This exploratory clinical study will evaluate the efficacy and feasibility of combining a GSL synthase inhibitor with a granulocyte-macrophage colony stimulating factor (GM-CSF) in patients with advanced or metastatic neuroblastoma. Six to eight eligible patients are expected to be treated in this clinical trial: 1) Assessing the anti-tumour effects of GSL synthase inhibitors in combination with immune checkpoint inhibitors and/or GM-CSF; 2) To assess immunological or clinical predictive biomarkers of efficacy and toxicity; and 3) Detecting changes in the tumour microenvironment (TME) and the dynamics of peripheral blood immune cells after treatment with a GSL synthase inhibitor combined with GM-CSF.