A meta-analysis of randomized controlled trials indicates that autologous stem cell transplantation (ASCT) following the achievement of complete remission (CR) may lead to improved outcomes compared to chemotherapy alone in patients with acute myeloid leukemia (AML). The study, encompassing over 4200 patients, suggests potential benefits in disease-free survival and relapse rates with ASCT.
The analysis, published in Annals of Hematology, examined 17 randomized controlled trials involving patients without a matched sibling donor. Approximately two-thirds (n = 2782) of patients received chemotherapy, while 1499 patients underwent ASCT. The primary focus was to compare the efficacy of ASCT versus chemotherapy in maintaining remission and overall survival.
Impact on Disease-Free Survival
The meta-analysis revealed that patients receiving ASCT had a statistically significant 37% increased rate of disease-free survival (DFS) (OR, 1.37; 95% CI, 1.02-1.84) based on data from 15 studies. This suggests that ASCT may offer a more durable remission compared to chemotherapy in the studied population. However, when follow-up exceeded 5 years, the difference in DFS between the two groups was not statistically significant.
Relapse-Free Survival and Relapse Rates
Further analysis of 3 studies indicated significantly higher relapse-free survival (RFS) rates for patients undergoing ASCT (OR, 2.78; 95% CI, 1.28-6.02). Additionally, the risk of relapse was halved in patients receiving ASCT compared to those receiving chemotherapy (OR, 0.49; 95% CI, 0.41-0.57), based on data from 12 studies. These findings underscore the potential of ASCT in reducing the likelihood of disease recurrence.
Overall Survival
Despite the observed benefits in DFS and relapse rates, pooled data from all 17 studies showed no significant difference in overall survival (OS) between the ASCT and chemotherapy groups (OR, 1.12; 95% CI, 0.85-1.48), regardless of follow-up duration. This suggests that while ASCT may improve disease control, it does not necessarily translate to a survival advantage in the long term.
Study Limitations
The researchers noted several limitations in their analysis. "Firstly, a large number of patients did not actually receive their assigned treatment due to concerns from doctors or patients related to treatment-related toxicity, poor hematological recovery, and uncertainty about treatment benefits. Therefore, the final data in some studies were not ideal," they wrote. "Secondly, there was a problem with diversity in chemotherapy regimens administered to patients receiving ASCT and those receiving chemotherapy alone, and all studies exhibited significant clinical heterogeneity."
The group also pointed out that most studies included in their analysis were conducted more than a decade ago, potentially affecting the relevance of the findings due to advancements in treatment strategies.
Comparison to Allogeneic Transplantation
The article also referenced a German randomized controlled trial that explored the impact of allogeneic hematopoietic cell transplantation (allo-HCT) in AML patients. The data showed that allo-HCT was associated with significantly improved DFS compared with chemotherapy (69% vs 40%). However, similar to the ASCT meta-analysis, overall survival was similar between the two treatments.
