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Dec 24 (Reuters) - The U.S. Food and Drug Administration has approved Omeros' OMER.O drug for a dangerous transplant complication, marking the first treatment to be greenlit for the condition, the company said on Wednesday.

The drug, branded as Yartemlea, is used to treat a condition known as transplant-associated thrombotic microangiopathy (TA-TMA), a serious complication that can develop after stem cell transplants, particularly those that use healthy cells from a donor.

The disease occurs due to damaged blood vessels during or after a stem cell transplant as a result of an overactive immune system, causing inflammation. This leads to tiny blood clots that can harm organs such as the kidneys, sometimes causing life-threatening problems.

A stem cell transplant replaces damaged or unhealthy blood-making cells with healthy ones from either the patient or a donor, aiding the body to generate new cells — vital for treating diseases and enabling a robust immune response.

Omeros said it expects the treatment to be available on the market by January 2026.

The company did not immediately respond to a Reuters request for a comment on Yartemlea's pricing.

(Reporting by Padmanabhan Ananthan and Puyaan Singh in Bengaluru; Editing by Alan Barona and Krishna Chandra Eluri)

((Padmanabhan.Ananthan@thomsonreuters.com))