Acute lymphoblastic leukemia (ALL) with Philadelphia chromosome positivity (Ph+) has a poor prognosis historically; hence allogeneic hematopoietic cell transplantation (allo-HCT) is advised after the first complete remission (CR1). The quick achievement of complete molecular remission (CMR), however, was associated with favorable outcomes without allo-HCT in the tyrosine kinase inhibitor (TKI) era, indicating transplant may not be necessary for these individuals. For a study, researchers looked backward to find adult Ph+ ALL patients who had induction treatment, such as TKIs, and received CMR within 90 days of diagnosis at 5 transplant facilities in the US in order to test this theory. 

They examined the results of patients who received allo-HCT in the first remission vs those who did not. They located 230 patients (allo-HCT: 98; non-HCT: 132). The allo-HCT cohort had superior performance status and was younger. Allo-HCT was not related to increased overall survival (adjusted hazard ratio [aHR]: 1.05; 95% CI, 0.63-1.73) or relapse-free survival (aHR: 0.86; 95% CI, 0.54-1.37) compared to non-HCT therapy on multivariable analysis (MVA). Allo-HCT was linked to a higher non-relapse mortality (aHR: 2.59; 95% CI, 1.37-4.89) but a decreased cumulative incidence of relapse (aHR: 0.32; 95% CI, 0.17-0.62). 

The results of the MVA were verified by a matching analysis using propensity scores. There was no statistically significant difference between reduced-intensity HCT and non-HCT for any of the aforementioned outcomes. 

In the retrospective investigation, allo-HCT in CR1 did not result in a survival benefit for adult Ph+ ALL patients who achieved CMR within 90 days of initiating therapy.

Reference: ashpublications.org/blood/article/140/20/2101/486005/The-role-of-allogeneic-transplant-for-adult-Ph-ALL