South Brazilian Chronic Myeloid Leukemia (CML) Profile Patients: How We Treat and Our Results

CML is a well characterized disease with a known chromosomal abnormality. The inhibition of BCR-ABL protein tyrose kinase activity represented an advance in the treatment of this disease. Imatinib is effective in chronic, accelerated and blastic phase disease, and is the CML first line treatment around the world. In Brazil, this drug is provided by the State since 2003. The drug is available for second line treatment in chronic phase and for accelerated and blastic phase as the first line therapy. In chronic phase, the patients are treated first with interferon. If this treatment is too toxic or not effective, the choice therapy is imatinib 400 mg and the dose can be escalated up 600 mg. In accelerated and blastic phases the treatment is imatinib 600 mg. Mutational studies are not routinely performed and the failing patients are encourage to participate in bone marrow transplantation programs or clinical research centers. The present data are obtained from public health hospital database and included 400 CML Ph+ patients from Rio Grande do Sul, south of Brazil. 232 patients are male and 158 female and around 70% were Caucasian. The median age at diagnosis was 46, 79 y (median 49, 28). The mean laboratory values at diagnosis were: hematocrit 33 (median 34, 8), hemoglobin 11, 08 (median 11, 40), white blood cells 158.594 (median 110.000) and platelets 466.000 (median 380.000). From the 400 patients, 300 pts were diagnosed in chronic phase, 52 pts in accelerated phase and 20 pts in blastic phase. In 28 patients the disease phase was unknown. In the majority of patients Imatinib was started because interferon treatment was not tolerated (121 patients) or ineffective (123 patients). Of these patients 285 were in chronic, 59 pts in accelerated and 17 pts in blastic phases. The cytogenetic response evaluated at 12 months of treatment was available in 231 patients: 164 complete responses, 20 major responses, 15 minor responses and 32 patients demonstrated none or minimal response to therapy. In 169 patients the response is unknown. The progression free survival for the chronic phase patients in 80 months of observation is 90% and the event free survival for the entire group is 60% in the same period. The progression from chronic to accelerated or blastic phase was more common in the first year of imatinib treatment and decreased progressively until the fifth year of therapy. This data demonstrate the epidemiologic profile and the treatment results of CML patients in south of Brazil. Imatinib is available in public health system as a second line treatment and the survival rate is quite good. Since last July this drug has been available as first line treatment, even in chronic phase. A longer follow up and a uniform database registry are needed to study the impact of imatinib treatment in this population.