Patent ID: 8796241

Claim:
A method for treating a subject having a cancer or infectious disease comprising: (a) administering to the subject a competitive antagonist of adenine or methionine in an amount effective to treat the cancer or infectious disease, wherein the competitive antagonist of adenine is a substrate for a phosphoribosyltransferase selected from the group consisting of adenine phosphoribosyltransferase (APRT), hypoxanthine-guanine phosphoribosyltransferase (HGPRT), orotate phosphoribosyltransferase (OPRT), quinolinate phosphoribosyltransferase (QPRT), nicotinate phosphoribosyltransferase (NAPRT) and nicotinamide phosphoribosyltransferase (NAMPRT); and (b) administering to the subject a protective agent in an amount effective to increase the level of adenine or methionine in a population of host cells of the subject, thereby reducing the toxicity of the competitive antagonist to the subject, wherein the subject has a methylthioadenosine phosphorylase (MTAP) negative target cell and wherein the protective agent is a MTAP substrate.