CHICAGO – Minimal residual disease (MRD)–negative complete remission was strongly associated with improved survival outcomes in patients with B-cell acute lymphocytic leukemia (ALL) who received CD19 chimeric antigen receptor (CAR) T cells, results of a retrospective study showed.
Allogeneic hematopoietic stem cell transplant (HSCT) appeared to improve both disease-free and overall survival in those patients who had achieved MRD-negative complete remission, according to results of the study, which were presented at the annual meeting of the American Society of Clinical Oncology.
“Based upon our interaction testing, the potential benefit [of transplant] appears to exist in both good-risk and bad-risk patients as identified through multivariate modeling,” said study investigator Kevin Anthony Hay, MD, of Fred Hutchinson Cancer Research Center, Seattle.
In a comment on the results,, noted that the benefits of allogeneic transplant were apparent regardless of whether the patients met criteria for the good-risk subgroup, which was defined by levels of lactate dehydrogenase (LDH) and platelets along with exposure to fludarabine as part of the conditioning regimen.
“I think this suggests that the goal at this point is to get patients to an MRD-negative state and to potentially curative transplant,” said Dr. Cooley, director of investigator-initiated research at Masonic Medical Center at the University of Minnesota, Minneapolis.
The retrospective analysis by Dr. Hay and his colleagues included 53 adults with relapsed or refractory ALL who had bone marrow or extramedullary disease at baseline and had received CD19 CAR T cells at or under the maximum tolerated dose at least 1 year prior to this analysis. Of that group, 45 (85%) achieved MRD-negative complete remission.
Those patients who did achieve MRD-negative complete remission had an improved median disease-free survival at 7.6 months versus 0.8 months (P less than .0001) and improved overall survival at 20.0 months versus 5.0 months (P = 0.014).