The present disclosure provides for isolated non-naturally occurring, mutant-human IAPP polypeptides. These polypeptides can be formulated or co-formulated at physiological pH, which enable the polypeptides of the instant disclosure to be delivered to a subject having an amyloid-based disease in a single injection with an insulin agent. The present disclosure also provides methods and compositions for treating amyloid-based disease in a subject in need thereof, comprising administering an effective amount of an isolated, mutant-hIAPP polypeptide, including formulations or co-formulations thereof.
