Impact of antecedent myelodysplastic syndrome treatment on outcomes and treatment response in patients with subsequent secondary acute myeloid leukemia.

e18516 Background: Secondary acute myeloid leukemia (sAML) is a diagnostic qualifier of AML that develops in patients previously diagnosed with a myeloid neoplasm such as myelodysplastic (MDS). sAML has worse outcomes compared to de novo AML, but it has not been established how previous treatment of MDS impacts treatment responses and outcomes for sAML. Methods: This was a single-center retrospective cohort study using the University of Minnesota AML registry. Adults with a diagnosis of sAML between 2014 and 2022 and a prior history of MDS were included. Data extracted includes previous treatment for MDS (azacitidine, decitabine, cytarabine, venetoclax, daunorubicin, or hematopoietic stem cell transplant (HCT)) Patients whose antecedent MDS was treated were compared to previously untreated patients. Statistical comparison was performed using a Chi-squared test for categorical variables and a Kaplan-Meier analysis for overall survival (OS), defined as the date of diagnosis to the date of death or date of data analysis in live patients. A p-value of <0.05 was deemed to be statistically significant. Results: 110 patients were included in the analysis. 45% received therapy for MDS and 56% did not. 37% of patients in the MDS-untreated group achieved CR after first-line sAML therapy compared to 16% in the MDS-treated group, p = 0.016. 60% of patients in the MDS-untreated group achieved CR at any time in their sAML treatment course compared to 20% of patients in the MDS-treated group, p <0.0001. 43% of patients in the MDS-untreated group underwent an HCT for sAML compared to 12% in the MDS-treated group, p = 0.0003. The mean OS was 13.8 months for the sAML patients in the MDS-untreated group compared to 6.1 months for sAML patients in the MDS-treated group, p = 0.002. The 2-year OS was 38.3% of sAML patients in the MDS-untreated group compared to 15% of sAML patients in the MDS-untreated group, p = 0.002. Conclusions: Patients with sAML who had precedent treatment for MDS have inferior responses therapy and significantly reduced survival. MDS-untreated (n) MDS-treated (n) % MDS-untreated % MDS-treated p-value CR (First Line) 22 8 37% 16% 0.016 CR (Ever) 36 10 60% 20% <0.0001 HCT for sAML 26 6 43% 12% 0.0003 OS (months) 13.8 6.1 - - 0.002 2yr survival 23 6 38% 12% 0.002 Median Age at Diagnosis (yrs) 67.69 68.02 - - 0.38 TP53 WT 44 39 72% 76% 0.57 Prior Malignancy 10 16 16% 31% 0.061 Prior Chemotherapy 7 12 11% 24% 0.09 Prior Radiation 4 12 7% 24% 0.01