This non-interventional retrospective chart review study aims to evaluate the clinical outcomes of patients with RRMM receiving lenalidomide/dexamethasone (Len/Dex) treatment at 1st relapse and the treatment patterns following progressive disease as part of the routine clinical practice in Greece.

Inclusion Criteria:

Subjects must fulfill ALL of the following criteria:

• Subjects of both genders, aged 18 years or older
• Subjects must have a relapsed or refractory MM diagnosis according to IMWG or EBMT criteria
• Subjects must have initiated second-line therapy with lenalidomide/dexamethasone according to the approved products' Summary of Product Characteristics (SmPC) between 01 January 2009 and 01 March 2014
• Subjects must have available medical files/records and detailed historical data on their disease course and clinical management
• Provision of signed ICF for collecting and analyzing medical data pertinent to the objectives of this study

Exclusion Criteria:

For the candidate subjects NONE of the following criteria should apply:

• Prior malignancy (within the 3 years preceding initial diagnosis of MM)
• Concurrent administration of anti-cancer regimens for malignancies other than MM between the time of initial MM diagnosis and time of second relapse
• Subject participation in an interventional study

A total of approximately 220 patients with RRMM that started second-line treatment with lenalidomide/dexamethasone between 01 January 2009 to 01 March 2014 and who fulfill all study-specific eligibility criteria at the investigators' discretion will be included in this study