We have previously reported a median overall survival (OS) of 19.7 months in patients with CML in blast phase (CML-BP), with a 5-year OS of 38%. A recent ELN Blast Phase Registry analysis derived a prognostic risk score from six independent factors. AIM To validate this prognostic model in an independent, contemporary cohort using the Cure CML Consortium blast-phase dataset. METHODS All patients diagnosed with CML-BP between 2010 and 2025 by modified MD Anderson criteria (≥30% blasts or extramedullary disease) were included in this multi-institution retrospective study. Prognostic risk score S = 0.061 ×(blasts % / 10)− 0.082 ×platelets [per 100×10⁹/L] + 0.034 ×age² / 100− 0.405  [if de novo BP]− 0.865  [if lymphoid phenotype]+ 0.541  [if extramedullary disease] Score per Lauseker M et al. Leukemia. 2026;40:751–758. RESULTS 284 Patients with CML-BP 50 yrs Median age (16–86) 47 mo Median follow-up P<0.0001 OS across risk groups PATIENT & DISEASE CHARACTERISTICS Disease onset Progressed from CP/AP  72.2% (n=205) De novo BP  27.8% (79) Blast phenotype Myeloid  63.4% (n=180) Lymphoid  36.6% (104) Sex Male  65.5% (n=186) Female  34.5% (98) Extramedullary disease at BP Present  27.1% (n=77) Absent  72.9% BCR::ABL1 transcript (of n = 238 tested) PROGNOSTIC RISK GROUPS —OVERALL SURVIVAL HIGH Median OS 10.3 mo n = 77 (27.1%) INTERMEDIATE Median OS 25.9 mo n = 137 (48.2%) LOW Median OS Not reached n = 22 (7.7%) Risk score not evaluable in 48 patients (16.9%) owing to missing variables.  Log-rank P < 0.001. SURVIVAL BY RISK GROUP Figure 1. Overall survival by ELN Blast-Phase Registry risk group (high vs intermediate vs low). Median OS 10.3 vs 25.9 months vs not reached; P<0.0001. CONCLUSIONS In this large multi-institutional cohort of patients with CML-BP, the ELN Blast Phase Registry prognostic model showed significant prognostic discrimination for OS in an external dataset. Although treatment-related variables (e.g., TKI, chemotherapy and allogeneic stem cell transplantation) were not incorporated, the model retained clinical utility across a contemporary treatment landscape and may aid risk stratification at diagnosis and in future clinical-trial design..