Using this registry, the 3306 study assessed the time from the completion of previous chemotherapy to switch from MRD negativity to positivity (“molecular relapse”) in HDC/IL-2-treated patients for comparison against carefully matched contemporary controls retrieved from the German-Austrian Cooperative Group registries.20 The results suggested that treatment with HDC/IL-2 reduced the incidence of molecular relapse in patients carrying NPM1 mutations (n = 25, HR 0.28, p = 0.07 vs controls) and within the group of patients with myelomonocytic/monocytic NPM1-mutated AML (n = 15, HR 0, p = 0.03). Here, IL2 is linked to acute myeloid leukemia.