Backbone modification of a polypeptide drug alters duration of action in vivo.

Systematic modification of the backbone of bioactive polypeptides through β-amino acid residue incorporation could provide a strategy for generating molecules with improved drug properties, but such alterations can result in lower receptor affinity and potency. Using an agonist of parathyroid hormone receptor-1 (PTHR1), a G protein-coupled receptor in the B-family, we present an approach for α→β residue replacement that enables both high activity and improved pharmacokinetic properties in vivo.