CML Management At Tertiary Care Centres in Abu Dhabi, United Arab Emirates

Abstract 4451

Chronic myeloid leukaemia (CML) is a clonal myeloproliferative disorder characterized by the presence of a balanced reciprocal translocation involving the long arms of chromosomes 9 and 22. The fusion gene created by this translocation (BCR–ABL1) encodes for a constitutively active protein tyrosine kinase that is primarily responsible for the leukemic phenotype. CML occurs in all age groups, with a median age at diagnosis of 66 years in Western populations. The overall prognosis for CML has changed significantly with the introduction of tyrosine kinase inhibitors (TKI’s) in the treatment of CML. While demographic and response to therapy data is abundantly available from the Western countries, such data is scarce from the Middle East. We undertook a review of the CML patient characteristics at diagnosis and their response to therapy according to the European Leukaemia Network (ELN) guidelines at our two centres where most, if not all, of the patients suspected to have CML in the country are referred for treatment.

We diagnosed 25 patients with CML between January 2010 and June 2011. The median age at diagnosis was 35 years (range 23–69 years); male to female ratio 1.8:1. All patients were diagnosed in chronic phase. Sokal score was calculated for 23/25 patients and there were 7 low risk, 13 intermediate risk and 3 in the high risk group (Table 1). Of the 24/25 patients treated, 15 were treated with imatinib (one later changed to dasatinib due to suboptimal response); 4 with nilotinib (one later changed to dasatinib due to intolerance); and 5 with dasatinib as frontline therapy. The patients were followed as per ELN guidelines, with major milestones checked at 3, 6, 12 and 18 months and the median follow up was 12 months. Follow up data was available on 22/24 treated patients, all of which showed a Complete Hematological Response (CHR) after 3^rd month of treatment. At 6 months 9 were in Complete Cytogenetic Response (CCgR) while 2 patients on Imatinib had Partial Cytogenetic Response (PCgR). Of the patients with CCgR, 5 were on imatinib, 3 on nilotinib, and 1 on dasatinib. At 12 months one of the patients on imatinib with PCgR had converted to CCgR; while data is not available (ND) for other patients. Major molecular response (MMR) was seen in 10 patients (imatinib 5, nilotinib 3, dasatinib 2) who reached the 6–12 month milestone. Five of these patients had a Complete Molecular Response (CMR) with undetectable levels. Interestingly, 3 patients achieved MMR at 3 months of starting induction. All three were treated with 2^nd generation TKI’s (dasatinib 2, nilotinib 1).

This is the first analysis of CML patients from the UAE. Our data is limited but it shows that the median age is significantly lower as compared to that reported from Western countries (35 years vs. 66 years) reflecting the difference in the age distribution of the population of the UAE (80% of population is below the age of 65 years). Additionally, the CCgR is only 40% at 12 months, much lower than reported from the Western countries. Our experience shows that the lack of patients’ compliance to treatment is a major negative factor in their optimal care. We plan to address this issue through more rigorous patient education.