The impact of depth of response to tyrosine kinase inhibitors (TKIs) on survival is different in patients in the blast phase of chronic myeloid leukemia (CML), vs those in chronic phase, according to a study involving 386 individuals.

Participants—all of whom had blast phase CML and were treated with TKIs—were categorized based on depth of treatment response:

• No hematologic response (n=141).

• Hematologic response only (n=94).
• Complete cytogenetic response only (CCyR; n=31).
• Major molecular response (MMR; n=28).
• Molecularly undetectable leukemia (MUL; n=92).

Median overall survival was:

• No hematologic response: ~3.5 months.
• Hematologic response: 11 months.
• CCyR: ~18 months.
• MMR: ~34 months.
• MUL: ~132 months.

There was no significant difference in survival between patients who achieved CCyR and those who achieved hematologic response.

The authors noted that whereas achieving MMR is the primary goal of patients in chronic phase, blast phase patients who achieve MUL experience better outcomes.