Erythropoietin receptor compositions and methods of use thereof

A method of treating cancer in a subject in need thereof or of increasing sensitivity of a cancer in a subject to a therapy, wherein the method comprises:

• administering to the subject a therapeutically effective amount of a multispecific molecule, wherein the multispecific molecule is an inhibitor of erythropoietin receptor (EPOR) activity and comprises:
• (a) a first domain, wherein the first domain is an anti-erythropoietin (EPO) binding domain, an anti-erythropoietin receptor (EPOR) binding domain, or an anti-CD131 binding domain;
• and
• (b) a second domain, wherein the second domain binds to
• (I) a cell surface signaling receptor associated with immune cells,
• (II) a tumor antigen, or
• (III) a growth factor, cytokine, or a growth factor receptor;
• thereby treating the cancer in the subject in need thereof or increasing the sensitivity of the cancer to the therapy.