Chronic lymphocytic leukemia: an update on biology and treatment.

Combination chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) has emerged as the current standard of care in the treatment of chronic lymphocytic leukemia (CLL). Despite very high response rates, this treatment is too toxic for many patients, and it remains unclear as how to manage patients who do not respond to these agents or who relapse early after treatment. An increase in our understanding of the biology of CLL has led to the development of a wide range of therapies aimed at specific defects in this disease. B-cell receptor signaling is aberrantly increased in CLL, and so many of these drugs target key steps in these pathways. Antitumor immunity is also impaired, and a number of strategies are being developed to repair this acquired immune dysfunction. This review highlights some of the emerging agents and describes the biological rationale for their use in CLL.