Therapeutic stem cell gene transfer relies on long-term gene expression achieved by integration of new DNA into the cellular genome. Current clinical trials featuring oncoretroviruses have encountered a number of roadblocks that include low levels of gene transfer, poor expression, and a recognized preferential insertion near promoter regions that increases the chance for insertional mutagenesis and leukemia. This proposal will link the advances made at Lentigen Corp. in large scale production of the newest generation lentiviral vectors (LV) with the clinical need for transferring the MGMT gene into hematopoietic stem cells. The goal of this application is to optimize the safety of lentiviral gene transfer of MGMT using preclinical assays followed by a clinical trial using this vector in cancer patients. Expression of the MGMT (O6-methylguanine-DNA- methyltransferase) enzyme has been established as an effective method for hematopoietic progenitor (HP) selection in vivo. The MGMT gene product (also known as AGT, O6-alkylguanine-DNA-alkyltransferase) repairs DNA damaged by alkylating agents. Hematopoietic progenitor cells (HP) can be transduced with a vector containing MGMT and selected for in vivo by administration of a DNA damaging drug therapy, i.e. the alkylating agent Temozolomide, whose potency is increase by co-administration of O6-benzylguanine (BG), a therapeutic inhibitor of the naturally occurring AGT. Using a well-characterized singe point mutation of MGMT, P140K, that is resistant to the inhibitory effects of BG, it is possible to selectively protect HP from the drug combination, providing a unique enrichment strategy for multilineage progenitors in vivo. LVs, a subclass of retroviral vectors, offer several advantages over oncoretroviral vectors including increased transduction efficiencies, long-term gene expression without silencing, and decreased risk of insertional oncogenesis. In Phase I of this application we will generate cGMP vector with improved safety characteristics, analyze the insertion site frequency and preference, and create a publically available database to share this information with other investigators and regulatory agencies. This will set a new standard in the field for sharing data generated from the use of a clinical gene vector with human cells. In the Phase II portion of this application, a clinical trial designed to demonstrate safe use of lentiviral vector with the potential to improve outcomes for patients with advanced glioma, will be initiated. This trial will be the first in man study of in vivo stem cell selection mediated by a drug resistance gene. This trial is of importance not only for patients with glioma, but as means to demonstrate the effective development of a platform for selecting gene-modified stem cells that could also be used for the correction of numerous monogenic disorders. , ,
Public Health Relevance: This proposal is a combined phase I and phase II application, Fast-Track, that will evaluate lentiviral gene vectors expressing the MGMT gene in pre-clinical models and in a clinical trial for glioma. The goal of this application is to optimize the safety of lentiviral gene transfer of MGMT. Demonstration of the safe use of this lentiviral vector in clinical studies will open the door to the treatment of not only glioma, but other malignancies in which hematotoxicity is a major side-effect, or in which malignant stem cells are replaced by donor-derived (allogeneic) or patient-derived (autologous) stem cells that can be selected for in vivo. Thus, this proposal represents a first step in improving the efficacy of stem cell therapeutics by providing the means to increase the number of cells carrying the gene to greater and potentially therapeutic levels.
Thesaurus Terms: 06-Benzyl Guanine;06-Benzylguanine;1,3-Bis(2-Chloroethyl)-1-Nitrosourea;3,4-Dihydro-3-Methyl-4-Oxoimidazo[5,1-D]-1,2,3,5-Tetrazine-8-Carboxamide;8-Carbamoyl-3-Methylimidazo[5,1-D]-1,2,3,5-Tetrazin-4(3h)-One;Agt;Address;Adverse Effects;Alkylating Agents;Alkylators;Allogenic;Animals;Assay;Astrocytoma, Grade Iv;Autologous;Bcnu;Bioassay;Biologic Assays;Biological Assay;Bis-Chloronitrosourea;Blood (Leukemia);Blood Precursor Cell;Cd34;Cd34 Gene;Ctep;Cancer Patient;Cancer Therapy Evaluation Program;Cancer, Oncology;Cancers;Carmustine;Carmustine (Bcnu);Cell Count;Cell Number;Cell Protection;Cells;Cessation Of Life;Characteristics;Clinical;Clinical Research;Clinical Study;Clinical Trial Protocol;Clinical Trials;Clinical Trials Design;Clinical Trials, Phase I;Clinical Trials, Unspecified;Clinical Trial Protocol Document;Cyclic Gmp;Cytoprotection;Cytotoxic Agent;Cytotoxic Drug;Dna;Dna Damage;Dna Damage Repair;Dna Injury;Dna Repair;Dna Sequence;Dna Lesion;Dna-6-O-Methylguanine[protein]-L-Cysteine S-Methyltransferase;Data;Data Banks;Data Bases;Data Set;Databank, Electronic;Databanks;Database, Electronic;Databases;Dataset;Death;Deoxyribonucleic Acid;Detection;Development;Disease;Disorder;Dose;Drug Combinations;Drug Therapy;Drug Resistance;Drug Usage;Ec 2;Ec 2.1.1.63;Early-Stage Clinical Trials;Enrollment;Enzymes;Essex Brand Of Temozolomide;Evaluable;Evaluable Disease;Fivb;Frequencies (Time Pattern);Frequency;Future;Gene Expression;Gene Transfer;Gene Transfer Clinical;Gene Transfer Procedure;Gene-Modified;Gene-Tx;Generations;Genes;Genetic Intervention;Genome;Glial Cell Tumors;Glial Neoplasm;Glial Tumor;Glioblastoma;Glioma;Goals;Grade Iv Astrocytic Neoplasm;Grade Iv Astrocytic Tumor;Grant;Guanine-O(6)-Alkyltransferase;Guanosine Cyclic 3',5'-Monophosphate;Guanosine Cyclic Monophosphate;Guanosine, Cyclic 3',5'-(Hydrogen Phosphate);Hpca1;Hsc Transplantation;Harvest;Hematopoietic;Hematopoietic Stem Cell Transplantation;Hematopoietic Stem Cells;Human;Human Genome;Human, General;In Vitro;Insertional Mutagenesis;Intervention, Genetic;Investigators;Lead;Lentiviral Vector;Lentivirus Vector;Leukemias, General;Link;Mgmt;Mgmt Gene;Malignant;Malignant - Descriptor;Malignant Neoplasms;Malignant Tumor;Man (Taxonomy);Man, Modern;Mediating;Methods;Methylated-Dna Protein-Cysteine Methyltransferase;Methylated-Dna-Protein-Cysteine S-Methyltransferase;Methylguanine-Dna Methyltransferase Gene;Molecular Biology, Gene Therapy;Molecular Biology, Recombinant Dna;Monitor;Mother Cells;Myelosuppression;N,N'-Bis(2-Chloroethyl)-N-Nitrosourea;Neoplasms Of Neuroglia;Neuroglial Neoplasm;Neuroglial Tumor;Newly Diagnosed;O(6)-Agt;O(6)-Alkylguanine-Dna Alkyltransferase;O(6)-Meg-Dna Methyltransferase;O(6)-Methylguanine Dna Transmethylase;O(6)-Methylguanine Methyltransferase;O(6)-Methylguanine-Dna Methyltransferase;O(6)-Bgua;O(6)-Benzylguanine;O6-Alkylguanine Dna Alkyltransferase;O6-Benzylguanine;Oncogenesis;Outcome;Patients;Pattern;Pb Element;Pharmacotherapy;Phase;Phase 1 Clinical Trials;Phase I Clinical Trials;Phase I Study;Point Mutation;Position;Positioning Attribute;Pre-Clinical Model;Preclinical Models;Preparation;Procedures;Process;Progenitor Cells;Progenitor Cells, Hematopoietic;Programs (Pt);Programs [publication Type];Promoter Regions;Promoter Regions (Genetics);Promotor Regions;Promotor Regions (Genetics);Proteins;Recombinant Dna;Research;Research Personnel;Researchers;Resistance;Retroviral Vector;Retroviridae;Retrovirus Vector;Retroviruses;Risk;Safety;Sampling;Schering Brand Of Temozolomide;Schering-Plough Brand Of Temozolomide;Series;Site;Stem Cells;System;System, Loinc Axis 4;Technology;Temodal;Temodar;Therapeutic;Therapy, Dna;Transduction Gene;Transferase;Treatment Side Effects;Tumor Cell;Tumors Of Neuroglia;Unscheduled Dna Synthesis;Urea, N,N'-Bis(2-Chloroethyl)-N-Nitroso-;Validation;Vector Mediated Transfer Genes;Virus-Retrovirus;Alkylguanine Dna Alkyltransferase;Bis Chloroethylnitrosourea;Cgmp;Cell Transduction;Cellular Transduction;Chemotherapy;Clinical Data Repository;Clinical Data Warehouse;Clinical Investigation;Clinical Research Site;Clinical Site;Data Repository;Design;Designing;Disease/Disorder;Drug Resistant;Drug Use;Enroll;Experience;Experiment;Experimental Research;Experimental Study;Gene Product;Gene Therapy;Genetic Promoter Element;Genetic Therapy;Glioblastoma Multiforme;Guanosine 3'5' Monophosphate;Heavy Metal Pb;Heavy Metal Lead;Imidazo[5,1-D]-1,2,3,5-Tetrazine-8-Carboxamide, 3, 4-Dihydro-3-Methyl-4-Oxo-;Improved;In Vivo;Inhibitor;Inhibitor/Antagonist;Innovate;Innovation;Innovative;Large Scale Production;Leukemia;Malignancy;Man;Man's;Methazolastone;Methylguanine Dna Methyltransferase;Mutant;Neoplasm/Cancer;Neoplastic Cell;Oncology;Peripheral Blood;Phase 1 Study;Phase 1 Trial;Phase 2 Study;Phase I Trial;Pre-Clinical;Preclinical;Preference;Progenitor;Programs;Protocol, Phase I;Public Health Relevance;Rdna;Relational Database;Repair;Repaired;Research Study;Resistance To Drug;Resistant;Resistant To Drug;Response;Sharing Data;Side Effect;Spongioblastoma Multiforme;Success;Temozolomide;Therapy Adverse Effect;Tool;Transduced Cells;Transduction Efficiency;Transfer Of A Gene;Treatment Adverse Effect;Tumor;Tumorigenesis;Vector
