Post hoc analysis of prior allo-HSCT conditioning regimens used following blinatumomab or chemotherapy in childhood B-ALL

For the 90 evaluable patients, post-transplant relapse occurred in 29% of patients who received blinatumomab compared with 62% of those who were treated with chemotherapy (irrespective of conditioning regimen). 

The estimated EFS at 36- and 48-months post-transplant for patients treated with blinatumomab were 63.8% and 60.2%, respectively, compared with 35.5% at both time points with SoC chemotherapy, regardless of the type of conditioning. 

Among patients treated with blinatumomab, EFS did not significantly differ between those who underwent TBI and those who received chemo-conditioning. 

Overall, pretransplant treatment with blinatumomab vs SoC chemotherapy was correlated with a statistically significant better OS based on a multivariate Cox regression model (HR, 0.33; 95% CI, 0.15–0.72; p = 0.005). 

The 2-year estimated OS was numerically higher in patients treated with blinatumomab who underwent TBI conditioning compared with in those who received chemo-conditioning (86.5% and 75.2%, respectively). 

This analysis demonstrated that children with high-risk first-relapse B-ALL who received blinatumomab as their third consolidation course before allo-HSCT had improved OS and EFS post allo-HSCT compared with those treated with SoC chemotherapy, regardless of whether they received TBI or chemo-conditioning.