A Study of Fresolimumab in Patients With Steroid-Resistant Primary Focal Segmental Glomerulosclerosis (FSGS)

Inclusion Criteria: * The patient's renal biopsy is consistent with the diagnosis of primary Focal Segmental Glomerulosclerosis (FSGS) including all histological subtypes. * The patient has an eGFR ≥ 30 mL/min/1.73 m2 * The patient has a urinary total protein:creatinine ratio ≥ 3 mg protein/mg creatinine * In the opinion of the Investigator, the patient has steroid-resistant FSGS. The patient must have been treated for FSGS with a course of high-dose steroid therapy for a minimum of 4 weeks * The patient has been treated with an ACEi (angiotensin converting enzyme inhibitor) and/or ARB (angiotensin receptor blocker) at a stable dose for a minimum of 4 weeks prior to Visit 2 (treatment start) Exclusion Criteria: * The patient has FSGS which in the Investigator's opinion is secondary to another condition * The patient has been taking prednisone at a dose \> 10 mg/day (or equivalent dose of an alternative glucocorticoid) within 4 weeks prior to Visit 1 (Screening Visit). * The patient has received any other systemically administered immunosuppressive drugs (other than glucocorticoids) within 8 weeks prior to Visit 1. * The patient has received rituximab within 6 months prior to Visit 1. * The patient has a history of organ transplantation.