The disclosure is directed to novel predictive methods and personalized therapies for treating asthma. Specifically, this disclosure relates to methods of treating a patient having asthma by selectively administering an IL-13 antagonist, on the basis of that patient being genetically predisposed to have a favorable response to treatment with the IL-13 antagonist. Also disclosed herein are transmittable forms of information, diagnostic methods, and kits useful in predicting the likelihood that a patient having asthma will respond to treatment with an IL-13 antagonist.