Omeros Announces Additional Positive Data in OMS721 Phase 2 Clinical Trial
Source: PR Newswire (US)
SEATTLE, Aug. 18, 2015 /PRNewswire/ -- Omeros Corporation (NASDAQ: OMER) today announced additional positive data in the company's Phase 2 clinical trial of OMS721 for the treatment of thrombotic microangiopathies (TMAs). TMAs are a family of rare, debilitating and life-threatening disorders characterized by excessive thrombi (clots) – aggregations of platelets – in the microcirculation of the body's organs, most commonly the kidney and brain. OMS721 is Omeros' lead human monoclonal antibody in its mannan-binding lectin-associated serine protease-2 (MASP-2) program for the treatment of TMAs, including atypical hemolytic uremic syndrome (aHUS).
The Phase 2 trial is designed to enroll primarily aHUS patients but can also enroll patients with thrombotic thrombocytopenic purpura (TTP) and hematopoietic stem cell transplant (HSCT)-related TMA. The trial has fully enrolled the first and second cohorts and is currently completing the third and final planned cohort of its dose-ranging stage. In each three-patient cohort, OMS721 is dosed for four weeks. Data from the first (low-dose) cohort were released on February 19, 2015. Today the company is releasing data from its second (mid-dose) cohort and data to date from its third (high-dose) cohort.
Three patients were treated in the second or mid-dose cohort, two of whom have aHUS and one with TTP. Both patients with aHUS were on renal dialysis prior to and at the time of study enrollment. Based on the positive data from the mid-dose cohort, the high-dose cohort was initiated and an aHUS patient has already completed the study treatment period. No patient with HSCT-related TMA has yet completed dosing with OMS721. The data referenced for all patients include measures to one week following the last dose.
A rare and devastating family of disorders, TMAs are characterized by thrombi or clumps of aggregated platelets in small blood vessels, which lead to thrombocytopenia (below-normal platelet counts) and schistocytes (fragmentation in red blood cells) that can cause dangerously low oxygen levels in organs like the brain and kidney as well as anemia. Thrombotic microangiopathies are life-threatening and can occur both in children and adults. While thrombi, thrombocytopenia and schistocytes are hallmarks of TMAs, other markers of damage within the blood vessels include an elevated plasma lactate dehydrogenase (LDH) and undetectable or reduced plasma haptoglobin levels. In addition, an elevated creatinine level – a result of the kidney damage caused by thrombi – is an indicator of impaired kidney function in patients who are not on renal dialysis.
As in Alexion's clinical trials supporting both U.S. and European regulatory approval of Soliris® for the treatment of aHUS, this Phase 2 clinical trial, given the life-threatening nature of the disease, has no placebo arm. Soliris trials used change from baseline in platelet count as a primary endpoint to obtain approval for the treatment of aHUS. Similarly, the pre-specified primary endpoint in this Phase 2 trial is change from baseline in platelet count. In this trial, platelet counts in all three aHUS patients in the mid- and high-dose cohorts (two in the mid-dose and one in the high-dose cohort) were normal after the treatment period, with a statistically significant mean increase from baseline of approximately 68,000 platelets/mL (p = 0.0055).
