Sanofi is currently defending several major lawsuits, headlined by a February 2026 kickback case brought by the Texas Attorney General, a breach-of-contract fight with its Dupixent partner Regeneron, an antitrust suit from Mylan over insulin, thousands of remaining Zantac cancer claims, and a separate Texas action targeting insulin pricing. The company has also accumulated close to $1.7 billion in regulatory penalties across roughly 40 violations since 2000.
Texas Kickback Suit Over Nurse and Insurance Support Programs
On February 19, 2026, Texas Attorney General Ken Paxton filed a petition in intervention in the 250th Judicial District Court of Travis County under Cause No. D-1-GN-25-002394. The state alleges Sanofi violated the Texas Health Care Program Fraud Prevention Act by providing in-kind bribes to physicians who prescribed its drugs for diabetes, multiple sclerosis, autoimmune disorders, and hemophilia.1Texas Attorney General. Attorney General Ken Paxton Sues Big Pharma Corporation Sanofi Illegally Giving Kickbacks Doctors2Texas Attorney General. Petition in Intervention, Cause No. D-1-GN-25-002394
Two Sanofi initiatives sit at the center of the case: a Free Nurse Program and a Support Services Program. The state says Sanofi deployed nurses and insurance-navigation staff to handle patient care tasks doctors would otherwise perform themselves or pay their own employees to do. That arrangement, according to Paxton’s office, functioned as “a powerful and improper inducement to prescribe Sanofi drugs over competing therapies.”3STAT News. Texas Sues Sanofi Over Nurses Kickbacks
Texas is seeking more than $1 million in monetary relief, including civil penalties, and an injunction barring Sanofi from continuing the programs.4Reuters. Texas Sues Sanofi for Allegedly Bribing Providers to Boost Drug Prescriptions Sanofi has denied the allegations, calling the case an attempt to “mischaracterize legitimate patient support programs” and saying it is “zealously defending this litigation.”3STAT News. Texas Sues Sanofi Over Nurses Kickbacks No rulings, hearings, or settlement discussions have been publicly reported as of mid-2026.
Regeneron v. Sanofi Over Dupixent Contract
Sanofi’s longtime immunology partner is now its courtroom adversary. In November 2024, Regeneron Pharmaceuticals sued Sanofi in the U.S. District Court for the Southern District of New York, Case No. 7:24-cv-08751, alleging Sanofi has breached the collaboration agreement covering Dupixent. Cumulative U.S. net sales of the drug exceed $30 billion.5Pearce IP. Regeneron v. Sanofi, USDC SDNY Complaint
The two companies have co-commercialized Dupixent since 2007 under a 50/50 U.S. profit split, with Sanofi recording sales and negotiating with pharmacy benefit managers. Regeneron says Sanofi has “stonewalled” repeated requests for full, unredacted access to those PBM contracts, offering only redacted documents or screen-shared views.6BioSpace. Regeneron Sues Sanofi Alleging Stonewalling in Dupixent Pact
The underlying worry is bundling. Regeneron suspects Sanofi is packaging Dupixent with other Sanofi drugs in PBM negotiations. If Sanofi allocates a disproportionate share of rebate liabilities to Dupixent in those multi-product deals, Regeneron would effectively subsidize the costs of drugs it has no stake in. The collaboration agreement explicitly prohibits Sanofi from bundling Dupixent in ways that disadvantage the drug to benefit other Sanofi products.5Pearce IP. Regeneron v. Sanofi, USDC SDNY Complaint A partial audit covering 2021 and 2022 already turned up what Regeneron describes as a “significant monetary adjustment, many multiples of $75,000” owed to it, including an unreported rebate Sanofi acknowledged only after being asked.6BioSpace. Regeneron Sues Sanofi Alleging Stonewalling in Dupixent Pact
Regeneron is seeking declaratory judgment, injunctive relief, and damages. Sanofi says it is “in full compliance with the terms of our collaboration agreement.”7Fierce Pharma. Regeneron Sues Partner Sanofi Over Commercial Transparency in Long-Running Dupixent
Mylan’s Insulin Antitrust Suit
Mylan (now Viatris Inc.) has sued Sanofi in the U.S. District Court for the Western District of Pennsylvania, alleging Sanofi maintained an unlawful monopoly over injectable insulin glargine by improperly listing patents in the FDA’s Orange Book. The Orange Book is a regulatory directory linking approved drugs to relevant patents, and an improper listing can trigger automatic stays of up to 30 months that block generic competitors. Mylan says Sanofi used that mechanism to delay the launch of its biosimilar Semglee against Sanofi’s branded Lantus.8Federal Trade Commission. FTC Files Amicus Brief Outlining Anticompetitive Harm Caused by Improper Orange Book Listings
In November 2023, the FTC filed an amicus brief arguing that improper Orange Book listings harm consumers by keeping drug prices artificially high. In January 2026, Judge Mark R. Hornak largely denied Sanofi’s motion to dismiss, allowing most of Mylan’s claims to proceed. The court dismissed Mylan’s “product hop” theory but granted leave to amend.9Law360. Mylan’s Sanofi Insulin Suit Mostly Survives Dismissal Bid
Texas Insulin Pricing Suit
Sanofi is also a defendant in a broader Texas action Paxton filed in October 2024 against the insulin supply chain. That case names three manufacturers, Eli Lilly, Novo Nordisk, and Sanofi, alongside three PBMs: Express Scripts, CVS Caremark, and Optum Rx. The state alleges a conspiracy to inflate insulin prices by as much as 1,000 percent, with manufacturers raising list prices to fund rebates that secured preferred formulary status while lower-cost alternatives were pushed off formularies. The complaint invokes the Texas Deceptive Trade Practices Act, unjust enrichment, and civil conspiracy. All named defendants have called the suit “meritless” or “baseless.”10Healthcare Dive. Texas Pharmacy Benefit Manager Pharma Company Lawsuit Insulin Prices
Zantac Cancer Claims
Sanofi is one of several defendants in litigation over Zantac (ranitidine), which plaintiffs say caused various cancers because ranitidine breaks down into a probable carcinogen. Multiple Sanofi entities are named in the federal multidistrict litigation consolidated in the U.S. District Court for the Southern District of Florida, Case No. 20-2924.11GovInfo. In re: Zantac (Ranitidine) Products Liability Litigation
The federal MDL judge dismissed the remaining cases in December 2022, citing insufficient evidence, and plaintiffs have indicated plans to appeal. State-court litigation has continued. In April 2024, Sanofi offered $100 million to settle 4,000 claims, and by May 2024 it agreed to pay between $200 million and $250 million to settle more than 10,000 lawsuits.12Drugwatch. Zantac Lawsuits Co-defendant GSK reached separate agreements in October 2024 to resolve roughly 93 percent of its state court cases, about 80,000 claims, for up to $2.2 billion. In Delaware, where substantial state proceedings continue, the state Supreme Court accepted an interlocutory appeal in August 2024 to review a lower court decision on the admissibility of plaintiffs’ expert testimony.13GSK. Zantac Litigation
Sanofi’s Penalty History
Sanofi’s cumulative regulatory record is substantial. According to the Violation Tracker database maintained by Good Jobs First, the company has accumulated nearly $1.7 billion in recorded penalties across 40 violations since 2000. False Claims Act cases account for the largest share, with 15 entries, followed by 12 records tied to price-fixing or anticompetitive conduct. Among the largest individual items: a $458 million product safety penalty assessed by the Hawaii Attorney General in 2024, a $350 million settlement with the Hawaii AG in 2025 for off-label or unapproved drug promotion, and a $190 million DOJ False Claims Act settlement in 2007 involving Sanofi’s predecessor Aventis Pharmaceuticals.14Good Jobs First. Violation Tracker – Sanofi
Federal enforcement has reached beyond U.S. borders. In September 2018, Sanofi agreed to pay $25.2 million to settle SEC charges that its subsidiaries in Kazakhstan and the Middle East violated the Foreign Corrupt Practices Act. The SEC found that Sanofi’s Kazakhstan operations used distributors to funnel kickbacks (coded internally as “marzipans”) to government procurement officials, while Middle East operations ran pay-to-prescribe schemes targeting healthcare providers. The resolution included $17.5 million in disgorgement, $2.7 million in prejudgment interest, and a $5 million civil penalty. Sanofi agreed to a cease-and-desist order without admitting or denying the findings.15SEC. SEC Charges Sanofi with FCPA Violations
The pattern of allegations across these cases is worth noting. The 2018 SEC action, the 2012 federal Hyalgan settlement of $109 million involving free product given to physicians,16U.S. Department of Justice. Sanofi US Agrees to Pay $109 Million to Resolve False Claims Act Allegations of Free Product Kickbacks and the current Texas kickback petition all revolve around a similar theory: that Sanofi used something of value beyond the drug itself to steer prescribing decisions.
Cases Where Sanofi Is Not the Wrongdoer
Two other high-profile matters involving Sanofi don’t fit the pattern of alleged corporate misconduct.
In Amgen Inc. v. Sanofi, 598 U.S. 594, decided unanimously in May 2023, the Supreme Court sided with Sanofi and invalidated Amgen’s patents on a class of cholesterol-lowering antibodies targeting the protein PCSK9. Amgen had identified 26 such antibodies but claimed protection over the entire universe of antibodies that bind certain PCSK9 residues, a universe potentially encompassing millions of variations. The Court held that Amgen’s specification failed the enablement requirement and characterized its disclosure as a “hunting license” requiring extensive trial-and-error work. The opinion reinforced that “the more one claims, the more one must enable,” raising the bar for broad functional patent claims across pharma and biotech.17Supreme Court of the United States. Amgen Inc. v. Sanofi, 598 U.S. 594
Separately, the conservative organization America First Legal filed federal civil rights complaints alleging Sanofi used race- and gender-based hiring quotas, citing a leaked video of a Sanofi executive describing a five-year plan to make one in five hires Black and one in ten Latino. AFL filed with both the EEOC and the Department of Labor’s Office of Federal Contract Compliance Programs, arguing the practices violated Title VII and equal opportunity clauses in Sanofi’s federal contracts. In September 2024, the OFCCP held an informal compliance conference with Sanofi. According to AFL’s account, the agency reported that Sanofi acknowledged and agreed to end the practices identified in the complaint.18America First Legal. Victory: Global Healthcare Company Sanofi Walks Back Illegal Discriminatory Hiring Practices Following Federal Civil Rights Complaint From AFL