Understanding Leukemia -- Diagnosis and Treatment
What Are the Treatments for Leukemia? continued...
A stem cell transplant has three stages: induction, conditioning, and transplantation. First, the individual’s white blood cell count is brought under control by chemotherapy. Then a single dose of chemotherapy may be given followed by a conditioning regimen of high dose chemotherapy. This will destroy the individual’s bone marrow and any residual leukemia cells that may be present. Then the donor cells will be infused.
Until the donor marrow cells start producing new blood, the individual is left with virtually no blood cells -- white cells, red cells, or platelets. This makes death by infection or bleeding a strong possibility. Once the donor stem cells grow sufficiently into the marrow, usually in two to six weeks, long-term remission becomes a strong possibility. In addition to chemotherapy, the person will receive medication to prevent and treat graft versus host disease. With this disease, donor cells attack the person's normal tissue cells. Medication is also given to prevent rejection of the donor stem cells. Allogeneic stem cell transplantation is both expensive and risky, but it offers the best chance for long-term remission for high risk AML and certain cases of ALL.
Chronic lymphocytic leukemia (CLL), a form of leukemia that usually affects older persons, typically progresses slowly. Therefore, treatment may be conservative. Not all patients require immediate treatment. Patients experiencing symptoms requiring treatment include the so called ‘B’ symptoms of fevers, night sweats for 14 consecutive days, or 10% unintentional body weight loss over 6 months. Other symptoms, such as painful swollen lymph glands, painful swollen liver or spleen, or evidence of bone marrow failure, also require treatment.
Oral chemotherapy can effectively control symptoms of CML for several years. In the past, most cases of CML eventually advanced to an acute phase despite treatment, so doctors advised bone marrow transplantation during the chronic phase. Allogeneic stem cell transplantation for CML is still a treatment option for disease resistant to treatment or for persons whose disease is in the acute phase.
The drug imatinib (Gleevec) has radically changed treatment for CML. Known as a molecular targeting drug, it attacks the genetic alterations that cause white blood cells to grow out of control. Gleevec doesn't cure CML, but it can result in long-term remission and survival of CML. This drug was shown to be superior to prior therapies such as busulfan, hydroxyurea, and interferon alpha. There are now four other drugs (bosutinib, dasatinib, nilotinib, and ponatinib) that can be used in CML if the leukemia becomes resistant to Gleevec. Nilotinib has FDA approval for CML in the chronic phase. Dasatinib is FDA approved for first line therapy of chronic phase CML. Bosutinib and ponatinib can be used during any phase of CML if a person is resistant to or cannot tolerate the other drugs. Still another drug, omacetaxine mepesuccinate (Synribo), is approved for those whose CML has progressed after treatment with two or more of the previous medications.