Mirum sues Sandoz, Hetero, Biophore and Zydus in Delaware over generic Livmarli; trial set for 2028

Mirum Pharmaceuticals, Inc. (Nasdaq: MIRM) is a plaintiff in four patent infringement cases against generic drug makers seeking to market copies of its drug Livmarli, according to its 10-Q filed August 5, 2026. Mirum, Satiogen Pharmaceuticals, Inc. and Shire Human Genetic Therapies, Inc. filed the four complaints on December 19, 2025 in the U.S. District Court for the District of Delaware. The 10-Q does not give case numbers.

The defendants are Sandoz Inc.; Annora Pharma Private Limited, Hetero Labs Limited and Hetero USA Inc. (together, Hetero); Zenara Pharma Private Limited and Biophore India Pharmaceuticals Private Limited (together, Biophore); and Zydus Lifesciences Global FZE, Zydus Lifesciences Limited and Zydus Pharmaceuticals (USA) Inc. (together, Zydus).

The case

The complaints allege infringement of Orange Book listed patents covering Livmarli. Each followed an abbreviated new drug application, or ANDA, that a defendant submitted for a generic version of the drug. The 10-Q says the suits were started under the procedures of the Hatch-Waxman Act. The defendants' ANDAs seek approval to market generics before one or more of the Livmarli patents expire, and they allege that one or more of the patents are invalid, unenforceable or not infringed.

Mirum asks for an order that the effective date of any FDA approval of the ANDAs be no earlier than the expiration of the asserted patents listed in the Orange Book, along with other relief the court deems appropriate. Because Mirum sued, the 10-Q says, the defendants face a 30-month stay of final FDA approval through March 29, 2029.

Defendants

All nine entities above are named in the 10-Q as defendants. Hetero, Biophore and Zydus are each described as groups of related companies. The 10-Q describes the suits as four complaints and does not match each defendant to its own case. Mirum is the plaintiff, with Satiogen and Shire Human Genetic Therapies as co-plaintiffs.

Where it stands

Sandoz asserted counterclaims on February 20, 2026 seeking declaratory judgments of non-infringement and invalidity for certain Livmarli patents. Biophore did the same on March 30, 2026.

On April 22, 2026 Mirum listed a newly issued patent, U.S. Patent No. 12,599,602, in the Orange Book. On May 18, 2026 Mirum and its co-plaintiffs filed amended complaints against Sandoz, Hetero, Biophore and Zydus asserting that patent. Biophore counterclaimed on June 1, 2026 and Sandoz on June 17, 2026, again seeking declarations of non-infringement and invalidity. Mirum and its co-plaintiffs deny all the declaratory claims.

On April 16, 2026 the court consolidated the four cases for pretrial purposes. It issued a scheduling order on May 19, 2026. A Markman hearing is set for April 21, 2027 and trial for September 18, 2028. Discovery is ongoing. Mirum says it cannot make any predictions about the final outcome of these matters or their timing.

Why it matters to shareholders

Livmarli product sales were $128.7 million for the three months ended June 30, 2026 and $242.5 million for the six months, according to the 10-Q.

Mirum's risk factors say the discovery, trial and appeals process in a patent suit is costly, time consuming and may result in generic competition if the ANDA applicant prevails. They also say that if the validity or enforceability of the Livmarli patents is not upheld, or an ANDA filer is found not to infringe, the generic competition that would follow the expiration of regulatory exclusivity would have a material adverse effect on revenue and results of operations. The 10-Q says Mirum has not recorded any accrual for loss contingencies associated with legal actions, and it gives no litigation costs for these cases.

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