This study will evaluate the efficacy, safety, pharmacodynamics, and pharmacokinetics (PK) of obinutuzumab compared with tacrolimus in participants with primary membranous nephropathy (pMN).

Inclusion Criteria:

• Diagnosis of primary membranous nephropathy (pMN) according to renal biopsy prior to or during screening
• Screening urinary protein-to-creatinine ratio (UPCR) >= 5 g/g from 24-hour urine collection after best supportive care for >= 3 months prior to screening or screening UPCR >= 4 g/g after best supportive care for >= 6 months prior to screening
• eGFR >= 40 mL/min/1.73m^2 or qualified endogenous creatinine clearance >= 40 mL/min/1.73m^2 based on 24-hour urine collection during screening
• Other inclusion criteria may apply

Exclusion Criteria:

• Participants with a secondary cause of MN
• Pregnancy or breastfeeding
• Evidence of >= 50% reduction in proteinuria during the previous 6 months prior to randomization
• Severe renal impairment, including the need for dialysis or renal replacement therapy
• Type 1 or 2 diabetes mellitus
• Receipt of an excluded therapy, including any anti-CD20 therapy less than 9 months prior to or during screening; or cyclophosphamide, tacrolimus, or cyclosporin less than 6 months prior to or during screening
• Significant or uncontrolled medical disease which, in the investigator's opinion, would preclude participant participation
• Known active infection of any kind or recent major episode of infection
• Major surgery requiring hospitalization within the 4 weeks prior to screening
• Current active alcohol or drug abuse or history of alcohol or drug abuse within 12 months prior to screening
• Intolerance or contraindication to study therapies
• Other exclusion criteria may apply

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data\_sharing