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

Inclusion Criteria

• •1. Are age \>= 12 years old at screening (Visit 1).
• •2. Have a primary aHUS, diagnosed clinically, and have ADAMTS13 activity \> 5% in plasma. Participants are eligible with or without a documented complement mutation or anti-CFH antibody. Participants are categorized according to their response to plasma therapy (plasma exchange or plasma infusion):
• •* Plasma therapy-resistant aHUS participants must have all of the following:
• •* Screening platelet count \< 150,000/μL despite at least four plasma therapy treatments in a 7-day period prior to screening
• •* Evidence of microangiopathic hemolysis (at least one of:
• •1. presence of schistocytes,
• •2. serum LDH \> 1.5 times upper limit of normal (ULN), and
• •3. haptoglobin \< LLN)
• •* Serum creatinine \> ULN
• •* Plasma therapy-responsive aHUS participants must have all of the following:
• •* Have a documented history of requiring plasma therapy to prevent aHUS exacerbation defined as all of the following:
• •* decrease in platelet count \> 25% when plasma therapy frequency has been decreased (including discontinuation of plasma therapy)
• •* LDH \> 1.5 times ULN when plasma therapy frequency has been decreased (including discontinuation of plasma therapy)
• •* Have received plasma therapy at least once every 2 weeks at an unchanged frequency for at least 8 weeks before first dose of OMS721
• •3. If sexually active and of childbearing potential, must agree to practice a highly effective method of birth control until the end of the study, defined as one that results in a low failure rate (i.e., less than 1% per year) when used consistently and correctly, such as implants, injectables, combined oral contraceptives, some intrauterine devices, sexual abstinence or vasectomized partner.
• •4. Do not have access to eculizumab treatment, have not derived therapeutic benefit from eculizumab treatment, or have not been able to tolerate eculizumab treatment.