Acute myeloid leukaemia (AML) is the most common aggressive leukaemia in adults and is incurable in most patients. Up to 15% of adult AML patients have a mutation in the IDH2 gene. The resulting abnormal IDH2 enzyme produces a chemical not normally found in blood cells called 2-hydroxyglutarate (2-HG). 2-HG stops the bone marrow from producing normal mature blood cells, including neutrophils and monocytes, cells that are essential for fighting life-threatening infections. Instead, immature leukaemia cells accumulate in the patient’s bone marrow and blood. AML patients need regular blood transfusions, and have a very poor immune system.
Most treatments for AML involve aggressive chemotherapy drugs that work by killing leukaemia cells, but these drugs have serious side-effects and are not suitable for the majority of AML patients. A new drug, Enasidenib, operates in a different way to conventional chemotherapy treatments. Instead of killing leukaemia cells, Enasidenib re-programmes them into neutrophils and monocytes that can function normally as part of a healthier immune system. An international team of researchers, including scientists at the MRC Molecular Hematology Unit at the MRC Wethearall Institute of Medicine, led by Prof Paresh Vyas and Dr Lynn Quek (Radcliffe Department of Medicine) recently published exciting results of their Phase 1 clinical trial of Enasidenib.
The researchers report that Enasidenib was effective in 40% of the 176 AML patients who participated in the study, with 19% achieving complete remission. Patients had improved immune systems and required fewer or no blood transfusions. In addition, the majority of participants showed few side effects to the drug. Crucially, most patients in this clinical trial had not responded to other AML treatments. Enasidenib represents an important addition to the currently limited range of effective treatments for this disease.
The results of this clinical trial, together with supporting scientific data, have helped secure FDA approval for Enasidenib. The Oxford team is now leading the research programme to investigate why Enasidenib is not effective in all patients and if it can be more effective in combination with other AML therapies.
Find out more:
Amatangelo, Quek et al (2017) Enasidenib induces acute myeloid leukemia cell differentiation to promote clinical response, Blood, 130 (6) 732-741
Stein EM, DiNardo CD (2017) Enasidenib in mutant IDH2 relapsed or refractory acute myeloid leukemia, Blood, 130 (6) 722-731