The maintenance period includes carfilzomib alone on days 1, 2, 15, 16 at 36mg/m2. For patients who show evidence of progression during maintenance phase, the frequency of Carfilzomib can be increased to days 1, 2, 8, 9, 15, 16 at the discretion of the investigator. It will be initiated at the end of the 9th course and will be stopped at progression or intolerance. The median expected duration of the maintenance treatment is approximately 2 years.