Pivotal trial of OMS 721 shows good response rate in hematopoietic stem cell transplant-associated thrombotic microangiopathy.- Omeros Corp

Omeros Corporation announced that the results of its pivotal trial of OMS 721 (narsoplimab) in the treatment of hematopoietic stem cell transplant-associated thrombotic microangiopathy (HSCT-TMA) demonstrating that targeted upstream inhibition of the lectin pathway of complement – specifically MASP-2 – is a promising treatment strategy for HSCT-TMA. he detailed clinical trial data presented underscore the importance of narsoplimab as a potentially significant advance in the treatment of often-fatal HSCT-TMA.

The data shows there was 54 percent complete response rate in all patients (n = 28) and 65 percent complete response rate in patients receiving at least 4 weeks of narsoplimab treatment (n = 23), along with a 100-day survival rate of 68 percent among all patients receiving any dose of narsoplimab. In addition there was a 83 percent 100-day survival in patients receiving at least 4 weeks of narsoplimab treatment and a 93 percent 100-day survival among complete responders. Statistically and clinically significant improvements from baseline were seen in platelet count (p = 0.001), lactate dehydrogenase (LDH) (p = 0.008), and haptoglobin (p < 0.001).

The drug also had a well-tolerated safety profile: no infusion side effects reported in patients receiving narsoplimab; most common adverse events were nausea, vomiting, diarrhea, hypokalemia, neutropenia, and fever – all common in this patient population; 6 patents died during the study, again all due to causes common in HSCT with most early in the course of narsoplimab treatment. Data were shared during an oral presentation at the virtual edition of the 25th Congress of the European Hematology Association.