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

Eligibility Criteria

• * Competent to provide informed consent, or if a minor, have at least one parent or legal guardian to provide informed consent with written assent from the subject.
• * Are at least 12 years old at screening (Visit 1).
• * Have a clinically diagnosis of primary atypical hemolytic uremic syndrome (aHUS), with ADAMTS13 activity greater than 5% in plasma.
• * Plasma therapy-resistant aHUS patients must have a screening platelet count less than 150,000/uL, evidence of microangiopathic hemolysis, and serum creatinine greater than upper limit of normal.
• * Plasma therapy-responsive aHUS patients must have documented history of requiring plasma therapy to prevent aHUS exacerbation and received plasma therapy at least once every 2 weeks at an unchanged frequency for at least 8 weeks before first dose of OMS721.
• * Have STEC-HUS, a direct positive Coombs test, history of hematopoietic stem cell transplant, and/or HUS from an identified drug.
• * History of vitamin B12 deficiency-related HUS, systemic lupus erythematosus, and/or antiphospholipid syndrome.
• * Active cancer or history of cancer (except non-melanoma skin cancers) within 5 years of screening.
• * Have been on hemodialysis or peritoneal dialysis for greater than or equal to 12 weeks.
• * Have an active systemic bacterial or fungal infection requiring systemic antimicrobial therapy (prophylactic antimicrobial therapy administered as standard of care is allowed).
• * Baseline resting heart rate less than 45 beats per minute or greater than 115 beats per minute.
• * Baseline QTcF greater than 470 milliseconds.
• * Have malignant hypertension (diastolic blood pressure \[BP\] greater than 120 mm Hg with bilateral hemorrhages or "cotton-wool" exudates on funduscopic examination).
• * Have a poor prognosis with a life expectancy of less than three months in the opinion of the Investigator.
• * Are pregnant or lactating.
• * Have received treatment with an investigational drug or device within four weeks prior to screening.
• * Have abnormal liver function tests defined as ALT or AST \> five times ULN.
• * Have HIV infection.
• * History of cirrhosis of the liver.
• * Have previously completed treatment in an OMS721study.