Mirum sues generic drugmakers over Livmarli patent infringement

Mirum Pharmaceuticals Inc. (NASDAQ: MIRM) filed patent infringement lawsuits on December 19, 2025, against four generic drug manufacturers in the United States District Court for the District of Delaware.

The company sued Sandoz Inc., Annora Pharma Private Limited, Zydus Lifesciences Global FZE, and Zenara Pharma Private Limited after receiving notice letters indicating the companies had submitted applications to the FDA seeking approval for generic versions of Livmarli (maralixibat).

Mirum received the first Paragraph IV Certification Notice Letter from Sandoz in November 2025, followed by additional letters from the other companies. These letters notify patent holders when generic manufacturers file Abbreviated New Drug Applications with the FDA.

The lawsuits allege the generic manufacturers infringed Mirum's Orange Book listed patents for Livmarli by filing their applications. Mirum seeks a court order preventing FDA approval of the generic applications until after the expiration of the company's patents.

The filing of these lawsuits triggers an automatic 30-month stay that prevents the FDA from issuing final approval of the generic applications during the litigation period, according to the company's statement.

Livmarli is Mirum's branded pharmaceutical product, and the company maintains patents listed in the FDA's Orange Book, which catalogs approved drug products and their associated patent information.

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