Product Liability - Clinical Trial Claims: Why Causation - Not Fault - Is the Real Battleground
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Insight Article 02 March 2026 02 March 2026
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UK & Europe
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Insurance
The UK’s clinical trials market operates under a liability and compensation framework unlike any other product-related risk. Alongside traditional negligence-based claims, pharmaceutical sponsors routinely adhere to the ABPI Clinical Trial Compensation Guidelines, committing to compensate participants for injury caused by their participation in a clinical trial - even where no fault is established.
For insurers and claims professionals more familiar with conventional product liability claims, this regime can appear deceptively similar. In reality, ABPI clinical trial claims differ in fundamental ways. Most notably, causation - rather than defect or fault - becomes the primary point of contention. The reason for this is that products in a clinical trial phase cannot be deemed “defective” because they have not been tested fully or approved for sale.
From Product Defect to Trial Causation
In a standard pharmaceutical product liability claim (where the trial is not run under ABPI Guidelines), the focus is typically on whether:
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The product was defective or unsafe
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Adequate warnings were provided
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The manufacturer reached a duty of care
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The defect caused the claimant’s injury
By contrast, ABPI clinical trial claims do not require proof of defect, negligence, or failure to warn. The investigational product is, by definition, unproven. Participants consent to known and unknown risks, and the legal analysis shifts accordingly.
Under the ABPI guidelines, the central question is narrower but more complex: Was the participant’s injury caused by the investigational medicinal product or the trial procedures? This distinction fundamentally alters how claims must be assessed and defended.
Why Causation Can Often Be More Complex Than In Other Product Liability Matters
ABPI causation disputes differ from conventional product liability claims in several key respects:
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No “defect” benchmark - In product liability, the product is measured against an expected standard of safety. In clinical trials, there is no such benchmark. The investigational product may carry unknown risks, making causation assessment inherently uncertain.
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Heavily confounded claimant profiles - Clinical trial participants are often seriously ill and receiving multiple therapies. Unlike consumer product claims, injury may be indistinguishable from disease progression or co-morbidities.
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Evolving scientific evidence - Product liability claims often rely on established post-marketing safety data. ABPI claims may arise when clinical data is limited, incomplete, or still emerging.
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Known risk does not equal causation - Even where an adverse event is a known side effect disclosed in consent documentation, insurers must still determine whether it was actually caused by the trial - not merely temporally associated.
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Sympathy-driven pressure - Unlike consumer product claims, ABPI claims often involve vulnerable participants and ethical oversight, creating heightened reputational sensitivity and pressure to compensate.
ABPI Claims Are “No-Fault” - But Not No-Evidence
The ABPI guidelines are frequently described as a “no-fault” regime, but this can be misleading.
While negligence does not need to be established, causation must still be proven on the balance of probabilities. The guidelines expressly allow sponsors to decline compensation where injury cannot be attributed to trial participation. As a result, ABPI claims often resemble defended product liability claims stripped of defect arguments, leaving causation as the sole and decisive issue.
What Good ABPI Claims Handling Looks Like (and Why It’s Different)
Claims in the ABPI context require specialised emphasis in order to ensure effective handling:
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Earlier medical engagement than in other types of product liability matter.
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Causation analysis - not liability strategy - drives outcomes. Early expert input is often more important than legal positioning albeit privilege over documentation remains an effective safety net for insurers.
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Deeper reliance on the trial documentation - Protocols, investigator brochures, consent forms, and pharmacovigilance data are central evidence - often more so than manufacturing or design records.
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Tighter control of precedent risk - Because ABPI compensation is ex gratia, inconsistent payments can create expectations and erode future causation defences.
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Parallel exposure management - ABPI causation disputes frequently sit alongside potential negligence or regulatory claims. Coordinated handling across policies is essential.
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As clinical trials grow more complex, ABPI causation disputes are becoming a core claims challenge, not a niche issue.
Conclusion: A Different Risk Demands a Different Claims Mindset
ABPI clinical trial claims sit at the intersection of ethics, science, and insurance. Unlike conventional product liability claims, they are not about defect or fault - they are about causation in an environment of uncertainty.
For insurers and claims leaders, success in this space depends on recognising that difference - and building claims capability accordingly.
In the event that support is required for businesses with any aspect of this article or any issues arising from Life Sciences or product liability claims more generally, please contact Peter Barnes and Charlotte Kelly.
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