Compositions and methods of enhancing immunotherapies

A method of stimulating a subject's immune system against cancer cells or treating a subject having cancer, the method consists of administering to the subject Agent (1) epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), gallocatechin gallate (GCG), gallocatechin (GC), catechin gallate (CG), or catechin, or an ester, polyester, mono-glyceride, di-glyceride, tri-glyceride, pharmaceutically acceptable salt, glycoside, or metabolite thereof, Agent (2) a nucleoside analogue, and Agent (3) a checkpoint inhibitor, wherein a weight ratio of Agent (1) to Agent (2) is from about 25:1 to about 40:1;

• wherein the metabolite of epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), gallocatechin gallate (GCG), gallocatechin (GC), catechin gallate (CG), or catechin is selected from the group consisting of 3′-O-methyl EGC;
• 4′-O-methyl EGC;
• 3′-O-methyl EC;
• 4′-O-methyl EC;
• 1-(3′,4′,5′-trihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)propan-2-ol;
• and
• 1-(3′,5′-dihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)propan-2-ol.