French pharmaceutical company Sanofi has agreed in principle to settle a longstanding US antitrust lawsuit alleging that it used patent protections to restrict competition for its Lantus diabetes treatment, potentially bringing an end to nearly a decade of litigation.
The proposed agreement was disclosed in a filing submitted Tuesday to a federal court in Massachusetts, according to Reuters reports. The case had been scheduled to go to trial in January.
Financial details of the settlement have not been made public. Sanofi confirmed Wednesday that the terms would remain confidential and emphasized that the agreement does not constitute an admission of wrongdoing, Reuters reported.
The dispute centers on allegations that Sanofi improperly used the US pharmaceutical patent system to protect its Lantus SoloStar insulin injection pens from competing products, allowing the company to maintain higher prices for longer than it otherwise could have.
Among the plaintiffs were Cencora, Cardinal Health and McKesson, three of the largest pharmaceutical distributors in the United States. Other purchasers, including FWK Holdings and Meijer, also participated in the litigation.
According to Reuters, the companies argued that Sanofi’s patent practices delayed market competition and caused them to pay more for insulin products.
Patent Filings at Center of Dispute
The lawsuit focused on Sanofi’s use of the US Food and Drug Administration’s Orange Book, which identifies patents associated with approved brand-name medications.
Under the Hatch-Waxman Act, certain patent disputes can trigger a 30-month suspension of FDA approval for competing generic products. The provision is intended to balance incentives for pharmaceutical innovation with the introduction of lower-cost alternatives.
The purchasers alleged that Sanofi exploited those rules by listing patents that did not qualify for inclusion in the Orange Book, creating obstacles for manufacturers seeking to introduce competing insulin treatments.
Lantus, which contains the long-acting insulin insulin glargine, first received FDA approval in 2000. Its original active-ingredient patent expired in 2014.
The plaintiffs maintained that competitors could have sought regulatory approval for alternative products as early as 2015 without the disputed patent listings. Instead, they alleged, Sanofi’s actions prevented full competition until at least 2020, according to Reuters.
The allegations specifically concerned Lantus SoloStar, a prefilled insulin injection pen used by people with diabetes.
Sanofi has disputed claims that its conduct unlawfully delayed competing products.
In its response to the settlement, the company maintained that the allegations lacked merit and reiterated that it had not accepted legal responsibility, Reuters reported.
Years of Litigation Near an End
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The legal battle began in 2016 as a proposed class-action lawsuit brought by pharmaceutical purchasers seeking compensation for alleged antitrust violations.
The litigation subsequently changed direction in 2022, when the plaintiffs elected to pursue their claims collectively as individual purchasers rather than continue seeking class-action status.
That procedural change reflected characteristics of the market for the insulin treatment, according to the Reuters account.
The case also encountered significant judicial scrutiny over the years. According to information published by plaintiffs’ law firm Hagens Berman Sobol Shapiro, a federal judge ruled in March 2026 that Sanofi had improperly submitted certain SoloStar device patents for Orange Book listing, while leaving other contested issues for trial.
The settlement would eliminate the need for the January trial if the agreement is finalized.
Thomas Sobol, an attorney representing the purchasers at Hagens Berman, did not respond to Reuters’ request for comment.
Broader Implications for Pharmaceutical Competition
The case highlights the legal and commercial importance of patent listings in the US prescription drug market, particularly when regulatory procedures can affect how quickly competitors gain approval.
For pharmaceutical manufacturers, patent protections can preserve the commercial value of medical innovations. For distributors and purchasers, disputes over the legitimacy of those protections can have substantial financial consequences.
The Lantus litigation illustrates that tension, with purchasers alleging that patent filings extended Sanofi’s competitive advantage beyond the period justified by applicable law.
Although the settlement could resolve the claims brought by the participating wholesalers, its confidential terms leave the financial consequences for Sanofi unclear.
Source: Reuters
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