ALK/ATR combination therapy is effective in neuroblastoma mouse tumors driven by MYCN

Summary paragraphOne of the key features of high-risk neuroblastoma (NB) is MYCN-amplification. While MYCN is still regarded as therapeutically challenging despite intensive efforts to find targeting compounds, inhibitors against Anaplastic Lymphoma Kinase (ALK) are now being evaluated among ALK-driven NB patients with promising results. There is a pressing need to find alternative treatment regimens for ALK naive MYCN-amplified patients, as current regimes are accompanied by significant mortality and morbidity. Here we show that genetically removing Alk in the Th-MYCN-driven engineered NB mouse model (GEMM) resulted in decreased tumor penetrance, and survival of Th-MYCN homozygote GEMMs, suggesting that Alk activity contributes to aggressiv e neuroblastoma development in this model. Given the high levels of replication stress induced in Th-MYCN tumors, we employed inhibitors of Ataxia Telangiectasia Rad3 related (ATR), combining ATR and ALK inhibition in a 14-day treatment regime, and comparing with ATR inhibitor monotreatment. Th-MYCN tumor bearing mice that received ATRi/ALKi combination treatment exhibited significantly increased survival compared to ATRi alone, that was sustained over time. Together, our data highlight a potentially effective treatment option for the currently challenging category of MYCN-amplified NB patients lacking ALK mutations.