Photo by Chad McNeeley
HSCT preparation
The European Commission has granted orphan designation to OMS721 for use in the setting of hematopoietic stem cell transplant (HSCT).
OMS721 is a monoclonal antibody targeting MASP-2, the effector enzyme of the lectin pathway of the complement system.
Omeros Corporation is developing OMS721 as a treatment for HSCT-associated thrombotic microangiopathy (TMA) and other conditions.
OMS721 is currently under evaluation in a phase 2 trial (NCT02222545) of patients with HSCT-TMA, and Omeros released some results from this study in February.
Results were reported for 18 adults with HSCT-TMA persisting for at least 2 weeks following immunosuppressive regimen modification or more than 30 days post-transplant.
The patients received weekly OMS721 treatments for 4 to 8 weeks at the discretion of the investigator.
These patients had a significantly longer median overall survival than historical controls—347 days and 21 days, respectively (P<0.0001).
Omeros also reported that markers of TMA activity significantly improved following OMS721 treatment.
The mean platelet count increased from 18,100 x 106/mL at baseline to 52,300 x 106/mL (P=0.017). The mean LDH decreased from 591 U/L to 250 U/L (P<0.001). And the mean haptoglobin increased from 8 mg/dL to 141 mg/dL (P=0.003).
Mean creatinine remained stable—at approximately 120 μmol/L—but a majority of patients had co-existing conditions for which they were receiving nephrotoxic medications. These conditions included graft-versus-host disease, cytomegalovirus and human herpes virus 6 infections, prior sepsis, diffuse alveolar hemorrhage, and residual underlying malignancies.
The most commonly reported adverse events in this trial were diarrhea and neutropenia.
Four deaths occurred. One of these—due to acute renal and respiratory failure—was considered possibly related to OMS721.
The other deaths were due to progression of acute myeloid leukemia (n=1) and neutropenic sepsis (n=2).
About orphan designation
Orphan designation from the European Commission is available to companies developing products intended to treat a life-threatening or chronically debilitating condition that affects fewer than 5 in 10,000 people in the European Union.
The designation allows for financial and regulatory incentives that include 10 years of marketing exclusivity in the European Union after product approval, protocol assistance from the European Medicines Agency at reduced fees during the product development phase, and access to centralized marketing authorization.