OMER Stock Explodes 81% Following FDA Green Light For Yartemlea In TA-TMA Treatment

Omeros Corporation’s shares experienced a dramatic rally, climbing 81.14% to finish at $15.85—a substantial $7.10 gain from the previous day’s close of $8.75. The catalyst behind this explosive move was the U.S. FDA’s approval of Yartemlea (narsoplimab-wuug), marking a landmark moment for treating transplant-associated thrombotic microangiopathy (TA-TMA).

The Market Response

Trading activity surged as investors reacted to the regulatory milestone. The NasdaqGS-listed stock opened near $12.10, peaked intraday at approximately $16.50, and bottomed around $11.95, demonstrating the significant volatility accompanying the announcement. This magnitude of gain signals how markets value breakthrough therapeutics in underserved medical niches.

Clinical Significance and Market Position

Yartemlea now stands as the sole FDA-approved treatment specifically designed for TA-TMA across both adult and pediatric populations aged two and above. This approval eliminates a critical therapeutic gap, as TA-TMA remains a rare yet frequently life-threatening complication following stem cell transplantation, previously lacking adequate treatment alternatives.

The drug operates by selectively inhibiting the MASP-2 enzyme within the lectin complement pathway, addressing the underlying disease mechanism. Clinical trial results demonstrated measurable improvements in patient survival rates, providing the evidence base for regulatory approval.

Forward-Looking Implications

OMER’s 52-week trading range recently reflected lower valuations, but the sharp recovery has been fueled by expanded revenue potential as Yartemlea approaches commercial launch anticipated for early 2026. The approval transforms the company’s competitive position in the rare disease therapeutics sector, with meaningful revenue generation expected once the product reaches patients.