What happened

Shares of Omeros (OMER 2.94%) were down 12.9% early Monday afternoon after the clinical-stage biopharmaceutical company released a presentation it made regarding a therapy to treat a rare blood disease. The stock has climbed 189% so far this year.

So what

Omeros specializes in treating immunologic disorders, including complement-mediated diseases, cancers, and addictive and compulsive disorders. On Monday, the company released a presentation it made last week at the European Hematology Association (EHA) Congress in Frankfurt, Germany. The poster was regarding OMS906, its therapy to treat paroxysmal nocturnal hemoglobinuria (PNH), a rare blood disorder.

PNH occurs when the immune system attacks and damages red blood cells and platelets. The disease is very rare, affecting 15.9 in 1 million people, according to a 2018 study. Untreated, it can cause chronic kidney disease, blood clots in blood vessels, and hemolytic anemia. While all 10 patients dosed with OMS906 showed improved hemoglobin levels, and there were few adverse events, apparently investors were unimpressed with the data.

The concern with Omeros is it has struggled to move along its therapies through trials. Its lead therapy candidate is Narsoplimab, a monoclonal antibody designed to prevent complement-mediated inflammation and damage to the endothelial cells (the cells that line blood and lymphatic vessels) without affecting the body's natural immune systems. The company received a complete response letter from the Food and Drug Administration regarding Narsoplimab and so far has been unsuccessful in appealing the decision.

Now what

Omeros lost $33.7 million in the first quarter and said it had $371.4 million in cash, enough to fund operations into 2025. Today's dip is likely short lived. The healthcare company has a big portfolio with 13 programs, so there's plenty of potential. Another catalyst for the stock could come later this week, as it is slated to rejoin the Russell 3000 index, which would expose the stock to more mutual funds.