A first-in-human phase 0 clinical study of RNA interference-based spherical nucleic acids in patients with recurrent glioblastoma

The lack of precision therapies combined with limited therapeutic access to intracranial tumor sites due to the presence of the blood-brain/blood-tumor barriers have contributed to glioblastoma (GBM) being one of the most difficult cancers to effectively treat. We have developed a novel precision medicine approach for GBM treatment that involves the use of brain-penetrant RNA interference (RNAi)-based spherical nucleic acids (SNAs). In this study, we used SNAs consisting of gold nanoparticle cores covalently conjugated with radially oriented and densely packed siRNA oligonucleotides. Based upon previous preclinical evaluation, we conducted toxicology and toxicokinetic studies in non-human primates, and a single-arm, open-label phase 0 first-in-human trial (NCT03020017) to determine safety, pharmacokinetics, intratumoral accumulation and gene-suppressive activity of systemically administered SNAs carrying siRNA specific for the GBM oncogene Bcl2Like12 (Bcl2L12). Patients with recurrent GBM were treated with intravenous administration of siBcl2L12-SNAs (drug moniker: NU-0129), at a dose corresponding to 1/50th of the no-observed-adverse-event-level (NOAEL), followed by tumor resection. Safety assessment revealed no significant treatment-related toxicities. Inductively coupled plasma mass spectrometry, X-ray fluorescence microscopy, and silver staining of resected GBM tissue demonstrated that intravenously administered SNAs reached patient tumors, with gold (Au) enrichment observed in the tumor-associated endothelium, macrophages and tumor cells. NU-0129 uptake into glioma cells correlated with significant reduction in tumor-associated Bcl2L12 protein expression, as indicated by comparison of NU-0129-treated recurrent vs. matched primary (i.e., untreated) tumor. Our results establish SNA nanoconjugates as a brain-penetrant precision medicine approach for the systemic treatment of GBM.