Drug repurposing can fill an important gap for rare disease patient groups with large unmet medical needs. In comparison to traditional drug development, drug repurposing reduces the time and costs for drug development, regulatory approval, and market authorization. Yet, we need to increase the efficiency of the drug repurposing pathway to provide broader access to new therapeutic modalities for larger groups of patients. SIMPATHIC’s main objective is to accelerate drug repurposing for rare neurological, neurometabolic and neuromuscular disorders. SIMPATHIC’s main accelerating innovation is the simultaneous drug development for groups of patients with different genetic diagnoses but overlapping neurological symptoms and molecular pathomechanisms. SIMPATHIC’s key outputs accelerating the drug repurposing pathway include: Standard operating procedures for culturing stem cell-derived neuronal cell models with proven relevance for clinical symptoms and amenable to high-throughput drug screens; New drug repurposing candidates with proven efficacy in advanced brain-on-a-chip and 3D brain organoid models, as demonstrated by reversal of molecular biomarker signatures and cellular readouts associated with clinical symptoms; Designs of innovative basket clinical trials to which patients with different disorders are recruited, utilizing and aggregating personalized clinical endpoints; A training module for patients and patient organizations to empower them as drivers of the drug repurposing pathway; Blueprints for intellectual property strategies, business models, regulatory dossiers and patient access strategies, developed in co-creation between all relevant stakeholders. SIMPATHIC’s proof-of-concept for the simultaneous development of repurposed drugs for multiple indications will show the path forward to development of personalized treatment opportunities for groups of rare disease patients in a cost- and time-efficient manner.