- Cytotoxic chemotherapy ≤ 3 weeks, or biologic therapy ≤ 2 weeks, or corticosteroids ≤ 2 weeks, prior to registration. Patients may be receiving chronic corticosteroids if they are being given for disorders other than WM such as auto-immune diseases. Plasmapheresis is not considered as an active therapy and can be used at the physician's discretion.