FDA drug review delays keep growing under Trump-era disruptions

What: The FDA has delayed its ruling on Omeros’ drug narsoplimab for transplant-associated thrombotic microangiopathy (TA-TMA) by three months, moving the decision date from Sept. 25 to Dec. 26.

Why it matters: TA-TMA is a rare, life-threatening complication of stem cell transplants with no approved treatments. Approval would give patients the first therapy targeting the condition and open a new market for Omeros.

Backstory:

• Narsoplimab is an anti-MASP-2 antibody targeting the lectin pathway of the complement system.

• Omeros first sought approval in 2021 but was rejected due to concerns about limited data from a 28-patient trial.

• The FDA later advised comparing trial results to an external control group of 100+ patients. A new analysis showed narsoplimab improved survival by 68%.

• Omeros resubmitted its application in March 2025.

Big picture: This delay highlights growing scrutiny of rare disease approvals and comes amid broader FDA slowdowns linked to leadership changes and staffing cuts under the Trump administration. Omeros’ CEO noted that although the FDA’s data requests were extensive, their communication has been "responsive and collaborative."

Yes, but: Omeros was not the only biotech company to announce FDA delays on Friday as Neurizon’s ALS drug NUZ-001 remains on clinical hold, with the FDA pushing its decision to October after asking for further animal data. In contrast to Omeros, Neurizon directly blamed the delays on staffing shortages and organizational changes under the current administration.

What’s next: The delays aren’t isolated and they’re even becoming the norm. A growing list of companies, including Bayer, Stealth Biotherapeutics, Novavax, Vanda, and GSK, have all been caught in the FDA’s widening review backlog.

• This growing stack of delays suggests a deeper institutional challenge at the FDA. Unless staffing and leadership stability are restored, biopharma companies — and patients — should brace for a future where regulatory uncertainty is the default.