A study presented at the 11th Annual Meeting of the Society of Hematologic Oncology (SOHO) in Houston, Texas, detailed relapses in a cohort of 118 patients diagnosed with acute myeloid leukemia (AML) who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) between January 2009 and December 2019. The researchers, from the Institut Paoli Calmettes, Marseille, France, sought to understand the outcomes and treatment approaches in this challenging clinical scenario.
Of the 118 patients (age, median 53 years, range 20-69 years), FLT3 mutations, associated with a higher risk of AML relapse, were present in 22%. More than half of the patients (53%) had adverse genetic risk profiles according to European LeukemiaNet criteria, indicating a complex disease prognosis. At the time of relapse, 79% of patients had previously undergone transplantation and were in complete remission, while 21% had active disease.
The conditioning regimens used for the initial transplant were either myeloablative (39%) or reduced-intensity (61%). Eighteen patients received prophylactic donor lymphocyte infusion (DLI) to mitigate the risk of relapse. A significant proportion of patients developed graft versus host disease (GVHD), with 22 experiencing acute GVHD and 23 developing chronic GVHD. The median time from allo-HSCT to relapse was relatively short, at 4.7 months.
Various treatment strategies were used for the relapsed patients. Patients who underwent intensive salvage therapy (28%) achieved a 54% complete remission (CR) rate but with an early mortality rate of 18%. A larger portion (64%) opted for non-intensive salvage therapy, which resulted in a lower CR rate of 18%. Some patients achieved CR through treatment with azacytidine combined with sorafenib and/or DLI. A small subset (8%) received supportive care exclusively.
Seventeen patients chose to undergo a second transplant, with 14 achieving CR. Most of these patients received reduced-intensity conditioning, and 90% had a different donor. GVHD still posed a challenge, with 25% experiencing acute and 15% chronic GVHD. However, the early treatment-related mortality after the second transplant was 25%. Four patients (25%) who underwent intensive salvage treatment and a second transplant are currently in CR.
The 1-year overall survival (OS) rate following relapse was 25%, with a median OS of 5.1 months.
Several factors influenced OS, including the Sorror comorbidity score at the time of the first transplant, the time elapsed between transplant and relapse, and the type of salvage treatment. Multivariate analysis identified performance status at relapse as an independent factor affecting OS.
These results show the severity of the challenge of post-transplantation relapse in AML. While intensive salvage therapy can lead to reasonable response rates, long-term disease-free survival often necessitates subsequent cellular therapies.
Hicheri Y, Castoldi C, Devillier R, et al. Outcome of Acute Myeloid Leukemia Relapse After Allogenic Stem Cell Transplantation: A Single-Institution Retrospective Study. Abstract AML-110. Presented at the 11th Annual Meeting of the Society of Hematologic Oncology; September 6-9, 2023; Houston, Texas.