Methods and apparatus utilising liquid biopsy to identify and monitor pharmacodynamic markers of disease

A method of treating an individual subject, wherein the individual is the intended recipient of a pharmaceutical treatment, the method comprising establishing a personalised pharmacodynamic profile for the individual subject prior to or during the treatment, the method comprising the steps of:

• isolating total cell free RNA (cfRNATOTAL) from a liquid biopsy obtained from the individual subject;
• identifying an amount of a first cell free RNA (cfRNA) present in the liquid biopsy, wherein the first cfRNA originates from a specified compartment within the body of the subject, and wherein the first cfRNA encodes a first protein from the compartment that has a pharmacodynamic activity relevant to the pharmaceutical treatment;
• determining a pharmacodynamic activity relevant to the pharmaceutical treatment for the individual subject based upon the presence or absence, or a level of the protein within the specified compartment of the subject;
• generating the personalised pharmacodynamic profile for the individual subject;
• and
• treating the individual according to a dosage regimen for the pharmaceutical treatment that is optimized to the individual based upon their personalised pharmacodynamic profile.