Humoral immune response against tumor antigens after treatment with a cancer antigen specific active immunotherapy and its association with improved clinical outcome

A method of determining therapeutic response in prostate cancer patients undergoing sipuleucel-T treatment, the method comprising the steps of:

• i. obtaining a baseline level of antibody reactive to one or more non-target predetermined biomarker antigens, said non-target predetermined biomarker antigens selected from the group consisting of PSA, KLK2, KRAS, ERAS, LGALS8, and LGALS3;
• ii. administering to the cancer patient T cells activated ex vivo using a protein comprising a PAP amino acid sequence;
• iii. obtaining a post-treatment antibody level reactive to the one or more non-target predetermined biomarker antigens from a patient blood sample after treating with the activated T cells;
• and,
• iv. measuring differences between the baseline and post-treatment reactive antibody levels to the one or more non-target predetermined biomarker antigens where an increase in antibody level for the one or more non-target predetermined biomarker antigens over their baseline level predicts a positive therapeutic response.

A method of identifying target antigens for cancer treatment with improved patient survival, the method comprising:

• i. obtaining baseline level of antibody reactive to one or more non-target predetermined biomarker antigens;
• ii. treating a patient suffering from cancer with cancer immunotherapy;
• iii. obtaining a post-treatment level of antibody reactive to the one or more non-target predetermined biomarker antigens from a patient blood sample after treating with the cancer immunotherapy;
• iv. comparing the baseline and post-treatment reactive antibody levels to determine one or more non-target predetermined biomarker antigens in which the reactive antibody level is increased;
• v. correlating the increase in the one or more non-target predetermined biomarker antigen reactive antibody levels to an increase in survival;
• and
• vi. identifying the one or more non-target predetermined biomarker antigens in which the increase in reactive antibody levels are correlated with survival as target antigens for cancer treatment with improved patient survival.

A system for determining a cancer patient's therapeutic response to cancer antigen specific active immunotherapy (CASAI) treatment with a target cancer antigen, the system comprising:

• i. a processor;
• ii. a memory coupled with the processor via an interconnect;
• iii. a communications interface coupled with the interconnect and adapted to:
• a. receive a first set of electronic data signals representing a set of pre-treatment interrelated values, each value indicative of a baseline antibody level reactive to one or more non-target predetermined biomarker antigens before CASAI treatment;
• b. receive a second set of electronic data signals representing a set of post-treatment interrelated values corresponding to the set of pre-treatment values, each of the second set of values indicating an antibody level reactive to the one or more non-target predetermined biomarker antigens from a patient blood sample after treating with CASAI;
• iv. a comparison engine coupled with the processor and configured to compare the set of pre-treatment values with the set of post-treatment values to determine which of the set of post-treatment values have changed from the set of pre-treatment values;
• and
• v. an output module configured to provide output data signals representing which of the set of post-treatment values have changed from the set of pre-treatment values, wherein an increase in the antibody level reactive to the one or more non-target predetermined biomarker antigens over their baseline level predicts a positive therapeutic response.

A method of determining therapeutic response in prostate cancer patients undergoing immunomodulatory treatment, the method comprising the steps of:

• i. obtaining a baseline level of antibody reactive to one or more predetermined biomarker antigens, said predetermined biomarker antigens selected from the group consisting of PSA, KLK2, KRAS, ERAS, LGALS8, and LGALS3;
• ii. administering to the prostate cancer patient an immunomodulatory agent;
• iii. obtaining a post-treatment level of antibody reactive to one or more predetermined biomarker antigens from a patient blood sample after treating with the immunomodulatory agent, said predetermined biomarker antigens selected from the group consisting of PSA, KLK2, KRAS, ERAS, LGALS8, and LGALS3;
• and
• iv. comparing differences between the baseline and post-treatment reactive antibody levels to the one or more predetermined biomarker antigens,
• wherein an increase in antibody level for the predetermined biomarker antigens over their baseline level predicts a positive therapeutic response.