in concentrated markets can credibly frame lost sales as irreparable and damages as inadequate; licensing patentees face a steeper climb.
  • Plead the causal nexus to the capability, not just the claim. Tie the patented method to the feature that actually drives demand, and be ready to show the demand-driving capability is unattainable without practicing the claims.
  • Defendants should attack the nexus and the market definition early. Disaggregating demand among unpatented features, or showing available non-infringing substitutes, undermines both irreparable harm and the public-interest case.
  • In the life sciences, litigate scope, not just entitlement. Courts are receptive to carve-outs that protect patients and research; a refusal to engage on tailoring can leave a defendant with a broad injunction.
  • Remember the royalty fallback. Where an injunction fails the eBay test, an ongoing royalty under Paice is the likely substitute—an outcome worth modeling before deciding whether to seek or oppose injunctive relief.

Frequently asked questions

Does eBay apply to preliminary injunctions? The four equitable considerations eBay restored—irreparable harm, inadequacy of legal remedies, balance of hardships, and public interest—run through both preliminary and permanent injunction analysis. The preliminary stage adds a likelihood-of-success requirement, but Natera applies the same equitable factors that govern after a final judgment.

What is the causal-nexus requirement, and why did it matter here? The causal nexus requires a patentee to show that its irreparable harm flows from the patented feature, not merely from the infringer’s product as a whole. In Natera, the court found the demand-driving capability—highly sensitive tumor-informed testing—could not be achieved without practicing the claimed amplification method, so the nexus was satisfied.

Can a court issue a money-based remedy instead of an injunction? Yes. When the eBay factors do not support an injunction—often where the patentee is a non-practicing licensor whose harm is compensable—courts may impose an ongoing royalty on continued infringement under Paice LLC v. Toyota, allowing the activity to continue at a court-set rate.

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