Start Your Free Review
Answer 2-3 quick questions to review your potential case.
What Is an MDL and Why It Matters for Dupixent Plaintiffs
Multidistrict litigation (MDL) is a procedural mechanism under 28 U.S.C. § 1407 that allows the Judicial Panel on Multidistrict Litigation to transfer civil actions pending in different federal districts to a single district for coordinated pretrial proceedings. The rationale is efficiency: when hundreds or thousands of cases involve common questions of fact — such as whether Dupixent causes CTCL, whether Sanofi knew of the risk, and whether the label was inadequate — it is wasteful to have each case conduct independent discovery, retain separate experts, and litigate the same Daubert motions in dozens of courtrooms.
For Dupixent plaintiffs, MDL consolidation offers both advantages and risks. The advantages include shared resources: plaintiffs' attorneys pool their expertise and funding through a Plaintiffs' Steering Committee (PSC), conduct unified discovery against Sanofi and Regeneron, and develop common expert reports on general causation, regulatory history, and internal corporate knowledge. The risks include delay: MDL proceedings can take years before bellwether trials begin, and individual plaintiffs cannot unilaterally accelerate their cases. Additionally, the MDL judge's rulings on Daubert and summary judgment apply across all cases, meaning an unfavorable ruling can affect every plaintiff simultaneously.
The Venue Dispute: N.D. Georgia vs. S.D. New York
The choice of MDL venue is one of the most consequential early decisions in mass tort litigation. Plaintiffs in the Dupixent CTCL litigation have proposed the Northern District of Georgia (Atlanta) as the transferee court, citing the district's experienced judiciary, manageable docket, efficient case management history, and geographic accessibility for plaintiffs' counsel. Atlanta's federal courthouse has handled significant pharmaceutical and product liability cases, and the Northern District's local rules facilitate streamlined discovery scheduling.
Sanofi and Regeneron prefer the Southern District of New York, where Regeneron is headquartered in nearby Tarrytown, Westchester County. The defense argument centers on convenience for corporate witnesses and the SDNY's familiarity with complex pharmaceutical litigation. However, plaintiffs counter that housing the MDL in a defendant's home district creates an inherent appearance of favoritism, and that the SDNY's notoriously heavy docket may cause scheduling delays. Other districts mentioned as potential venues include the Eastern District of Pennsylvania (Philadelphia's pharmaceutical MDL pedigree), the District of New Jersey (Sanofi US headquarters), and the Northern District of Illinois (Chicago's experienced mass tort bench).
The JPML will weigh several factors in its venue decision: the convenience of the parties and witnesses, the number of cases already pending in each district, the experience of judges in the candidate districts with pharmaceutical MDLs, and the overall efficiency of the proposed transferee court. The Panel's decision is expected in mid-to-late 2026, and the selected venue will become the procedural home for all federal Dupixent CTCL cases through pretrial completion.
Current Case Count and Filing Trajectory
As of early 2026, over 250 individual Dupixent CTCL lawsuits have been filed in federal courts across at least 15 districts. The filing rate has accelerated following media coverage of the CTCL risk and the announcement of the MDL petition. Legal analysts project the case count could reach 1,000 to 5,000 within 12 to 18 months as attorney advertising drives case acquisition and more Dupixent patients undergo skin biopsies revealing CTCL. The trajectory mirrors early filings in the Zantac and Roundup litigations, both of which grew from hundreds to tens of thousands of cases within two to three years of MDL formation.
The earliest cases — Richardson v. Sanofi (W.D. Tennessee, October 2025), Johnson v. Sanofi (N.D. Illinois, December 2025), and Fraioli v. Sanofi (S.D. Florida, January 2026) — will likely be considered for bellwether selection given their early filing dates and developed factual records. Bellwether trials are test cases selected to gauge jury response and establish settlement values. In pharmaceutical MDLs, bellwether outcomes often determine whether global settlement negotiations proceed and at what range.
What MDL Means for Your Individual Case
If you have filed or plan to file a Dupixent CTCL lawsuit in federal court, MDL consolidation means your case will be transferred to the selected transferee district for pretrial proceedings. You will retain your own attorney, but your case will be managed alongside all other federal cases under the MDL judge's case management orders. Discovery conducted by the Plaintiffs' Steering Committee will benefit all cases — you will have access to internal Sanofi documents, expert reports, and deposition testimony without your individual attorney needing to independently subpoena those materials.
Your case will not go to trial in the MDL unless it is selected as a bellwether. After MDL pretrial proceedings conclude — which typically takes 2 to 4 years — cases that have not settled are remanded (sent back) to their original filing districts for individual trial. However, most pharmaceutical MDLs result in global settlement before remand. The settlement amount for individual cases is typically determined by a settlement grid that scores cases based on injury severity (CTCL stage), duration of Dupixent use, quality of medical documentation, and other factors.
Key Upcoming Milestones
The Dupixent CTCL litigation is in its earliest stages, with several milestones expected in 2026 and 2027. The JPML is expected to issue its MDL transfer order in mid-to-late 2026, selecting the transferee court and judge. Following transfer, the MDL judge will appoint a Plaintiffs' Steering Committee and issue initial case management orders governing discovery schedules, Plaintiff Fact Sheets (PFS), and defendant document production. General causation expert discovery and Daubert proceedings will follow, likely in late 2027 or early 2028. Bellwether trial selection and preparation could begin in 2028, with the first trials potentially in 2029.
For plaintiffs considering filing, the key takeaway is urgency. Statutes of limitations continue to run regardless of MDL status. Filing now ensures your claim is preserved and positions you to benefit from the earliest stages of coordinated discovery. Cases filed before MDL formation may receive preferential consideration for bellwether selection, and early-filing attorneys often play leadership roles on the Plaintiffs' Steering Committee. Waiting does not improve your position — it risks deadline expiration and places you further back in the queue.
State Court Alternatives to MDL
Not all Dupixent CTCL cases must be filed in federal court. Plaintiffs who file in state court are not subject to MDL transfer. State court filing may be strategically advantageous in plaintiff-friendly jurisdictions like Philadelphia (Pennsylvania), Cook County (Illinois), St. Louis (Missouri), or Madison County (Illinois). Several states have their own mass tort coordination mechanisms — California's JCCP, New York's NYCAL model, and New Jersey's Middlesex County mass tort program — that can achieve consolidation benefits without federal MDL transfer.
The choice between federal and state court filing involves strategic considerations that an experienced pharmaceutical liability attorney can evaluate based on the plaintiff's home state, the applicable law, the quality of the state court venue, and the plaintiff's tolerance for the MDL timeline. Some plaintiffs choose to file in state court to maintain more individual control over their case progression, while others prefer the resources and coordination of the federal MDL. Both paths can lead to favorable outcomes; the decision should be made with full awareness of the trade-offs.
Frequently Asked Questions
Related Pages
CTCL Diagnosis After Dupixent Use
Cutaneous T-cell lymphoma is a rare and aggressive blood cancer that masquerades as eczema, psoriasis, and other benign skin conditions — making it uniquely dangerous for Dupixent patients who already carry dermatitis diagnoses. Misdiagnosis rates exceed 40 percent in early-stage CTCL because the symptoms overlap so precisely with the conditions Dupixent is prescribed to treat. Dermatologists expect itchy, red patches in their Dupixent patients; what they may not expect is that those patches now harbor malignant T-cells. Staging ranges from IA (limited patches) to IVB (visceral organ involvement and blood-borne Sezary cells), and the difference between a Stage IA diagnosis and a Stage IIB diagnosis can mean the difference between a normal life expectancy and a five-year survival rate below 40 percent. The critical diagnostic tool is a skin biopsy with immunohistochemistry, which can reveal hallmark Pautrier microabscesses — clusters of malignant T-cells in the epidermis that do not appear in benign dermatitis. Every Dupixent patient whose skin condition worsens, changes character, or fails to respond to continued treatment should demand a biopsy, not another refill.
Dupixent Eye Problems and Ocular Side Effects
Conjunctivitis is the most common adverse event associated with Dupixent, occurring in approximately 30 percent of atopic dermatitis patients in clinical trials — a rate ten times higher than placebo. But conjunctivitis is just the visible surface of a broader ocular toxicity profile that includes blepharitis, keratitis, dry eye syndrome, limbal stem cell deficiency, and in rare but devastating cases, corneal perforation requiring emergency surgical intervention. These eye problems often develop within the first three months of treatment and can persist even after Dupixent is discontinued. Sanofi and Regeneron have acknowledged conjunctivitis on the Dupixent label but have minimized the severity spectrum, leading patients and prescribers to underestimate the risk of serious, vision-threatening complications. For patients who have suffered permanent vision impairment, corneal scarring, or required corneal transplantation due to Dupixent-related ocular injury, the manufacturer's characterization of these events as manageable side effects is contradicted by their clinical experience.
Dupixent Pediatric Use and CTCL Risk in Children
Sanofi and Regeneron have aggressively expanded Dupixent's pediatric indications, securing FDA approval for atopic dermatitis in children as young as 6 months old in 2022, following earlier approvals for ages 6 to 11 in 2020 and adolescents aged 12 to 17 in 2019. This expansion exposed millions of children with developing immune systems to a biologic drug that blocks IL-4 and IL-13 — cytokines critical to immune maturation, T-cell differentiation, and tumor surveillance. While CTCL is rare in children overall, the long-term consequences of sustained immune modulation during critical developmental windows are unknown because Sanofi's pediatric trials were not designed to detect rare cancers and follow-up periods were insufficient to capture latent malignancies. Pediatric Dupixent claims carry unique urgency: children have longer remaining lifespans over which to develop delayed-onset lymphoma, the immune insult occurs during a period of rapid lymphocyte development, and parents made treatment decisions based on safety assurances that did not account for the emerging CTCL signal. The duty to warn is heightened for pediatric drugs because parents — not the patient — make the consent decision, and they deserve complete risk information to exercise informed judgment.
Dupixent Wrongful Death Claims
When cutaneous T-cell lymphoma caused by Dupixent progresses to advanced stages and the patient dies, surviving family members may pursue wrongful death and survival action claims against Sanofi and Regeneron. Richardson v. Sanofi, filed in October 2025 in the Western District of Tennessee, was one of the first named Dupixent CTCL lawsuits and involved allegations of fatal lymphoma progression. Wrongful death claims compensate the decedent's family for loss of companionship, financial support, and funeral expenses, while survival actions compensate the decedent's estate for the pain, suffering, and medical costs the patient endured before death. These are legally distinct claims with different standing requirements, damage calculations, and statutes of limitations. State law controls who may bring a wrongful death claim — in some states, only a surviving spouse or children have standing, while in others, parents, siblings, or domestic partners may also qualify. The interplay between wrongful death statutes and product liability discovery rules creates filing deadline complexities that can extinguish viable claims if not handled promptly.
Dupixent Lawsuit Lawsuit
Dupixent (dupilumab) is a monoclonal antibody biologic drug developed by Regeneron Pharmaceuticals and marketed jointly with Sanofi-Aventis and its subsidiary Genzyme Corporation. The FDA first approved Dupixent in March 2017 for adults with moderate-to-severe atopic dermatitis (eczema) who had not responded adequately to topical treatments. Subsequent FDA approvals expanded its use to moderate-to-severe asthma in October 2018, chronic rhinosinusitis with nasal polyps (CRSwNP) in June 2019, eosinophilic esophagitis (EoE) in May 2022, prurigo nodularis in September 2022, and chronic obstructive pulmonary disease (COPD) with an eosinophilic phenotype in September 2024. With more than 37 million prescriptions dispensed globally, Dupixent became one of the best-selling biologic drugs in the world, generating over $13 billion in annual revenue for its manufacturers. The drug works by inhibiting interleukin-4 (IL-4) and interleukin-13 (IL-13) signaling — two cytokines that drive type 2 inflammation. While this mechanism was considered targeted and relatively safe, post-market surveillance and independent research have identified a concerning association between Dupixent use and cutaneous T-cell lymphoma (CTCL). CTCL is a rare cancer in which T-cells become malignant and attack the skin, often presenting initially as rashes or patches that can be mistaken for eczema. The critical concern is that symptoms of CTCL closely mimic the very conditions Dupixent is prescribed to treat, potentially masking the cancer and delaying diagnosis. A peer-reviewed study analyzing 19,612 patients found that Dupixent users faced a 4.5 times higher risk of developing CTCL compared to patients not using the drug. The FDA placed Dupixent on its drug safety watchlist in March 2025 and escalated to a formal investigation in September 2025 after receiving over 300 adverse event reports related to lymphoma and blood cancers. As of February 2026, individual lawsuits are being filed against Regeneron Pharmaceuticals, Sanofi-Aventis, and Genzyme Corporation. Plaintiffs allege that the manufacturers knew or should have known about the cancer risk and failed to adequately warn patients and prescribing physicians. Specific allegations include failure to warn, defective design of the drug's labeling, negligence in post-market surveillance, and fraudulent concealment of safety data. A wrongful death suit was filed in Tennessee in October 2025 on behalf of Chandra Richardson. Additional cases have been filed in Florida (January 2026) and Illinois (December 2025). Legal experts anticipate that the Judicial Panel on Multidistrict Litigation will consolidate federal cases into an MDL within the next 12 months.
View full case overview