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# Omeros BLA for Narsoplimab Gets Review Extension
- URL: https://www.fdaweb.com/omeros-bla-for-narsoplimab-gets-review-extension/
- Published: 2025-08-15T12:00:00.000Z
- Updated: 2026-09-14T15:19:11.000Z
- Author: David McFarland
- Tags: Biologics, #legacy-id-D5159695

A resubmitted Omeros BLA for narsoplimab in hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA) has been hit with a three-month extension after the company provided additional information pursuant to an FDA request. The new user fee review action target date is 12/26.

In communicating the extension, FDA stated that, assuming no major deficiencies are identified during its review, labeling discussions are planned to begin no later than October, the company says. “To date, all analyses requested by FDA as part of its review have been consistent with and have provided statistically significant support of narsoplimab’s benefit demonstrated in the analyses submitted as part of the BLA resubmission,” it adds.

In March, FDA accepted the BLA resubmission that addressed issues raised in a 2021 complete response letter on the original BLA, in which the agency said it was difficult to estimate narsoplimab’s treatment effect and requested additional information to support approval, according to the company. At the time, FDA reportedly said there were no chemistry, manufacturing and controls, safety, or non-clinical issues standing in the way of approval.

The resubmission included the primary set of analyses comparing overall survival for narsoplimab-treated patients to overall survival for an external control group of TA-TMA patients, Omeros said at the time. “Results of those analyses showed clinically meaningful and statistically significant improvements in survival associated with narsoplimab treatment,” it said. Also included in the resubmission are data describing survival in Omeros’ expanded access program.

Narsoplimab is designed to target mannan-binding lectin-associated serine protease-2, the effector enzyme of the lectin pathway of complement, the company says.