Sandoz targets Mirum’s Livmarli with ANDA and patent challenge

Rhea-AI Filing Summary

Mirum Pharmaceuticals, Inc. reported that it received a Paragraph IV Certification Notice Letter from Sandoz, Inc., which has filed an Abbreviated New Drug Application with the U.S. FDA seeking approval to market a generic version of Mirum’s drug Livmarli (maralixibat). Sandoz alleges that five Livmarli patents listed in the FDA Orange Book are invalid, unenforceable, or not infringed by its proposed generic. Under U.S. law, Mirum may file a patent infringement lawsuit within 45 days of receiving the notice, which would trigger an automatic 30-month stay on final FDA approval of the ANDA. Mirum states that it plans to vigorously enforce its intellectual property, promptly sue Sandoz and any other ANDA filers, and seek a permanent injunction against generic versions that would infringe its patents.

Positive

• None.

Negative

• Generic challenge to Livmarli patents: Sandoz has filed an ANDA with a Paragraph IV certification seeking approval to market a generic version of Livmarli, directly contesting five Orange Book–listed patents.

• IP litigation overhang: Mirum plans to promptly file a patent infringement suit, introducing legal uncertainty and potential long-term pressure on Livmarli’s exclusivity if generics ultimately obtain approval.

Insights

Biopharma IP and market exclusivity analyst

Mirum’s key drug Livmarli faces a generic challenge, with litigation likely and a potential 30-month approval stay.

Mirum Pharmaceuticals has disclosed that Sandoz filed an ANDA with a Paragraph IV certification targeting Livmarli, its maralixibat product. Sandoz is challenging five Orange Book–listed patents by claiming they are invalid, unenforceable, or not infringed. Paragraph IV filings are a standard pathway for generic entry but can pressure future pricing power if generics eventually reach the market.

U.S. law allows Mirum to respond by suing Sandoz within 45 days of the notice. If Mirum does so, an automatic 30-month stay would prevent the FDA from granting final approval of the ANDA while the dispute proceeds, preserving Livmarli’s current position for that period unless there is an earlier court resolution. Mirum states it intends to vigorously defend its intellectual property and seek a permanent injunction, but the ultimate outcome and timing depend on future legal proceedings and any additional ANDA filers.

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

____________________________________________________

FORM 8-K

____________________________________________________

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): November 17, 2025

____________________________________________________

Mirum Pharmaceuticals, Inc.

(Exact name of Registrant as Specified in Its Charter)

____________________________________________________

Delaware			001-38981			83-1281555
(State or Other Jurisdiction of Incorporation)			(Commission File Number)			(IRS Employer Identification No.)
989 East Hillsdale Boulevard Suite 300
Foster City, California						94404
(Address of Principal Executive Offices)						(Zip Code)

Registrant’s Telephone Number, Including Area Code: (650) 667-4085

N/A

(Former Name or Former Address, if Changed Since Last Report)

____________________________________________________

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o   Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o   Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o   Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o   Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class

Trading Symbol(s)

Name of each exchange on which registered

Common stock, par value $0.0001 per share

MIRM

Nasdaq Global Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

On November 17, 2025, Mirum Pharmaceuticals, Inc. (the “Company”) received a Paragraph IV Certification Notice Letter (the “Notice Letter”) from Sandoz, Inc. (“Sandoz”) providing notification to the Company that Sandoz has submitted an Abbreviated New Drug Application (“ANDA”) to the U.S. Food and Drug Administration (“FDA”) seeking approval to manufacture, use or sell a generic version of Livmarli® (maralixibat).

In the Notice Letter, Sandoz alleges that five of the patents listed in the FDA Orange Book for Livmarli, U.S. Patent Numbers 11,229,647, 11,260,053, 11,376,251, 11,497,745 and 11,918,578, are invalid, unenforceable or will not be infringed by Sandoz’s manufacture, use or sale of the generic product described in its ANDA submission.

Under the Food and Drug Cosmetic Act, as amended by the Drug Price Competition and Patent Term Restoration Act of 1984, as amended, after receipt of a valid Paragraph IV Notice Letter, the Company may bring a patent infringement suit against Sandoz. If such suit is commenced within 45 days of receipt of the Notice Letter, this triggers an automatic 30-month stay, which would prevent the FDA from issuing final approval of Sandoz’s ANDA until the expiration of the stay.

The Company expects to receive additional Paragraph IV Certification Notice Letters in the future from ANDA filers seeking approval of a generic version of Livmarli.

The Company intends to vigorously defend and enforce its intellectual property rights relating to Livmarli and plans to promptly file a patent infringement suit against Sandoz and any other ANDA filer with respect to Livmarli, seeking, among other remedies, a permanent injunction to prevent such parties from introducing a generic version of Livmarli that would infringe the Company’s patents.

Forward-Looking Statements

Statements contained in this report regarding matters that are not historical facts are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. Such forward-looking statements include statements regarding, among other things, the Company’s intention to defend and enforce its intellectual property rights relating to Livmarli and file a lawsuit against Sandoz and any other ANDA filer, and the expectation of receiving additional Paragraph IV Certification Notice Letters. Because such statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Words such as “intend,” “may,” “potential,” and similar expressions are intended to identify forward-looking statements. These forward-looking statements are based upon Mirum’s current expectations and involve assumptions that may never materialize or may prove to be incorrect. Actual results could differ materially from those anticipated in such forward-looking statements as a result of various risks and uncertainties, which include, without limitation, risks and uncertainties associated with Mirum’s business in general, the impact of geopolitical and macroeconomic events, and the other risks described in Mirum’s Annual Report for the year ended December 31, 2024, filed with the Securities and Exchange Commission on February 26, 2025, and subsequent filings with the Securities and Exchange Commission, which are available at www.sec.gov. All forward-looking statements contained in this report speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date. Mirum undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

			Mirum Pharmaceuticals, Inc.
Date: November 17, 2025			By:			/s/ Christopher Peetz
						Christopher Peetz
						Chief Executive Officer

FAQ

What did Mirum Pharmaceuticals (MIRM) announce in this 8-K?

Mirum reported receiving a Paragraph IV Certification Notice Letter from Sandoz, which filed an ANDA with the U.S. FDA seeking approval to market a generic version of Livmarli (maralixibat) and is challenging five Livmarli patents.

Which Mirum drug is affected by the Sandoz Paragraph IV challenge?

The challenge targets Livmarli (maralixibat), for which Sandoz has submitted an ANDA and alleges that five Orange Book–listed patents are invalid, unenforceable, or not infringed.

How can Mirum (MIRM) respond to the Paragraph IV Notice Letter?

Under the Food and Drug Cosmetic Act, Mirum may file a patent infringement lawsuit against Sandoz within 45 days of receiving the Paragraph IV Notice Letter to challenge the ANDA filing.

What is the 30-month stay mentioned in Mirum’s disclosure?

If Mirum files a patent infringement suit within 45 days of receiving the Paragraph IV notice, an automatic 30-month stay would prevent the FDA from issuing final approval of Sandoz’s ANDA during that period, unless there is an earlier court decision.

What legal actions does Mirum plan to take regarding Livmarli generics?

Mirum states it intends to vigorously defend and enforce its intellectual property, promptly sue Sandoz and any other ANDA filer related to Livmarli, and seek a permanent injunction to stop infringing generic versions from entering the market.

Does Mirum expect more Paragraph IV notices related to Livmarli?

Yes. Mirum notes that it expects to receive additional Paragraph IV Certification Notice Letters in the future from other ANDA filers seeking approval to market generic versions of Livmarli.