‘Dismal prognosis’ of blast-phase CML patients highlighted

Oct 22 2015

By Shreeya Nanda, Senior medwireNews Reporter

A team of Mexican researchers reports on the poor outcomes of a large series of Mexican patients with chronic myeloid leukaemia (CML) in blast phase.

This chart review included 51 blast-phase CML patients diagnosed and treated between 1988 and 2013. Of these, 13.7% presented in blast phase at diagnosis while the rest had progressed from chronic or accelerated phase.

Just over half (52.9%) of the patients received standard induction chemotherapy alone, while 31.4% were treated with a combination of chemotherapy and tyrosine kinase inhibitors (TKIs; mainly imatinib). A complete haematological response (CHR) was achieved by 42.0% of the 38 evaluable patients, excluding the five who died within the first 4 weeks of therapy initiation.

Significantly more patients with lymphoid blast phase achieved a response compared with those with myeloid blast phase, at 72.9% versus 25.9%. And multivariate analysis showed that myeloid lineage and receipt of chemotherapy alone were the only factors significantly associated with a lower probability of achieving CHR.

The researchers note that the CHR rate in patients given chemotherapy plus imatinib was comparable to that reported in studies of second-generation TKIs, suggesting that combined therapy “could be a suitable strategy in developing countries with limited access to second generation [TKIs]”.

Median overall survival (OS) for the whole cohort was 4 months, while patients who did and did not achieve CHR had a median OS of 7 and 2 months, respectively, a significant difference. However, OS did not vary significantly between patients with lymphoid and those with myeloid lineage blast phase.

In multivariate analysis, age over 60 years, haemoglobin levels below 10 g/dL and presence of a complex karyotype were significant risk factors for worse OS.

Among patients who achieved CHR, median disease-free survival was 5 months. However, the researchers did not find any significant associations between patient or treatment characteristics and disease-free survival.

The majority (98.0%) of patients had died at the time of analysis, with just one patient alive 10 years after receiving allogeneic haematopoietic stem cell transplantation.

“These results underline the dismal prognosis of [blast-phase CML] and highlight the importance of close surveillance to identify promptly progression from [chronic phase] to advanced phases in CML patients”, conclude Xavier López-Karpovitch and co-authors, from the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, in Clinical Lymphoma, Myeloma and Leukemia.

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