# US 2013/0156764 A1 · Neutralization of flt3 ligand as a leukemia therapy > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156764 A1 - Document ID: US20130156764A1 - Status: Published application - Kind: A1 - Application number: 13/634,439 - Filed: 2011-03-14 - Published: 2013-06-20 - Earliest claimed: 2010-03-12 - Assignees: The Johns Hopkins University - Inventors: Mark J. Levis; Donald Small - Web page: https://patentgrep.com/patent/US20130156764A1 ## CPC - A61K 39/39558: {against tumor tissues, cells, antigens} - A61K 31/136: having the amino group directly attached to the aromatic ring, e.g. benzeneamine - A61K 31/403: condensed with carbocyclic rings, e.g. carbazole - A61K 31/404: Indoles, e.g. pindolol - A61K 31/416: condensed with carbocyclic ring systems, e.g. indazole - A61K 31/44: Non condensed pyridines; Hydrogenated derivatives thereof - A61K 31/496: Non-condensed piperazines containing further heterocyclic rings, e.g. rifampin, thiothixene or sparfloxacin - A61K 31/517: ortho- or peri-condensed with carbocyclic ring systems, e.g. quinazoline, perimidine - A61K 31/5377: not condensed and containing further heterocyclic rings, e.g. timolol - A61K 31/553: having at least one nitrogen and one oxygen as ring hetero atoms, e.g. loxapine, staurosporine - A61K 31/704: attached to a condensed carbocyclic ring system, e.g. sennosides, thiocolchicosides, escin, daunorubicin {(digitoxin A61K31/7048)} - A61K 31/7048: having oxygen as a ring hetero atom, e.g. leucoglucosan, hesperidin, erythromycin, nystatin {, digitoxin or digoxin} - A61K 31/7068: having oxo groups directly attached to the pyrimidine ring, e.g. cytidine, cytidylic acid - A61K 38/1793: {for cytokines; for lymphokines; for interferons} - A61K 38/45: Transferases (2) - A61K 39/3955: {against proteinaceous materials, e.g. enzymes, hormones, lymphokines} - A61K 45/06: Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca - A61P 35/00: Antineoplastic agents - A61P 35/02: specific for leukemia - 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) - A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS ## Abstract Disclosed herein are methods and compositions for treating leukemia and preventing leukemia relapse related to the administration of agents that inhibit the binding of FLT3 ligand to FLT3. ## Claims ### Claim 1 A method of treating leukemia in a subject comprising administering to the subject a therapeutically effective amount of a first agent that inhibits the tyrosine kinase activity of FLT3 and administering to the subject a therapeutically effective amount of a second agent that inhibits the binding of FLT3L to FLT3. ### Claim 2 (depends on 1) The method of claim 1, wherein the first agent is a small molecule. ### Claim 3 (depends on 2) The method of claim 2, wherein the first agent is lestaurtinib, midostaurin, sorafenib, KW-2449, or AC220. ### Claim 4 (depends on 1) The method of claim 1, wherein the second agent is an antibody or antibody fragment that specifically binds to FLT3L. ### Claim at position 5 5-7. (canceled) ### Claim 8 (depends on 1) The method of claim 1, wherein the second agent is a polypeptide comprising a portion of the FLT3 extracellular domain. ### Claim 9 (depends on 8) The method of claim 8, wherein the polypeptide further comprises an immunoglobulin constant domain or portion thereof. ### Claim 10 (depends on 1) The method of claim 1, further comprising administering a chemotherapy to the subject. ### Claim 11 (depends on 10) The method of claim 10, wherein the chemotherapy comprises: administering mitoxatrone, etoposide and cytarabine to the subject; administering high dose cytarabine to the subject; or administering cytarabine, daunorubicin and etoposide to the subject. ### Claim 12 (depends on 1) The method of claim 1, wherein leukemia cells in the subject comprise a FLT3 activating mutation. ### Claim 13 (depends on 12) The method of claim 12, wherein the FLT3 activating mutation is an internal tandem duplication in the FLT3 juxtamembrane region or a point mutation in the FLT3 tyrosine kinase domain. ### Claim 14 (depends on 1) The method of claim 1, wherein the leukemia is AML, ALL or CML. ### Claim 15 (depends on 1) The method of claim 1, wherein the administration of the second agent occurs after the administration of the first agent. ### Claim 16 A method of preventing a leukemia relapse in a subject who had previously been treated for leukemia with a first agent that inhibits the tyrosine kinase activity of FLT3, the method comprising administering to the subject a therapeutically effective amount of a second agent that inhibits the binding of FLT3L to FLT3. ### Claim 17 (depends on 16) The method of claim 16, wherein the first agent is a small molecule. ### Claim 18 (depends on 17) The method of claim 17, wherein the first agent is lestaurtinib, midostaurin, sorafenib, KW-2449, or AC220. ### Claim 19 (depends on 16) The method of claim 16, wherein the second agent is an antibody or antibody fragment that specifically binds to FLT3L. ### Claim 20 (canceled) ### Claim 21 (depends on 16) The method of claim 16, wherein the second agent is an antibody or antibody fragment that specifically binds to FLT3. ### Claim at position 20 22-24. (canceled) ### Claim 25 (depends on 16) The method of claim 16, wherein the previous leukemia treatment further comprised administration of a chemotherapy to the subject. ### Claim 26 (canceled) ### Claim 27 (depends on 16) The method of claim 16, wherein the leukemia cells of the subject comprise a FLT3 activating mutation. ### Claim at position 24 28-29. (canceled) ### Claim 30 A kit for treating leukemia in a subject comprising a therapeutically effective amount of a first agent that inhibits the tyrosine kinase activity of FLT3 and a therapeutically effective amount of a second agent that inhibits the binding of FLT3L to FLT3. ### Claim at position 26 31-40. (canceled)