A Study to Examine the Efficacy and Safety of Zanubrutinib Given to Adults With Primary Membranous Nephropathy

Inclusion Criteria:

• Biopsy-confirmed PMN within 5 years before the initial screening (ie, the day theinformed consent is signed)

• UPCR (based on 24-hour urine collection) > 3.5 at initial screening and atconfirmation assessment

• Treatment with a maximally tolerated or allowed dose of an angiotensin-convertingenzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) for ≥ 24 weeksbefore randomization (12 weeks before initiation of study drug for Part 1) and withadequate blood pressure control (blood pressure < 130/80 mmHg, measured on ≥ 2occasions [not on the same day] within 4 weeks before the assignment of studytreatment)

• Anti-PLA2R antibody > 50 RU/mL at confirmation assessment (Part 1 only)

Exclusion Criteria:

• Participants with a secondary cause of membranous nephropathy

• Type 1 or 2 diabetes mellitus with hemoglobin A1c (HbA1c) ≥ 7% at screening

• Severe renal disease as determined by rapid decline in eGFR (defined as > 15mL/min/1.73m^2 within 24 weeks prior to randomization, not otherwise explained)

• A known history of a primary immunodeficiency or an underlying condition such ashuman immunodeficiency virus (HIV) infection or splenectomy that predisposes theparticipant to infections

• Patients at risk for tuberculosis at screening

• Known infection with serologic status reflecting active or chronic hepatitis B virusinfection, or presence of hepatitis C virus antibody

• Severe hepatic insufficiency (Child-Pugh C)

• Clinically significant cardio-cerebrovascular diseases

Note: Other protocol defined Inclusion/Exclusion criteria may apply.