What is imatinib?
Imatinib (trade name Glivec®) is a drug from the group of tyrosine kinase inhibitors, which is used in the treatment of chronic myeloid leukemia, for the treatment of malignant tumors of the gastrointestinal tract and for the treatment of other malignant diseases. The chemical empirical formula of imatinin is C29H31N7O.
Chronic myeloid leukemia is caused by the so-called Philadelphia chromosome, a genetic mutation. In the Philadelphia chromosome there is a translocation of genetic material of chromosome 9 and chromosome 22. Through this translocation, the gene for the natural enzyme tyrokinase ABL on chromosome 9 "fuses" with the fragment of the BCR gene on chromosome 22.
The mutated cells produce instead of the tyrosine kinase ABL a so-called fusion protein BCR-ABL. BCR-ABL is a more active tyrosine kinase compared to ABL. This BCR-ABL leads to the uncontrolled proliferation of white blood cells (leukocytes) and is significantly involved in the development of chronic myeloid leukemia.
Imatinib inhibits (inhibits) the activity of the tyrosine kinase and thus suppresses the pathologically increased multiplication of the mutated blood stem cells. The substance is administered orally in the form of a tablet; orally, imatinib mesilate, a salt, is used. The aim of the treatment is to reduce the pathological cell clone as far as possible.
In more than 95% of imatinib-treated patients with chronic myeloid leukemia, normalization of the blood count is achieved.
Medical application & use
As already mentioned, the substance is mainly used in the treatment of chronic myeloid leukemia. He is, however, also effective against a number of other cancers. It is also indicated for acute lymphoblastic leukemia, hypereosinophilic syndrome, various tumors of the skin, malignant tumors of the gastrointestinal tract, aggressive mastocytosis and certain myeloproliferative disorders.
Chronic myeloid leukemia, a neoplastic disease of the hematopoietic system, is increasingly associated with immature forms of leukocytes in the blood, due to the pathologically increased proliferation of leukocytes in the blood and blood-forming bone marrow.
Chronic myeloid leukemia results from a (genetic) disorder of the hematopoietic (hematopoietic) stem cells found in the bone marrow. For this reason, chronic myeloid leukemia is a myeloproliferative neoplasia. The cause of the disease is the alteration and subsequent multiplication of a single multipotent hematopoietic progenitor cell. This change is due in almost all cases to the previously described Philadelphia chromosome.
Due to the novel drugs from the group of tyrosine kinase inhibitors, which include imatinib, the prognosis of chronic myeloid leukemia has been significantly improved. Treatment with tyrosine kinase inhibitors is a well-effective and relatively low-side-effect option of the treatment and is considered a targeted therapy.
The survival rate has greatly increased with the introduction of tyrosine kinase inhibitors. When there were no treatment options for chronic myeloid leukemia, patients' median survival was between three and four years.
Chronic myeloid leukemia was the disease with the worst prognosis from myeloproliferative neoplasia. The introduction of hydroxycarbamide, a cytostatic drug, has increased this median survival to four and a half years. Interferon resulted in a further increase in median survival to approximately five and a half years.
Meanwhile, the treatment with tyrosine kinase inhibitors is considered the standard therapy. The 5-year survival rate for imatinib treatment is over 90%. The follow-up of imatinib-treated patients is now more than 10 years, and the "median survival" has not yet been established. This suggests that it is well above the mean survival of previously used therapies (with hydroxycarbamide and interferon).
Risks & Side Effects
The tolerability of imatinib is generally good. However, diarrhea, vomiting, abdominal pain, nausea, indigestion, fatigue, headache, edema, weight gain, muscle cramps, muscle aches, joint pain, skin rash, bone pain, and changes in the blood count may occur.
Imatinib is contraindicated only in case of hypersensitivity or intolerance to imatinib.
Imatinib should not be taken concomitantly with paracetamol as it inhibits glucuronidation (binding to glucuronic acid during metabolism) of paracetamol. In addition, certain subunits of the cytochrome P450 are affected, which may lead to interactions with other drugs.