Dupixent MCL in New Jersey: Plaintiffs and Sanofi Jointly Ask for Middlesex County Coordination

The Dupixent litigation now has a second front: plaintiffs and the drug's manufacturers have jointly asked the New Jersey Supreme Court to create a Dupixent MCL, a Multicounty Litigation that would centralize every state-court case alleging that dupilumab causes or accelerates cutaneous T-cell lymphoma (CTCL) before a single Middlesex County judge. The application, dated 15 September 2026 and listed by the Judiciary on 2 October, is unusual mainly because it is joint, and it matters because New Jersey is both the home of the federal MDL 3180 and the corporate home of Sanofi's U.S. business, which makes the state court an obvious alternative venue for claimants.

The request does not change the federal docket, but it decides where a second stream of Dupixent claims will be managed and how closely it will track the federal schedule. If the Court grants it, a Middlesex County judge would run the state cases in parallel with Judge Zahid N. Quraishi in Trenton, roughly 25 miles away.

What did the parties ask the New Jersey Supreme Court to do?

The letter application asks for two things. First, that all pending and future New Jersey state-court actions alleging injury from Dupixent be designated as Multicounty Litigation under Rule 4:38A, the court rule that authorizes centralized management of mass cases. Second, that the Dupixent MCL be assigned to Middlesex County. The parties also requested expedited consideration, citing the value of coordinating the state and federal proceedings while both remain at an early stage; the federal court's initial case management conference was then set for 1 October 2026.

The applicants are the plaintiffs with state-court cases and the defendants, Sanofi-Aventis U.S. LLC, Regeneron Pharmaceuticals, Inc. and Genzyme Corporation. The letterhead on the publicly posted copy is that of Weitz & Luxenberg, a firm that has publicly championed the federal MDL. The defendants join the request for coordination while expressly disputing the plaintiffs' allegations, including the core claim that Dupixent causes or exacerbates CTCL.

Joint MCL applications are not unheard of, but they are less common than contested ones. Defendants frequently resist state-court centralization because a designated MCL makes a state forum more efficient and therefore more attractive to filers. Here, both sides apparently concluded that a single coordinated state docket is preferable to cases scattered across New Jersey's 21 counties, each with its own discovery schedule and its own risk of an early trial date.

Has the Dupixent MCL been approved?

No. As of 19 October 2026, the New Jersey Courts' Multicounty Litigation page lists the "Dupixent MCL Application" dated 2 October 2026 among the applications currently before the Court, and no designation order or notice of decision has been published. The Supreme Court decides MCL applications after notice and an opportunity for comment, so the joint nature of the filing does not make approval automatic, although it removes the most common source of objection.

How does the New Jersey MCL process work?

New Jersey's equivalent of the federal Multidistrict Litigation (MDL) system is created by court rule rather than statute. Rule 4:38A provides that the Supreme Court may designate a case or category of cases as Multicounty Litigation for centralized management under guidelines the Court adopts. The current guidelines are Directive #02-19, issued 22 February 2019, which superseded Directive #08-12.

Under those guidelines, an application is submitted to the Administrative Director of the Courts, with notice to all parties, Assignment Judges and Civil Presiding Judges. The Judiciary then publishes a Notice to the Bar inviting comments on and objections to the application within a stated period. Recent notices illustrate the timing: the June 2026 notice on the No Surprises Act MCL application set a comment deadline one month after publication, with comments directed to the Administrative Director or to the Judiciary's comments mailbox. After reviewing the comments, the Court issues an order either designating the litigation and assigning it to a vicinage and a judge, or denying the application, as it did in 2026 with the Daniel's Law MCL application.

What criteria does the Court apply?

Directive #02-19 lists the characteristics the Court weighs in deciding whether MCL treatment is warranted. They include whether the litigation:

• involves large numbers of parties;
• involves many claims with common, recurrent issues of law and fact associated with a single product, mass disaster, or complex environmental or toxic tort;
• involves geographic dispersion of parties;
• involves a high degree of commonality of injury or damages among plaintiffs;
• presents a value interdependence between different claims, meaning the perceived strength of causation and liability turns on how similar suits fare elsewhere; and
• involves remoteness between the trial court and where the actual decision-makers for the parties are located.

The guidelines separately list factors for choosing the vicinage, such as the location of the parties and counsel, existing caseloads, and the experience of available judges with complex litigation.

How does the Dupixent application fit those criteria?

On the face of the record, closely. The claims all concern a single product, all allege the same injury (CTCL, commonly mycosis fungoides or Sézary syndrome), and all turn on the same Failure to Warn theory: that the label carried no lymphoma warning despite adverse event reports and published studies. Value interdependence is acute, because a General Causation ruling in either forum will shape the settlement value of every claim. The weakest criterion is volume; the state docket is still small.

How many Dupixent cases are in New Jersey state court and in MDL 3180?

The application itself states that approximately 36 cases were pending before Judge Quraishi in the federal MDL when it was written. Secondary trackers give slightly higher later figures, reporting 38 federal actions by early October 2026. For the state side, the Lawsuit Information Center reported that about a dozen Dupixent cases had been filed in New Jersey Superior Court by mid-September 2026; that figure has not been confirmed from a court-published count and should be treated as approximate.

Date	Event	Source
13 Feb 2026	Motion to centralize federal cases filed with the JPML	JPML docket
4 Jun 2026	JPML creates MDL No. 3180 in D.N.J. before Judge Quraishi; 15 actions from 12 districts	Transfer order
15 Sep 2026	Joint letter application for a Dupixent MCL in Middlesex County	NJ Courts
1 Oct 2026	Initial case management conference in MDL 3180	Initial Procedure Order
2 Oct 2026	Judiciary lists the Dupixent MCL Application as pending	NJ Courts MCL page
6 Oct 2026	New Jersey Law Journal reports the application	Law.com
Pending	Notice to the Bar, comment period, Supreme Court decision	Directive #02-19

Why Middlesex County?

Middlesex County is New Jersey's most experienced pharmaceutical MCL venue. The Supreme Court has previously sent the Propecia, Risperdal/Seroquel/Zyprexa and Taxotere litigations there, among others, and the vicinage has judges accustomed to managing parallel state and federal drug dockets. Its location in central New Jersey, near both the federal courthouse in Trenton and Sanofi's U.S. operations in Bridgewater, supports the practical goal the parties cited: coordinating depositions and document production with the federal MDL rather than duplicating them.

The application, as publicly described, asks for Middlesex County but does not bind the Court to a particular judge. The Supreme Court names the designated judge in its order.

What is the Dupixent lawsuit about?

Dupixent (dupilumab), marketed by Sanofi and Regeneron, is a biologic approved for atopic dermatitis, asthma and several other inflammatory conditions. The plaintiffs allege that the drug causes, accelerates, or unmasks CTCL, a rare lymphoma of the skin that can be mistaken for eczema in its early stages, and that the manufacturers failed to warn patients and prescribers. Defendants deny those allegations. The federal cases rely in part on published retrospective cohort and pharmacovigilance studies, and on the FDA's March 2025 listing of dupilumab among drugs with potential signals of serious risk. The prescribing information still carries no lymphoma warning.

Because Dupixent is a prescription drug, the Learned Intermediary Doctrine will frame warning adequacy in both forums, and federal Preemption (Products) defenses based on the FDA labeling regime are likely to be raised in each.

How would a Dupixent MCL interact with MDL 3180?

State and federal mass dockets run on separate tracks; an MCL judge is not bound by an MDL judge's rulings. In practice, though, New Jersey MCL judges and federal transferee judges commonly coordinate through joint conferences, shared deposition protocols and cross-noticed discovery. The parties' request for expedited consideration signals that they want exactly that, and early: if the MCL is created before the federal court issues its first substantive scheduling orders, the two dockets can share a single General Causation discovery plan.

The federal joint management report proposed, among other dates, lifting a stay on general causation discovery on 16 November 2026, Plaintiff Fact Sheet (PFS)-style profile forms around 18 December 2026, and completion of general causation expert depositions by 28 February 2028, all subject to Judge Quraishi's approval. A coordinated MCL would likely adopt parallel deadlines.

The divergence risk is the Daubert Challenge. New Jersey applies its own expert-admissibility standard under In re Accutane Litigation (2018), which brought the state close to the federal Daubert approach but not identical to it. A causation ruling favorable to plaintiffs in one forum and adverse in the other would split the litigation's value, which is why both sides have an incentive to sequence the rulings.

Can Dupixent plaintiffs file in New Jersey state court instead of federal court?

Generally, a plaintiff may sue a defendant in its home state, and Sanofi-Aventis U.S. LLC is headquartered in New Jersey. Filing there by a non-New Jersey plaintiff against a New Jersey-based defendant can also defeat removal under the forum-defendant rule in 28 U.S.C. § 1441(b)(2), although snap-removal practice complicates that in the Third Circuit. Statute of Limitations questions, choice of law and personal jurisdiction over the other defendants remain case-specific. The existence of an MCL makes the state forum more predictable, not more favorable on the merits.

What it means for practitioners

• Claimants' counsel: A designated MCL would give a single, experienced venue for filings and likely a master complaint and short-form complaint process. Firms weighing federal versus state filing should watch the Notice to the Bar and the eventual designation order for case management terms.
• Defendants: Joining the application lets the manufacturers shape coordination from the start and avoid inconsistent discovery across counties; the cost is a more efficient state forum that may attract additional filings.
• Litigation funders: Two coordinated dockets with a shared causation timeline concentrate risk on one or two General Causation rulings; portfolio valuations should model correlated, not independent, outcomes.
• Other stakeholders: Any party or counsel with views on venue or designation should file comments within the period stated in the Notice to the Bar once it is published.

FAQ

What is the Dupixent MCL?

It is a proposed New Jersey Multicounty Litigation that would centralize all state-court Dupixent CTCL cases before one Middlesex County judge under Rule 4:38A. It has been applied for but not yet designated.

Who applied for the Dupixent MCL?

The plaintiffs and defendants Sanofi-Aventis U.S. LLC, Regeneron Pharmaceuticals, Inc. and Genzyme Corporation applied jointly, by letter dated 15 September 2026.

Where would the Dupixent MCL be heard?

The parties asked for Middlesex County, which has handled earlier pharmaceutical MCLs including Propecia and Taxotere. The Supreme Court will choose the judge.

How many Dupixent cases are pending?

The application cites about 36 federal cases in MDL 3180; trackers report 38 by early October 2026 and roughly a dozen New Jersey state-court cases by mid-September.

Does the MCL replace the federal Dupixent MDL?

No. MDL 3180 continues in the District of New Jersey; the MCL would run in parallel and coordinate with it.

What injury do the Dupixent lawsuits allege?

They allege that dupilumab caused or accelerated cutaneous T-cell lymphoma and that the label failed to warn of that risk, which the manufacturers deny.