Phase II and biomarker study of programmed cell death protein 1 inhibitor nivolumab and metronomic cyclophosphamide in paediatric relapsed/refractory solid tumours: Arm G of AcSé-ESMART, a trial of the European Innovative Therapies for Children With Cancer Consortium

Claudia Pasqualini, Jonathan Rubino, Caroline Brard, Lydie Cassard, Nicolás André, Windy Rondof, Jean‐Yves Scoazec, Antonin Marchais, Souad Nebchi, Lisa Boselli, Jonathan Grivel, Isabelle Aerts, Estelle Thébaud, Xavier Paolettí, Véronique Minard‐Colin, Gilles Vassal, Birgit Geoerger