P518: PEDAL/EUPAL INTERNATIONAL COLLABORATION TO IMPROVE THE OUTCOME OF CHILDREN WITH RELAPSED OR REFRACTORY ACUTE MYELOID LEUKEMIA - V. Ceolin; S. Ishimaru; F. Bautista; B. Goemans; E. A. Kolb; L. Di Laurenzio; T. M. Cooper; M. Bakker; J. Wahlstrom; G. Sunkersett; G. Ku; C. Zwaan; et al. (HemaSphere, 2022)