Safety issues such as opportunistic infection cause concern. Alemtuzumab should be used with appropriate safeguards. While alemtuzumab is expensive, it is used when no alternative treatment is available (for patients with refractory B-CLL). Data on survival outcomes are needed to accurately estimate its cost-effectiveness. It is anticipated that in future trials, patients will be stratified based on the molecular and cytogenetic profiles of their leukemia cells, to clarify alemtuzumab s role in certain poor risk groups. Available data indicate that salvage therapy with alemtuzumab is associated with control of leukemia in approximately a third of patients, but it is also associated with harm. Without good quality data from RCTs, it is impossible to establish the role of alemtuzumab in patients with B-CLL.