The main purpose of this study is to evaluate safety and effectiveness of the treatment of multiple myeloma with bortezomib in daily practice in the Netherlands.

Bortezomib has become commercially available in the European Union in May 2004 for the third line treatment of patients with multiple myeloma. The registration was based on two phase II studies while more research was ongoing. Some experience was already gained with the use of this product in the Netherlands by means of a compassionate use program before the initial registration. However, the data available from the use of bortezomib in daily clinical practice is limited. Therefore, there is a need to closely study the use of bortezomib in daily clinical practice. During the course of the study, the registration of bortezomib was extended. In April 2005, bortezomib was registered for second line treatment of multiple myeloma. Consequently, safety and effectiveness data from patients in this line of treatment could be collected in this project as well (arm A). Data of a large phase 3 trial showed that response rates differ between patients treated for multiple myeloma in the second line and patients treated in the third line. Therefore the protocol was amended to compare the response rates in two arms, dependent on the number of previous treatment lines for multiple myeloma: The protocol was also amended to determine the time to progression and response rate in both patients who received thalidomide earlier versus patients who didn't (arm B). ARM A: Patients with relapsed multiple myeloma who have received not more than 1 previous line of treatment and show progression on that therapy; ARM B: Patients with relapsed or refractory multiple myeloma who have received at least 2 prior lines of treatment and show progression on most recent therapy. This project is a 'post authorization study (PAS)'. This means that only routinely available medical data is collected, with the patients' permission, and no additional interventions or diagnostic procedures should be done specifically for this study. Because the study is observational, dosage, administration and duration of treatment is at discretion of treating physician.

Inclusion Criteria:

• Patients have to sign a statement that they agree with collection of their clinical data for this project
• the patient is eligible, in the investigator's opinion, based on the criteria in the summary of product characteristics for bortezomib

Exclusion Criteria:

• If patients meet the eligibility criteria, there are no exclusion criteria.

Multiple Myeloma patients treated with bortezomib in second or later line of therapy