Swedish research-based biopharma company BioArctic AB (STO:BIOA-B) announced on Thursday that regulatory authorities in Spain and Poland have approved the inclusion of Multiple System Atrophy (MSA) patients in its ongoing EXIST Phase 2a study of exidavnemab.

The EXIST (EXIdavnemab Synucleinopathy Trial) study is a randomised, double-blinded, placebo-controlled clinical trial originally designed to evaluate the safety and tolerability of exidavnemab in Parkinson's disease patients. With the approved protocol amendment, an additional cohort of 12 MSA patients will be added to the 24 existing Parkinson's disease participants.

The trial will assess not only safety and tolerability, but also a wide range of biomarkers in plasma, cerebrospinal fluid, and through digital measurements. Conducted in Spain and Poland, the study aims to generate early insights into exidavnemab's potential for broader therapeutic application.

MSA is a rare, rapidly progressing neurodegenerative disease marked by alpha-synuclein aggregation, which impairs the central and autonomic nervous systems. There is currently no cure or treatment that slows disease progression.

Exidavnemab is a monoclonal antibody designed to target and clear toxic alpha-synuclein aggregates, with the goal of preserving neuronal function and slowing disease advancement.