The disclosure is directed to novel predictive methods and personalized therapies for treating psoriatic arthritis (PsA). Specifically, this disclosure relates to methods of treating a patient having PsA by selectively administering an IL-17 antagonist, e.g., an IL-17 antibody, such as secukinumab, to the PsA patient on the basis of that patient being predisposed to have a favorable response to treatment with the IL-17 antagonist. Also disclosed herein are diagnostic methods useful in predicting the likelihood that a patient having PsA will respond to treatment with an IL-17 antagonist, e.g., an IL-17 antibody, such as secukinumab.
