Novel therapies for chronic lymphocytic leukemia.

New therapies for chronic lymphocytic leukemia (CLL) are moving away from non-specific cytotoxic to more targeted approaches. The monoclonal antibody alemtuzumab induces responses in 33% to 43% of patients with relapsed or refractory disease, with 2-5% CR. Side effects include infusional reactions as well as immunosuppressive effects. Rituximab has limited activity in relapsed refractory patients, but response rates are comparable to follicular non-Hodgkin's lymphoma in untreated patients. Other antibodies in early phases of development include anti-CD23 [IDEC-152], anti-CD22 [epratuzumab], Hu1D10 [apolizumab], and anti-CD80 [anti-B7, IDEC-114]. Other agents that are being studied include denileukin diftitox fusion protein (Ontak), and bcl-2 antisense [G3139, Genasense]. The mechanism of action of the new drugs and their role in CLL, as well as the emergence of new prognostic markers are discussed.