Health In Focus
  • Patients with chronic myeloid leukemia are commonly treated with a group of drugs called tyrosine kinase which includes drugs like imatinib mesylate and dasatinib.
  • These drugs improve chronic myeloid leukemia survival rate but usually do not result in a complete cure.
  • A novel approach using precision medicine to kill the chronic myeloid leukemia stem cells that give rise to the cancer cells has potential in curing cancer.

Researchers from the University of Glasgow are adopting a new approach for the treatment of chronic myeloid leukemia stem cells to bring about a complete cure of the cancer. In their study, they used an EZH2-specific inhibitor that specifically targets the cancer-forming cells without affecting normal body cells. The results of the study were published in the Cancer Discovery.
New Approach Being Explored for the Treatment of Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is a type of blood cancer . Patients undergo three phases, the chronic phase, the accelerated phase and the blast phase. CML is diagnosed based on a peripheral blood smear and a bone marrow test. Patients have an abnormal chromosome called Philadelphia chromosome which can be detected in the bone marrow cells.

Patients with chronic myeloid leukemia are often treated with a group of drugs called tyrosine kinase inhibitors, which have improved the prognosis of the cancer. These drugs target a protein produced by the abnormal gene. Drugs in this group include imatinib mesylate, dasatinib , nilotinib , bosutinib and ponatinib These drugs clear the leukemic cells from the blood but do not affect the CML stem cells in the bone marrow that produce more cancerous cells. Most patients have to take these drugs throughout their life and are quite expensive. Their side effects may also be intolerable to the patient. Some patients may not respond to the treatment while some may develop resistance.

Other drugs used in the treatment of chronic myeloid leukemia include interferon alfa hydroxyurea , busulfan and omacetaxine. Leukapheresis, which is a process through which excess white blood cells are removed from the blood and bone marrow or stem cell transplantation may be used in some cases.

Persistent research has led to the discovery of a treatment that can specifically kill the stem cells in the bone marrow that generate the cancer cells, and thereby treat CML. This medication, an EZH2-specific inhibitor (EZH2i), inhibits a protein called EZH2 that is important for the survival of these stem cells. Since the protein is not found in normal body cells, an EZH2-specific inhibitor may not cause serious effects to other parts of the body. Researchers believe that this drug can kill more than 90% of stem cells and could possibly result in a cure for the deadly cancer.

The new treatment has a potential to be used with tyrosine kinase inhibitors to possibly bring about a complete cure of cancer. It will be used as a pill that is taken orally. The researchers hope to start clinical trials and move to the next step in the development of the drug, which could be a life saver to several blood cancer patients.

References :

  1. Scott MT et al. Epigenetic Reprogramming Sensitizes CML Stem Cells to Combined EZH2 and Tyrosine Kinase Inhibition. Cancer Discov 2016; 6(11); 1-10
Source: Medindia

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