Zanubrutinib in Patients With IgG4-Related Disease

Inclusion Criteria:

* Men or women aged 18 to 85, inclusive, at the time of initial screening
* Have histopathologically confirmed IgG4-RD in the submandibular gland and/or the lacrimal gland confirmed by international consensus pathology criteria

* Presence of a lymphoplasmacytic infiltrate with 10 IgG4+ plasma cells per high-power field and/or an IgG4+/IgG+ plasma cell ratio of 40%
* All women must test negative for pregnancy and agree to use a reliable method of birth control
* No current treatment with immunosuppressive medications other than prednisone 40mg daily (or other glucocorticoid equivalent) with stable dosing for 28 days

Exclusion Criteria:

* Unstable prescribed dose of glucocorticoids within 28 days prior to baseline
* Any treatment with a synthetic DMARD including but not limited to hydroxychloroquine, methotrexate, leflunomide, or sulfasalazine within 28 days prior to baseline
* Any treatment with a cytotoxic or immunosuppressive drug including but not limited to cyclophosphamide, mycophenolic acid, azathioprine, cyclosporine, sirolimus, or tacrolimus within 28 days prior to baseline
* Any treatment with a BTK inhibitor within 6 months before baseline
* Any treatment with a JAK inhibitor within 28 days prior to baseline
* Use of biologic agents including infliximab, abatacept, or tocilizumab within 56 days prior to baseline
* Use of a B cell depleting therapy (such as rituximab) within 12 months prior to baseline
* A history of, or current, inflammatory or autoimmune disease (that could affect the interpretation of safety or efficacy outcomes) other than IgG4-related disease
* Evidence of active tuberculosis, HIV, or hepatitis B or C infection
* History of cancer other than non-melanoma skin cancer, cervical dysplasia or carcinoma in situ (cured \>1 year), prostate cancer (cured \>5 years), or colon cancer (cured \>5 years)