P583: PATIENTS AT HIGH RISK OF RELAPSE POST-TRANSPLANT: A PHASE 1 STUDY DESIGN WITH A NOVEL TREATMENT STRATEGY USING THE ESTIMAND FRAMEWORK - R. Zeiser; C. Schmid; G. Al-Atrash; Y. Xu; H.-J. Weber; L. Eldjerou; S. Weber; L. Widmer; C. Craddock (HemaSphere, 2022)