Abstract
Introduction: Chronic myeloid leukemia (CML) is a clonal myeloproliferative disorder; the molecular hallmark of the disease is the BCR-ABL gene rearrangement, which usually occurs as the result of a reciprocal translocation between chromosomes 9 and 22. Tyrosine kinase inhibitors (TKI) were the first drugs that targeted the constitutively active BCR-ABL kinase and it have become the standard frontline therapy for CML. Monitoring the treatment of CML patients with detection of bcr-abl transcript levels with real time qualitative polymerase chain reaction (RQ-PCR) is essential in evaluating the therapeutic response.
Material and method: At the Clinical Hematology and BMT Unit Tîrgu Mureș, between 2008-2011, we performed the molecular monitoring of bcr-abl transcript levels with RQ-PCR in 16 patients diagnosed with CML.
Results: We have 11 patients on imatinib treatment who achieved major molecular response. One patient lost the complete molecular response after 5 years of treatment. Two patients in blast crisis underwent allogeneic hematopoietic stem cell transplantation from identical sibling donors. The first patient is in complete molecular remission after 4 years of the transplant with mild chronic GVHD. The other patient had an early relapse with treatment refractory disease and died from evolution of the disease. Three patients with advanced phases of the disease present increasing transcript levels. We performed the dose escalation, and for two of them the switch to the second generation of TKI.
Conclusions: Regular molecular monitoring of individual patients with CML is clearly desirable. It allows for a reassessment of the therapeutic strategy in cases of rising levels of BCR-ABL as an early indication of loss of response.