Metabolism and Excretion of Therapeutic Peptides: Current Industry Practices, Perspectives, and Recommendations

Abstract

Therapeutic peptides (TPeps) have expanded from the initial endogenous peptides to complex modified peptides through medicinal chemistry efforts for almost a century. Different from small molecules and large proteins, the diverse submodalities of TPeps have distinct structures and carry different absorption, distribution, metabolism, and excretion (ADME) properties. There is no distinct regulatory guidance for the industry on conducting ADME studies (what, how, and when) for TPeps. Therefore, the Peptide ADME Working Group sponsored by the Translational and ADME Sciences Leadership Group of the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ) was formed with the goal to develop a white paper focusing on metabolism and excretion studies to support discovery and development of TPeps. In this paper, the key learnings from an IQ industry survey and FDA/EMA submission documents of TPeps approved between 2011 and 2022 are outlined in detail. In addition, a comprehensive assessment of in vitro and in vivo metabolism and excretion studies, mitigation strategies for TPep metabolism, analytical tools to conduct studies, regulatory status, and MIST considerations are provided. Finally, an industry recommendation on conducting metabolism and excretion studies is proposed for regulatory filing of TPeps.