Lucas Warner suffered devastating neurological injuries after taking Aimovig. He was only 23 years old.

A single dose, followed by a devastating medical crisis

In June 2018, Lucas Warner was 23 years old and living with a medical history that made his migraines especially difficult to treat. He had been diagnosed with an arteriovenous malformation, an abnormal connection between blood vessels, at age six. The condition was associated with frequent, severe migraines and periodic brain bleeds. He underwent procedures in 2011 and 2012, and suffered a subacute hemorrhage in 2014.

His doctor prescribed Aimovig, a biologic medicine designed to prevent migraines by blocking the receptor for calcitonin gene-related peptide, or CGRP. At the time, Aimovig was the first drug of its class to be reviewed for FDA approval.

Lucas’s doctor did not know that the clinical trials supporting Aimovig had excluded people with any history of seizure disorders or major neurological disorders. The label that doctors and patients could consult did not disclose that lifetime exclusion criterion.

On June 17, 2018, Lucas took one dose. Less than 48 hours later, he suffered seizures and was placed in a coma. He experienced multi-organ failure. According to the complaint described by the First Circuit, his doctors believed Aimovig had crossed the blood-brain barrier and attempted to remove the drug from his brain and blood.

The consequences were profound. Lucas suffered significant, irreversible brain damage, including near-total loss of short-term memory. He could no longer eat or drink independently and struggled to stand or walk. His cognitive impairment forced him to discontinue his university studies. The opinion says his doctors could not reverse the damage.

His condition worsened in 2020, when he suffered repeated seizures. Lucas died on November 17, 2020, at age 25. His death certificate identified respiratory failure associated with stroke, refractory seizures, and cerebral angiopathy. It also recorded complications from Aimovig as contributing to his death.

Those details come from the allegations and records described in the court’s opinion. They explain the stakes of the dispute, but they do not mean that the appeals court independently established the complete medical chain of causation.

The question was whether the information available to doctors and patients adequately conveyed what remained unknown about the drug’s safety for people with histories like Lucas’s. Summary of the dispute described in the First Circuit’s opinion

What the label said, and what it left out

Drug labels are not just marketing inserts. They are part of the safety system surrounding prescription medicines. They communicate known risks, describe appropriate use, and help clinicians weigh potential benefits against uncertainty for individual patients.

Before a biologic can be sold, its manufacturer must submit a Biologics License Application to the FDA. The agency reviews clinical and nonclinical evidence and evaluates proposed labeling. In Aimovig’s case, the FDA approved the application in May 2018, one year after Amgen submitted it.

The approved label’s “Clinical Studies” section disclosed that people with certain recent cardiovascular conditions, including stroke and transient ischemic attacks within the previous 12 months, had been excluded from clinical trials. But it did not disclose that people with any history of seizure disorders or major neurological disorders had also been excluded. Nor did the label contain a warning about the theoretical risks associated with those exclusions.

That distinction matters because a trial can provide evidence about the people who participated in it, while leaving uncertainty about people who were screened out. The absence of a documented problem in a trial population does not, by itself, establish safety for a different population that was not studied.

But the reverse is also true: exclusion from a trial does not prove that a drug is dangerous for the excluded group. It means that the evidence base has limits. Whether those limits justify a warning depends on the science, the available evidence, and the regulatory standards that govern labeling.

Lucas’s mother, Elissa Warner, argued that the label should have disclosed the broader exclusions and the potential complications that might not have been detected because people with those histories were not included in the trials. Her claim was that this information would have mattered to Lucas and his doctor.

The FDA considered the concern, but did not put it on the label

The First Circuit’s opinion makes an important distinction between the original label and information that may have emerged or become meaningful later.

During its original review, the FDA knew that the clinical trials had excluded people with seizure disorders and significant neurological conditions. An FDA reviewer initially proposed language noting a theoretical concern for patients with major cerebrovascular disease. The agency’s risk-management division rejected that suggestion, finding insufficient evidence to include the theoretical risk in the label. The FDA also rejected a proposed caution concerning certain recent cardiovascular events.

The final label contained no contraindications, warnings, or precautions. It listed injection-site reactions and constipation as the most common adverse reactions. The FDA’s decision reflected its assessment of the evidence available during approval, including the concern that warnings based on speculative risks can obscure more established risks or deter appropriate treatment.

This point is central to the case. The First Circuit agreed that Amgen could not be held liable on the theory that it should simply have asked the FDA to approve a different original label. The manufacturer’s ability to request a labeling change is not the same as having the unilateral legal authority to make that change, and the record showed that the FDA had considered and rejected the type of warning Warner proposed.

That ruling does not establish that every later safety concern was resolved in 2018. It addresses what the FDA knew and decided during the original approval process, and what the law allows a plaintiff to challenge about that decision.

The scientific question: could later evidence have changed the warning?

Warner’s second theory focused on four scientific publications concerning CGRP and the brain. She argued that this material provided a basis for Amgen to use a regulatory process known as “Changes Being Effected,” or CBE, to strengthen the approved label after approval and before Lucas took Aimovig.

The CBE process can allow a manufacturer to update an approved label without waiting for prior FDA approval when qualifying new information supports adding or strengthening a warning, precaution, contraindication, or adverse reaction. The process is not a general permission to add any conceivable risk. It depends on regulatory criteria, including whether the information qualifies as newly acquired and whether there is a sufficient basis for the warning.

The four publications the First Circuit found potentially significant explored how CGRP may interact with the brain’s protective mechanisms, including the blood-brain barrier and the brain’s response to injury. In broad terms, Warner argued that blocking CGRP might reduce some protective effects in the setting of cerebral injury, potentially worsening outcomes for people with histories such as Lucas’s.

The studies did not establish that Aimovig caused Lucas’s injuries. Some involved animals, some examined CGRP rather than Aimovig itself, and the evidence did not resolve the precise causal pathway. The appeals court recognized those limitations. Its question was narrower: at the pleading stage, could it say with certainty that the evidence could not qualify as newly acquired information or support the proposed warning?

The court concluded it could not. It identified four publications that, considered together, plausibly raised a concern about CGRP antagonism and cerebral injury:

The panel did not declare these publications definitive proof of danger. Nor did it conclude that the FDA would necessarily have accepted a warning based on them. Instead, it found that the current record did not conclusively show that the publications failed the legal and regulatory standards relevant to the proposed claim.

Why the timing of the research did not settle the issue

Some of the publications predated Aimovig’s FDA approval. Amgen argued that this timing undermined the claim that they constituted “newly acquired information.” The court explained that publication before approval is not automatically disqualifying. Information can qualify if it was not previously submitted to the FDA, and later analyses can sometimes give existing data a different significance.

The record also did not establish that the FDA had considered the particular research questions Warner raised about CGRP’s role in the blood-brain barrier and neuroprotection outside its effect on blood-vessel dilation. The FDA had examined theoretical risks involving CGRP antagonism and ischemia, but the appeals court said it could not simply assume that this review covered every mechanism discussed in the four publications.

There were real scientific gaps. The research included animal studies, and the connection between experimental findings and the effects of a specific medicine in a specific patient was not settled. The court did not fill those gaps with speculation. It held that the gaps could not, on the record then available, conclusively defeat Warner’s proposed claim before further proceedings.

That is a meaningful but limited distinction. A plausible basis to investigate whether a warning should have changed is not the same thing as proof that a warning was legally required, that a manufacturer should have known a particular outcome would occur, or that the drug caused an individual patient’s injuries.

What the court actually decided

The First Circuit issued a mixed ruling. It affirmed dismissal of Warner’s original claim, which challenged the label as approved in the first instance. But it reversed the decision denying her leave to amend the complaint, limited to the theory that four scientific publications could have supported a post-approval label change.

The panel’s reasoning turned on the posture of the case. It was reviewing whether the proposed amended complaint could be rejected as futile, without discovery, expert testimony, or factual findings. To affirm dismissal on the basis of Amgen’s preemption defense, the court needed to be certain that the defense defeated the proposed claim. It concluded that certainty was not possible on this record.

The court also noted that Amgen had not relied on a separate argument that the FDA would clearly have rejected the proposed warning even if it had been fully informed of the four publications. Because that defense was not used to sustain the futility ruling at this stage, the panel did not decide its merits.

The human cost is clear. The legal and scientific answers remain open.

For Lucas and his family, the stakes were not abstract questions about label wording. The complaint described a young man who lost much of his short-term memory, became unable to eat or drink independently, could no longer continue his university studies, and later died. The death certificate listed complications from Aimovig as a contributing factor.

The broader public-interest question is also concrete. Prescription decisions depend on the information available to doctors and patients. When clinical trials exclude people with particular medical histories, labels and post-approval safety monitoring become important parts of how uncertainty is communicated and reassessed.

But accountability requires more than a tragic outcome. A fair assessment must distinguish a known danger from a theoretical risk, a trial exclusion from proof of harm, a plausible scientific concern from established causation, and an appellate ruling on whether a claim may proceed from a final finding of liability.

The First Circuit did not settle those scientific and factual questions. It held that Warner should have the opportunity to pursue a narrow theory that Amgen could have updated Aimovig’s label based on the four publications, rather than having that theory rejected before the evidence could be developed.

What to watch next

• Whether the amended claim survives further proceedings. The district court must address the limited theory the appeals court allowed to proceed.
• How the scientific evidence is evaluated. Expert testimony and a fuller record may clarify what the four publications do and do not show about CGRP inhibition, cerebral injury, and Aimovig.
• Whether the preemption defense can be established later. The appeals court did not resolve every possible defense, including whether the FDA would have rejected the proposed warning after full consideration of the relevant evidence.
• What the evidence establishes about causation. The decision did not make a final determination that Aimovig caused Lucas’s injuries or death.

The larger lesson: a drug label is a record of what is known, and what may still need to be learned

Drug regulation has to manage two risks at once. Missing or delayed warnings can leave patients and clinicians without information that matters to treatment decisions. Overstated or poorly supported warnings can also distort medical decisions and make meaningful safety information harder to identify.

The Warner case sits at that boundary. The FDA considered a theoretical concern during Aimovig’s original review and declined to add a warning. The later claim rests on a narrower question: whether additional research concerning CGRP and cerebral injury could support a label change after approval, even though the research did not conclusively establish what happened in Lucas’s case.

That question now returns to the lower court. The appellate ruling is not a verdict against Amgen. It is a decision that the limited amended claim should not have been stopped before the evidence could be more fully considered.

For patients, the underlying issue is straightforward: they and their doctors need drug information that accurately communicates both established risks and important uncertainties. Whether Warner can prove that Amgen had a legal duty to strengthen Aimovig’s warning, and whether that duty was breached, remain unresolved.

Source document: Warner v. Amgen Inc., No. 25-1268, United States Court of Appeals for the First Circuit, opinion dated October 9, 2026. The source document is attached below.