Safety Study of IgAN, LN, MN, & C3 Glomerulopathy Including Dense Deposit Disease Treated With OMS721

This is a Phase 2, multicenter study of OMS721 in subjects with the following diseases: IgA
Nephropathy (IgAN), Lupus Nephritis, Membranous Nephropathy (MN), or C3 Glomerulopathy,
including Dense Deposit Disease. Three cohorts will be enrolled. Cohort 1 will be subjects
with corticosteroid dependent IgAN, LN, MN, or C3 Glomerulopathy. Cohort 1 subjects will all
receive OMS721 in an uncontrolled, open-label design. Cohort 2 and 3 will be subjects with
IgA nephropathy who are not receiving corticosteroids. These cohorts will be randomized to
receive either OMS721 treatment or D5W vehicle in a randomized double-blind design.
Approximately 44 subjects will be enrolled (16 in Cohort 1, 10 in Cohort 2, and 18 in Cohort
3).

Inclusion Criteria:

- Are at least 18 years of age

- Have a diagnosis of: IgAN, Lupus Nephritis, MN, or C3 Glomerulopathy including Dense
Deposit Disease

- Have 24-hour urine protein > 1000 mg/24 hours

- For subjects in Cohort 1, have been on ≥ 10 mg of prednisone or equivalent dose for at
least 12 weeks prior to Screening

- If on immunosuppressive treatment (e.g., cyclophosphamide, mycophenolate mofetil),
have been on a stable dose for at least 2 months prior to Screening Visit 1 with no
expected change in the dose for the study duration

- eGFR >= 30 mL/min/1.73 m2 calculated by the MDRD equation

- Are on physician-directed, stable, optimized treatment with angiotensin converting
enzyme inhibitors (ACEI) and/or angiotensin receptor blockers (ARB) and have a
systolic blood pressure of < 150 mmHg and a diastolic blood pressure of < 90 mmHg at
rest

Exclusion Criteria:

- Have a hemoglobin < 9.0 g/dL

- Have a platelet count < 100,000/mm3

- Have an absolute neutrophil count < 500 cells/mm3

- Have an ALT or AST > 5.0 x the upper limit of normal

- Have systemic manifestations of Henoch-Schonlein purpura within 2 years prior to
Screening

- Have used: belimumab, eculizumab, or rituximab within 6 months prior to Screening

- Have a history of renal transplant

- Have a diagnosis of human immunodeficiency virus (HIV), hepatitis B, or hepatitis C
infection, or positive serology at Screening

- Have any significant infection requiring antibiotic treatment at Screening

- Have a malignancy except for adequately treated and cured basal or squamous cell skin
cancer, curatively treated in situ disease, or other cancer from which the patient has
been disease-free for 5 years or more

- Have an expectation of survival of less than 24 months

- For subjects in Cohort 2 and Cohort 3, have received corticosteroids within the 3
months prior to screening

- Subjects in Cohort 1 rolling into Cohort 3 must have IgAN and must have discontinued
corticosteroids prior to entry into Cohort 3, but the discontinuation may occur at any
time prior to Cohort 3 entry