A Retrospective Study of Clinical Profile and Long Term Outcome to Imatinib Mesylate Alone in Childhood Chronic Myeloid Leukemia in Chronic Phase.

OBJECTIVE: Chronic myeloid leukemia (CML) is relatively rare malignancy in childhood. There are limited studies of use of Imatinib Mesylate (IM) alone in management of CML in this age group.

METHOD: We retrospectively analyzed the outcome of 30 consecutive children with CML chronic phase treated with IM alone.

RESULTS: The median age at the time of diagnosis was 11 years with male preponderance. Asthenia and abdominal discomfort due to splenomegaly were the most common presenting features and splenomegaly a dominant sign. At time of starting IM, 19 children were in early CP while 11 were in late CP. Complete hematological remission was achieved in 90% with a median time to achieve CHR was 60 days. Among evaluable children, 83.3% achieved cytogenetic response (CyGR). Those who achieved complete CyGR were in major molecular remission at the time of last follow up. At 3 years, progression-free survival was 81.5% and overall survival was 100%. At 10 years, 12 (40%) children failed on IM therapy of which 3(10%) children developed primary IM resistance while 9 (30%) developed secondary IM resistance. IM was well tolerated and severe (grade III-IV) events were infrequent. Non-haematological toxicities were uncommon except hypopigmentation of skin which was seen in 60% of the cohort.

CONCLUSION: Presenting features of CML-CP in children is comparable to other Indian and international studies. IM is very effective and safe drug for the first line treatment of CML-CP in children. It is very effective in inducing CHR. Adherence to treatment is very important for achieving CyGR and long term survival. This data will be useful for financially deprived children in developing countries where allogeneic stem cell transplant (SCT) or second line tyrosine kinase inhibitors (TKIs) is not an affordable option.