The present invention provides methods for increasing the systemic
bioavailability of a polypeptide therapeutic administered orally, via
oral gavage, via nasogastric gavage, or
intragastric administration, comprising administering the polypeptide therapeutic to the
stomach of a human or non-
human animal as part of one or more dosage forms together with an alginate
oligomer and, optionally, a gastrointestinal
permeation enhancer, wherein the one or more dosage forms do not, in addition to the polypeptide therapeutic, the alginate
oligomer, and, if used, the gastrointestinal
permeation enhancer, have a
coating that provides substantial protection from the gastric environment. Such methods allow for the systemic treatment or prevention of diseases, conditions, or complications thereof that are responsive to or prevented by the polypeptide therapeutic via oral,
oral gavage, via nasogastric gavage, or
intragastric administration. Further provided are compositions comprising an alginate
oligomer, a polypeptide therapeutic, and, optionally, a gastrointestinal
permeation enhancer for use in such methods.