When Clinical Trials Meet Patents: Finding Balance in Law

Transparency rules in clinical trials attempt to strike a balance between ensuring essential safety and efficacy data reaches the public, and preserving truly proprietary information that fosters innovation. In principle, these disclosure systems function as carefully engineered filters so that researchers can collaborate more effectively, patients avoid duplicative or unnecessary risks, and follow-on innovation is spurred—while still protecting critical commercial details.

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However, regulatory efforts to promote openness can also create tensions with patent law, and the U.S. and EU have taken notably different approaches to managing these tensions. In the EU, the Clinical Trials Regulation (CTR) enforces a structured and comprehensive transparency framework—systematically publishing trial data through the Clinical Trials Information System (CTIS), with narrow, justified redactions permitted. This is complemented by the European Medicines Agency (EMA)’s Policies 70 and 43, which further govern access to clinical data for approved medicines. By contrast, the U.S. relies on a more inconsistent, reactive model: trial sponsors post basic registrations on ClinicalTrials.gov, but anyone seeking deeper disclosures must navigate a cumbersome Freedom of Information Act (FOIA) process that frequently results in redacted or withheld data. Recent court decisions, including Seife v. FDA and Food Marketing Institute v. Argus Leader, have further strengthened broad confidentiality protections.

In a series of recent cases, courts on both sides of the Atlantic have had to wrestle with how clinical trial disclosures interact with patent protection in practice. In the U.S., Salix Pharmaceuticals v. Norwich and Vanda Pharmaceuticals Inc. v. Teva demonstrate that clinical trial details disclosed under minimal transparency requirements—such as published protocols or summaries—can qualify as “prior art” (publicly accessible knowledge that may invalidate patents by rendering them obvious). Recent European Patent Office (EPO) decisions (T 1437/21 and T 0816/22) signal a more case-specific approach: In T 1437/21, the EPO reasoned that positive trial reports do not automatically make a treatment obvious if genuine uncertainties remain; in T 0816/22, the Board invalidated a patent when later Phase III data revealed the therapy did not truly work, illustrating the EPO’s stance that real-world efficacy must underpin an exclusive right.

While openness fosters collaboration, if not carefully calibrated, it can also undermine patent exclusivity, creating a “boomerang” effect. Greater transparency is indeed possible—and beneficial—so long as policymakers account for the unintended IP-related consequences of routine clinical trial data postings. Moreover, these developments suggest that each system can learn from the other. For the U.S. specifically, the rulings arrive in time to influence long-awaited initiatives to expand openness, stressing that any new transparency initiatives must factor in the unintended IP-related consequences of routine clinical trial data postings.

Trials, Errors, and IP Woes: The Boomerang of Transparency on Both Sides of the Atlantic

In Salix Pharmaceuticals v. Norwich, Salix’s patents on using rifaximin for irritable bowel syndrome were invalidated as obvious partly because a published Phase II protocol—although lacking full efficacy data—nonetheless placed a specific dosing regimen in the public domain. Combined with existing literature suggesting higher doses, the protocol made Salix’s chosen dose appear foreseeable. Similarly, in Vanda Pharmaceuticals v. Teva, a 20 mg dose of tasimelteon was deemed obvious once the court considered Vanda’s ongoing Phase II/III trials and prior Phase II summaries. Vanda argued it was effectively “punished” for meeting transparency expectations, but the Supreme Court declined to review.

European patent law, built on an absolute novelty standard, faced parallel challenges. In T 1437/21 (Empagliflozin/Boehringer), the EPO Board of Appeal assessed whether public reporting of positive Phase III results for a broader patient group made a specific sub-population claim obvious. The Board concluded that simply knowing a trial exists, or even that certain outcomes are “positive,” does not necessarily guarantee success in every subgroup. This aligns with earlier EPO decisions (e.g., T 239/16, T 1123/16) holding that a disclosed clinical trial protocol provides an “expectation of success” only if prior art strongly indicates the trial is likely to succeed.

On the other hand, T 0816/22 (Takeda) reveals the EPO’s commitment to truth and public interest when transparency exposes a patent’s shortcomings. Here, the EPO Board invalidated a patent covering a second medical use of an existing therapy (a C1-esterase inhibitor) intended to prevent kidney transplant rejection, after Phase III results revealed the therapy simply did not work. Thus, once that data indicated inefficacy, the EPO concluded the claimed invention lacked the required plausibility under Article 83 EPC (i.e., an invention must be backed by credible evidence that it works as claimed). From a public health perspective, the EPO’s approach is commendable because it holds patentees accountable to real-world outcomes. While this heightened scrutiny of trial outcomes could potentially incentivize sponsors to bury unfavorable findings that might later invalidate their patents, EU’s new Clinical Trials Regulation provides a counterbalance by mandating universal publication of all trial results.

Mastering the Balancing Act

The above discussed cases illustrate how clinical research transparency and patent law are inextricably linked. Both serve essential public interests—one by promoting open science and public health, the other by incentivizing innovation—and neither can be neglected. The task ahead is to weave these interests together so that one need not be sacrificed for the other.

How might each system make valuable reforms? The U.S. could rethink its approach by moving toward a structured, proactive transparency model that balances transparency and patentability through tailored redactions. This would prevent companies from being caught in a contradictory system that both mandates transparency and allows those same disclosures to undermine patent rights.

For the EU, the next step could be to introduce a narrowly targeted, novel clinical trial disclosure “grace period” that shields mandatory disclosures from being treated as prior art. That would help preserve the integrity of the absolute novelty rule while protecting compliance. The CTR ensures broad access to trial data but also forces companies to rush patent filings before required disclosures appear in the public domain. A tiered “grace period” approach could provide 18–24 months for early-phase trials, where discoveries often emerge, and 6–12 months for Phase III trials, which primarily confirm efficacy. Such a reform would provide more certainty for innovators while maintaining the public’s right to timely clinical data.

As pharmaceutical innovation becomes increasingly global, with clinical trials spanning continents and treatments serving worldwide markets, harmonizing U.S. and EU approaches becomes ever more critical.

About the author

Gabriela Lenarczyk is a Postdoctoral Fellow at the International Center for Bioscience Innovation Law (Inter-CeBIL). She has an academic and professional background in the field of intellectual property law, with a special focus on pharmaceutical intellectual property, regulatory exclusivities, and the protection of clinical trial data.