Search

Sudden blast phase (SBP) is a rare event that occurs in an unpredictable fashion amongst patients with chronic myeloid leukemia (CML) who otherwise appear to be responding satisfactorily to imatinib (IM) treatment. We investigated the incidence, clinical characteristics, treatment outcome and long-term follow-up of 213 patients with chronic phase CML treated with IM according to the European LeukemiaNet guidelines. Nine patients, eight of whom received IM as first-line therapy, developed SBP (4.2% of the total). They tended to have low or intermediate risk Sokal scores at diagnosis, a predominance of the lymphoid phenotype and a short interval from 'optimal' response to the development of BP. Five of the nine patients with SBP are alive in complete molecular remission; however, all of them underwent allogeneic hematopoietic stem cell transplant. The cumulative incidence of SBP for the patients who received IM as first-line therapy was 5.9% and the 2-year overall survival of the nine patients who developed SBP was 56%. Despite the improved outcome for patients with SBP receiving tyrosine kinase inhibitors (TKIs) and transplant, many of these patients are not salvaged with these therapies. This illustrates the need to develop predictive models to identify patients early whose response to TKI therapy will not be durable and hopefully prevent the transformation to advanced disease. [ABSTRACT FROM AUTHOR]

Abstract: Cytogenetic and molecular responses to standard-dose imatinib (IM) were correlated with trough IM plasma levels for 78 patients with chronic myeloid leukemia (CML) after a minimum of 12 months of IM therapy. The mean trough IM plasma level was 1065ng/ml (range, 203–2910). There was no correlation of mean plasma trough IM levels and complete cytogenetic response (CCR) at 1 year (CCR 1010ng/ml vs no CCR 1175ng/ml P =.29) or major molecular response (MMR) (MMR1067ng/ml vs no MMR 1063ng/ml P =.74) after a median of 1298 days of IM therapy. CCR and MMR did correlate with Sokal risk scores with the odds of achieving CCR or MMR for a low risk vs high risk score of 10.8 (95% CI 2.2–53.5) and 6.4 (95% CI 1.4–29.4), respectively. Furthermore, a longer duration of IM therapy also was associated with a greater likelihood of achieving MMR (P =.02). [Copyright &y& Elsevier]

Previous studies demonstrated that imatinib mesyiate (lM) induces autophagy in chronic myeloid leukemia (CML) and that this process is critical to cell survival upon therapy. However, it is not known if the autophagic process differs at basal levels between CML patients and healthy individuals and if pretreatment CML cells harbor unique autophagy characteristics that could predict patients' clinical outcomes. We now demonstrate that several key autophagy genes are differentially expressed in CD34+ hematopoietic stem/progenitor cells, with the highest transcript levels detected for ATG4B, and that the transcript and protein expression levels of ATG4 family members, ATG5 and BECLIN-1 are significantly increased in CD34+ cells from chronicphase CML patients (P < .05). Importantly, ATG4B is differentially expressed in pretreatment CML stem/progenitor ceiis from subsequent IM responders vs IM non-responders (P < .05). Knockdown of ATG4B suppresses autophagy, impairs the survival of CML stem/progenitor cells and sensitizes them to IM treatment. Moreover, deregulated expression of ATG4B in CD34+ CML ceiis inversely correlates with transcript levels of miR-34a, and ATG4B is shown to be a direct target of miR-34a. This study identifies ATG4B as a potential biomarker for predicting therapeutic response in treatment-naïve CML stem/progenitor cells and uncovers ATG4B as a possible drug target in these cells. [ABSTRACT FROM AUTHOR]