Thiopurine-induced myelotoxicity in patients with acute leukemia and benefits of preemptive pharmacogenetic testing prior to 6-mercaptopurine prescription
Mercaptopurine (МР) is a key element of the maintenance therapy of acute leukemias. Different amounts of active and toxic metabolites can be synthesized in patients who are receiving the same doses of the drug due to pharmacokinetic differences. This contributes to the unequal drug tolerability and the need of dose adjustment. For a long time, the only tool for adjusting 6-MP dose was the level of leukocytes and granulocytes in the peripheral blood. With the understanding of genetic factors affecting the metabolism of 6-MP and development of next-generation sequencing technology, clinical guidelines for thiopurine dosing based on a pharmacogenetic approach have been emerged. In this article, we report two patients belonging to a small ethnic group in Russia with abnormal 6-MP toleration and substantiate the advantages of a personalized, pharmacogeneticallybased approach to 6-MP administration. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.