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Lemtrada Lawsuits

Multiple sclerosis patients sued Sanofi Genzyme claiming its drug Lemtrada (alemtuzumab) caused serious injuries. Lemtrada lawsuits claim patients suffered ischemic stroke, hemorrhagic stroke, or head or neck arterial dissection within three days of receiving a Lemtrada infusion.

Last Modified: May 14, 2024
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As of June 2024, there have been no major developments, trials or publicly announced settlements in Lemtrada personal injury lawsuits. Drugwatch’s legal partners are currently not accepting Lemtrada cases.

However, Sanofi paid $315 million in 2019 to settle allegations that it delayed the Lemtrada’s release to avoid paying investors. The company also agreed to pay $11.85 million in 2020 to resolve kickback allegations.

More than 21,000 patients worldwide had received Lemtrada treatment as of October 2018, according to a Sanofi Genzyme press release. These people may have been at risk of rare strokes and tears in the walls of blood vessels in the head or neck, known as cervicocephalic arterial dissection.

Sanofi Genzyme began marketing Lemtrada for relapsing multiple sclerosis in 2014, but a warning for the risk of stroke or arterial dissection did not appear in United States prescribing information until November 2018.

FDA Warning for Stroke and Arterial Dissection

While Lemtrada can cause a number of side effects, ischemic stroke, hemorrhagic stroke, head or neck arterial dissection and death are the main injuries claimed in lawsuits.

In November 2018, the Food and Drug Administration warned about rare but serious risks of stroke and blood vessel wall tears with alemtuzumab.

According to the FDA’s safety announcement, most of the patients who experienced stroke or arterial dissection developed symptoms within one day of receiving the drug. In one case, symptoms started three days after treatment.

Lemtrada stroke illustration
Stroke and dissection injuries reported to the FDA occurred within three days of taking Lemtrada.

As of March 2024, the FDA Adverse Events Reporting System (FAERS) Public Dashboard showed 13 cases of strokes among people taking Lemtrada reported since 2017. The FDA also received seven reports of artery dissection, carotid aortic dissection and vertebral artery dissection. At least two cases were fatal.

An accurate number of people who actually suffered these problems is difficult to obtain because FAERS data is submitted voluntarily. The data does not necessarily mean that the use of the drug was a direct cause of the adverse event.

Accusations Against Sanofi Genzyme

Lawsuits claim Sanofi Genzyme failed to warn the public that its drug could cause strokes and tears in the arteries. If doctors and patients had known, they may have chosen another treatment option and avoided serious injury.

Other accusations made in lawsuits against Sanofi may include:
  • Aggressive and illegal marketing of Lemtrada
  • Breach of its duty of care by not warning about risks
  • Conscious disregard or indifference to the life, safety or rights of people injured by Lemtrada
  • Fraud and negligence
  • Intentionally failing to warn about Lemtrada’s risks for the sake of profit
  • Reckless conduct

Class Action Says Sanofi Misrepresented Drug’s Safety and Efficacy

The latest rash of Lemtrada lawsuits is not the first. In 2013, investors filed a class action lawsuit against Sanofi Genzyme for misrepresenting the safety and efficacy of the drug.

According to Solak v. Sanofi et al., “Sanofi (and Genzyme as its subsidiary) strongly touted the efficacy and safety of Lemtrada, by directing investors’ attention to two pivotal studies which the Company claimed demonstrated the safety and efficacy of Lemtrada.”

However, the FDA Advisory Committee on Peripheral and Central Nervous System Drugs found that “significant concerns exist regarding the safety profile of alemtuzumab [Lemtrada] and the adequacy of the efficacy data.”

The lawsuit, which was filed in the United States District Court Southern District of New York, claimed Sanofi also misled investors regarding the design of clinical trials for the drug. Sanofi did not disclose “trials contained high levels of placebo effect and observer bias,” which affected the FDA’s decision to approve the drug.

Three doctors on the FDA approval panel found numerous issues with the data submitted by Sanofi, according to the lawsuit.
Dr. Mentari
found numerous serious and potentially fatal safety concerns and could not recommend approval of the drug without proof of substantial clinical benefit.
Dr. Marler
found Sanofi did not submit enough evidence to support Lemtrada’s effectiveness.
Dr. Yan
found the design of the trials was “troublesome” and Sanofi did not provide evidence from adequate and well-controlled studies of the drug’s effectiveness in multiple sclerosis.
Please seek the advice of a medical professional before making health care decisions.