MDL Track
MDL 3180
Dupixent (dupilumab) cutaneous T-cell lymphoma
Pharmaceutical · claims alleging dupilumab (Dupixent) causes or accelerates cutaneous T-cell lymphoma (CTCL) and other lymphoproliferative disorders
Defendant
Sanofi-Aventis U.S. LLC
MDL / Track
MDL 3180
Judge
Various
Plaintiffs
15 pending
Bellwether / Trial
No verdicts yet
Settlement Status
No settlements
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Case overview
Plaintiffs are filing product liability lawsuits against Sanofi and Regeneron alleging Dupixent (dupilumab) causes cutaneous T-cell lymphoma (CTCL). Michael Durkin filed a complaint in the U.S. District Court for the Middle District of Florida on Feb. 4, 2026, claiming the manufacturers failed to warn that the IL-4/IL-13 inhibitor could trigger mycosis fungoides and Sézary syndrome. No MDL has been established as of March 2026; litigation remains in early investigative stages with plaintiffs' counsel screening cases where CTCL was diagnosed after Dupixent initiation.
Causation Theory
The causation theory centers on dupilumab's immunomodulatory mechanism: IL-4Rα blockade may upregulate IL-13RA2 signaling, alter T-cell microenvironment dynamics, and unmask or accelerate occult CTCL. A 2024 Journal of the American Academy of Dermatology study reported a 4.1-fold increased CTCL risk in atopic dermatitis patients treated with dupilumab versus untreated patients, with most diagnoses occurring more than one year after initiation. A January 2026 Frontiers in Medicine large-scale retrospective cohort study found no statistically significant increased lymphoma risk with dupilumab, though plaintiffs distinguish this as suffering from selection bias by comparing against other systemic therapies rather than untreated controls. A 2025 PubMed review of 124 dupilumab-associated lymphoproliferative disorder cases identified a median 5-month time-to-diagnosis and histopathologic features including epidermotropism with spongiosis and T-cell marker loss.
Case Management Orders
Litigation status
Plaintiffs filed a motion for transfer with the JPML on February 13, 2026, seeking consolidation of all federal Dupixent lymphoma cases into an MDL in the Northern District of Georgia. At least 15 cases are pending across 12 district courts, with four already filed in the Northern District of Georgia.
MDL Track
MDL 3180
Dupixent (dupilumab) cutaneous T-cell lymphoma
Geographic exposure
Over 1 million patients treated with Dupixent since 2017 FDA approval; 200+ CTCL cases reported through 2024 per litigation. No MDL established as of March 2026; individual cases filed in Fla., La., Tenn. FDA evaluating label update but no recall issued.
Michael Durkin v. Sanofi-Aventis U.S. LLC et al., filed Feb. 4, 2026, M.D. Fla. — CTCL (Mycosis Fungoides type) diagnosis Oct. 2025 after Dupixent treatment for eczema.
Michael Phillips v. Sanofi/Regeneron, filed Dec. 2025, E.D. La. — Dual CTCL diagnosis (Mycosis Fungoides and Sezary Syndrome) after one year of Dupixent injections for adult-onset eczema.
Richardson v. Sanofi/Regeneron, filed Oct. 2025 — Wrongful death action alleging Dupixent caused PTCL death of Cynthia Hyde.
Population-based study of asthma patients (Sheng-Kai Ma et al., 2025) shows dupilumab associated with 1.79-fold increased lymphoma risk (HR 1.79; 95% CI 1.19–2.71), strongest for mature T-cell and NK-cell neoplasms; 54 vs. 43 cases.
FDA Adverse Event Reporting System analysis shows 30.0-fold increased proportional reporting ratio for CTCL in dupilumab users (95% CI 25.0-35.9). Over 200 CTCL cases identified since 2017 approval per litigation filings.
Hasan et al. retrospective matched cohort: atopic dermatitis patients on Dupixent had 4.1-fold higher CTCL risk vs. non-users; most diagnoses occurred >1 year after treatment initiation.
Key defendants
Sanofi-Aventis U.S. LLC
Role: Manufacturer
Named in all filed complaints; MDL motion filed Feb. 13, 2026 seeks consolidation of at least 15 federal cases. No answer or dismissal motion yet noted.
Regeneron Pharmaceuticals Inc.
Role: Manufacturer
Co-defendant with Sanofi; joint development and marketing of Dupixent. No separate defense posture reported; both defendants aligned in early litigation stage.
| Defendant | Role | Intelligence Note |
|---|---|---|
| Sanofi-Aventis U.S. LLC | Manufacturer | Named in all filed complaints; MDL motion filed Feb. 13, 2026 seeks consolidation of at least 15 federal cases. No answer or dismissal motion yet noted. |
| Regeneron Pharmaceuticals Inc. | Manufacturer | Co-defendant with Sanofi; joint development and marketing of Dupixent. No separate defense posture reported; both defendants aligned in early litigation stage. |
Timeline
FDA Approves Dupixent for Atopic Dermatitis
FDA grants approval to Dupixent (dupilumab) for moderate-to-severe atopic dermatitis. Manufacturers: Sanofi and Regeneron.
Retrospective Study Links Dupixent to CTCL
Study published April 6, 2024 (Hasan et al.) finds Dupixent-treated atopic dermatitis patients had 4.1003-fold increased odds of developing cutaneous T-cell lymphoma versus non-users. Most cases diagnosed more than one year post-initiation.
JAAD Publishes Full CTCL Study
Journal of the American Academy of Dermatology publishes complete retrospective cohort study confirming elevated CTCL risk in Dupixent users with atopic dermatitis.
FDA Adds Dupixent to Serious Risks List
FDA places Dupixent on quarterly 'Potential Signals of Serious Risks/New Safety Information' list due to reports of CTCL.
FDA Analysis of 181,575 Adverse Events
FDA analysis of FAERS data identifies 181,575 total Dupixent adverse event reports with elevated CTCL reporting rates.
European Respiratory Journal Study
Study in European Respiratory Journal identifies CTCL cases among Dupixent-treated asthma patients.
Individual Lawsuits Filed; No MDL
Individual product liability lawsuits filed against Sanofi and Regeneron alleging failure to warn of CTCL risk. No MDL petition filed; no class action certified.
Litigation Remains Pre-Consolidation
No MDL established for Dupixent CTCL litigation. Cases proceeding individually. No bellwether trials scheduled. No settlements reported.
Statute of limitations
No MDL established as of March 2026. Individual cases filed in federal courts including M.D. Tenn. (Richardson, response deadline Jan. 7, 2026 per Magistrate Judge Alistair Newbern). Primary accrual theories: (1) date of CTCL diagnosis; (2) date of discovery of Dupixent-CTCL link. FDA placed Dupixent on potential serious risks list March 2025; label still lacks CTCL warning per November 2025 reports. Discovery rule critical in most jurisdictions given latency period (August 2024 JAAD study showed 4.1x increased risk, median diagnosis >1 year post-initiation). Federal preemption defenses likely; no federal recall. Screen for: minimum 1 month Dupixent use; CTCL, mycosis fungoides, or Sézary syndrome diagnosis; no prior lymphoma/leukemia.
Delaware
2 years from date of injury or diagnosis
Rule: Product liability and personal injury claims must be filed within two years of the date of injury or diagnosis per Morris James LLP guidance
Discovery: Accrual may begin when symptoms first appeared, when diagnosis was made, or when connection to Dupixent was discovered
Exceptions may apply; early consultation advised given multiple potential accrual triggers
Tennessee
1 year from accrual (typical wrongful death)
Rule: Wrongful death claim filed October 2025 in M.D. Tenn. (Richardson v. Regeneron/Sanofi) with response deadline January 7, 2026 per Magistrate Judge Alistair Newbern order
Discovery: Accrual tied to death date or discovery of causation; case management conference held December 8, 2025
Federal court handling early bellwether; no MDL yet established
Illinois
2 years from accrual (typical personal injury)
Rule: Cancer lawsuit filed December 2025 per Sokolove Law update; standard Illinois product liability SOL applies
Discovery: Discovery rule likely available given CTCL latency period (studies show median diagnosis >1 year post-initiation)
Filed as individual action; no consolidation yet
California
2 years from discovery of injury
Rule: Discovery rule standard; accrual when plaintiff knew or should have known of injury and its cause
Discovery: Critical given August 2024 JAAD study publication and March 2025 FDA serious risks list placement as potential notice triggers
No state revival statute applicable; federal preemption defenses expected
New York
3 years from accrual
Rule: CPLR 214(2) product liability; 3 years from date of injury or discovery
Discovery: Discovery rule applies; continuous treatment doctrine may toll if misdiagnosis ongoing
Large plaintiff pool expected given Dupixent prescribing volume; screen for eczema patients with delayed CTCL diagnosis
Texas
2 years from accrual
Rule: Tex. Civ. Prac. & Rem. Code § 16.003; product liability claims subject to 2-year SOL
Discovery: Discovery rule applies; fraudulent concealment possible given lack of CTCL warning on label
No pending revival legislation; federal court filings likely given manufacturer diversity
Florida
4 years from accrual (2 years wrongful death)
Rule: Fla. Stat. § 95.11(3)(a) product liability; 4 years for personal injury, 2 years for wrongful death
Discovery: Discovery rule applies; statute begins when injury discovered or should have been discovered with due diligence
Longer SOL window but early filing strategic given potential MDL formation
| State | SOL | Rule | Discovery Rule | Notes |
|---|---|---|---|---|
| Delaware | 2 years from date of injury or diagnosis | Product liability and personal injury claims must be filed within two years of the date of injury or diagnosis per Morris James LLP guidance | Accrual may begin when symptoms first appeared, when diagnosis was made, or when connection to Dupixent was discovered | Exceptions may apply; early consultation advised given multiple potential accrual triggers |
| Tennessee | 1 year from accrual (typical wrongful death) | Wrongful death claim filed October 2025 in M.D. Tenn. (Richardson v. Regeneron/Sanofi) with response deadline January 7, 2026 per Magistrate Judge Alistair Newbern order | Accrual tied to death date or discovery of causation; case management conference held December 8, 2025 | Federal court handling early bellwether; no MDL yet established |
| Illinois | 2 years from accrual (typical personal injury) | Cancer lawsuit filed December 2025 per Sokolove Law update; standard Illinois product liability SOL applies | Discovery rule likely available given CTCL latency period (studies show median diagnosis >1 year post-initiation) | Filed as individual action; no consolidation yet |
| California | 2 years from discovery of injury | Discovery rule standard; accrual when plaintiff knew or should have known of injury and its cause | Critical given August 2024 JAAD study publication and March 2025 FDA serious risks list placement as potential notice triggers | No state revival statute applicable; federal preemption defenses expected |
| New York | 3 years from accrual | CPLR 214(2) product liability; 3 years from date of injury or discovery | Discovery rule applies; continuous treatment doctrine may toll if misdiagnosis ongoing | Large plaintiff pool expected given Dupixent prescribing volume; screen for eczema patients with delayed CTCL diagnosis |
| Texas | 2 years from accrual | Tex. Civ. Prac. & Rem. Code § 16.003; product liability claims subject to 2-year SOL | Discovery rule applies; fraudulent concealment possible given lack of CTCL warning on label | No pending revival legislation; federal court filings likely given manufacturer diversity |
| Florida | 4 years from accrual (2 years wrongful death) | Fla. Stat. § 95.11(3)(a) product liability; 4 years for personal injury, 2 years for wrongful death | Discovery rule applies; statute begins when injury discovered or should have been discovered with due diligence | Longer SOL window but early filing strategic given potential MDL formation |
Live intelligence
AI litigation brief
Dupixent CTCL remains pending consolidation with 39 current signals in the accepted feed.
Overview
Plaintiffs filed a motion for transfer with the JPML on February 13, 2026, seeking consolidation of all federal Dupixent lymphoma cases into an MDL in the Northern District of Georgia. At least 15 cases are pending across 12 district courts, with four already filed in the Northern District of Georgia.
Key developments
Trajectory
Press and regulatory signals are moving in tandem for Dupixent CTCL. The next escalation check is whether these agency actions prompt new PACER filings or MDL scheduling orders.
Editorial intelligence
MDL 3180 should stay on the lead docket watch because it is the primary consolidation vehicle for Dupixent CTCL.
Generated May 27, 2026, 5:00 PM UTC
39 events detected
Google News (9)
Regeneron Opens Lower After Cancer Trial Setback - TechStock²
Friday Five – Updates from AACR, ASCO and AAN, Sanofi's second life for Dupixent, Regeneron's free gene therapy, and more… - FirstWord Pharma
Dupilumab and Lymphoma Risk in AD? - Conexiant
FDA Action Alert: Sanofi/Regeneron, Merck, REGENXBIO and More - BioSpace
Dupilumab use is associated with lower all-cause mortality but increased risk of lymphoma in asthma patients - 2 Minute Medicine
Dupilumab treatment is associated with improved mortality but increased risk of lymphoma in asthma patients - 2 Minute Medicine
Sanofi Eczema Drug Linked To Lymphoma, Suit Says - Law360
Dupixent and cancer risks: What patients need to know about lymphoma concerns - TribLIVE.com
Sanofi, Regeneron Shares Tumble as Dupixent Follow-Up Fails Phase III COPD Test - BioSpace
The Journal of allergy and clinical immunology • Wang Y • PMID 42153932 • Letter.
Cancer medicine • Li H • PMID 42178747 • Journal Article.
Clinical and experimental dermatology • Pujol RM • PMID 41972340 • Journal Article.
The Journal of allergy and clinical immunology • Guenova E • PMID 41967816 • Journal Article.
Journal of the European Academy of Dermatology and Venereology : JEADV • Beylot-Barry M • PMID 41821352 • Journal Article.
No recent court filing signals. Monitoring is active — this section updates automatically.
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LexGenius Ranking
84Score
Court, news, and regulatory activity are elevated
Monitoring
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Last: May 27, 2026, 5:00 PM UTC
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Source Monitoring
PACER
PACER
Google News
FDA
PubMed
Event feed
39
events detected
AI Brief
Dupixent CTCL remains pending consolidation with 39 current signals in the accepted feed.
Overview
Plaintiffs filed a motion for transfer with the JPML on February 13, 2026, seeking consolidation of all federal Dupixent lymphoma cases into an MDL in the Northern District of Georgia. At least 15 cases are pending across 12 district courts, with four already filed in the Northern District of Georgia.
Key developments
TechStock² news on May 18: Regeneron Opens Lower After Cancer Trial Setback - TechStock². ‖ FAERS FDA alert on Mar 31: FAERS Filing 26559545: T-cell lymphoma. ‖ PubMed research on May 18: New or exacerbated atypical head and neck lesions as sentinel clinical features of dupilumab-associated cutaneous T-cell lymphoma..
Generated May 27, 2026, 5:00 PM UTC
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