Measurement of cortical, nerve, and muscle excitability in early phase clinical drug development

Abstract

This thesis describes a set of excitability measurements -transcranial magnetic stimulation (TMS) combined with electromyography (EMG) and electroencephalography (EEG), nerve excitability threshold tracking (NETT), and muscle velocity recovery cycles (MVRC)- and the applicability of these tools in early phase clinical drug development. We validated the biomarkers in healthy subjects with registered drugs and showed that the measurements are all repeatable and sensitive to pharmacological effects, even in a small number of subjects. Furthermore, we have evaluated effects of a novel AMPA-positive allosteric modulator with TMS-EMG/EEG, and a first-in-class skeletal muscle-specific chloride channel (ClC-1) inhibitor with MVRC, and the findings helped us to confirm proof-of-mechanism of these compounds in healthy subjects. In conclusion, these measurements proved to be valuable pharmacodynamic biomarkers in two drug development programs, encouraging their further use in clinical development of other future drug candidates targeting cortical-, neuronal-, and muscle cell excitability. The use of such clinical pharmacodynamic biomarkers could improve the quality and efficiency of the development process of drugs for e.g. amyotrophic lateral sclerosis, chronic pain, depression, treatment-resistant epilepsy, and neuromuscular diseases.