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Journal of Pharmaceutical Sciences Oct 2023NDec is a novel combination of oral decitabine and tetrahydrouridine that is currently under clinical development for the treatment of sickle cell disease (SCD). Here,...
NDec is a novel combination of oral decitabine and tetrahydrouridine that is currently under clinical development for the treatment of sickle cell disease (SCD). Here, we investigate the potential for the tetrahydrouridine component of NDec to act as an inhibitor or substrate of key concentrative nucleoside transporters (CNT1-3) and equilibrative nucleoside transporters (ENT1-2). Nucleoside transporter inhibition and tetrahydrouridine accumulation assays were performed using Madin-Darby canine kidney strain II (MDCKII) cells overexpressing human CNT1, CNT2, CNT3, ENT1, and ENT2 transporters. Results showed that tetrahydrouridine did not influence CNT- or ENT-mediated uridine/adenosine accumulation in MDCKII cells at the concentrations tested (25 and 250 µM). Accumulation of tetrahydrouridine in MDCKII cells was initially shown to be mediated by CNT3 and ENT2. However, while time- and concentration-dependence experiments showed active accumulation of tetrahydrouridine in CNT3-expressing cells, allowing for estimation of K (3,140 µM) and V (1,600 pmol/mg protein/min), accumulation of tetrahydrouridine was not observed in ENT2-expressing cells. Potent CNT3 inhibitors are a class of drugs not generally prescribed to patients with SCD, except in certain specific circumstances. These data suggest that NDec can be administered safely with drugs that act as substrates and inhibitors of the nucleoside transporters included in this study.
Topics: Humans; Animals; Dogs; Nucleoside Transport Proteins; Nucleosides; Tetrahydrouridine; Equilibrative Nucleoside Transporter 1; Membrane Transport Proteins
PubMed: 37364771
DOI: 10.1016/j.xphs.2023.06.012 -
Xenobiotica; the Fate of Foreign... Jan 20221. NDec is a novel, oral, fixed-dose formulation of decitabine and tetrahydrouridine that is currently being developed for the treatment of patients with sickle cell...
1. NDec is a novel, oral, fixed-dose formulation of decitabine and tetrahydrouridine that is currently being developed for the treatment of patients with sickle cell disease. Here, we examine the potential for both components of NDec to interact with key drug metabolising enzymes (tetrahydrouridine only) and drug transporters (decitabine and tetrahydrouridine).2. This study assessed the inhibition and induction of cytochrome P450 (CYP) enzymes by tetrahydrouridine, as well as the involvement of specific drug metabolising enzymes in tetrahydrouridine metabolism. Inhibition of efflux and uptake transporters by both decitabine and tetrahydrouridine was also studied.3. Tetrahydrouridine did not inhibit or induce relevant CYP enzymes at concentrations ranging from 0.1 to 100 μM. Metabolism of tetrahydrouridine did not occur in the presence of the human drug metabolising enzymes tested. Tetrahydrouridine showed weak inhibition towards the MATE2-K transporter (∼30% inhibition at 5 and 50 μM), which was not deemed clinically relevant. Tetrahydrouridine did not inhibit any of the remaining uptake or efflux transporters. Decitabine (0.5 and 5 μM) did not inhibit any of the evaluated uptake or efflux drug transporters.4. Data presented confirm that tetrahydrouridine and decitabine are unlikely to be involved in metabolism- or transporter-based drug-drug interactions.
Topics: Biological Transport; Decitabine; Drug Interactions; Humans; Membrane Transport Proteins; Tetrahydrouridine
PubMed: 34913834
DOI: 10.1080/00498254.2021.2018628 -
European Journal of Haematology Sep 2023Sickle cell disease (SCD) is caused by an inherited structural abnormality of adult hemoglobin causing polymerization. Fetal hemoglobin interferes with polymerization...
BACKGROUND
Sickle cell disease (SCD) is caused by an inherited structural abnormality of adult hemoglobin causing polymerization. Fetal hemoglobin interferes with polymerization but is epigenetically silenced by DNA methyltransferase 1 (DNMT1) in adult erythropoiesis. Decitabine depletes DNMT1 and increases fetal and total hemoglobin in SCD patients, but is rapidly catabolized by cytidine deaminase (CDA) in vivo. Tetrahydrouridine (THU) inhibits CDA, safeguarding decitabine.
METHODS
The pharmacokinetics and pharmacodynamics of three oral combination formulations of THU and decitabine, with different coatings producing different delays in decitabine release, were investigated in healthy participants.
RESULTS
Tetrahydrouridine and decitabine were rapidly absorbed into the systemic circulation after a single combination oral dose, with relative bioavailability of decitabine ≥74% in fasted males compared with separate oral administration of THU followed by decitabine 1 h later. THU and decitabine C and area under the plasma concentration versus time curve were higher in females versus males, and fasted versus fed states. Despite sex and food effect on pharmacokinetics, the pharmacodynamic effect of DNMT1 downregulation was comparable in males and females and fasted and fed states. Treatments were well tolerated.
CONCLUSION
Combination oral formulations of THU with decitabine produced pharmacokinetics and pharmacodynamics suitable for oral DNMT1-targeted therapy.
Topics: Male; Adult; Female; Humans; Tetrahydrouridine; Decitabine; Biological Availability; Hemoglobins; Administration, Oral
PubMed: 37417197
DOI: 10.1111/ejh.14009 -
American Journal of Hematology Mar 19855-Azacytidine (azaC) has previously been shown to raise Hb F levels in the repeatedly phlebotomized baboon (PCV: around 20%). The administration of tetrahydrouridine...
5-Azacytidine (azaC) has previously been shown to raise Hb F levels in the repeatedly phlebotomized baboon (PCV: around 20%). The administration of tetrahydrouridine (THU), an inhibitor of the enzymatic conversion of azaC to 5-azauridine, made it possible to reduce the amount of azaC and also of 2-deoxy-5-azacytidine (d-azaC) by more than 90% and still achieve maximal Hb F elevations. However, the granulocytopenia, usually occurring after 5-azaC, was not altered by the lowering of the dosages in the presence of THU. Thus, the granulocytopenia is not due to 5-azauridine or other catabolic products resulting from deamination. It is also unlikely that it is caused by a direct influence of azaC on RNA since d-azaC also causes granulocytopenia. The persistence of reticulocytosis throughout the treatment with azaC or d-azaC makes it appear likely that the observed increase in Hb F levels to more than 60% of total hemoglobin is not due to a cytotoxic effect on erythropoiesis resulting in a shift of cell populations toward greater immaturity, but to a direct influence of the drug on the regulation of gamma globin chain production.
Topics: Agranulocytosis; Animals; Azacitidine; Cytidine Deaminase; Decitabine; Fetal Hemoglobin; Gene Expression Regulation; Globins; Granulocytes; Papio; Tetrahydrouridine; Uridine
PubMed: 2579548
DOI: 10.1002/ajh.2830180310 -
Journal of Clinical Pharmacology 1978
Topics: Administration, Oral; Half-Life; Humans; Injections, Intravenous; Injections, Subcutaneous; Kinetics; Tetrahydrouridine; Uridine
PubMed: 641214
DOI: 10.1002/j.1552-4604.1978.tb02444.x -
Seminars in Hematology Jan 2021One mechanism by which lymphoid malignancies resist standard apoptosis-intending (cytotoxic) treatments is genetic attenuation of the p53/p16-CDKN2A apoptosis axis.... (Clinical Trial)
Clinical Trial
One mechanism by which lymphoid malignancies resist standard apoptosis-intending (cytotoxic) treatments is genetic attenuation of the p53/p16-CDKN2A apoptosis axis. Depletion of the epigenetic protein DNA methyltransferase 1 (DNMT1) using the deoxycytidine analog decitabine is a validated approach to cytoreduce malignancy independent of p53/p16. In vivo decitabine activity, however, is restricted by rapid catabolism by cytidine deaminase (CDA). We, therefore, combined decitabine with the CDA-inhibitor tetrahydrouridine and conducted a pilot clinical trial in patients with relapsed lymphoid malignancies: the doses of tetrahydrouridine/decitabine used (∼10/0.2 mg/kg orally (PO) 2×/week) were selected for the molecular pharmacodynamic objective of non-cytotoxic, S-phase dependent, DNMT1-depletion, guided by previous Phase 1 studies. Patients with relapsed/refractory B- or T-cell malignancies (n = 7) were treated for up to 18 weeks. Neutropenia without concurrent thrombocytopenia is an expected toxicity of DNMT1-depletion and occurred in all patients (Grade 3/4). Subjective and objective clinical improvements occurred in 4 of 7 patients, but these responses were lost upon treatment interruptions and reductions to manage neutropenia. We thus performed parallel experiments in a preclinical in vivo model of lymphoma to identify regimen refinements that might sustain DNMT1-targeting in malignant cells but limit neutropenia. We found that timed-alternation of decitabine with the related molecule 5-azacytidine, and combination with inhibitors of CDA and de novo pyrimidine synthesis could leverage feedback responses of pyrimidine metabolism to substantially increase lymphoma cytoreduction but with less neutropenia. In sum, regimen innovations beyond incorporation of a CDA-inhibitor are needed to sustain decitabine DNMT1-targeting and efficacy against chemo-resistant lymphoid malignancy. Such potential solutions were explored in preclinical in vivo studies.
Topics: Antimetabolites, Antineoplastic; Azacitidine; Decitabine; Epigenesis, Genetic; Humans; Lymphoma; Pilot Projects; Tetrahydrouridine
PubMed: 33509441
DOI: 10.1053/j.seminhematol.2020.11.008 -
Blood Feb 2012The deoxycytidine analog decitabine (DAC) can deplete DNA methyl-transferase 1 (DNMT1) and thereby modify cellular epigenetics, gene expression, and differentiation.... (Comparative Study)
Comparative Study
The deoxycytidine analog decitabine (DAC) can deplete DNA methyl-transferase 1 (DNMT1) and thereby modify cellular epigenetics, gene expression, and differentiation. However, a barrier to efficacious and accessible DNMT1-targeted therapy is cytidine deaminase, an enzyme highly expressed in the intestine and liver that rapidly metabolizes DAC into inactive uridine counterparts, severely limiting exposure time and oral bioavailability. In the present study, the effects of tetrahydrouridine (THU), a competitive inhibitor of cytidine deaminase, on the pharmacokinetics and pharmacodynamics of oral DAC were evaluated in mice and nonhuman primates. Oral administration of THU before oral DAC extended DAC absorption time and widened the concentration-time profile, increasing the exposure time for S-phase-specific depletion of DNMT1 without the high peak DAC levels that can cause DNA damage and cytotoxicity. THU also decreased interindividual variability in pharmacokinetics seen with DAC alone. One potential clinical application of DNMT1-targeted therapy is to increase fetal hemoglobin and treat hemoglobinopathy. Oral THU-DAC at a dose that would produce peak DAC concentrations of less than 0.2μM administered 2×/wk for 8 weeks to nonhuman primates was not myelotoxic, hypomethylated DNA in the γ-globin gene promoter, and produced large cumulative increases in fetal hemoglobin. Combining oral THU with oral DAC changes DAC pharmacology in a manner that may facilitate accessible noncytotoxic DNMT1-targeted therapy.
Topics: Administration, Oral; Animals; Antimetabolites; Antimetabolites, Antineoplastic; Area Under Curve; Azacitidine; Biological Availability; DNA Damage; DNA Methylation; Decitabine; Drug Interactions; Female; Hematopoietic Stem Cells; Inactivation, Metabolic; Injections, Intravenous; Injections, Subcutaneous; Mice; Papio anubis; Tetrahydrouridine
PubMed: 22160381
DOI: 10.1182/blood-2011-08-371690 -
Journal of Neuro-oncology Jan 2016Chemotherapies active in preclinical studies frequently fail in the clinic due to lack of efficacy, which limits progress for rare cancers since only small numbers of...
Chemotherapies active in preclinical studies frequently fail in the clinic due to lack of efficacy, which limits progress for rare cancers since only small numbers of patients are available for clinical trials. Thus, a preclinical drug development pipeline was developed to prioritize potentially active regimens for pediatric brain tumors spanning from in vitro drug screening, through intracranial and intra-tumoral pharmacokinetics to in vivo efficacy studies. Here, as an example of the pipeline, data are presented for the combination of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in three pediatric brain tumor models. The in vitro activity of nine novel therapies was tested against tumor spheres derived from faithful mouse models of Group 3 medulloblastoma, ependymoma, and choroid plexus carcinoma. Agents with the greatest in vitro potency were then subjected to a comprehensive series of in vivo pharmacokinetic (PK) and pharmacodynamic (PD) studies culminating in preclinical efficacy trials in mice harboring brain tumors. The nucleoside analog 5-fluoro-2'-deoxycytidine (FdCyd) markedly reduced the proliferation in vitro of all three brain tumor cell types at nanomolar concentrations. Detailed intracranial PK studies confirmed that systemically administered FdCyd exceeded concentrations in brain tumors necessary to inhibit tumor cell proliferation, but no tumor displayed a significant in vivo therapeutic response. Despite promising in vitro activity and in vivo PK properties, FdCyd is unlikely to be an effective treatment of pediatric brain tumors, and therefore was deprioritized for the clinic. Our comprehensive and integrated preclinical drug development pipeline should reduce the attrition of drugs in clinical trials.
Topics: Animals; Antineoplastic Agents; Apoptosis; Brain; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Deoxycytidine; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Evaluation, Preclinical; Epigenesis, Genetic; Mice; Mice, Nude; Tetrahydrouridine
PubMed: 26518542
DOI: 10.1007/s11060-015-1965-0 -
PloS One 2012Tetrahydrouridine (THU) is a well characterized and potent inhibitor of cytidine deaminase (CDA). Highly expressed CDA catalyzes and inactivates cytidine analogues,...
Tetrahydrouridine (THU) is a well characterized and potent inhibitor of cytidine deaminase (CDA). Highly expressed CDA catalyzes and inactivates cytidine analogues, ultimately contributing to increased gemcitabine resistance. Therefore, a combination therapy of THU and gemcitabine is considered to be a potential and promising treatment for tumors with highly expressed CDA. In this study, we found that THU has an alternative mechanism for inhibiting cell growth which is independent of CDA expression. Three different carcinoma cell lines (MIAPaCa-2, H441, and H1299) exhibited decreased cell proliferation after sole administration of THU, while being unaffected by knocking down CDA. To investigate the mechanism of THU-induced cell growth inhibition, cell cycle analysis using flow cytometry was performed. This analysis revealed that THU caused an increased rate of G1-phase occurrence while S-phase occurrence was diminished. Similarly, Ki-67 staining further supported that THU reduces cell proliferation. We also found that THU regulates cell cycle progression at the G1/S checkpoint by suppressing E2F1. As a result, a combination regimen of THU and gemcitabine might be a more effective therapy than previously believed for pancreatic carcinoma since THU works as a CDA inhibitor, as well as an inhibitor of cell growth in some types of pancreatic carcinoma cells.
Topics: Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cytidine Deaminase; Deoxycytidine; Enzyme Inhibitors; Humans; Lung Neoplasms; Pancreatic Neoplasms; Tetrahydrouridine; Gemcitabine
PubMed: 22616006
DOI: 10.1371/journal.pone.0037424