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

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 U.S. Food and Drug Administration/European Medicines Agency 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 Metabolites in Safety Testing considerations are provided. Finally, an industry recommendation on conducting metabolism and excretion studies is proposed for regulatory filing of TPeps. SIGNIFICANCE STATEMENT: This white paper presents current industry practices for metabolism and excretion studies of therapeutic peptides based on an industry survey, regulatory submission documents, and expert opinions from the participants in the Peptide Absorption, Distribution, Metabolism, and Excretion Working Group of the International Consortium for Innovation and Quality in Pharmaceutical Development. The group also provides recommendations on the Metabolites in Safety Testing considerations and metabolism and excretion studies for regulatory filing of therapeutic peptides.

Evaluation of Molecular Properties versus In Vivo Performance of Aflibercept, Brolucizumab, and Ranibizumab in a Retinal Vascular Hyperpermeability Model.

Purpose: To evaluate the molecular, pharmacokinetic, and pharmacological properties of three anti-vascular endothelial growth factor (VEGF) agents-aflibercept, brolucizumab, and ranibizumab-and to provide a prediction of the optimal design of an intravitreal VEGF challenge in rabbits to assess the preclinical in vivo activity of the different anti-VEGF agents. Methods: Biochemical analyses and cellular and animal models of retinopathy were used to characterize anti-VEGF efficacy. Anti-VEGF biochemical binding affinity was determined through a kinetic exclusion assay. The in vitro potency was investigated by a calcium mobilization assay. Pharmacokinetic parameters were estimated for each drug to predict intraocular exposure relationships among the agents. The in silico modeling efforts informed the design of an in vivo rabbit model of VEGF-induced retinal hyperpermeability to determine the extent of VEGF neutralization in vivo. Consequently, data generated from the in vivo study enabled pharmacokinetic analysis and the generation of a logistical model describing the impact of the anti-VEGF agents on the VEGF-induced vascular leakage in rabbits. Results: The three anti-VEGF agents ranked from most efficacious to least efficacious as aflibercept, brolucizumab, and ranibizumab, with results consistent and significant within each individual characterization experiment. Conclusions: This composite study demonstrated how the molecular properties of aflibercept, brolucizumab, and ranibizumab translate into differences of in vivo efficacy, with results in line with the reported literature. Translational Relevance: In silico, in vitro, and in vivo integrated studies provide information that enables the enhanced characterization of translational properties of anti-VEGF agents currently used for the treatment of retinal diseases.

Emodepside targets SLO-1 channels of Onchocerca ochengi and induces broad anthelmintic effects in a bovine model of onchocerciasis.

Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected tropical disease mostly affecting sub-Saharan Africa and is responsible for >1.3 million years lived with disability. Current control relies almost entirely on ivermectin, which suppresses symptoms caused by the first-stage larvae (microfilariae) but does not kill the long-lived adults. Here, we evaluated emodepside, a semi-synthetic cyclooctadepsipeptide registered for deworming applications in companion animals, for activity against adult filariae (i.e., as a macrofilaricide). We demonstrate the equivalence of emodepside activity on SLO-1 potassium channels in Onchocerca volvulus and Onchocerca ochengi, its sister species from cattle. Evaluation of emodepside in cattle as single or 7-day treatments at two doses (0.15 and 0.75 mg/kg) revealed rapid activity against microfilariae, prolonged suppression of female worm fecundity, and macrofilaricidal effects by 18 months post treatment. The drug was well tolerated, causing only transiently increased blood glucose. Female adult worms were mostly paralyzed; however, some retained metabolic activity even in the multiple high-dose group. These data support ongoing clinical development of emodepside to treat river blindness.

Potent and Selective Human Prostaglandin F (FP) Receptor Antagonist (BAY-6672) for the Treatment of Idiopathic Pulmonary Fibrosis (IPF).

Idiopathic pulmonary fibrosis (IPF) is a rare and devastating chronic lung disease of unknown etiology. Despite the approved treatment options nintedanib and pirfenidone, the medical need for a safe and well-tolerated antifibrotic treatment of IPF remains high. The human prostaglandin F receptor (hFP-R) is widely expressed in the lung tissue and constitutes an attractive target for the treatment of fibrotic lung diseases. Herein, we present our research toward novel quinoline-based hFP-R antagonists, including synthesis and detailed structure-activity relationship (SAR). Starting from a high-throughput screening (HTS) hit of our corporate compound library, multiple parameter improvements-including increase of the relative oral bioavailability Frel from 3 to ≥100%-led to a highly potent and selective hFP-R antagonist with complete oral absorption from suspension. BAY-6672 (46) represents-to the best of our knowledge-the first reported FP-R antagonist to demonstrate in vivo efficacy in a preclinical animal model of lung fibrosis, thus paving the way for a new treatment option in IPF.

Inhibition of the Keap1-Nrf2 protein-protein interaction protects retinal cells and ameliorates retinal ischemia-reperfusion injury.

The Nrf2-Keap1 pathway regulates transcription of a wide array of antioxidant and cytoprotective genes and offers critical protection against oxidative stress. This pathway has demonstrated benefit for a variety of retinal conditions. Retinal ischemia plays a pivotal role in many vision threatening diseases. Retinal vascular endothelial cells are an important participant in ischemic injury. In this setting, Nrf2 provides a protective pathway via amelioration of oxidative stress and inflammation. In this study, we investigated a potent small molecule inhibitor of the Nrf2-Keap1 protein-protein interaction (PPI), CPUY192018, for its therapeutic potential in retinal cells and retinal ischemia-reperfusion injury. In human retinal endothelial cells (HREC), treatment with CPUY192018 increased Nrf2 protein levels and nuclear translocation, stimulated Nrf2-ARE-induced transcriptional capacity, and induced Nrf2 target gene expression. Furthermore, CPUY192018 protected HREC against oxidative stress and inflammatory activation. CPUY192018 also activated Nrf2 and suppressed inflammatory response in macrophages. In the retinal ischemia-reperfusion (I/R) model, administration of CPUY192018 induced Nrf2 target gene activation in the retina. Both systemic and topical treatment with CPUY192018 rescued visual function after ischemia-reperfusion injury. Taken together, these findings indicate that small molecule Keap1-Nrf2 PPI inhibitors can activate the Nrf2 pathway in the retina and provide protection against retinal ischemic and inflammatory injury, suggesting Keap1-Nrf2 PPI inhibition in the treatment of retinal conditions.

Antibody-Drug Conjugates with Pyrrole-Based KSP Inhibitors as the Payload Class.

The number of cytotoxic payload classes successfully employed in antibody-drug conjugates (ADCs) is still rather limited. The identification of ADC payloads with a novel mode of action will increase therapeutic options and potentially increase the therapeutic window. Herein, we describe the utilization of kinesin spindle protein inhibitors (KSPi) as a novel payload class providing highly potent ADCs against different targets, for instance HER-2 or TWEAKR/Fn14. Aspects of technical optimization include the development of different linker attachment sites, the stabilization of ADC linkage to avoid payload deconjugation and finally, the tailor-made design of active metabolites with a long lasting intracellular exposure in the tumor matching the mode of action of KSP inhibition. These KSPi-ADCs are highly potent and selective in vitro and demonstrate in vivo efficacy in a broad panel of tumor models including complete regressions in a patient-derived urothelial cancer model.