New strategies in refractory and recurrent neuroblastoma: translational opportunities to impact patient outcome

Abstract

Neuroblastoma remains responsible for a disproportionate amount of childhood cancer morbidity and mortality despite recent significant advances in understanding the genetic basis of tumor initiation and progression. About half of newly diagnosed patients can be reliably identified as having tumors of low malignant potential, and these children have cure rates of greater than 95% with little or no cytotoxic therapy. On the other hand, the other half of neuroblastomas typically present in an explosive fashion with widely metastatic disease, and reliable tumor-specific biomarkers have been defined for this phenotype as well. Empiric approaches to high-risk neuroblastoma therapy have relied on dramatic escalation of chemotherapy dose intensity and, recently, the incorporation of targeted immunotherapy, but nearly 50% of children with high-risk disease will be refractory to therapy or suffer a relapse, both of which are invariably fatal. Future improvements in high-risk neuroblastoma outcomes will require the identification of disease and patient-specific oncogenic vulnerabilities that can be leveraged therapeutically. Rational development of novel approaches to neuroblastoma therapy requires forward-thinking strategies to unequivocally prove activity in the relapse setting and, ultimately, efficacy in curing patients when integrated into frontline treatment plans.

Figure 1

Targeted therapy in neuroblastoma: Current approaches to targeted therapy for neuroblastoma involve several modalities including 1. small molecular inhibitors of activated signaling pathways (ALK, IGF1R, MEK, PLK1, AURKA, PI3K and mTOR inhibitors) 2. radiopharmaceuticals targeting the NET receptor (¹³¹I-MIBG, ²¹¹At-MABG) and 3. immunotherapy (anti-GD2 antibodies).

Figure 2