Clonal chromosomal abnormalities appearing in Philadelphia chromosome–negative metaphases during CML treatment

Clonal chromosomal abnormalities in Philadelphia chromosome-negative (CCA/Ph^-) metaphases emerge as patients with chronic phase chronic myeloid leukemia (CP-CML) are treated with tyrosine kinase inhibitors (TKIs). We assessed the characteristics and prognostic impact of 598 patients with CP-CML treated on clinical trials with various TKIs. CCA/Ph^- occurred in 58 patients (10%); the most common were 2Y in 25 (43%) and trisomy 8 in 7 patients (12%). Response to TKI therapy was similar for patients with CCA/Ph^- and those without additional chromosomal abnormalities (ACAs). We further categorized CCA/Ph^- into those in which –Y was the only clonal abnormality, and all others. We found that patients with non –Y CCA/Ph^- had worse failure-free survival (FFS), event-free survival (EFS), transformation-free survival (TFS), and overall survival (OS) compared with those without ACAs with the following 5-year rates: FFS (52% vs 70%, P 5 .02), EFS (68% vs 86%, P 5 .02), TFS (76% vs 94%, P < .01), and OS (79% vs 94%, P 5 .03). In a multivariate analysis, non –Y CCA/Ph^- increased the risk of transformation or death when baseline characteristics were considered with a hazard ratio of 2.81 (95% confidence interval, 1.15-6.89; P 5 .02). However, this prognostic impact was not statistically significant when achieving BCR-ABL <10% at 3 months was included in the analysis. In conclusion, non –Y CCA/Ph^- are associated with decreased survival when emerging in patients with chronic-phase CML across various TKIs. This trial was registered at www.clinicaltrials.gov as #NCT00048672, #NCT00038649, and #NCT00050531 (imatinib); #NCT00254423 (dasatinib); #NCT00129740 (nilotinib); and NCT01570868 (ponatinib).