Abstract: Disclosed herein are safe doses of dual-V-region antibody-like binding proteins or fragments thereof, as well as methods for assessing binding of dual-V-region antibody-like proteins or fragments thereof to their targets, and methods of treating idiopathic pulmonary fibrosis (IPF) by administering safe doses of dual-V-region antibody-like binding proteins or fragments thereof. In some embodiments, the dual-V-region antibody-like binding proteins or fragments thereof bind both IL-4 and IL-13.