Methods
After IRB approval, a retrospective chart review identified patients diagnosed with acute leukemia or MDS at age 30 years or younger who received venetoclax combination therapy at UCSF Benioff Children’s Hospitals. Eligible diagnoses included AML, MDS, and ALL. Patients who were treated on a clinical trial were excluded from this study.
Complete remission (CR) was defined as disappearance of all clinical and/or radiologic evidence of disease, plus absolute neutrophil count (ANC) ≥1.0 × 103/L, platelet count ≥100 × 103/L, and bone marrow differential with <5% blasts by morphology or flow cytometry of bone marrow.  Partial response (PR) was defined as no peripheral blasts or peripheral blood absolute blast count decreased by ≥ 50% from baseline, bone marrow with 5 – 25% blasts and at least a 50% decrease in bone marrow blast percent from baseline, and no evidence of extramedullary disease. Progressive disease (PD) was defined as > 50% increase in absolute peripheral or bone marrow blasts by morphology or flow cytometry. Stable disease (SD) was defined as the conditions under which criteria for CR, PR, or PD were not met.
Minimal residual disease (MRD) was defined as multiparameter flow cytometry of bone marrow with less than 0.01% blasts. Venetoclax toxicities were graded per the Common Terminology Criteria for Adverse Events version 5.0. Overall survival (OS) defined as the time in months from the start of venetoclax therapy to death, and progression-free survival (PFS) was defined as the time from the start of venetoclax administration until disease progression or relapse. Patients alive without relapse or progression were censored at their date of last follow-up. Kaplan–Meier curves of OS and PFS were generated.