The Gly82Ser polymorphism in the receptor for advanced glycation endproducts increases the risk for coronary events in the general population.

The receptor for advanced glycation endproducts (RAGE) has pro-inflammatory and pro-atherogenic effects. Low plasma levels of soluble RAGE (sRAGE), a decoy receptor for RAGE ligands, have been associated with increased risk for major adverse coronary events (MACE) in the general population. We performed a genome-wide association study to identify genetic determinants of plasma sRAGE in 4338 individuals from the cardiovascular arm of the Malmö Diet and Cancer study (MDC-CV). Further, we explored the associations between these genetic variants, incident first-time MACE and mortality in 24,640 unrelated individuals of European ancestry from the MDC cohort. The minor alleles of four single nucleotide polymorphisms (SNPs): rs2070600, rs204993, rs116653040, and rs7306778 were independently associated with lower plasma sRAGE. The minor T (vs. C) allele of rs2070600 was associated with increased risk for MACE [HR 1.13 95% CI (1.02-1.25), P = 0.016]. Neither SNP was associated with mortality. This is the largest study to demonstrate a link between a genetic sRAGE determinant and CV risk. Only rs2070600, which enhances RAGE function by inducing a Gly82Ser polymorphism in the ligand-binding domain, was associated with MACE. The lack of associations with incident MACE for the other sRAGE-lowering SNPs suggests that this functional RAGE modification is central for the observed relationship.

Determination of the segmental hepatic clearance rate of 99mTc-mebrofenin and its application in the functional assessment of future liver remnant after liver resection.

99mTc-mebrofenin hepatobiliary scintigraphy with SPECT/CT (HBS-M) has become an important quantitative method to evaluate global liver function and future liver remnant (FLR) function in patients who are candidates for resective liver surgery. The purpose of this work was to describe the method in the prediction of post-surgical liver failure. The overall liver function and that of the FLR are obtained by analysis of the initial dynamic phase of the scan. Liver volume to be preserved is expressed as a percentage of the total liver volume measured in both CT sections. HBS-M is able to accurately gauge regional liver function abnormalities that could be represented as normal liver tissue parenchyma in the CT study. This technique can provide very valuable prognostic information for the estimation of the postoperative risk of liver failure in all patients who are candidates for resective liver surgery.

Metabolomic Detection Between Pancreatic Cancer and Liver Metastasis Nude Mouse Models Constructed by Using the PANC1-KAI1/CD82 Cell Line.

Background: Pancreatic cancer (PC) has a poor prognosis and is prone to liver metastasis. The KAI1/CD82 gene inhibits PC metastasis. This study aimed to explore differential metabolites and enrich the pathways in serum samples between PC and liver metastasis nude mouse models stably expressing KAI1/CD82. Methods: KAI1/CD82-PLV-EF1α-MCS-IRES-Puro vector and PANC1 cell line stably expressing KAI1/CD82 were constructed for the first time. This cell line was used to construct 3 PC nude mouse models and 3 liver metastasis nude mouse models. The different metabolites and Kyoto encyclopedia of genes and genomes (KEGG) and human metabolome database (HMDB) enrichment pathways were analyzed using the serum samples of the 2 groups of nude mouse models on the basis of untargeted ultra-performance liquid chromatography-tandem mass spectrometry platform. Results: KAI1/CD82-PLV-EF1α-MCS-IRES-Puro vector and PANC1 cell line stably expressing KAI1/CD82 were constructed successfully, and all nude mouse models survived and developed cancers. Among the 1233 metabolites detected, 18 metabolites (9 upregulated and 9 downregulated) showed differences. In agreement with the literature data, the most significant differences between both groups were found in the levels of bile acids (taurocholic acid, chenodeoxycholic acid), glycine, prostaglandin E2, vitamin D, guanosine monophosphate, and inosine. Bile recreation, primary bile acid biosynthesis, and purine metabolism KEGG pathways and a series of HMDB pathways (P < .05) contained differential metabolites that may be associated with liver metastasis from PC. However, the importance of these metabolites on PC liver metastases remains to be elucidated. Conclusions: Our findings suggested that the metabolomic approach may be a useful method to detect potential biomarkers in PC.

Prospective analysis of circulating metabolites and endometrial cancer risk.

BACKGROUND: Endometrial cancer is strongly associated with obesity and dysregulation of metabolic factors such as estrogen and insulin signaling are causal risk factors for this malignancy. To identify additional novel metabolic pathways associated with endometrial cancer we performed metabolomic analyses on pre-diagnostic plasma samples from 853 case-control pairs from the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: A total of 129 metabolites (acylcarnitines, amino acids, biogenic amines, glycerophospholipids, hexoses, and sphingolipids) were measured by liquid chromatography-mass spectrometry. Conditional logistic regression estimated the associations of metabolites with endometrial cancer risk. An analysis focusing on clusters of metabolites using the bootstrap lasso method was also employed. RESULTS: After adjustment for body mass index, sphingomyelin [SM] C18:0 was positively (OR1SD: 1.18, 95% CI: 1.05-1.33), and glycine, serine, and free carnitine (C0) were inversely (OR1SD: 0.89, 95% CI: 0.80-0.99; OR1SD: 0.89, 95% CI: 0.79-1.00 and OR1SD: 0.91, 95% CI: 0.81-1.00, respectively) associated with endometrial cancer risk. Serine, C0 and two sphingomyelins were selected by the lasso method in >90% of the bootstrap samples. The ratio of esterified to free carnitine (OR1SD: 1.14, 95% CI: 1.02-1.28) and that of short chain to free acylcarnitines (OR1SD: 1.12, 95% CI: 1.00-1.25) were positively associated with endometrial cancer risk. Further adjustment for C-peptide or other endometrial cancer risk factors only minimally altered the results. CONCLUSION: These findings suggest that variation in levels of glycine, serine, SM C18:0 and free carnitine may represent specific pathways linked to endometrial cancer development. If causal, these pathways may offer novel targets for endometrial cancer prevention.

Quantitation of ivosidenib in human plasma via LC-MS/MS and its application in clinical trials.

Aim: Ivosidenib is a potent and selective small molecule inhibitor of mutant isocitrate dehydrogenase 1. Accurate measurement of ivosidenib is the key to ivosidenib pharmacokinetics in clinical trials. Materials & methods: Quantitation of ivosidenib was conducted by using a stable isotope labeled compound (ivosidenib-d4) as the internal standard. Results: This assay was validated and successfully applied to support multiple clinical trials. Selected clinical samples were also tested by a chiral LC-MS/MS method against four ivosidenib isomer standards to exclude the possibility of in vivo racemization of ivosidenib. Conclusion: A robust LC-MS/MS method was validated for ivosidenib in human plasma. This is the first time for ivosidenib bioanalytical method in any human matrix to be reported.

Effect of Mild and Moderate Hepatic Impairment on the Pharmacokinetics, Safety, and Tolerability of a Single Dose of Oral Ivosidenib in Otherwise Healthy Participants.

Ivosidenib, a small-molecule inhibitor of mutant isocitrate dehydrogenase 1, is primarily cleared by hepatic metabolism. This open-label study investigated the impact of hepatic impairment on ivosidenib pharmacokinetics (ClinicalTrials.gov: NCT03282513). Otherwise healthy participants with mild (n = 9) or moderate (n = 8) hepatic impairment (Child-Pugh score) and matched participants with normal hepatic function (n = 16) received 1 oral dose of 500-mg ivosidenib. Mild hepatic impairment had a negligible effect on total ivosidenib plasma exposure, with geometric mean ratios (90% confidence interval [CI]) of 0.933 (0.715-1.22) for maximum concentration (Cmax ) and 0.847 (0.624-1.15) for area under the plasma concentration-time curve (AUC) in participants with mild hepatic impairment versus matched controls. Moderate hepatic impairment reduced total ivosidenib exposure by 28% to 44%, with geometric mean ratios (90%CI) of 0.565 (0.419-0.763) for Cmax and 0.716 (0.479-1.07) for AUC, although the 90%CI for AUC included 1.00. The ivosidenib unbound fraction was concentration dependent and higher in participants with mild/moderate hepatic impairment compared with matched controls. There was no apparent trend to increasing unbound Cmax with increased hepatic impairment severity. A single 500-mg ivosidenib dose was well tolerated, with no serious or severe adverse events and no adverse events leading to discontinuation. We conclude that mild/moderate hepatic impairment did not lead to clinically relevant changes in ivosidenib exposure following a single 500-mg dose.

Mendelian Randomization Study on Amino Acid Metabolism Suggests Tyrosine as Causal Trait for Type 2 Diabetes.

Circulating levels of branched-chain amino acids, glycine, or aromatic amino acids have been associated with risk of type 2 diabetes. However, whether those associations reflect causal relationships or are rather driven by early processes of disease development is unclear. We selected diabetes-related amino acid ratios based on metabolic network structures and investigated causal effects of these ratios and single amino acids on the risk of type 2 diabetes in two-sample Mendelian randomization studies. Selection of genetic instruments for amino acid traits relied on genome-wide association studies in a representative sub-cohort (up to 2265 participants) of the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam Study and public data from genome-wide association studies on single amino acids. For the selected instruments, outcome associations were drawn from the DIAGRAM (DIAbetes Genetics Replication And Meta-analysis, 74,124 cases and 824,006 controls) consortium. Mendelian randomization results indicate an inverse association for a per standard deviation increase in ln-transformed tyrosine/methionine ratio with type 2 diabetes (OR = 0.87 (0.81-0.93)). Multivariable Mendelian randomization revealed inverse association for higher log10-transformed tyrosine levels with type 2 diabetes (OR = 0.19 (0.04-0.88)), independent of other amino acids. Tyrosine might be a causal trait for type 2 diabetes independent of other diabetes-associated amino acids.

Metabolomics and psychological features in fibromyalgia and electromagnetic sensitivity.

Fibromyalgia (FM) as Fibromyalgia and Electromagnetic Sensitivity (IEI-EMF) are a chronic and systemic syndrome. The main symptom is represented by strong and widespread pain in the musculoskeletal system. The exact causes that lead to the development of FM and IEI-EMF are still unknown. Interestingly, the proximity to electrical and electromagnetic devices seems to trigger and/or amplify the symptoms. We investigated the blood plasma metabolome in IEI-EMF and healthy subjects using 1H NMR spectroscopy coupled with multivariate statistical analysis. All the individuals were subjected to tests for the evaluation of psychological and physical features. No significant differences between IEI-EMF and controls relative to personality aspects, Locus of Control, and anxiety were found. Multivariate statistical analysis on the metabolites identified by NMR analysis allowed the identification of a distinct metabolic profile between IEI-EMF and healthy subjects. IEI-EMF were characterized by higher levels of glycine and pyroglutamate, and lower levels of 2-hydroxyisocaproate, choline, glutamine, and isoleucine compared to healthy subjects. These metabolites are involved in several metabolic pathways mainly related to oxidative stress defense, pain mechanisms, and muscle metabolism. The results here obtained highlight possible physiopathological mechanisms in IEI-EMF patients to be better defined.

Distinct lipid signatures are identified in the plasma of rats with chronic inflammation induced by estradiol benzoate and sex hormones.

INTRODUCTION: Prostatitis is likely to occur in younger or middle-aged men, while prostate cancer is likely to occur in older men. Although amino acids and lipids as biomarkers of prostate cancer have been examined using prostate cancer cell lines/tissues, no previous studies have evaluated amino acids or lipids as potential chronic prostatitis biomarkers. OBJECTIVES: The study's aim was to identify amino acids and lipids that could serve as potential biomarkers of chronic prostatitis. METHODS: We profiled the amino acids and lipids found in plasma from rats collected in a previous study. In brief, a total of 148 Sprague-Dawley rats (offspring) were dosed with estradiol benzoate (EB) on postnatal days (PNDs) 1, 3 and 5, and subsequently dosed with testosterone (T)/estradiol (E) tubes via subcutaneous implants from PND 90 to 200. Plasma was collected on PNDs 30, 90, 100, 145 and 200. Analysis was conducted with a Xevo TQ-S triple-quadrupole mass spectrometer using a Biocrates AbsoluteIDQ p180 kit. RESULTS: Plasma acylcarnitines [(C2, C16:1, C18, C18:1, C18:1-OH, and C18:2)], glycerophospholipids (lysophosphatidylcholine-acyl, -di-acyl, and -di-acyl acyl-alkyl) and sphingomyelins [SM (OH) C16:1, SM C18:0, SM C18:1, and SM C20:2] significantly increased on PND 145, when chronic inflammation was observed in the dorsolateral prostate of rats dosed with EB, T, and E. No statistical significances of amino acid levels were observed in the EB + T + E group on PND 145. CONCLUSION: Exposure to EB, T, and E altered lipid levels in rat plasma with chronic prostate inflammation. These findings suggest that the identified lipids may be predictive chronic prostatitis biomarkers. The results require confirmation through additional nonclinical and human studies.

Evaluating ivosidenib for the treatment of acute myeloid leukemia.

INTRODUCTION: Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults, but the results for patients with AML are still unsatisfactory. The discovery of new mutations in AML, including IDH mutations, has opened the door for treatment with targeted agents. Ivosidenib is a selective, potent inhibitor of the IDH1 mutant protein. AREAS COVERED: This review summarizes the mechanism of action, safety profile and efficacy of ivosidenib for patients with IDH1-mutated AML. The authors then provide their expert perspectives on the use of the drug including their future perspectives. EXPERT OPINION: Ivosidenib is a promising, most probably practice changing, new drug for the treatment of IDH1-mutated AML. Current phase III trials are ongoing to evaluate the addition of ivosidenib to the current standards-of-care. In the near future, more drug combinations are awaited. Challenges for the future include the development of resistance and establishing the duration of maintenance therapy.

Clinical pharmacokinetics and pharmacodynamics of ivosidenib, an oral, targeted inhibitor of mutant IDH1, in patients with advanced solid tumors.

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 RegistrationClinicalTrials.gov (NCT02073994).

A Previously Unknown Drug-Drug Interaction Is Suspected in Delayed Elimination of Plasma Methotrexate in High-Dose Methotrexate Therapy.

Background: High-dose methotrexate (HD-MTX) therapy is widely implemented for leukemia, osteosarcoma, and lymphoma. Although various measures have been taken to avoid toxicity from high serum MTX concentrations, there are many cases of delayed elimination of MTX. Objective: We suspected that delayed elimination of serum MTX was caused by unknown interactions between MTX and concomitant drugs. Methods: Concerning concomitant drugs in the case of delayed elimination of MTX, we performed screening tests in 35 patients who had undergone HD-MTX therapy. We then investigated the risk factors for delayed MTX elimination in 94 patients with leukemia, lymphoma, or osteosarcoma retrospectively. Results: The percentages of concomitant use of Stronger Neo-Minophagen C (SNMC), a glycyrrhizin preparation, and vincristine were higher in the delayed group. The percentage of delayed MTX elimination in patients receiving HD-MTX therapy was 41%. Multiple logistic regression analysis revealed that the concomitant use of SNMC solely was a significant risk factor for delayed MTX (odds ratio = 12.20; 95% CI = 1.06-139.84). Conclusion and Relevance: Concomitant use of SNMC was shown to be related to delayed elimination of serum MTX, and our results suggested a previously unknown drug-drug interaction between MTX and SNMC.

Substitution of Dietary Sulfur Amino Acids by dl-2-Hydroxy-4-Methylthiobutyric Acid Reduces Fractional Glutathione Synthesis in Weaned Piglets.

BACKGROUND: Cys is limiting for reduced glutathione (GSH) synthesis and can be synthesized from Met. We hypothesized that the dietary Met hydroxyl analogue dl-2-hydroxy-4-methylthiobutyric acid (dl-HMTBA) affects Cys and GSH metabolism and oxidative stress defense differently than Met. OBJECTIVE: The objective was to elucidate whether dl-HMTBA supplementation of a Met-deficient diet affects Cys flux, GSH fractional synthetic rate (FSR), and the basal oxidative stress level relative to Met supplementation in pigs. METHODS: Twenty-nine male German Landrace piglets aged 28 d were allocated to 3 dietary groups: a basal diet limiting in Met (69% of Met plus Cys requirement) supplemented with either 0.15% l-Met (LMET; n = 9), 0.15% dl-Met (DLMET; n = 11), or 0.17% dl-HMTBA (DLHMTBA; n = 9) on an equimolar basis. At age 54 d the pigs received a continuous infusion of [1-13C]-Cys to calculate Cys flux and Cys oxidation. After 3 d, GSH FSR was determined by [2,2-2H2]-glycine infusion, and RBC GSH and oxidized GSH concentrations were measured. At age 62 d the animals were killed to determine hepatic mRNA abundances of enzymes involved in GSH metabolism, GSH concentrations, and plasma oxidative stress defense markers. RESULTS: The Cys oxidation was 21-39% and Cys flux 5-15% higher in the fed relative to the feed-deprived state (P < 0.001). On average, GSH FSR was 49% lower (P < 0.01), and RBC GSH and total GSH concentrations were 12% and 9% lower, respectively, in DLHMTBA and DLMET relative to LMET pigs (P < 0.05). In the feed-deprived state, Gly flux, the GSH:oxidized glutathione (GSSG) ratio, RBC GSSG concentrations, plasma oxidative stress markers, and the hepatic GSH content did not differ between groups. CONCLUSIONS: Although GSH FSR was higher in LMET compared with DLMET or DLHMTBA feed-deprived pigs, these differences were not reflected by lower oxidative stress markers and antioxidant defense enzymes in LMET pigs.

Associations between Dietary Patterns and Bile Acids-Results from a Cross-Sectional Study in Vegans and Omnivores.

Bile acids play an active role in fat metabolism and, in high-fat diets, elevated concentrations of fecal bile acids may be related to an increased risk of colorectal cancer. This study investigated concentrations of fecal and serum bile acids in 36 vegans and 36 omnivores. The reduced rank regression was used to identify dietary patterns associated with fecal bile acids. Dietary patterns were derived with secondary and conjugated fecal bile acids as response variables and 53 food groups as predictors. Vegans had higher fiber (p < 0.01) and lower fat (p = 0.0024) intake than omnivores. In serum, primary and glycine-conjugated bile acids were higher in vegans than in omnivores (p ≤ 0.01). All fecal bile acids were significantly lower in vegans compared to omnivores (p < 0.01). Processed meat, fried potatoes, fish, margarine, and coffee contributed most positively, whereas muesli most negatively to a dietary pattern that was directly associated with all fecal bile acids. According to the pattern, fat intake was positively and fiber intake was inversely correlated with bile acids. The findings contribute to the evidence that, in particular, animal products and fat may play a part in higher levels of fecal bile acids.

Validated HPLC method for simultaneous quantification of mutant IDH1/2 inhibitors (enasidenib, ivosidenib and vorasidenib) in mouse plasma: Application to a pharmacokinetic study.

Isocitrate dehydrogenase (IDH) inhibitors comprise a novel class of anticancer drugs, which are approved to treat acute myeloid leukemia patients having mutations on IDH1/2. We report the development and validation of a high-performance liquid chromatography (HPLC) method for the simultaneous quantitation of IDH inhibitors, namely enasidenib (EDB), ivosidenib (IDB) and vorasidenib (VDB), in mouse plasma as per the US Food and Drug Administration regulatory guidelines. The method involves extraction of EDB, IDB and VDB along with internal standard (IS; phenacetin) from mouse plasma (100 µl) using a simple protein precipitation process. The chromatographic analysis was performed on an HPLC system using a gradient mobile phase (comprising 10 mm ammonium acetate and acetonitrile in a flow-gradient) and an X-Terra Phenyl column. The UV detection wave length was set at λmax 265 nm. EDB, IDB, VDB and the IS eluted at 7.36, 8.60, 9.50 and 5.12 min, respectively, with a total run time of 10 min. The calibration curve was linear over a concentration range of 0.20-12.5 µg/ml for EDB and 0.50-12.5 µg/ml for IDB and VDB (r2  = ≥0.998 for all of the analytes). Validation results met the acceptance criteria. The validated HPLC method was successfully applied to a pharmacokinetic study in mice.

Magnetic Resonance Spectroscopy-based Metabolomic Biomarkers for Typing, Staging, and Survival Estimation of Early-Stage Human Lung Cancer.

Low-dose CT has shown promise in detecting early stage lung cancer. However, concerns about the adverse health effects of radiation and high cost prevent its use as a population-wide screening tool. Effective and feasible screening methods to triage suspicious patients to CT are needed. We investigated human lung cancer metabolomics from 93 paired tissue-serum samples with magnetic resonance spectroscopy and identified tissue and serum metabolomic markers that can differentiate cancer types and stages. Most interestingly, we identified serum metabolomic profiles that can predict patient overall survival for all cases (p = 0.0076), and more importantly for Stage I cases alone (n = 58, p = 0.0100), a prediction which is significant for treatment strategies but currently cannot be achieved by any clinical method. Prolonged survival is associated with relative overexpression of glutamine, valine, and glycine, and relative suppression of glutamate and lipids in serum.

Increased circulating conjugated primary bile acids are associated with hyperandrogenism in women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is a common metabolic disorder with hyperandrogenism as the core pathophysiologic feature. Increased bile acids and altered bile acid pool composition have been implicated in the pathogenesis of several metabolic diseases. Thus, this study aimed to clarify the specific alterations in circulating bile acids in patients with PCOS and investigate its associations with hyperandrogenism. We recruited 37 patients with PCOS and 35 age- and BMI-matched control subjects. Serum bile acids and androgen profiles were assessed by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Compared with control subjects, glycine- and taurine-conjugated primary bile acids were significantly elevated in patients with PCOS (P = 0.001 and P < 0.001). In addition, these conjugated primary bile acids were significantly and positively associated with serum concentrations of total testosterone and androstenedione in the PCOS group. In conclusion, increased circulating conjugated primary bile acids are positively associated with hyperandrogenism in women with PCOS. Further studies are warranted to explore the underlying mechanism.

Quantitation of Ivosidenib, A Novel Mutant IDH1 Inhibitoron Mice DBS: Application to a Pharmacokinetic Study.

Ivosidenib is an approved drug for relapsed or refractory IDH1 mutant AML patients. The goal of the present work is to develop and validate an LC-MS/MS method for the quantitation of ivosidenib in mice dried blood spots (DBS) as per regulatory guideline in the linearity range of 1.10-3293 ng/mL. To date there is no bioanalytical method reported for quantitation of ivosidenib. The chromatographic resolution of ivosidenib and internal standard (warfarin) was achieved on a C18 column with an isocratic mobile phase. All validation parameters met the acceptance criteria. The intra- and inter-day precision was in the range of 2.79-10.5 and 5.76-9.02%, respectively. Ivosidenib was stable for 3 freeze/thaw cycles, up to 7 days at room temperature and for one month at -80°C. The applicability of the validated method is shown in a mice pharmacokinetic study. Ivosidenib was quantifiable up to 24 and 36 h following intravenous and oral administration to mice, respectively. The oral bioavailability was 48%. Comparison of DBS vs. plasma concentrations of ivosidenib showed excellent correlation, indicating DBS can be used as an alternative for plasma for pharmacokinetic analysis.

Pharmacokinetics, absorption, metabolism, and excretion of [14C]ivosidenib (AG-120) in healthy male subjects.

PURPOSE: Pharmacokinetics, absorption, metabolism, and excretion of ivosidenib, a mutant isocitrate dehydrogenase-1 inhibitor, were determined in healthy male subjects. METHODS: In this open-label phase I study, a single dose of [14C]ivosidenib (500 mg, 200 µCi/subject) was orally administered to eight subjects (CYP2D6 extensive, intermediate, or poor metabolizers) under fasted conditions. Blood, plasma, urine, and fecal samples were assayed for radioactivity and profiled for metabolites. Ivosidenib plasma concentrations were determined using LC-MS/MS. Metabolites were separated using reverse-phase HPLC and analyzed using high-resolution LC-MS and LC-MS/MS. RESULTS: Ivosidenib was readily absorbed and slowly eliminated from plasma. Median Tmax of both unchanged ivosidenib and radioactivity in plasma was 4 h. Plasma t½ values for total radioactivity and ivosidenib were 71.7 and 53.4 h, respectively. The mean AUC0-72 blood-to-plasma total radioactivity concentration ratio was 0.565, indicating minimal partitioning to red blood cells. CYP2D6 genotype had no effect on ivosidenib exposure. The mean recovery of radioactivity in excreta was 94.3% over 360 h post-dose; the majority was excreted in feces (77.4 ± 9.62%) with a low percentage recovered in urine (16.9 ± 5.62%), suggesting fecal excretion is the primary route of elimination. Unchanged [14C]ivosidenib accounted for 67.4% of the administered radioactivity in feces. Only [14C]ivosidenib was detected in plasma, representing 92.4% of the total plasma radioactivity. Thirteen metabolites were structurally identified in excreta. CONCLUSION: Ivosidenib was well-absorbed, slowly metabolized to multiple oxidative metabolites, and eliminated by fecal excretion, with no CYP2D6 effect observed. Unchanged ivosidenib was the only circulating species in plasma.

Activated glycine receptors may decrease endosomal NADPH oxidase activity by opposing ClC-3-mediated efflux of chloride from endosomes.

Receptor-mediated activation of NADPH oxidase complexes commonly occurs in endosomes; the hydrogen peroxide produced by the dismutation of superoxide generated within the endosomes often functions to boost receptor function by reversibly inhibiting protein tyrosine phosphatases or by promoting formation of signaling complexes. NADPH oxidase-mediated formation of superoxide entails transfer of two electrons (provided by NADPH) from the cytosol to the endosomal lumen, where two molecules of superoxide are generated. This charge transfer must be balanced if NADPH oxidase activity is to be sustained. In many cells, this balance is achieved by ClC-3, a chloride-proton antiporter which can extrude two chlorides from the endosome to balance the importation of two electrons. The efficiency of this chloride extrusion will evidently be contingent on the cytosolic chloride level. Pro-inflammatory hormones which stimulate NADPH oxidase activity in endosomes have been shown to promote chloride extrusion from the cell, thereby expediting endosomal chloride export. Conversely, high cytosolic chloride could potentially slow endosomal NADPH oxidase activity by impeding ClC-3-mediated chloride export. Glycine-activated, strychnine-inhibitable chloride channels, which boost intracellular chloride in cells which maintain intracellular chloride levels lower than that of plasma, have shown anti-inflammatory and anti-angiogenic activity in cell culture and rodent studies. It is proposed that many of these effects may be attributable to glycine-mediated suppression of endosomal NADPH oxidase activity. This model suggests that supplemental glycine may have utility for prevention and control of atherosclerosis, heart failure, angiogenesis associated with cancer or retinal disorders, and a range of inflammation-driven syndromes - including metabolic syndrome; and it might complement the suppression of NADPH oxidase activity achievable with phycocyanobilin-enriched spirulina extracts.