Peptides are recognized for being highly selective and efficacious and, at the same time, relatively safe
and well tolerated. Consequently, there is an increased interest in peptides in pharmaceutical research
and development (R&D), and approximately 140 peptide therapeutics are currently being evaluated in
clinical trials. Given that the low-hanging fruits in the form of obvious peptide targets have already been
picked, it has now become necessary to explore new routes beyond traditional peptide design. Examples
of such approaches are multifunctional and cell penetrating peptides, as well as peptide drug conjugates.
Here, we discuss the current status, strengths, and weaknesses of peptides as medicines and the emerging
new opportunities in peptide drug design and development.