Improved Outcome for AML Relapse after Allogeneic Transplant with High Intensity Chemotherapy Followed By 2nd Allogeneic Stem Cell Transplant or Donor Lymphocyte Infusion; A Retrospective Analysis

Background Acute myeloid leukemia (AML) relapse after allogeneic stem cell transplant (allo SCT) remains a major therapeutic challenge. While patients with longer remission after initial allo SCT are recommended to receive either 2nd allo SCT or donor lymphocyte infusion (2nd allo SCT/DLI), survival probability for patients relapsing within 6 months of SCT are dismal. We evaluated the outcomes of AML relapse after allo SCT to assess the impact of 2nd allo SCT/DLI on long term survival. Methods and Results One hundred and seventy-two patients with AML underwent allo SCT at Penn State Cancer Institute from Jan 2014 to Aug 2019. Sixty-nine patients relapsed after allo SCT (median age, 60 years; range, 10-75). Of these, 4 patients underwent 2nd allo SCT and 26 received DLI. Overall survival (OS) was defined as days from the relapse and evaluated with Kaplan-Meier survival curves and log rank tests. One-year OS in all cases was 22.4% (95% CI: 13.3-32.9%). Patients with ECOG performance status (PS) 0-2 at relapse (n=60) showed a better 1-year OS compared to those with ECOG PS 3-4 (n=9) (24 vs 11.1%, p Conclusions Relapsed AML after allo SCT treated with high intensity chemotherapy followed by 2nd allo SCT/DLI showed a better OS. Similar benefit was shown even for patients who relapsed within 6 months of allo SCT.