As of the latest noted price at the time of writing, Omeros Corporation's (OMER, Financials) stock price jumped to $12.54, up $5.08 or 68.1%. The rise corresponds with the announcement that its main endpoint in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy reached a noteworthy mark, so targeting the lectin pathway of complement activation. The outcomes showed a three-fold lower death risk than those of patients not receiving narsoplimab.

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The business claims that an independent group performed the main statistical analysis and compared general survival rates between 28 narsoplimab-treated patients and over 100 high-risk TA-TMA patients in an external control registry. The study produced a hazard ratio of 0.32 with a p-value of less than 0.00001 and a confidence range of 0.23 to 0.44. Omeros said these findings support the therapeutic effectiveness of narsoplimab.

These results lead Omeros to intend to resubmit its Biologics License Application to the U.S. Food and Drug Administration for approval as the first therapy for TA-TMA. In the second quarter of 2025 the business also plans to submit an application for a marketing license with the European Medicines Agency.

Often resulting from a severe complication of hematopoietic stem cell transplantation, TA-TMA causes multi-organ failure and death. There are few current therapy choices and no medicines authorized especially for this disorder. Professionals in the area have praised narsoplimab's ability to fill in this need in medicine. The efficacy of the medication in treating TA-TMA in expanded access programswhere over half of patients exhibited improvementwas noted by hematology professor Alessandro Rambaldi, M.D., of the University of Milan.

Targeting the MASP-2 enzyme, the drug's mode of action sets it as a potential treatment for disorders marked by endothelial dysfunction, including acute respiratory distress syndrome.

Sensitivity studies and comparisons with other extended access program data are among the current further investigations. Omeros expects these results to back up its regulatory filings. The business also revealed intentions to publish 2025 trial findings in peer-reviewed publications.

Omeros reports that narsoplimab has not raised any notable safety issues across all clinical studies. For the treatment of TA-TMA, the medicine has received orphan drug classification from the FDA and EMA as well as breakthrough therapy.