Objective: To compare the therapeutic effects of STI 571 in treating Philadelphia chromosome (Ph)-positive patients with chronic-phase and acceleration phase chronic myeloid leukemia (CML-CP and CML-AP, respectively).
Methods: A total of 19 CML patients with Ph chromosome and/or fluorescence in situ hybridization (FISH)-bcr/abl fusion gene positivity rates over 90% and a median age of 38 years were recruited in this study, 12 of whom had previously failed to respond to interferon-alpha. Five of the 19 patients were in accelerated phase and 14 in chronic phase, 9 of the latter patient group in early stage of CML-CP (within 1 year since diagnosis) and 5 in advanced stage (3-6 years since diagnosis). All the patients were given oral STI 571 at the dose of 300-500 mg/d for a median treatment course of 5 months, and the 5 patients with CML-AP also received homoharringtonine at dose of 1-2 mg/d for an average of 1.5 treatment cycles (7-14 d for a complete treatment cycle). The Ph chromosome and the FISH-bcr/abl were analysed again 3 months after the treatment.
Results: STI 571 induced 100% complete hematological remission (CHR) and 79% major cytogenetic responses (MCR) in these patients. The complete cytogenetic remission (CCR) rates of CML-AP patients and CML-CP patients in advanced stage were lower than that of CML- CP patients in early stage (0% and 40% vs 88.9%).
Conclusion: STI 571 can achieve high rate of CHR and MCR in CML-CP patients, especially in those in early stage of the disease.