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Chronic myeloid leukemia (CML) is a myeloproliferative disorder caused by the BCR-ABL1 tyrosine kinase. Although ABL1-specific tyrosine kinase inhibitors (TKIs) including nilotinib have dramatically improved the prognosis of patients with CML, the TKI efficacy depends on the individual patient. In this work, we found that the patients with different nilotinib responses can be classified by using the estimated parameters of our simple dynamical model with two common laboratory findings. Furthermore, our proposed method identified patients who failed to achieve a treatment goal with high fidelity according to the data collected only at three initial time points during nilotinib therapy. Since our model relies on the general properties of TKI response, our framework would be applicable to CML patients who receive frontline nilotinib or other TKIs. [ABSTRACT FROM AUTHOR]

For patients who have chronic myeloid leukemia (CML), one of the primary treatment options is administration of nilotinib 300 mg twice daily (BID). In previous studies which compared outcomes associated with nilotinib or imatinib treatment, nilotinib achieved a higher rate of deep molecular response (MR). We conducted a phase II, open‐label, multicenter study to investigate an intrapatient nilotinib dose‐escalation strategy for patients with newly diagnosed chronic‐phase (CP) CML based on early MR4.5 achievement. The primary study endpoint was achievement of MR4.5 by 24 months following the initiation of nilotinib 300 mg BID. Fifty‐three patients were enrolled, 51 received nilotinib, and 37 completed the treatment. An increase in the nilotinib dose (to 400 mg BID) was allowed when patients satisfied our criteria for no optimal response at any time point. The median (range) dose intensity was 600 (207‐736) mg/day. Of 46 evaluable patients, 18 achieved an optimal response and 28 did not. Of the latter, nine patients underwent dose escalation to 400 mg BID, and none achieved MR4.5. The remaining 19 patients could not undergo dose escalation, 12 (63%) because of adverse events (AEs), and 7 (37%) for non‐AE related reasons. Four of these patients achieved MR4.5. The MR4.5 rate by 24 months was 45.7%. The progression‐free, overall and event‐free survival were each 97.6%. No new safety concerns were observed. Our findings support the use of continuous nilotinib at a dose of 300 mg BID for newly diagnosed patients with CML‐CP. [ABSTRACT FROM AUTHOR]

The Japan Adult Leukemia Study Group (JALSG) Ph+ALL202 study reported a high complete remission (CR) rate for Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) patients treated with imatinib-combined chemotherapy. However, the long-term treatment efficacy remains uncertain. Here, we report a final analysis of the JALSG Ph+ALL202 study. The outcomes were compared with those of the JALSG ALL93 and ALL97 studies, which were conducted in the pre-imatinib era. Ninety-nine newly diagnosed Ph+ALL patients were enrolled in Ph+ALL202 (median age, 45 years; median follow-up, 4.5 years). CR was achieved in 96/99 (97%) patients. Fifty-nine of these 96 patients (61%) underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in their first CR (CR1). The 5-year overall and disease-free survival (DFS) rates were 50 and 43%, respectively, which were significantly higher compared to those in the pre-imatinib era (15 and 19%, respectively). Multivariate analysis revealed that imatinib administration, allo-HSCT in CR1, and a white blood cell count < 30 × 109/L were favorable independent prognostic factors for long-term DFS. Improved odds of receiving allo-HSCT and a lower relapse rate leaded to good long-term outcomes. The 3-year DFS tended to be higher in PCR-negative than that in PCR-positive patients (29 vs. 14%) in the non-HSCT patients, and this tendency was also seen in the allo-HSCT patients (59 vs. 50%). The higher rate of CR upon imatinib use may have contributed to these improvements. [ABSTRACT FROM AUTHOR]

BCR–ABL oncogene, the molecular hallmark of chronic myelogenous leukemia, arises in a primitive hematopoietic stem cell that has the capacity for both differentiation and self-renewal. Its product, Bcr–Abl protein, has been shown to activate signal transducers and activators of transcription 3 (STAT3) and to promote self-renewal in embryonic stem (ES) cells, even in the absence of leukemia inhibitory factor (LIF). MEK kinase 1 (MEKK1) is a 196-kDa mitogen-activated protein kinase (MAPK) kinase kinase involved in Bcr–Abl signal transduction. To investigate the role of MEKK1 in Bcr–Abl-induced transformation of stem cells, p210 Bcr–Abl was stably transfected into wild-type (WTp210) and MEKK1−/− (MEKK1−/−p210) ES cells. Bcr–Abl enhanced MEKK1 expression in ES transfectants, as it does in other Bcr–Abl-transformed cells. In the absence of LIF, WTp210 cells showed constitutive STAT3 activation and formed rounded, compact colonies having strong alkaline phosphatase activity, a characteristic phenotype of undifferentiated ES cells. MEKK1−/−p210 cells, by contrast, showed less STAT3 activity than WTp210 cells and formed large, flattened colonies having weak alkaline phosphatase activity, a phenotype of differentiated ES cells. These results indicate that MEKK1 plays a key role in Bcr–Abl-induced STAT3 activation and in ES cells’ capacity for LIF-independent self-renewal, and may thus be involved in Bcr–Abl-mediated leukemogenesis in stem cells.Oncogene (2005) 24, 7592–7598. doi:10.1038/sj.onc.1208899; published online 25 July 2005 [ABSTRACT FROM AUTHOR]