Perifosine in Relapsed or Refractory Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

Chronic lymphocytic leukemia and small B-cell lymphocytic lymphoma represent different manifestations of the same disease. CLL/SLL (hereafter denoted by CLL) is a clonal disorder of small B lymphocytes expressing a characteristic morphology and immunophenotype. The B cells express CD19, dim CD 20, dim CD 5, CD 23, CD 43, CD 79a, and weakly express surface immunoglobin. CLL can present asymptomatically in 25% of patients when diagnosed on a complete blood count. It also can present with diffuse painless lymphadenopathy and, in a smaller number of patients, B symptoms. CLL is characterized by accumulation of circulating B cells predominantly in the G0 phase of the cell cycle. These cells are resistant to apoptosis. CLL has been found to have aberrant signaling in several pathways including NF-kB, Akt/PI3K, and JNK/STAT pathways. Akt is important in promoting CLL survival and viability, as seen in in vitro experiments where blocking its activity results in apoptosis. Thus an AKT inhibitor may lead to increased apoptosis and may have a role in the treatment of this disease. Treatment options for CLL range from a watch and wait approach to high dose chemotherapy with stem cell support. Currently, there is no consensus on the best treatment regimen, since no treatment has been shown to improve survival in randomized prospective clinical trials. New approaches to treatment, especially those with lower toxicity rates, are needed. Perifosine has been shown to inhibit or otherwise modify signaling through a number of different signal transduction pathways, including Akt, MAPK, and JNK. These pathways are involved in the development of cancers and resistance to chemotherapy. Perifosine is of particular interest, especially due to the difficulty in discovery of drugs that inhibit these pathways with minimal toxicity. The effect of perifosine on CLL cells has been tested in the laboratory and has been shown to be an active agent against primary CLL cells in vitro.