Aimovig Wrongful Death Lawsuit Revived: First Circuit Lets Mother Amend Seizure Claim Against Amgen

The First Circuit reopens the Aimovig wrongful death lawsuit

The Aimovig wrongful death lawsuit against Amgen is back in play: on October 9, 2026, the U.S. Court of Appeals for the First Circuit in Warner v. Amgen Inc., No. 25-1268, affirmed dismissal of the mother's original complaint as preempted but reversed the district court's refusal to let her amend, ruling that post-approval studies she identified could amount to "newly acquired information" allowing Amgen to strengthen the migraine drug's label on its own. The case returns to the District of Massachusetts, where Elissa Warner can now try to plead a Failure to Warn claim tied to her son's fatal seizure after an Aimovig injection in June 2018.

The split result is the story. On the question most drug defendants care about, whether a manufacturer can be sued for not pushing the FDA for a stronger warning before approval, the First Circuit sided with Amgen. On the question plaintiffs' lawyers care about, whether a judge can shut the door at the pleading stage by deciding that new studies were not new enough, the court sided with the plaintiff. That second holding is what makes the ruling worth reading for anyone litigating pharmaceutical Preemption (Products) defenses in the First Circuit, which covers Massachusetts, the home of much of the biotech industry, as well as Maine, New Hampshire, Rhode Island and Puerto Rico.

What did the First Circuit decide in Warner v. Amgen?

The First Circuit decided two things. It affirmed the dismissal of the original complaint, and it reversed the denial of leave to amend.

On the first point, the panel agreed with the district court that federal law preempted the claim as originally pleaded. As summarized in the court's opinion, Amgen could not unilaterally alter Aimovig's label while the drug was under FDA review, and the FDA would have rejected the label changes the plaintiff said Amgen should have proposed. A state-law duty that could only be satisfied by doing something federal law did not allow is the classic setting for impossibility preemption.

On the second point, the panel concluded that the plaintiff had plausibly alleged that certain studies could have permitted Amgen to update the label after approval through the FDA's Changes Being Effected procedure, so amendment was not futile. HarrisMartin, reporting the decision on October 12, 2026, described the ruling as reinstating the suit because the plaintiff presented possible "newly acquired evidence" that would have warranted a label change, and said the panel concluded she should be granted leave to amend.

In practical terms, the disposition is affirmed in part and reversed in part. The plaintiff does not get a trial date. She gets the chance to file an amended complaint that a district judge must evaluate against the standard the First Circuit set.

Issue	District court (Feb. 13, 2025)	First Circuit (Oct. 9, 2026)
Pre-approval claim (Amgen should have sought a stronger warning before approval)	Preempted; FDA knew the trial exclusion criteria	Affirmed: preempted, Amgen could not change the label alone during review
Post-approval claim (Amgen should have used CBE after approval)	Preempted; no newly acquired information in the month between approval and injury	Not foreclosed: studies could plausibly qualify as newly acquired information
Leave to amend	Denied as futile	Reversed: amendment allowed
Practical result	Case dismissed	Case returns to D. Mass. for an amended complaint

Is there an Aimovig lawsuit for seizures?

Yes. Warner v. Amgen is a wrongful death action alleging that Aimovig, the injectable migraine-prevention drug sold as erenumab-aooe, triggered a seizure that killed Lucas Warner. According to the pleadings as reported, Warner had an arteriovenous malformation, a tangle of abnormal blood vessels in the brain, that caused migraine headaches. He received Aimovig in June 2018, shortly after the FDA approved the drug in May 2018 as the first preventive treatment targeting the calcitonin gene-related peptide (CGRP) pathway. He suffered a seizure that, the complaint alleges, ultimately led to his death.

His mother, Elissa Warner, sued as personal representative of his estate. She filed in Middlesex Superior Court on November 17, 2023, naming Amgen and Novartis Institutes for BioMedical Research, Inc., which co-developed the drug. Law360 reported at filing that the suit sought at least $6 million and that the decedent's doctors believed the seizure was triggered by Aimovig. Amgen removed the case to federal court in March 2024 on diversity grounds. On appeal, the parties were Warner and Amgen Inc. and Amgen USA Inc.; the Novartis research entity was not a party to the appeal.

The core allegation is about who was studied. Patients with a diagnosed seizure disorder or cerebrovascular disease were excluded from Aimovig's clinical trials. The plaintiff's theory is that, as a result, the label told prescribers nothing about how the drug might affect seizure-prone patients, and that Amgen should have warned about that gap. The current Aimovig prescribing information carries warnings for hypersensitivity reactions, constipation with serious complications, hypertension and Raynaud's phenomenon, but no seizure warning.

A note on search results: most pages that rank for "Aimovig lawsuit" concern a different case, the 2019 contract fight between Amgen and Novartis over their Aimovig collaboration, which the companies later settled. That commercial dispute has nothing to do with patient injuries.

Why was the Aimovig wrongful death lawsuit dismissed?

U.S. District Judge Julia Kobick dismissed the Aimovig wrongful death lawsuit on February 13, 2025, in Warner v. Amgen Inc., No. 1:24-cv-10632 (D. Mass.), and denied leave to amend. She split the case into two time periods and found each preempted.

Before approval. To the extent the plaintiff argued that Amgen should have submitted a stronger warning to the FDA before approval, Judge Kobick held the claim preempted because the FDA was fully aware of the exclusion criteria used in Aimovig's trials. If the agency approved the label knowing seizure patients had not been studied, a state jury could not second-guess that judgment by faulting the manufacturer for not asking for more.

After approval. A manufacturer can change a label without waiting for the FDA only when it has "newly acquired information." Judge Kobick found that Amgen had established that no such information came to light in the roughly one month between Aimovig's May 2018 approval and the June 2018 injection. With no window in which Amgen could have acted alone, the post-approval claim was preempted too. The court found the studies the plaintiff pointed to insufficient and denied amendment as futile.

The plaintiff filed a notice of appeal on March 14, 2025. The First Circuit left the first half of that reasoning in place and rejected the second half's use as a pleading-stage bar.

What is the Changes Being Effected regulation and why does it matter?

The Changes Being Effected (CBE) regulation is the FDA rule that lets a brand-name manufacturer add or strengthen a warning, precaution or adverse-reaction statement and put the new label into use immediately, before the agency approves the supplement. For conventional drugs the provision is 21 C.F.R. § 314.70(c)(6)(iii); biologics such as Aimovig, a monoclonal antibody, are governed by a parallel labeling rule at 21 C.F.R. § 601.12(f).

CBE is the hinge of modern pharmaceutical preemption. In Wyeth v. Levine, 555 U.S. 555 (2009), the Supreme Court held that because CBE lets brand manufacturers strengthen warnings on their own, state failure-to-warn claims are generally not preempted unless there is "clear evidence" the FDA would have rejected the change. In Merck Sharp & Dohme Corp. v. Albrecht, 587 U.S. 299 (2019), the Court added that preemption is a question of law for the judge, and that the manufacturer must show it fully informed the FDA of the justifications for the warning and that the FDA, acting within its lawful authority, told it the change was not allowed.

Generic manufacturers stand differently: because they must copy the brand label, PLIVA, Inc. v. Mensing (2011) held that failure-to-warn claims against them are preempted. Aimovig is a brand-name biologic, so the brand framework applies.

What counts as "newly acquired information" for a label change?

The FDA defines "newly acquired information" in 21 C.F.R. § 314.3(b) as data, analyses or other information not previously submitted to the agency, including new clinical studies, adverse-event reports, or new analyses such as meta-analyses of previously submitted data, if they reveal risks of a different type or greater severity or frequency than previously included in submissions to the FDA.

That definition is why Warner matters. The First Circuit's earlier decisions, including In re Celexa & Lexapro Marketing & Sales Practices Litigation, 779 F.3d 34 (1st Cir. 2015), and Gustavsen v. Alcon Laboratories, Inc., 903 F.3d 1 (1st Cir. 2018), require a plaintiff to plead a labeling deficiency the manufacturer could have fixed through CBE, which in practice means pointing to information that qualifies as new. Defendants routinely argue at the motion-to-dismiss stage that a plaintiff's studies were already known to the FDA, were not materially different, or came too late. Judge Kobick accepted that argument. The First Circuit held that the plaintiff's proposed allegations were enough to get past it, at least for pleading purposes.

The short timeline makes the ruling more striking. Only about a month separated approval and injection. A court that accepts a plausible CBE theory in a one-month window is signaling that the "newly acquired information" question is usually one of fact and expert evidence, not a matter to be resolved on the face of the complaint.

Timeline of the Aimovig wrongful death lawsuit

Date	Event
May 2018	FDA approves Aimovig (erenumab-aooe) for migraine prevention
June 2018	Lucas Warner receives Aimovig; suffers a seizure that allegedly led to his death
Nov. 17, 2023	Elissa Warner sues Amgen and Novartis Institutes for BioMedical Research in Middlesex Superior Court
March 2024	Amgen removes the case to the District of Massachusetts (No. 1:24-cv-10632)
Feb. 13, 2025	Judge Julia Kobick dismisses the case as preempted and denies leave to amend
March 14, 2025	Plaintiff files notice of appeal (First Circuit No. 25-1268)
Oct. 9, 2026	First Circuit affirms dismissal of original complaint, reverses denial of leave to amend
Oct. 12, 2026	Decision reported by HarrisMartin

Where the ruling sits in the 2026 preemption landscape

Warner lands in a year dominated by preemption fights. In June 2026, the Supreme Court's decision in Monsanto Co. v. Durnell held that federal pesticide law preempts state failure-to-warn claims that would require a label different from the one the EPA approved, and trial courts have spent the months since sorting which Roundup theories survive. Drug and device defendants have pressed similar arguments in the GLP-1 and Depo-Provera litigation. FDA drug cases operate under a different statute and a different line of Supreme Court authority, and Warner is a reminder that the brand-drug framework built on Wyeth still leaves a real path for plaintiffs who can identify post-approval evidence.

The decision also illustrates a recurring split in how courts treat pre-approval claims. A theory that a manufacturer should have designed better trials or sought a different label during review runs straight into the FDA's approval decision. A theory that a manufacturer learned something after approval and failed to act on it runs through CBE, which Wyeth treats as a manufacturer's own responsibility. Plaintiffs who plead the first kind of claim will keep losing in the First Circuit; plaintiffs who plead the second kind with specific studies have a better chance.

Does the Warner ruling mean there is an Aimovig class action or MDL?

No. Warner v. Amgen is a single wrongful death case. There is no Aimovig Multidistrict Litigation (MDL), no motion before the Judicial Panel on Multidistrict Litigation (JPML), and no certified class or settlement program. The ruling does not establish that Aimovig causes seizures; it addresses only whether the claim can be pleaded around preemption. Any plaintiff would still have to prove General Causation and Specific Causation with admissible expert testimony and would face the Learned Intermediary Doctrine, under which the warning runs to the prescribing physician. Wrongful death claims are also subject to state Statute of Limitations rules, which in Massachusetts generally run three years, subject to the Discovery Rule.

What it means for plaintiffs' counsel, drug defendants and the PI bar

For plaintiffs' counsel. The ruling rewards precision. Complaints that attack the clinical-trial design or the original approval will be dismissed. Complaints that identify specific post-approval studies, adverse-event signals or analyses, explain why they reveal a risk of a different type or greater severity than the FDA had seen, and connect them to a warning the manufacturer could have added through CBE now have appellate support in the First Circuit for getting to discovery. Requesting leave to amend, with a proposed amendment that names the new evidence, preserved the issue here.

For drug and biologic manufacturers. Pre-approval preemption remains strong. But defendants should expect less success arguing at the pleading stage that a plaintiff's studies were not "newly acquired." That fight is likely to move to summary judgment, where Albrecht requires the manufacturer to show the FDA would have rejected a properly supported warning. Regulatory files, internal safety reviews and communications with the agency about the new data become central discovery targets.

For personal injury firms evaluating drug cases. The decision does not create a new mass tort. It does show that preemption is not an automatic bar to brand-drug claims where the label is silent about a population excluded from trials. Firms screening cases should look for post-approval literature and adverse-event data, not just the absence of a warning.

For insurers and litigation funders. A single reversed dismissal rarely moves reserves. But a published appellate ruling that resists early CBE dismissals increases the expected cost of defending brand-drug failure-to-warn claims in the First Circuit and may influence how Third-Party Litigation Funding providers price early-stage pharmaceutical portfolios.

What happens next in the Aimovig case?

The case returns to Judge Kobick in the District of Massachusetts. The plaintiff is expected to file an amended complaint pleading the post-approval CBE theory. Amgen can move to dismiss again, but must do so under the First Circuit's ruling that the studies plausibly allege newly acquired information. If the amended complaint survives, the case proceeds to discovery on what Amgen knew, when it knew it, and what the FDA was told, followed by expert discovery on causation and, likely, a summary-judgment motion renewing preemption on a full record. Amgen could also seek rehearing en banc in the First Circuit or petition the Supreme Court, though a fact-bound pleading ruling is a weak vehicle for certiorari.

FAQ

What did the court decide in the Aimovig wrongful death lawsuit?

The First Circuit, in Warner v. Amgen Inc., No. 25-1268, decided on October 9, 2026, affirmed dismissal of the original complaint as preempted but reversed the denial of leave to amend, allowing the plaintiff to plead a post-approval failure-to-warn claim based on newly acquired information.

Can you sue a drug company for failing to warn about a risk the FDA knew about?

Generally not for the pre-approval period: the First Circuit held a claim faulting Amgen for not seeking a stronger warning before approval was preempted because the FDA knew seizure patients were excluded from trials. A claim can proceed if new information after approval would have let the manufacturer change the label on its own.

Who is suing Amgen over Aimovig?

Elissa Warner, as personal representative of the estate of her son Lucas Warner, who allegedly suffered a fatal seizure after an Aimovig injection in June 2018. The suit was filed in Massachusetts state court in November 2023 and removed to federal court in March 2024.

Does Aimovig cause seizures?

No court has found that it does. The Aimovig label does not list seizures as a warning, and the Warner ruling addresses only whether the claim survives preemption at the pleading stage, not causation.

Is there an Aimovig class action or settlement?

No. As of October 13, 2026, Warner v. Amgen is an individual wrongful death case. There is no Aimovig MDL, class action or settlement fund.

What is newly acquired information under FDA rules?

Under 21 C.F.R. § 314.3(b), it is data or analyses not previously submitted to the FDA, such as new studies, adverse-event reports or meta-analyses, that reveal risks of a different type or greater severity or frequency than the agency had already seen.