Counterpoint: Aim for complete remission
Ronald B. Walter, MD, PhD, argued the counterpoint: that residual disease before transplantation is associated with worse posttransplant outcomes and represents a meaningful pretransplant therapeutic target.
The goal of intensifying treatment for patients with residual disease is to erase disease vestiges prior to transplantation.
“The idea is that by doing so you might optimize the benefit-to-risk ratio and ultimately improve outcomes,” said Dr. Walter, of the translational science and therapeutics division at the Fred Hutchinson Cancer Research Center in Seattle.
Several reports support this view that patients who are MRD negative at the time of transplant have significantly better survival outcomes than patients with residual disease who undergo transplant.
A 2016 study from Dr. Walter and colleagues at Fred Hutchinson, for instance, found that 3-year overall survival was significantly higher among patients with no MRD who underwent myeloablative alloHCT: 73% vs. 26% of those in MRD-positive morphologic remission and 23% of patients with active AML.
Another study, published the year before by a different research team, also revealed that “adult patients with AML in morphologic [complete remission] but with detectable MRD who undergo alloHCT have poor outcomes, which approximates those who undergo transplantation with active disease,” the authors of the 2015 study wrote in a commentary highlighting findings from both studies.
Still, providing intensive therapy prior to transplant comes with drawbacks, Dr. Walter noted. These downsides include potential toxicity from more intense therapy, which may prevent further therapy with curative intent, as well as the possibility that deintensifying therapy could lead to difficult-to-treat relapse.
It may, however, be possible to reduce the intensity of therapy before transplant and still achieve good outcomes after transplant, though the data remain mixed.
One trial found that a reduced-intensity conditioning regimen was associated with a greater risk of relapse post transplant and worse overall survival, compared with standard myeloablative conditioning.
However, another recent trial in which patients with AML or high-risk myelodysplastic syndrome were randomly assigned to either a reduced-intensity conditioning regimen or an intensified version of that regimen prior to transplant demonstrated no difference in relapse rates and overall survival, regardless of patients’ MRD status prior to transplant.
“To me, it’s still key to go into transplant with as little disease as possible,” Dr. Walter said. How much value there is in targeted treatment to further reduce disease burden prior to transplant “will really require further careful study,” he said.
The ASAP trial was sponsored by DKMS. Dr. Schetelig has received honoraria from BeiGene, BMS, Janssen, AstraZeneca, AbbVie, and DKMS. Dr. Walter reported no relevant financial relationships.
A version of this article appeared on Medscape.com.