Speech-based digital endpoints track ALS progression and align with standard clinical outcomes: evidence from the VRG50635 trial

We report on the utility of speech-based digital endpoints measured during a Phase 1b study of VRG50635 in Amyotrophic Lateral Sclerosis (ALS). Fifty-four participants with ALS were enrolled and participated in an 8-week pretreatment run-in, followed by three 8-week dosing periods and an 8-week follow-up. They completed a speech assessment every two weeks in the clinic or at home. We observed moderate to high correlations between digital measures of speech timing and articulatory motor function, and the ALS Functional Rating Scale-Revised, slow vital capacity and plasma neurofilament light chain. Furthermore, speech measures can show functional decline before the ALSFRS-R does, while also capturing differences between participants with bulbar symptoms and those without. The results support the feasibility and utility of digital speech endpoints to study disease impact in ALS clinical trials.