Dora Adamic

High-risk neuroblastoma is an aggressive pediatric malignancy characterized by a high proliferative capacity, intrinsic replication stress, and poor clinical outcomes. Although mitotic inhibitors show preclinical efficacy, their clinical use is limited by dose-dependent toxicity. In this study, we performed high-throughput combinatorial drug screening using MYCN-amplified (MNA) human neuroblastoma tumoroids to identify drugs with orthogonal mechanisms that synergize with low-dose mitotic inhibition. Promising drug combinations were prioritized using a multifactorial approach including dose–response matrices across multiple neuroblastoma tumoroids and CD34+ cord blood cells, synergy area scores, and machine learning–based response predictions. Several therapeutic classes were selected, including kinase inhibitors, differentiation agents, and hormone therapies. Notably, combined ataxia telangiectasia and Rad 3–related (ATR) inhibition by elimusertib and mitotic kinesin spindle protein (KSP) inhibition showed additive to mild synergy and induced neuroblastoma cell death. This combination reduced tumor growth and prolonged survival in neuroblastoma MNA, chemoresistant patient-derived xenografts. Furthermore, alternating dosing schedules were well tolerated and maintained stable disease control in vivo. Collectively, these findings establish combined ATR and low-dose mitotic inhibition as a promising therapeutic strategy for MNA neuroblastoma.

Relapse and treatment resistance are common in children with high-risk neuroblastoma, and novel therapies are needed. Conventional drug discovery is slow, expensive, often fails in practice, and consequently falls short in addressing pediatric and rare conditions. In such instances, drug repurposing is a promising strategy. Here, we used two independent in silico prediction tools including machine learning to identify approved drugs for repurposing against neuroblastoma. The combination of statins and phenothiazines showed strong synergistic effects in human neuroblastoma organoids, decreased tumor growth, and prolonged survival in MYCN -amplified neuroblastoma patient-derived xenografts. The drug combination altered cholesterol metabolism through two different mechanisms and induced a phenotypic change toward an adrenergic state in vitro, which was associated with enhanced chemosensitivity. Integration of the drug combination into standard-of-care chemotherapy regressed tumors and prolonged survival in chemoresistant patient-derived xenografts. Thus, a combination of safe and approved medications added to standard-of-care chemotherapy outperforms chemotherapy alone in chemoresistant neuroblastoma.