Objective: To analyze and evaluate the clinical efficacy and safety of imatinib mesylate (IM) as a tyrosine kinase inhibitor on Ph-positive or BCR/ABL positive chronic myelogenous leukemia (CML).
Methods: 120 patients diagnosed as CML with positive Ph chromosome were treated with IM 400 mg/d for CML in chronic phase (CP) (n = 90) or 600 mg/d for CML in accelerated or blastic phase (AP or BP) (n = 30) once daily. Hematological, cytogenetic and molecular effects of IM on the disease process of these patients were evaluated with blood and marrow cells morphology examination, G-band conventional cytogenetics analysis for Ph chromosome and PCR assay for BCR/ABL gene. The treatment efficacy and safety were retrospectively studied.
Results: (1) In CML-CP patients, after a follow-up of 9 ( range 3-42) months, cumulative complete hematological response (CHR), complete cytogenetic response (CCyR) and complete molecular response (CMR) rates were 73.3%, 66.7% and 54.4%, which was not influenced by prior treatment of interferon. CMR was better when time from diagnosis to treatment with IM was < or = 6 months (P < 0.05). The effect was not related with sex or age (P < 0.05). It is significant that the time to first CHR and time to first CCyR were related with the time to first CCyR and the time to first negative BCR/ ABL, respectively (both P < 0.05), while there was no relation between the time to first CHR and the time to first negative BCR/ABL (P > 0.05). (2) CHR, CCyR and CMR rates of the patients with progressive course (AP and BP) were 43.3%, 25.9% and 25.0%, respectively. The total mortality rate was 30.0%. (3) The mortality rate of the patients with age < or = 25 was higher than those >25 (P < 0.05). (4) Grade 3 leukocytopenia occurred in 16.0% of the patients and grade 3 thrombocytopenia in 18.0% of the patients and they 12 (5-20) weeks and 9 (3-16) weeks after the treatment, respectively. Nonhematological toxicities were common and tolerable.
Conclusion: IM can lead to considerable hematological, cytogenetic and molecular response rates in CML, especially CML-CP patients, with minor tolerable side effects.