Chronic lymphocytic leukemia (or "chronic lymphoid leukemia"), known for short as CLL, is a type of leukemia in which too many lymphocytes are produced. Although the malignant lymphocytes in CLL may look normal and mature, they are not and these cells may not cope effectively with infection.
CLL is the most common form of leukemia in adults. Men are twice as likely to develop CLL as women. However, the key risk factor is age. Over 75% of new cases are diagnosed in patients over age 50. More than 7,000 new cases of CLL are diagnosed in the U.S. each year.
Whilst generally considered incurable CLL progresses slowly in most cases. Many people with CLL lead normal and active lives for many years - in some cases for decades. Because of its slow onset, early-stage CLL is generally not treated since it is believed that early CLL intervention does not improve survival time or quality of life. Instead, the condition is monitored over time.
Chronic myelogenous leukemia (CML) is a form of chronic leukemia characterized by increased and unregulated clonal production of predominantly myeloid cells in the bone marrow. CML is a myeloproliferative disease associated with a characteristic chromosomal translocation called the Philadelphia chromosome. Historically, it has been treated with chemotherapy, interferon and bone marrow transplantation, although targeted therapies introduced at the beginning of the 21st century have radically changed the management of CML.
Chronic phase CML is treated with imatinib mesylate (marketed as Gleevec® or Glivec®; previously known as STI-571). In the past, antimetabolites (e.g. cytarabine, hydroxyurea), alkylating agents, interferon alfa 2b, and steroids were used, but this has been replaced by imatinib. Imatinib is a new agent, approved by the US FDA in 2001, which specifically targets BCR/abl, the constitutively activated tyrosine kinase fusion protein caused by the Philadelphia chromosome translocation that is felt to be responsible for driving the abnormal cell proliferation of CML. It is better tolerated and more effective than previous therapies. Bone marrow transplantation was also used as initial treatment for CML in younger patients before the advent of imatinib, and while it can often be curative, there is a high rate of transplant-related mortality.
Another new drug, dasatinib (marketed as Sprycel®; previously known as BMS-354825), which has a similar mechanism of action to imatinib but inhibiting a broader spectrum of tyrosine kinases, was approved by the U.S. FDA in June 2006 for use in patients with CML who are no longer responding to, or who can no longer tolerate, therapy with imatinib.  Pre-clinical research indicates that the anti-leukemic effect of dasatinib may be further enhanced by the addition of a small molecular inhibitor known as PD184352 
Various combinations of the different treatment modalities are being explored.
In 2005 favourable results of vaccination were reported with the BCR/abl p210 fusion protein in patients with stable disease, with GM-CSF as an adjuvant.
Two other drugs, ceflatonin (homoharringtonine) and nilotinib (AMN 107) are currently in active clinical trials in patients with CML who have developed resistance to imatinib. .
 Blast crisis
Blast crisis carries all the symptoms and characteristics of either acute myelogenous leukemia or acute lymphoblastic leukemia, and has a very high mortality rate. This stage can most effectively be treated by a bone marrow transplant after high-dose chemotherapy. In young patients in the accelerated phase, a transplant may also be an option. However the likelihood of relapse after a bone marrow transplant is higher in patients in blast crisis or in the accelerated phase as compared to patients in the chronic phase.