Preclinical efficacy against acute myeloid leukaemia of SH1573, a novel mutant IDH2 inhibitor approved for clinical trials in China

Acute myeloid leukaemia (AML) is the most common form of acute leukaemia in adults, with increasing incidence with age and a generally poor prognosis. Almost 20% of AML patients express mutant isocitrate dehydrogenase 2 (mIDH2), which leads to the accumulation of the carcinogenic metabolite 2-hydroxyglutarate (2-HG), resulting in poor prognosis. Thus, global institutions have been working to develop mIDH2 inhibitors. SH1573 is a novel mIDH2 inhibitor that we independently designed and synthesised. We have conducted a comprehensive study on its pharmacodynamics, pharmacokinetics and safety. First, SH1573 exhibited a strong selective inhibition of mIDH2 R140Q protein, which could effectively reduce the production of 2-HG in cell lines, serum and tumors of an animal model. It could also promote the differentiation of mutant AML cell lines and granulocytes in PDX models. Then, it was confirmed that SH1573 possessed characteristics of high bioavailability, good metabolic stability and wide tissue distribution. Finally, toxicological data showed that SH1573 had no effects on the respiratory system, cardiovascular system and nervous system, and was genetically safe. This research successfully promoted the approval of SH1573 for clinical trials (CTR20200247). All experiments demonstrated that, as a potential drug against mIDH2 R140Q acute myeloid leukaemia, SH1573 was effective and safe.

Current Progress in Isocitrate Dehydrogenase Mutations and Its Inhibitors in Gliomas / 中国药学杂志

Glioma is a primary brain tumor produced by canceration of the glial cells in the brain and spinal cord, accounting for 74.6% of the malignant tumors in the central nervous system. Isocitrate dehydrogenase (IDH) is the rate-limiting enzyme of the tricarboxylic acid cycle and catalyzes the oxidative decarboxylation of isocitrate to produce α-ketoglutarate (α-KG). Its mutant (mIDH) is a new point mutation, not only lose its original function but also gain new activity: catalyzing the production of carcinogenic R-2-hydroxyglutarate (2HG) by α-KG. Isocitrate dehydrogenase inhibitors can reduce the production of 2HG and induce the demethylation of histones, thereby inhibiting tumor progression. Although discovered in 2008, the mIDH has become a tumor diagnostic marker and therapeutic target, mIDH2 and mIDH1 inhibitors for acute myeloid leukemia have been approved for marketing in 2017and 2018,respectively.For the treatment of acute myeloid leukemia, the reliability of isocitrate dehydrogenase mutants as tumor therapeutic targets was confirmed.At present, many pharmaceutical institutions around the world are conducting research and development of isocitrate dehydrogenase inhibitors.This article reviews the current research status of current IDH inhibitors.

Effect of IDH gene mutation on acute myeloid leukemia / 上海交通大学学报（医学版）

Isocitrate dehydrogenase (IDH) is an important metabolic enzyme involved in the tricarboxylic acid cycle. In recent years, IDH has become the most frequent tumor metabolic mutation gene in acute myeloid leukemia (AML). Unlike other mutations, it gains new functions which can catalyze α-ketoglutarate (α-KG) to produce the tumor metabolite D-2-hydroxyglutarate (D-2-HG). The increased D-2-HG in the cells can affect bone marrow cell differentiation and proliferation and induce myeloid tumors by the genetic controls, cell signaling, bone marrow microenvironment changes and other ways. Currently, the new IDH2 inhibitors AG-221 and IDH1 inhibitors become the first-line drugs targeted therapy in patients with IDH mutations in AML. This paper focused on the mutation of IDH and its mutation characteristics, the formation mechanism of AML by the metabolites produced by mutation, the metabolic pathway of tumor metabolites and the research progress of IDH inhibitors.

In-Vivo Proton Magnetic Resonance Spectroscopy of 2-Hydroxyglutarate in Isocitrate Dehydrogenase-Mutated Gliomas: A Technical Review for Neuroradiologists

The diagnostic and prognostic potential of an onco-metabolite, 2-hydroxyglutarate (2HG) as a proton magnetic resonance spectroscopy (1H-MRS) detectable biomarker of the isocitrate dehydrogenase (IDH)-mutated (IDH-MT) gliomas has drawn attention of neuroradiologists recently. However, due to severe spectral overlap with background signals, quantification of 2HG can be very challenging. In this technical review for neuroradiologists, first, the biochemistry of 2HG and its significance in the diagnosis of IDH-MT gliomas are summarized. Secondly, various 1H-MRS methods used in the previous studies are outlined. Finally, wereview previous in vivo studies, and discuss the current status of 1H-MRS in the diagnosis of IDH-MT gliomas.

Isocitrate dehydrogenase gene mutations in intrahepatic cholangiocarcinoma / 中华肝胆外科杂志

Mutations in isocitrate dehydrogenase are among the most common genetic alterations in intrahepatic cholangiocarcinoma (ICC).Mutant IDH proteins in ICC and other malignancies acquire an abnormal enzymatic activity, allowing the conversion of alpha-ketoglutarate (alphaKG) to 2-hydroxyglutarate (2HG), which inhibits the activity of multiple alphaKG-dependent dioxygenases, and results in alterations in cell differentiation and tumorigenesis.This review will focus on recent advances, which may help understand the function of IDH mutation in intrahepatic cholangiocarcinoma.

Identification of a New Selective Chemical Inhibitor of Mutant Isocitrate Dehydrogenase-1

BACKGROUND: Recent genome-wide sequencing studies have identified unexpected genetic alterations in cancer. In particular, missense mutations in isocitrate dehydrogenase-1 (IDH1) at arginine 132, mostly substituted into histidine (IDH1-R132H) were observed to frequently occur in glioma patients. METHODS: We have purified recombinant IDH1 and IDH1-R132H proteins and monitored their catalytic activities. In parallel experiments, we have attempted to find new selective IDH1-R132H chemical inhibitor(s) from a fragment-based chemical library. RESULTS: We have found that IDH1, but not IDH1-R132H, can catalyze the conversion of isocitrate into alpha-ketoglutarate (alpha-KG). In addition, we have observed that IDH1-R132H was more efficient than IDH1 in converting alpha-KG into (R)-2-hydroxyglutarate (R-2HG). Moreover, we have identified a new hit molecule, e.g., 2-(3-trifluoromethylphenyl)isothioazol-3(2H)-one as a new selective IDH1-R132H inhibitor. CONCLUSIONS: We have observed an underlying biochemical mechanism explaining how a heterozygous IDH1 mutation contributes to the generation of R-2HG and increases cellular histone H3 trimethylation levels. We have also identified a novel selective IDH1-R132H chemical hit molecule, e.g., 2-(3-trifluoromethylphenyl)isothioazol-3(2H)-one, which could be used for a future lead development against IDH1-R132H.