Sanofi sues Sarepta over Elevidys gene therapy patent infringement

Six months after overcoming a patent dispute over its $3.2 million gene therapy, Sarepta now faces a new legal challenge from another gene therapy company. Sanofi's subsidiary, Genzyme, has initiated a lawsuit in the U.S. District Court in Delaware, alleging that Sarepta’s approved treatment for Duchenne muscular dystrophy (DMD), Elevidys, infringes on two of Genzyme's active patents related to viral vector manufacturing. The lawsuit was reported by Reuters on Tuesday.

Genzyme's complaint asserts that its patents cover specific "formulations and related methods" that ensure the solubility of viral vector particles and prevent them from clumping during production. These patents are slated to expire on June 1, 2025. Although Genzyme also mentioned Sarepta’s contract manufacturer, Catalent, in the lawsuit, it did not name Catalent as a defendant. Genzyme is seeking a jury trial and monetary damages.

This fresh legal issue follows Sarepta's recent legal victory in January, where U.S. District Judge Richard Andrews dismissed the claims of Regenxbio and the University of Pennsylvania. These entities had alleged that Sarepta infringed on a patent related to gene therapy, but the judge ruled that the patent in question was invalid. Despite this ruling, Regenxbio and the University of Pennsylvania have another ongoing lawsuit against both Sarepta and Catalent.

Since Elevidys received approval in June of last year, it has seen remarkable commercial success, raking in $334 million in sales during the first quarter of this year. Recently, the FDA expanded the eligibility for Elevidys to include all DMD patients aged 4 and older, both ambulatory and non-ambulatory. Initially, the treatment was only available to ambulatory boys between the ages of 4 and 5.

Analyst Tim Lugo from William Blair forecasts that Elevidys' sales could peak at $5 billion by 2027, before potentially declining as the pool of eligible patients diminishes. Additionally, Roche is responsible for regulatory efforts and the commercialization of Elevidys outside the U.S., under a $1 billion partnership with Sarepta.