A number of human cancers harbor somatic point mutations in the genes encoding isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2). These mutations alter residues in the enzyme active sites and confer ...a gain-of-function in cancer cells, resulting in the accumulation and secretion of the oncometabolite (R)-2-hydroxyglutarate (2HG). We developed a small molecule, AGI-6780, that potently and selectively inhibits the tumor-associated mutant IDH2/R140Q. A crystal structure of AGI-6780 complexed with IDH2/R140Q revealed that the inhibitor binds in an allosteric manner at the dimer interface. The results of steady-state enzymology analysis were consistent with allostery and slow-tight binding by AGI-6780. Treatment with AGI-6780 induced differentiation of TF-1 erythroleukemia and primary human acute myelogenous leukemia cells in vitro. These data provide proof-of-concept that inhibitors targeting mutant IDH2/R140Q could have potential applications as a differentiation therapy for cancer.
Summary
Background
Mutant isocitrate dehydrogenase 1 and 2 (IDH1/IDH2) enzymes produce the oncometabolite D-2-hydroxyglutarate (2-HG). Ivosidenib (AG-120) is a targeted mutant IDH1 inhibitor under ...evaluation in a phase 1 dose escalation and expansion study of IDH1-mutant advanced solid tumors including cholangiocarcinoma, chondrosarcoma, and glioma. We explored the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of ivosidenib in these populations.
Methods
Ivosidenib was administered orally once (QD) or twice (BID) daily in continuous 28-day cycles; 168 patients received ≥1 dose within the range 100 mg BID to 1200 mg QD. PK and PD were assessed using validated liquid chromatography-tandem mass spectrometry assays.
Results
Ivosidenib demonstrated good oral exposure after single and multiple doses, was rapidly absorbed, and had a long terminal half-life (mean 40–102 h after single dose). Exposure increased less than dose proportionally. Steady state was reached by day 15, with moderate accumulation across all tumors (1.5- to 1.7-fold for area-under-the-curve at 500 mg QD). None of the intrinsic and extrinsic factors assessed affected ivosidenib exposure, including patient/disease characteristics and concomitant administration of weak CYP3A4 inhibitors/inducers. After multiple doses in patients with cholangiocarcinoma or chondrosarcoma, plasma 2-HG was reduced by up to 98%, to levels seen in healthy subjects. Exposure-response relationships for safety and efficacy outcomes were flat across the doses tested.
Conclusions
Ivosidenib demonstrated good oral exposure and a long half-life. Robust, persistent plasma 2-HG inhibition was observed in IDH1-mutant cholangiocarcinoma and chondrosarcoma. Ivosidenib 500 mg QD is an appropriate dose irrespective of various intrinsic and extrinsic factors.
Trial Registration
ClinicalTrials.gov
(NCT02073994).
Mutations of IDH1 and IDH2, which produce the oncometabolite 2-hydroxyglutarate (2HG), have been identified in several tumors, including acute myeloid leukemia. Recent studies have shown that ...expression of the IDH mutant enzymes results in high levels of 2HG and a block in cellular differentiation that can be reversed with IDH mutant-specific small-molecule inhibitors. To further understand the role of IDH mutations in cancer, we conducted mechanistic studies in the TF-1 IDH2 R140Q erythroleukemia model system and found that IDH2 mutant expression caused both histone and genomic DNA methylation changes that can be reversed when IDH2 mutant activity is inhibited. Specifically, histone hypermethylation is rapidly reversed within days, whereas reversal of DNA hypermethylation proceeds in a progressive manner over the course of weeks. We identified several gene signatures implicated in tumorigenesis of leukemia and lymphoma, indicating a selective modulation of relevant cancer genes by IDH mutations. As methylation of DNA and histones is closely linked to mRNA expression and differentiation, these results indicate that IDH2 mutant inhibition may function as a cancer therapy via histone and DNA demethylation at genes involved in differentiation and tumorigenesis.
•IDH2 R140Q expression in TF-1 cells can induce DNA and histone hypermethylation that mirrors human IDH2 mutant acute myeloid leukemia.•The hypermethylation can be reversed on treatment with AGI-6780, an IDH2 mutant-specific small-molecule inhibitor.
Significance Current genomic and biochemical analysis revealed mutations in isocitrate dehydrogenase ( IDH ) genes associated with several neoplasms and a novel enzymatic activity of IDH mutations to ...catalyze α-ketoglutarate to d -2-hydroxyglutarate, contributing to tumorigenesis. We identified a broad range of IDH1 mutations, including a previously unidentified IDH1 -R132Q mutation, in cartilage tumors. Cartilage-specific Col2a1-Cre/ERT2;Idh1-R132 mutant knock-in mice developed multiple enchondroma-like lesions. These data show that mutant Idh in growth-plate cells causes persistence of chondrocytes, giving rise to enchondromas adjacent to the growth cartilage in bone.
Enchondromas are benign cartilage tumors and precursors to malignant chondrosarcomas. Somatic mutations in the isocitrate dehydrogenase genes ( IDH1 and IDH2 ) are present in the majority of these tumor types. How these mutations cause enchondromas is unclear. Here, we identified the spectrum of IDH mutations in human enchondromas and chondrosarcomas and studied their effects in mice. A broad range of mutations was identified, including the previously unreported IDH1 -R132Q mutation. These mutations harbored enzymatic activity to catalyze α-ketoglutarate to d -2-hydroxyglutarate ( d -2HG). Mice expressing Idh1 -R132Q in one allele in cells expressing type 2 collagen showed a disordered growth plate, with persistence of type X-expressing chondrocytes. Chondrocyte cell cultures from these animals or controls showed that there was an increase in proliferation and expression of genes characteristic of hypertrophic chondrocytes with expression of Idh1 -R132Q or 2HG treatment. Col2a1-Cre; Idh1 -R132Q mutant knock-in mice (mutant allele expressed in chondrocytes) did not survive after the neonatal stage. Col2a1-Cre/ERT2;Idh1-R132 mutant conditional knock-in mice, in which Cre was induced by tamoxifen after weaning, developed multiple enchondroma-like lesions. Taken together, these data show that mutant IDH or d -2HG causes persistence of chondrocytes, giving rise to rests of growth-plate cells that persist in the bone as enchondromas.
Mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2) have been discovered in several cancer types and cause the neurometabolic syndrome D2-hydroxyglutaric aciduria (D2HGA). The mutant enzymes ...exhibit neomorphic activity resulting in production of D2-hydroxyglutaric acid (D-2HG). To study the pathophysiological consequences of the accumulation of D-2HG, we generated transgenic mice with conditionally activated IDH2(R140Q) and IDH2(R172K) alleles. Global induction of mutant IDH2 expression in adults resulted in dilated cardiomyopathy, white matter abnormalities throughout the central nervous system (CNS), and muscular dystrophy. Embryonic activation of mutant IDH2 resulted in more pronounced phenotypes, including runting, hydrocephalus, and shortened life span, recapitulating the abnormalities observed in D2HGA patients. The diseased hearts exhibited mitochondrial damage and glycogen accumulation with a concordant up-regulation of genes involved in glycogen biosynthesis. Notably, mild cardiac hypertrophy was also observed in nude mice implanted with IDH2(R140Q)-expressing xenografts, suggesting that 2HG may potentially act in a paracrine fashion. Finally, we show that silencing of IDH2(R140Q) in mice with an inducible transgene restores heart function by lowering 2HG levels. Together, these findings indicate that inhibitors of mutant IDH2 may be beneficial in the treatment of D2HGA and suggest that 2HG produced by IDH mutant tumors has the potential to provoke a paraneoplastic condition.
Abstract
Background: Somatic mutations in the isocitrate dehydrogenase 1 (IDH1) gene have been reported in ~25% of patients with intrahepatic cholangiocarcinoma (CC). The mutant IDH1 (mIDH1) enzyme ...has a gain-of-function activity, catalyzing the reduction of alpha-ketoglutarate to D-2-hydroxyglutarate (2-HG). Accumulation of 2-HG leads to epigenetic dysregulation, and potential silencing of genes that control cellular differentiation. In a preclinical model of liver development, IDH1 mutation resulted in HNF4A silencing and impaired hepatocyte differentiation. AG-120 (ivosidenib) is a first-in-class, oral, selective inhibitor of mIDH1 that has been shown to reduce 2-HG levels in plasma and tumor tissue in preclinical and clinical studies, and to induce differentiation of leukemic blasts in patients with acute myeloid leukemia. In solid tumors, the consequences of IDH1 mutations and the effects of inhibition are less understood. In AG120-C-002 (ClinicalTrials.gov NCT02073994), a phase 1 clinical trial in mIDH1 advanced solid tumors, 73 patients with CC were treated with AG-120 at doses ranging from 100 mg twice daily to 1200 mg once daily. Among the phase 1 CC subjects who underwent on-study biopsies, we assessed morphologic and gene expression profile changes to understand the relationship between these parameters. Methods: Biopsy samples were collected from patients with CC enrolled in AG120-C-002 at screening, Cycle 3 Day 1, and in some cases Cycle 7 Day 1, disease progression, and end of treatment. Fourteen pre- and post-dose formalin-fixed paraffin-embedded (FFPE) tumor sample pairs were evaluable for morphology assessment (from 27 FFPE pre- and post-dose pairs collected), and 19 pre- and post-dose fresh frozen tumor sample pairs underwent gene expression profiling (from 38 pre- and post-dose pairs collected). Both morphology and gene expression data were assessed in eight patients to elucidate their relationship. Hematoxylin and eosin stained sections were evaluated for a cholangiocellular growth pattern and cytoplasmic alterations by two gastrointestinal pathologists from independent institutions. Gene expression profiles were generated by RNA sequencing to relate to morphologic changes. Results: Morphologic assessment of 14 pre- and post-dose sample pairs showed that upon 8-24 weeks of AG-120 treatment, a subset of CCs exhibited change in two phenotypes: (a) an increase of 20% or more in the cholangiocellular growth pattern (n=5), and (b) a reduction in the volume of cytoplasm (n=8). Changes in both phenotypes (a) and (b) were seen in five cases. RNA sequence profiling in samples with increased cholangiolar histology also showed a trend toward increased liver-specific gene expression. Conclusions: This is the first demonstration that AG-120 treatment may induce morphologic and molecular changes in a subset of mIDH1 CCs. Correlation of changes in morphology and gene expression with specific clinical outcomes will be described. Further studies, such as methylation changes, protein change by immunohistochemistry, and preclinical studies, are warranted to understand the biology of these morphologic and gene expression changes.
Citation Format: Yuko Ishii, Carlie Sigel, Maeve A. Lowery, Lipika Goyal, Camelia Gliser, Liewen Jiang, Susan Pandya, Bin Wu, Sung Choe, Vikram Deshpande. AG-120 (ivosidenib), a first-in-class mutant IDH1 inhibitor, promotes morphologic changes and upregulates liver-specific genes in IDH1 mutant cholangiocarcinoma abstract. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A071.
Abstract only
4015
Background: Mutations in the metabolic enzyme isocitrate dehydrogenase 1 (mIDH1) occur in patients (pts) with cholangiocarcinoma (CC) and are detected in up to 25% of intrahepatic ...CC. mIDH1 produce the oncometabolite, D-2-hydroxyglutarate (2-HG), resulting in epigenetic and genetic dysregulation and oncogenesis. AG-120 is a first-in-class, potent, oral inhibitor of mIDH1 tested in this phase I study in mIDH1 solid tumors, including CC. Methods: AG-120 was escalated in a 3+3 design from 100 mg twice daily to 1200 mg once daily (QD) in 28-day cycles (N = 60, mIDH1 advanced solid tumors). Key eligibility for CC: recurrence of progressive mIDH1 CC following standard therapy (dose escalation) or at least a prior gemcitabine-based regimen (expansion cohort). Response (RECIST 1.1) was assessed every 8 weeks. Plasma and tumor tissue were collected for exploratory analyses. Results: Based on the safety, pharmacokinetic, and pharmacodynamic data from dose escalation, the 500 mg QD dose was selected for expansion in mIDH1 CC and other mIDH1 solid tumors. As of Dec 16, 2016, 73 pts with mIDH1 CC had been dosed in the dose escalation (n = 24) and expansion (n = 49) cohorts. Demographics: M/F = 24/49, median number of prior therapies = 2 (range 1–5), ECOG 0–1 = 26/47. There were no dose-limiting toxicities. Treatment-related adverse events (AEs) in ≥5% pts: fatigue (21%), nausea (18%), vomiting (12%), diarrhea (10%), decreased appetite (8%), dysgeusia (5%), QT prolongation (5%). Two (3%) pts experienced related grade 3 AEs: fatigue and low phosphorus. There were no AG-120-related AEs leading to discontinuation. Among the 72 efficacy evaluable (≥1 post baseline response assessment or discontinued prematurely) mIDH1 CC pts (24 in escalation and 48 in expansion cohort), 6% (n = 4) had a confirmed partial response and 56% (n = 40) experienced stable disease. The progression-free survival rate at 6 months was 40%, and 8 pts have been treated with AG-120 for ≥1 year. Conclusions: In this pretreated mIDH1 CC population, AG-120 was associated with a favorable safety profile and prolonged stable disease. A global, phase III, randomized, placebo-controlled study of AG-120 in mIDH1 CC has been initiated (ClarIDHy). Clinical trial information: NCT02073994.
Isocitrate dehydrogenase 1 (IDH1) mutations occur in approximately 13% of patients with intrahepatic cholangiocarcinoma, a relatively uncommon cancer with a poor clinical outcome. The aim of this ...international phase 3 study was to assess the efficacy and safety of ivosidenib (AG-120)—a small-molecule targeted inhibitor of mutated IDH1—in patients with previously treated IDH1-mutant cholangiocarcinoma.
This multicentre, randomised, double-blind, placebo-controlled, phase 3 study included patients from 49 hospitals in six countries aged at least 18 years with histologically confirmed, advanced, IDH1-mutant cholangiocarcinoma who had progressed on previous therapy, and had up to two previous treatment regimens for advanced disease, an Eastern Cooperative Oncology Group performance status score of 0 or 1, and a measurable lesion as defined by Response Evaluation Criteria in Solid Tumors version 1.1. Patients were randomly assigned (2:1) with a block size of 6 and stratified by number of previous systemic treatment regimens for advanced disease to oral ivosidenib 500 mg or matched placebo once daily in continuous 28-day cycles, by means of an interactive web-based response system. Placebo to ivosidenib crossover was permitted on radiological progression per investigator assessment. The primary endpoint was progression-free survival by independent central review. The intention-to-treat population was used for the primary efficacy analyses. Safety was assessed in all patients who had received at least one dose of ivosidenib or placebo. Enrolment is complete; this study is registered with ClinicalTrials.gov, NCT02989857.
Between Feb 20, 2017, and Jan 31, 2019, 230 patients were assessed for eligibility, and as of the Jan 31, 2019 data cutoff date, 185 patients were randomly assigned to ivosidenib (n=124) or placebo (n=61). Median follow-up for progression-free survival was 6·9 months (IQR 2·8–10·9). Progression-free survival was significantly improved with ivosidenib compared with placebo (median 2·7 months 95% CI 1·6–4·2 vs 1·4 months 1·4–1·6; hazard ratio 0·37; 95% CI 0·25–0·54; one-sided p<0·0001). The most common grade 3 or worse adverse event in both treatment groups was ascites (four 7% of 59 patients receiving placebo and nine 7% of 121 patients receiving ivosidenib). Serious adverse events were reported in 36 (30%) of 121 patients receiving ivosidenib and 13 (22%) of 59 patients receiving placebo. There were no treatment-related deaths.
Progression-free survival was significantly improved with ivosidenib compared with placebo, and ivosidenib was well tolerated. This study shows the clinical benefit of targeting IDH1 mutations in advanced, IDH1-mutant cholangiocarcinoma.
Agios Pharmaceuticals.
Surgery is the primary therapy for localized chondrosarcoma; for locally advanced and/or metastatic disease, no known effective systemic therapy exists. Mutations in the isocitrate dehydrogenase 1/2 ...(IDH1/2) enzymes occur in up to 65% of chondrosarcomas, resulting in accumulation of the oncometabolite D-2-hydroxyglutarate (2-HG). Ivosidenib (AG-120) is a selective inhibitor of mutant IDH1 approved in the United States for specific cases of acute myeloid leukemia. We report outcomes of patients with advanced chondrosarcoma in an ongoing study exploring ivosidenib treatment.
This phase I multicenter open-label dose-escalation and expansion study of ivosidenib monotherapy enrolled patients with mutant
advanced solid tumors, including chondrosarcoma. Ivosidenib was administered orally (100 mg twice daily to 1,200 mg once daily) in continuous 28-day cycles. Responses were assessed every other cycle using RECIST (version 1.1).
Twenty-one patients (escalation, n = 12; expansion, n = 9) with advanced chondrosarcoma received ivosidenib (women, n = 8; median age, 55 years; range, 30-88 years; 11 had received prior systemic therapy). Treatment-emergent adverse events (AEs) were mostly grade 1 or 2. Twelve patients experienced grade ≥ 3 AEs; only one event was judged treatment related (hypophosphatemia, n = 1). Plasma 2-HG levels decreased substantially in all patients (range, 14%-94.2%), to levels seen in healthy individuals. Median progression-free survival (PFS) was 5.6 months (95% CI, 1.9 to 7.4 months); the PFS rate at 6 months was 39.5%. Eleven (52%) of 21 patients experienced stable disease.
In patients with chondrosarcoma, ivosidenib showed minimal toxicity, substantial 2-HG reduction, and durable disease control. Future studies of ivosidenib monotherapy or rational combination approaches should be considered in patients with advanced mutant
chondrosarcoma.
TPS4197 Background: Cholangiocarcinoma (CCA) is a rare cancer with limited therapeutic options, though molecularly targeted therapies have demonstrated anti-tumor activity in certain subsets. ...Approximately 15% of patients with intrahepatic CCA harbor activating mutations in isocitrate dehydrogenase-1 (mIDH1), and treatment with the mIDH1 inhibitor, ivosidenib (IVO) improved progression-free survival in the phase 3 ClarIDHy trial. mIDH1 is associated with an immune-excluded tumor microenvironment, and anti-CTLA4 immune checkpoint inhibition (ICI) augments anti-tumor activity when combined with IVO in preclinical models. Preliminary anti-tumor activity of dual immune checkpoint inhibitors (IPI, NIVO) has been reported in biliary tract cancers. Methods: This is a phase 1/2, non-comparative, multicenter, open-label study of IVO, IPI, NIVO, in subjects with unresectable or metastatic CCA with mIDH1. Key eligibility criteria include: a histopathological diagnosis; tumor mIDH1 based on local testing; progression on and/or intolerance to 1-2 prior lines of systemic therapy, at least one of which contained either gemcitabine and/or 5-fluorouracil; prior anti-PD-(L)1 therapy is allowed in the safety lead in; Eastern Cooperative Oncology Group performance status (ECOG PS) of 0 or 1; at least 1 measurable lesion as defined by RECIST version 1.1. The study has a safety lead-in phase and an expansion phase with 2 different expansion cohorts: cohort 1, ICI-naive; cohort 2, prior ICI allowed. The primary objective is to evaluate the safety and tolerability of IVO in combination with IPI plus NIVO and determine the recommended combination dose (RCD). This phase will enroll ~6 to 12 dose-limiting toxicity (DLT)–evaluable patients. The first 6 patients enrolled will receive IVO 500 mg orally once daily in combination with IPI 1 mg/kg IV infusion and NIVO 3 mg/kg IV infusion concurrently once every 3 weeks for 4 doses followed by NIVO at 480 mg IV once every 4 weeks until progression or unacceptable toxicity (up to a maximum of 24 months of NIVO). DLTs will be evaluated during the first 2 cycles of treatment. An additional 6 patients may be enrolled to assess an alternative dose of ivosidenib 250 mg once daily. Upon determination of the RCD, the two expansion cohorts will be initiated to assess the clinical activity of the triplet combination in patients with and without prior ICI. First patient in occurred in November 2023. Clinical trial information: NCT05921760 .
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