The present disclosure relates to pharmaceutical compositions comprising a non-naturally occurring fusion molecule and one or more pharmaceutically acceptable carriers, formulated for oral delivery to a subject, and designed to provide for improved, effective therapies for treatment of, e.g., inflammatory diseases, autoimmune diseases, cancer, metabolic disorders, and growth deficiency disorders. The present disclosure relates to a non-toxic mutant form of the Vibrio cholera Cholix gene (ntCholix), a variant of Cholix truncated at amino acid A386 (Cholix386) and the use of other various Cholix-derived polypeptide sequences to enhance intestinal delivery of biologically-active therapeutics. The systems and methods described herein provide for: the ability to deliver macromolecule doses without injections; the ability to deliver cargo such as siRNA or antisense molecules into intracellular compartments where their activity is required; and the delivery of nanoparticles and dendrimer-based carriers across biological membranes.