# US 5,703,056 A · Non-invasive imaging of gene transfer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,703,056 A - Document ID: US5703056A - Status: Granted - Kind: A - Application number: 08/404,513 - Filed: 1995-03-15 - Granted: 1997-12-30 - Earliest claimed: 1995-03-15 - Assignees: Sloan-Kettering Institute for Cancer Research - Inventors: Ronald G. Blasberg; Juri Tjuvajev - Web page: https://patentgrep.com/patent/US5703056A ## CPC - A61K 51/0491: {Sugars, nucleosides, nucleotides, oligonucleotides, nucleic acids, e.g. DNA, RNA, nucleic acid aptamers} - A61K 48/00: Medicinal preparations containing genetic material which is inserted into cells of the living body to treat genetic diseases; Gene therapy - A61K 51/1203: {in a form not provided for by groups A61K51/1206 - A61K51/1296, e.g. cells, cell fragments, viruses, virus capsides, ghosts, red blood cells, viral vectors} - A61K 2123/00: Preparations for testing in vivo - A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D) ## Abstract The subject invention provides a method of detecting gene transfer to and expression in a target tissue of a host subject comprising: (a) administering to the host subject a transfer vector containing a marker gene not naturally present in the host and nontoxic to the host, wherein the transfer vector transfects cells of the target tissue, under conditions such that the marker gene is expressed in transfected cells of the target tissue, thereby generating a marker gene product; (b) administering to the host subject a labelled marker substrate which is not metabolized by non-transfected cells, under conditions such that the marker substrate is metabolized by the marker gene product of step (a) to produce a labelled marker metabolite which is substantially retained in the transfected cells throughout a time-period sufficient for imaging the labelled marker metabolite; and (c) imaging the labelled marker metabolite, thereby detecting gene transfer to and expression in the target tissue. The subject invention provides a non-invasive, clinically applicable method for imaging gene transfer and expression which can be implemented using existing imaging techniques to monitor and evaluate in vivo gene therapy in human subjects. ## Claims ### Claim 1 A method of detecting gene transfer to and expression in a target tissue of a host subject comprising: (a) delivering to the target tissue of the host subject a transfer vector containing a marker gene not naturally present in the host subject wherein the marker gene is selected from the group consisting of wild-type, mutant or genetically engineered herpes simplex virus-thymidine kinase gene, and wherein the transfer vector is introduced to cells of the target tissue, and the marker gene is expressed in the cells of the target tissue, thereby generating a marker gene product which accumulates only in the cells containing the transfer vector; (b) administering to the host subject a labeled marker substrate where cells expressing the marker gene product of step (a) metabolizes the labeled marker substrate to produce a labeled marker metabolite wherein the labeled marker substrate comprises a labeled 2'-fluoro-nucleoside analogue; and (c) non-invasively imaging the target tissue or cells containing the labeled marker metabolite after clearance of residual marker substrate not metabolized by the marker gene product from said host subject thereby detecting gene transfer to and expression in the target tissue. ### Claim 2 (depends on 1) The method of claim 1 further comprising waiting a time-period after step (b) sufficient to allow at least 67% of non-specific label derived from residual marker substrate not metabolized by the marker gene product to clear from the subject. ### Claim 3 (depends on 1) The method of claim 1 further comprising waiting a time-period after step (b) sufficient to allow at least 80% of non-specific label derived from residual marker substrate not metabolized by the marker gene product to clear from the subject. ### Claim 4 (depends on 1) The method of claim 1 further comprising waiting a time-period after step (b) sufficient to allow at least 90% of non-specific label derived from residual marker substrate not metabolized by the marker gene product to clear from the subject. ### Claim 5 (depends on 1) The method of claim 1 wherein the transfer vector is introduced to the cells of the target tissue by transduction. ### Claim 6 (depends on 1) The method of claim 1 wherein the marker substrate is labelled with a radioisotope suitable for imaging by positron emission tomography, gamma camera or single-photon emission computed tomography. ### Claim 7 (depends on 1) The method of claim 1 wherein the marker substrate and marker metabolite are compounds containing a stable-isotope nuclide selected from the group consisting of .sup.2 H, .sup.13 C, .sup.15 N and .sup.19 F. ### Claim 8 (depends on 1) The method of claim 1 wherein the labelled marker metabolite is imaged by positron emission tomography. ### Claim 9 (depends on 1) The method of claim 1 wherein the labelled marker metabolite is imaged by gamma camera or single-photon emission computed tomography. ### Claim 10 (depends on 1) The method of claim 1 wherein the labelled marker metabolite is imaged by magnetic resonance imaging. ### Claim 11 (depends on 1) The method of claim 1 wherein the transfer vector is nonspecific, incorporates the marker gene and suitable transcription promoter and enhancer elements, and is selected from the group consisting of a virus, a plasmid, a liposome, and a cell. ### Claim 12 (depends on 11) The method of claim 11 wherein the cell is transfected with the marker gene and suitable transcription promoter and enhancer elements ex vivo prior to administration to the host subject. ### Claim 13 (depends on 1) The method of claim 1 wherein the labelled 2'-fluoro-nucleoside analogue is selected from a group consisting of 5-›.sup.123 I!-, 5-›.sup.124 I!- and 5-›.sup.131 I!-2'-fluoro-5-iodo-1.beta.-D-arabinofuranosyl-uracil, 5-›.sup.18 F!-2'-fluoro-5-fluoro-1-.beta.-D-arabinofuranosyl-uracil, 2-›.sup.11 I!-and 5-(›.sup.11 C!-methyl)-2'-fluoro-5-methyl-1-.beta.-D-arabinofuranosyl-uracil, 2-›.sup.11 C!- and 5-(›.sup.11 C!-ethyl)-2'-fluoro-5-ethyl-1-.beta.-D-arabinofuranosyl-uracil, 5-(2-›.sup.18 F!-ethyl)-2'-fluoro-5-(2-fluoro-ethyl)-1-.beta.-D-arabinofuranosyl-uracil, 5-›.sup.123 I!-, 5-›.sup.124 I!- and 5-›.sup.131 I!-2'-fluoro-5-iodovinyl-1-.beta.-D-arabinofuranosyl-uracil, 5-›.sup.123 I!-, 5-›.sup.124 I!- and 5-›.sup.131 I!-2'-fluoro-5-iodo-1-.beta.-D-ribofuranosyl-uracil and 5-›.sup.123 I!-, 5-›.sup.124 I!- and 5-›.sup.131 I!-2'-fluoro-5-iodovinyl-1-.beta.-D-ribofuranosyl-uracil.