Therapeutic compositions containing fusion proteins (FPs) including elastin-like peptides (ELPs) and peptide active therapeutic agents, and methods of making and using such compositions and fusion proteins. Therapeutic compositions of such type enable improved efficacy of the peptide active therapeutic agent to be achieved, in relation to the peptide active therapeutic agent alone. Enhanced efficacy of the peptide active therapeutic agent in the therapeutic composition may include improved solubility, bioavailability, bio-unavailability, half-life, etc., as compared to corresponding compositions containing the same peptide active therapeutic agent without associated ELPs.