Treatment of chronic myeloid leukaemia: Lessons and challenges

The choice of primary treatment for patients with chronic myeloid leukaemia diagnosed in chronic phase has become exceedingly difficult. There is little doubt that allogeneic stem cell transplantation (allo-SCT) can eradicate the leukaemia and that a 'graft-versus-leukaemia' effect makes a major contribution to this result; conversely only a minority of patients are eligible for transplant, which still carries an appreciable risk of mortality or protracted morbidity. For the majority of patients interferon-alpha prolongs life to some degree in comparison with hydroxyurea but is associated with considerable toxicity. The newly introduced tyrosine kinase inhibitor imatinib mesylate (imatinib, Glivec) induces complete haematologic remission in almost all cases and is associated with a very high incidence of cytogenetic response; its capacity to prolong life in comparison with interferon-alpha is not yet established. Here we review some factors that predict survival after non-transplant therapy and after allografting for CML in chronic phase. We consider two contrasting options for managing the newly diagnosed patient and conclude that for the present allogeneic stem cell transplantation soon after diagnosis should continue to be offered as an option for selected patients. Further experience with the use of imatinib as a single agent or in combination with other anti-leukemic agents may alter the picture in the near future.