Search

Bosutinib is approved for newly diagnosed Philadelphia chromosome-positive (Ph+) chronic phase (CP) chronic myeloid leukemia (CML) and for Ph+ CP, accelerated (AP), or blast (BP) phase CML after prior treatment with tyrosine kinase inhibitors (TKIs). In the ongoing phase 4 BYOND study (NCT02228382), 163 CML patients resistant/intolerant to prior TKIs (n = 156 Ph+ CP CML, n = 4 Ph+ AP CML, n = 3 Ph-negative/BCR-ABL1+ CML) received bosutinib 500 mg once daily (starting dose). As of ≥1 year after last enrolled patient (median treatment duration 23.7 months), 56.4% of Ph+ CP CML patients remained on bosutinib. Primary endpoint of cumulative confirmed major cytogenetic response (MCyR) rate by 1 year was 75.8% in Ph+ CP CML patients after one or two prior TKIs and 62.2% after three prior TKIs. Cumulative complete cytogenetic response (CCyR) and major molecular response (MMR) rates by 1 year were 80.6% and 70.5%, respectively, in Ph+ CP CML patients overall. No patient progressed to AP/BP on treatment. Across all patients, the most common treatment-emergent adverse events were diarrhea (87.7%), nausea (39.9%), and vomiting (32.5%). The majority of patients had confirmed MCyR by 1 year and MMR by 1 year, further supporting bosutinib use for Ph+ CP CML patients resistant/intolerant to prior TKIs.

Recent studies suggest that a proportion of chronic myeloid leukemia (CML) patients in deep molecular remission can discontinue the tyrosine kinase inhibitor (TKI) treatment without disease relapse. In this multi-center, prospective clinical trial (EURO-SKI, NCT01596114) we analyzed the function and phenotype of T and NK cells and their relation to successful TKI cessation. Lymphocyte subclasses were measured from 100 imatinib-treated patients at baseline and 1 month after the discontinuation, and functional characterization of NK and T cells was done from 45 patients. The proportion of NK cells was associated with the molecular relapse-free survival as patients with higher than median NK-cell percentage at the time of drug discontinuation had better probability to stay in remission. Similar association was not found with T or B cells or their subsets. In non-relapsing patients the NK-cell phenotype was mature, whereas patients with more naive CD56(bright) NK cells had decreased relapse-free survival. In addition, the TNF-alpha/IFN-gamma cytokine secretion by NK cells correlated with the successful drug discontinuation. Our results highlight the role of NK cells in sustaining remission and strengthen the status of CML as an immunogenic tumor warranting novel clinical trials with immunomodulating agents., Funding Agencies|Nordic Cancer Union; Finnish Society of Hematology; Biomedicum Helsinki Foundation; Research Foundation of Blood Diseases in Finland; Academy of Finland; Finnish Cancer Organizations; Signe and Ane Gyllenberg Foundation; Finnish Cancer Institute; Doctoral Programme in Clinical Research in the University of Helsinki

Dasatinib (DAS) and interferon-a have antileukemic and immunostimulatory effects and induce deep responses in chronic myeloid leukemia (CML). We assigned 40 newly diagnosed chronic-phase CML patients to receive DAS 100 mg o.d. followed by addition of pegylated interferon-alpha 2b (PegIFN) after 3 months (M3). The starting dose of PegIFN was 15 mu g/week and it increased to 25 mu g/week at M6 until M15. The combination was well tolerated with manageable toxicity. Of the patients, 84% remained on PegIFN at M12 and 91% (DAS) and 73% (PegIFN) of assigned dose was given. Only one patient had a pleural effusion during first year, and three more during the second year. After introduction of PegIFN we observed a steep increase in response rates. Major molecular response was achieved in 10%, 57%, 84% and 89% of patients at M3, M6, M12 and M18, respectively. At M12, MR4 was achieved by 46% and MR4.5 by 27% of patients. No patients progressed to advanced phase. In conclusion, the combination treatment appeared safe with very promising efficacy. A randomized comparison of DAS +/- PegIFN is warranted., Funding Agencies|Bristol-Myers Squibb; Norwegian University of Science and Technology (NTNU, Trondheim, Norway)

We recently reported an increased incidence of second malignancies in chronic myeloid leukemia (CML) patients treated with tyrosine kinase inhibitors (TKI). To elucidate whether this increase may be linked, not to TKI but rather to a hereditary or acquired susceptibility to develop cancer, we estimated the prevalence of malignancies, autoimmune disease (AD) and chronic inflammatory disease (CID) in CML patients prior to their CML diagnosis. Nationwide population-based registers were used to identify patients diagnosed with CML in Sweden 2002-2012 and to estimate the prevalence of other malignancies, AD and CID prior to their CML diagnosis. For each patient with CML, five matched controls were selected from the general population. Conditional logistic regression was used to calculate odds ratios (OR). Nine hundred and eighty-four CML patients were assessed, representing more than 45 000 person-years of follow-up. Compared with matched controls, the prevalence of prior malignancies and AD was elevated in CML patients: OR 1.47 (95% confidence interval (CI) 1.20-1.82) and 1.55 (95% CI 1.21-1.98), respectively. No associations were detected between CML and previous CID. An increased prevalence of other malignancies and AD prior to the diagnosis of CML suggest that a hereditary or acquired predisposition to cancer and/or autoimmunity is involved in the pathogenesis of CML., Funding Agencies|Emil Andersson Research Fund; Nordic CML Study Group

Chronic myeloid leukemia (CML) stem cells appear resistant to tyrosine kinase inhibitors (TKIs) in vitro, but their impact and drug sensitivity in vivo has not been systematically assessed. We prospectively analyzed the proportion of Philadelphia chromosome-positive leukemic stem cells (LSCs, Ph+CD34+CD38=) and progenitor cells (LPCs, Ph+CD34+CD38+) from 46 newly diagnosed CML patients both at the diagnosis and during imatinib or dasatinib therapy (ClinicalTrials.gov NCT00852566). At diagnosis, the proportion of LSCs varied markedly (1-100%) between individual patients with a significantly lower median value as compared with LPCs (79% vs 96%, respectively, P = 0.0001). The LSC burden correlated with leukocyte count, spleen size, hemoglobin and blast percentage. A low initial LSC percentage was associated with less therapy-related hematological toxicity and superior cytogenetic and molecular responses. After initiation of TKI therapy, the LPCs and LSCs rapidly decreased in both therapy groups, but at 3 months time point the median LPC level was significantly lower in dasatinib group compared with imatinib patients (0.05% vs 0.68%, P = 0.032). These data detail for the first time the prognostic significance of the LSC burden at diagnosis and show that in contrast to in vitro data, TKI therapy rapidly eradicates the majority of LSCs in patients., QC 20170419