Introduction to pediatric cancer immunotherapy

Cancer immunotherapy comes of age for adult malignancies. Immune targeted antibodies aiming at disrupting immunosuppressive pathways such as the checkpoints PD-1/PD-L1 and CTLA-4/B7 are providing durable responses and overall survival benefits in multiple relapsing/refractory adult cancer types. Novel immunotherapies such as oncolytic viruses and adoptive CAR-T cells are also becoming approved immune therapies and revolutionize the world of drug development. These therapeutic innovations are currently fostering an unprecedented research effort in adult tumor immunology. Pediatric cancers have major histological, biological and developmental differences with adult cancers. Although the fundamental immunological rules remain the same between adults and children, the limited data currently available suggest that the immune cells and the immunosuppressive pathways that are at stake in pediatric cancers might be different than the ones acting in adult cancers. Clinical results of passive immunotherapy with tumor targeting antibodies, cytokines, bispecific T-cell engaging antibodies and CAR-T cells have recently demonstrated that pediatric cancers can be treated with immunotherapy. However, the benefits of these novel treatments are limited to a small fraction of pediatric cancers. Fundamental and translational research efforts are currently eagerly needed to better decipher what drives the immune surveillance and editing of pediatric cancers.