Method for optimizing the treatment of patients with biologics

Method of classifying a patient suffering from rheumatoid arthritis as a patient responds or does not respond to treatment, said treatment comprising administering to said patient a selected biological agent from the group comprising infliximab comprising and adalimumab which is administered 5 periodically by administrations repetitive, and wherein said patient has received at least one dose of said biological agent, said method comprising the steps of: a) determining the concentration of circulating biological agent in a sample from said patient at a time t1 in which said t1 corresponds to a time point within the period of time between two successive administrations of said biological agent; b) determining the concentration of antibodies to said drug in a biological sample from said patient at a time t1; c) comparing the concentration of circulating biological drug in said t1 with a reference value 1 (VR1) and the concentration of antibodies against said biological drug in said time t1 with a reference value 2 (VR2), wherein the sample selected from a blood sample, a plasma sample and a serum sample; VR1 is a threshold value of therapeutic efficacy of the concentration of circulating biological agent; and VR2 is the limit value of the concentration of said antibody to the biological drug, as determined in a group of individuals who have never been treated by the same assay as used for determining the concentration of antibody biological agent in step b), and wherein if the concentration of circulating biological drug is less than VR1 and the concentration of antibodies against said biological agent is higher than VR2, then he said patient is classified as a patient who does not respond to such treatment, and in the if the concentration of circulating biological agent is equal to or greater than VR1 and the concentration of antibodies against said biological agent is equal to, or less than VR2, then said patient is classified as a patient responsive to said treatment, and wherein if the biological agent is infliximab, then VR1 is 1.5 mg / ml and VR2 is 150 ng / ml; and wherein if the drug is adalimumab biological then VR1 is 0.8 mg / ml and VR2 is 32 ng / ml