- Prior history of immunosuppressant use (e.g., mitoxantrone, azathioprine, methotrexate, cyclophosphamide, mycophenolate, cladribine, rituximab), or exposure to intravenous immunoglobulin (IGIV), monoclonal antibodies, cytokines, growth factors, soluble receptors, other recombinant products, or fusion proteins in the last 12 months prior to study screening.