Histamine receptor agonists for cancer therapy in cancer patients unresponsive to cancer immunotherapy and with elevated myeloid derived suppressor cells

A method for treating a melanoma, the method comprising:

• selecting or identifying a subject having a population frequency of myeloid derived suppressor cells (MDSCs) greater than or equal to about 15%, wherein the population frequency comprises a percentage of HLA-DRlow/- cells among CD14+CD11b+ monocytes;
• and
• administering to the subject a pharmaceutical formulation comprising:
• a therapeutically effective amount of an active pharmaceutical ingredient (API), wherein the API comprises histamine, a histamine salt, a histamine derivative, a salt of a histamine derivative, or any combination of the foregoing, wherein the histamine derivative comprises a C1-6 alkyl histamine, and wherein the salt of the histamine derivative comprises a C1-6 alkyl histamine monocation or a C1-6 alkyl histamine polycation;
• and
• at least one of a pharmaceutically acceptable carrier, a pharmaceutically acceptable excipient, a pharmaceutically acceptable diluent, and any combination of the foregoing,
• wherein the pharmaceutical formulation comprises a dosage form selected from a coated tablet and a liquid form.