Based on those findings, an ongoing phase 1/2a, multicenter, open-label, ascending dose study, called PRV-PD101 (NCT04127578, PROPEL study), is evaluating the safety, tolerability, immunogenicity, biomarkers, and clinical effects of intracisternal high-dose and low-dose AAV9–GBA1 (LY3884961) administration in patients with moderate-to-severe PD who carry a GBA1 variant [95] (Table 1). Here, GBA1 is linked to Parkinson disease.