High Baseline WBC Identifies High-Risk Patients in Ph+ ALL on Chemo-Free Regimen

In this phase II trial investigating frontline ponatinib and blinatumomab in 76 Ph+ ALL patients, a 3-year event-free survival of 78% and overall survival of 88% were observed, with 13% of patients relapsing—most notably those with a white blood cell count ≥70 × 10^9/L at diagnosis, CNS involvement, or VPREB1 deletion. Extra-medullary relapses were common, and despite sustained CD19 expression at relapse, multivariate analysis highlighted high WBC as the sole independent predictor of relapse, with a striking sub-hazard ratio (sHR) of 16.29.

These findings underscore that patients with high WBC counts at diagnosis are at markedly increased risk of relapse on this chemotherapy-free regimen, indicating a need for alternative frontline strategies to improve long-term outcomes in this subgroup.