For patients who have completed approximately 1 year or more of follow up since Arzerra initiation, data on response to Arzerra, adverse events during treatment and subsequent to treatment, patient status, progression free survival and overall survival covering the period up to approximately one-year post-drug initiation will be collected. For patients who have not completed approximately l year of follow-up since Arzerra initiation, including those who have been lost to follow up or died prior to one year or have not yet had a full year to elapse in calendar time, similar data will be collected at the point in time at the last available patient contact with the physician using information in the record. After approach for informed consent from the patient or next of kin for patients who have died to review the medical record, no interaction with the patient will occur.