Omeros (NASDAQ: OMER) secures FDA nod for YARTEMLEA in TA-TMA

Rhea-AI Filing Summary

Omeros Corporation reported that the U.S. Food and Drug Administration has approved YARTEMLEA® (narsoplimab-wuug) to treat hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), a serious and often fatal complication of stem-cell transplantation linked to activation of the lectin pathway of complement. The company issued a revised press release on December 24, 2025 to update the date of its YARTEMLEA approval-related conference call and to add supplemental information about the experts quoted, with no other changes to the release.

Positive

• FDA approval of YARTEMLEA (narsoplimab-wuug) for treating hematopoietic stem cell transplant-associated thrombotic microangiopathy, moving the therapy into an approved commercial stage.

Negative

• None.

Insights

Biopharma regulatory and strategy analyst

FDA approval of YARTEMLEA gives Omeros a newly approved therapy for TA-TMA.

The company states that the U.S. Food and Drug Administration has approved YARTEMLEA (narsoplimab-wuug) for treating hematopoietic stem cell transplant-associated thrombotic microangiopathy, described as an often-fatal complication of stem-cell transplantation driven by lectin pathway activation. This converts a development-stage asset into an approved product in a highly specialized setting.

The condition targeted is severe, and the disclosure highlights its life‑threatening nature rather than commercial details. The company also revised its December 24, 2025 press release only to update the date of the approval-related conference call and to add information on quoted experts, explicitly stating that no other changes were made. Subsequent disclosures may provide details on launch timing, pricing, and commercial strategy.

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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): December 24, 2025

OMEROS CORPORATION

(Exact name of Registrant as Specified in Its Charter)

Washington	001-34475	91-1663741
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)
201 Elliott Avenue West Seattle, WA		98119
(Address of Principal Executive Offices)		(Zip Code)

Registrant’s Telephone Number, Including Area Code: (206) 676-5000

(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 (see General Instruction A.2. below):

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

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

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

☐ 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, $0.01 par value per share	OMER	The Nasdaq Stock Market LLC

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. ☐

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Item 8.01. Other Events.

On December 24, 2025, Omeros Corporation (the “Company” or “we”) issued a press release announcing that the U.S. Food and Drug Administration (FDA) has approved YARTEMLEA® (narsoplimab-wuug) for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), an often-fatal complication of stem-cell transplantation driven by activation of the lectin pathway of complement. A revised version of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference. The December 24, 2025 press release was revised to reflect the new date for the YARTEMLEA® approval-related conference call and to provide supplemental information regarding the experts quoted in the press release. No other changes were made.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit Number		Description
99.1		Press Release dated December 24, 2025 (as revised)
104		Cover Page Interactive Data File (embedded within the Inline XBRL document)

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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 hereunto duly authorized.

	OMEROS CORPORATION
Date: December 29, 2025	By:	/s/ Gregory A. Demopulos
		Gregory A. Demopulos, M.D.
		President, Chief Executive Officer and
		Chairman of the Board of Directors

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FAQ

What did Omeros Corporation (OMER) announce regarding YARTEMLEA?

Omeros announced that the U.S. Food and Drug Administration has approved YARTEMLEA® (narsoplimab-wuug) for the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA).

What condition is YARTEMLEA approved to treat for OMER?

YARTEMLEA is approved to treat hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA), described as an often-fatal complication of stem-cell transplantation driven by activation of the lectin pathway of complement.

When did Omeros issue the revised YARTEMLEA FDA approval press release?

Omeros issued the revised press release on December 24, 2025, updating the date of the YARTEMLEA approval-related conference call and providing supplemental information about the experts quoted.

Were there any substantive changes in Omeros’ revised YARTEMLEA press release?

No. Omeros states that the December 24, 2025 press release was revised only to reflect a new conference call date and to add supplemental information on the experts quoted, with no other changes.

Which regulator approved Omeros’ YARTEMLEA therapy?

The therapy YARTEMLEA® (narsoplimab-wuug) was approved by the U.S. Food and Drug Administration (FDA).

How does Omeros describe TA-TMA in relation to YARTEMLEA’s approval?

Omeros describes TA-TMA as an often-fatal complication of stem-cell transplantation that is driven by activation of the lectin pathway of complement.