Safety and Efficacy Study of OMS721 in Patients With Atypical Hemolytic Uremic Syndrome

This is a Phase 3, uncontrolled, open-label study to evaluate the effect of OMS721 in subjects with aHUS. The primary outcome to be measured is platelet count change from baseline. The secondary outcomes to be measured are other efficacy measures, safety, PK, PD, and immunogenicity (i.e., presence of anti-drug antibody \[ADA\] response. Subjects with plasma therapy-resistant aHUS and plasma therapy-responsive aHUS will be eligible. The efficacy endpoints, including the primary efficacy endpoint, may not be relevant for plasma therapy-responsive subjects because these subjects may enter the study with normal markers of aHUS activity due to successful treatment with plasma therapy. Therefore, efficacy analyses will be performed separately in the plasma therapy-resistant and plasma therapy responsive subjects. The principal efficacy analyses will be the analyses in the plasma therapy resistant cohort and efficacy analyses of the plasma therapy-responsive cohort will be supportive. Safety analyses will be conducted in all subjects.