Allogeneic hematopoietic cell transplantation is a better option than consolidation chemotherapy in patients with secondary acute myeloid leukemia, yielding significantly better survival outcomes, according to findings from an observational study.

Human cells with acute myelocytic leukemia (AML) in the pericardial fluid, shown with an esterase stain at 400x. National Institutes of Health/Wikimedia Commons/Public Domain

Although secondary AML has been identified as an independent predictor of poor prognosis, it is not included in current risk classifications that provide the basis of deciding when to perform HCT.

Christer Nilsson, MD, of Karolinska Institute, Stockholm, and colleagues, used two nationwide Swedish registries – the Swedish AML Registry and the Swedish Cancer Registry – to characterize how often HCT is performed in these patients and to evaluate its impact in a real-world setting. The registries include all patients with AML diagnosed between 1997 and 2013.

Their findings are in Biology of Blood and Marrow Transplantation.

The analysis included 3,337 adult patients with AML who were intensively treated and did not have acute promyelocytic leukemia. More than three-quarters of the patients had de novo AML and the remainder had secondary AML that was either therapy related or developed after an antecedent myeloid disease. In total, 100 patients with secondary AML underwent HCT while in first complete remission.

In terms of crude survival at 5 years after diagnosis, patients with secondary AML who did not undergo HCT did very poorly. The survival rate was 0% in those with AML preceded by myeloproliferative neoplasm (MPN-AML), 2% in patients with AML preceded by myelodysplastic syndrome (MDS-AML), and 4% in patients with therapy-related AML (t-AML). In contrast, the 5-year overall survival in patients who underwent HCT at any time point or disease stage was 32% for patients with MPN-AML, 18% for patients with MDS-AML, and 25% for patients t-AML.

These crude survival figures suggest that “HCT is the sole realistic curable treatment option for [secondary] AML,” the researchers wrote.

The researchers also performed a propensity score matching analysis of HCT versus chemotherapy consolidation in patients with secondary AML who had been in first complete remission for more than 90 days. The model matched 45 patients who underwent HCT with 66 patients treated with chemotherapy consolidation. The projected 5-year overall survival was 48% in the HCT group, compared with 20% in the consolidation group (P = .01). Similarly, 5-year relapse-free survival was also higher in the HCT group, compared with the consolidation group (43% vs. 21%, P = .02).

“Ideally, the role of transplantation in [secondary] AML should be evaluated in a prospective randomized trial, minimizing the risk of any bias,” the researchers wrote. “However, such a trial is lacking and most likely will never be performed.”

The researchers concluded that HCT should be considered for all patients with secondary AML who are eligible and fit for transplantation.

The study was supported by the Swedish Cancer Foundation, Swedish Research Council, Stockholm County Council, Gothenberg Medical Society, and Assar Gabrielsson Foundation. The researchers reported having no conflicts of interest.

SOURCE: Nilson C et al. Biol Blood Marrow Tranplant. 2019;25:1770-8.