Omeros Corp.'s (OMER:NASDAQ) resubmission of its biologics license application for narsoplimab was accepted by the U.S. Food and Drug Administration and assigned a PDUFA date in late September 2025, reported D. Boral Capital Analyst Jason Kolbert in a May 7 research note. This investigative, fully human monoclonal antibody targets hematopoietic stem cell transplant-associated thrombotic microangiopathy (TA-TMA).
"This development is significant, as there is currently no approved therapy for TA-TMA, a condition with high mortality rates," Kolbert wrote.
429% Upside Potential
Kolbert reiterated D. Boral's $36 per share target price on Omeros, now trading at about $6.81 per share. The target implies a potential return for investors of 429%.
The biopharma remains a Buy. Its market cap $397 million. Its 52-week range is $2.61–13.60 per share.
How it Works
Kolbert explained that narsoplimab targets MASP-2 (mannose binding lectin-associated serine protease-2), the key effector enzyme of the complement system's lectin pathway. While selectively inhibiting the lectin pathway, narsoplimab preserves the classical pathway, important for adaptive immunity.
This targeted approach is ideal for conditions like TA-TMA, in which endothelial injury triggers complement-mediated microvascular damage.
Supportive Data
With the resubmission, Omeros included proof of concept data from two sources, reported Kolbert. One was OMS721-TMA-001 that met its primary endpoint. This pivotal trial exhibited a statistically significant and clinically meaningful improvement in survival compared to an outside control group. The other source was the expanded access program in which positive survival outcomes were documented.
"These results provide robust support for [narsoplimab's] therapeutic potential in a condition with no approved treatments," Kolbert wrote.
Pipeline Updates
Omeros continues to advance is various clinical programs, Kolbert noted and provided a brief update on each one.
"These ongoing developments underscore Omeros' progress in its immunology and complement-focused pipeline, with upcoming regulatory milestones that could be transformative for the company," the analyst wrote.
Another indication in which Omeros is investigating narsoplimab is severe acute respiratory distress syndrome (ARDS), after preclinical data were positive, including from studies on H5N1 avian influenza. Concurrently, the biopharma is developing a test to detect lectin pathway hyperactivation in ARDS, COVID-19 and related conditions.
The company's MASP-2 inhibitor, or OMS1029, program continues to advance with a Phase 1 trial completed and preparations being made for a Phase 2. The Phase 1 showed that a single quarterly subcutaneous dose of narsoplimab was well tolerated and inhibited MASP-2 activity.
Another of Omeros' programs is zaltenibart, a MASP-3 inhibitor, currently in clinical trials for paroxysmal nocturnal hemoglobinuria (PNH) and for complement 3 (C3) glomerulopathy. In a Phase 2 trial of zaltenibart monotherapy, C5 inhibitor-refractory PNH patients were shown to have improved hemoglobin levels and reduced hemolysis. A Phase 3 study now is underway to assess zaltenibart in patients with PNH, which will encompass direct comparisons to C5 inhibitors.
Regarding C3 glomerulopathy, a Phase 2 trial of zaltenibart is in progress, and a Phase 3 study is planned depending on how strong the efficacy data are.
Further, the biopharma is investigating OMS527 for addictions and compulsive disorders. Preclinical data showed that this phosphodiesterase 7 inhibitor reduced the adverse effects of cocaine exposure. The National Institute on Drug Abuse agreed to provide $4.02 million to help fund a clinical trial of OMS527 for cocaine use disorder. This study is slated to start this year.
Lastly, Omeros is still advancing its oncology programs, including immunomodulators and adoptive T-cell therapies, and plans to release more information soon.
What is Ahead
Regarding its clinical program evaluating narsoplimab in TA-TMA, Omeros is preparing a marketing authorization application for the European Medicines Agency. It expects to submit it later in Q2/25.
Also on the horizon, Omeros intends to launch a Phase 3 trial for zaltenibart in C3 glomerulopathy in late 2025-early 2026.
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