Perttu Koskenvesa

Dasatinib crosses the blood-brain barrier and is an efficient therapy for central nervous system Philadelphia chromosome–positive leukemia

Although imatinib, a BCR-ABL tyrosine kinase inhibitor, is used to treat acute Philadelphia chromosome-positive (Ph(+)) leukemia, it does not prevent central nervous system (CNS) relapses resulting from poor drug penetration through the blood-brain barrier. Imatinib and dasa-tinib (a dual-specific SRC/BCR-ABL kinase inhibitor) were compared in a preclinical mouse model of intracranial Ph(+) leukemia. Clinical dasatinib treatment in patients with CNS Ph(+) leukemia was assessed. In preclinical studies, dasatinib increased survival, whereas imatinib failed to inhibit intracranial tumor growth. Stabilization and regression of CNS disease were achieved with continued dasa-tinib administration. The drug also demonstrated substantial activity in 11 adult and pediatric patients with CNS Ph(+) leukemia. Eleven evaluable patients had clinically significant, long-lasting responses, which were complete in 7 patients. In 3 additional patients, isolated CNS relapse occurred during dasatinib therapy; and in 2 of them, it was caused by expansion of a BCR-ABL-mutated dasatinib-resistant clone, implying selection pressure exerted by the compound in the CNS. Dasatinib has promising therapeutic potential in managing intracranial leukemic disease and substantial clinical activity in patients who experience CNS relapse while on imatinib therapy. This study is registered at ClinicalTrials.gov as CA180006 (#NCT00108719) and CA180015 (#NCT00110097).

Combination of pegylated IFN-alpha 2b with imatinib increases molecular response rates in patients with low- or intermediate-risk chronic myeloid leukemia

Biologic and clinical observations suggest that combining imatinib with IFN-α may improve treatment outcome in chronic myeloid leukemia (CML). We randomized newly diagnosed chronic-phase CML patients with a low or intermediate Sokal risk score and in imatinib-induced complete hematologic remission either to receive a combination of pegylated IFN-α2b (Peg-IFN-α2b) 50 μg weekly and imatinib 400 mg daily (n = 56) or to receive imatinib 400 mg daily monotherapy (n = 56). The primary endpoint was the major molecular response (MMR) rate at 12 months after randomization. In both arms, 4 patients (7%) discontinued imatinib treatment (1 because of blastic transformation in imatinib arm). In addition, in the combination arm, 34 patients (61%) discontinued Peg-IFN-α2b, most because of toxicity. The MMR rate at 12 months was significantly higher in the imatinib plus Peg-IFN-α2b arm (82%) compared with the imatinib monotherapy arm (54%; intention-to-treat, P = .002). The MMR rate increased with the duration of Peg-IFN-α2b treatment (< 12-week MMR rate 67%, > 12-week MMR rate 91%). Thus, the addition of even relatively short periods of Peg-IFN-α2b to imatinib markedly increased the MMR rate at 12 months of therapy. Lower doses of Peg-IFN-α2b may enhance tolerability while retaining efficacy and could be considered in future protocols with curative intent.

Activated innate lymphoid cells are associated with a reduced susceptibility to graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation (HSCT) is widely used to treat hematopoietic cell disorders but is often complicated by graft-versus-host disease (GVHD), which causes severe epithelial damage. Here we have investigated longitudinally the effects of induction chemotherapy, conditioning radiochemotherapy, and allogeneic HSCT on composition, phenotype, and recovery of circulating innate lymphoid cells (ILCs) in 51 acute leukemia patients. We found that reconstitution of ILC1, ILC2, and NCR(-)ILC3 was slow compared with that of neutrophils and monocytes. NCR(+) ILC3 cells, which are not present in the circulation of healthy persons, appeared both after induction chemotherapy and after allogeneic HSCT. Circulating patient ILCs before transplantation, as well as donor ILCs after transplantation, expressed activation (CD69), proliferation (Ki-67), and tissue homing markers for gut (α4β7, CCR6) and skin (CCR10 and CLA). The proportion of ILCs expressing these markers was associated with a decreased susceptibility to therapy-induced mucositis and acute GVHD. Taken together, these data suggest that ILC recovery and treatment-related tissue damage are interrelated and affect the development of GVHD.

The EUTOS population-based registry: incidence and clinical characteristics of 2904 CML patients in 20 European Countries

This population-based registry was designed to provide robust and updated information on the characteristics and the epidemiology of chronic myeloid leukemia (CML). All cases of newly diagnosed Philadelphia positive, BCR-ABL1+ CML that occurred in a sample of 92.5 million adults living in 20 European countries, were registered over a median period of 39 months. 94.3% of the 2904 CML patients were diagnosed in chronic phase (CP). Median age was 56 years. 55.5% of patients had comorbidities, mainly cardiovascular (41.9%). High-risk patients were 24.7% by Sokal, 10.8% by EURO, and 11.8% by EUTOS risk scores. The raw incidence increased with age from 0.39/100 000/year in people 20–29 years old to 1.52 in those >70 years old, and showed a maximum of 1.39 in Italy and a minimum of 0.69 in Poland (all countries together: 0.99). The proportion of Sokal and Euro score high-risk patients seen in many countries indicates that trial patients were not a positive selection. Thus from a clinical point of view the results of most trials can be generalized to most countries. The incidences observed among European countries did not differ substantially. The estimated number of new CML cases per year in Europe is about 6370.

Increased proportion of mature NK cells is associated with successful imatinib discontinuation in chronic myeloid leukemia

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 naïve CD56bright NK cells had decreased relapse-free survival. In addition, the TNF-α/IFN-γ 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.

Impact of malignant stem cell burden on therapy outcome in newly diagnosed chronic myeloid leukemia patients

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.

Dasatinib induces fast and deep responses in newly diagnosed chronic myeloid leukaemia patients in chronic phase: clinical results from a randomised phase-2 study (NordCML006)

We randomised 46 newly diagnosed patients with chronic myeloid leukaemia (median age 56) to receive dasatinib 100 mg QD or imatinib 400 mg QD and report outcome as an intention‐to‐treat analysis with 36 months follow‐up. Early cytogenetic and molecular responses were superior in the dasatinib group, with a tendency that imatinib patients caught up with time. For instance, MR3.0 was reached at 3 months in 36% vs. 8% (P = 0.02), at 12 months in 81% vs. 46% (P = 0.02) and at 18 months in 73% vs. 65% (n.s.) of the patients in the two groups. In contrast, MR4.5 was consistently superior in the dasatinib group at all time points from 6 months onwards, reaching 61% vs. 21% (P < 0.05) at 36 months. Sixty‐four vs. 71% of the patients in the dasatinib and imatinib arms, respectively, remained on assigned drug. Dasatinib dose was frequently reduced, but with maintained excellent effect. One imatinib patient progressed to blastic phase, but no CML‐related deaths occurred. In conclusion, our data compare favourably with those of the dasatinib registration study, DASISION. The fast and deep molecular responses induced by dasatinib compared with imatinib may be exploited to increase the proportion of patients who can achieve a treatment‐free remission after treatment discontinuation.

Chronic myeloid leukemia patients' adherence to peroral tyrosine kinase inhibitors compared with adherence as estimated by their physicians.

Purpose To evaluate chronic myeloid leukemia (CML) patients’ adherence to peroral tyrosine kinase inhibitors in Finland and to compare this with adherence as estimated by their physicians. Other aspects studied included how patients’ knowledge of the disease and its treatment influence adherence. Materials and methods A total of 120 CML patients were contacted between June 2012 and September 2013 in eight secondary or tertiary care hospitals in Finland. Of these, 86 participated in the study. This covers approximately 20% of all Finnish CML patients. The mean age was 57.8 years and 52% were male. Of the patients, 79.1% were using imatinib, 10.5% dasatinib, and 10.5% nilotinib. The patient-reported adherence (experienced adherence) was evaluated using the eight-item Morisky Medication Adherence Scale (MMAS). In addition, the treating physicians were asked to give their subjective opinion on their patients’ adherence (observed adherence). The experienced adherence was compared with the observed adherence using a three-level rating system (high, medium, low). All patients were personally interviewed and their demographic data collected. The statistical analysis of the data was based on descriptive statistics presented as frequencies, percentages, means, and medians. The kappa coefficient was calculated between the patient’s and the doctor’s assessment of adherence. Results A total of 23% (20/86) of the patients were fully adherent according to the MMAS, while physicians evaluated 94% (80/86) of the patients as fully adherent. The physicians’ estimate was too optimistic in 73% of cases. The discrepancy was confirmed by a kappa value of −0.004. The patients’ knowledge of the disease and its treatment was poor in all adherence levels. Conclusion The patient-reported adherence to tyrosine kinase inhibitor treatments in Finland was found to be the same as that found in the majority of previous studies. However, there seems to be a very weak agreement between the patient’s and the physician’s assessment of adherence. This study suggests that physicians overestimate the adherence of CML patients and base their assessment primarily on the clinical treatment response.

Treatment and outcome of 2904 CML patients from the EUTOS population-based registry

The European Treatment and Outcome Study (EUTOS) population-based registry includes data of all adult patients newly diagnosed with Philadelphia chromosome-positive and/or BCR-ABL1+ chronic myeloid leukemia (CML) in 20 predefined countries and regions of Europe. Registration time ranged from 12 to 60 months between January 2008 and December 2013. Median age was 55 years and median observation time was 29 months. Eighty percent of patients were treated first line with imatinib, and 17% with a second-generation tyrosine kinase inhibitor, mostly according to European LeukemiaNet recommendations. After 12 months, complete cytogenetic remission (CCyR) and major molecular response (MMR) were achieved in 57% and 41% of patients, respectively. Patients with high EUTOS risk scores achieved CCyR and MMR significantly later than patients with low EUTOS risk. Probabilities of overall survival (OS) and progression-free survival for all patients at 12, 24 and 30 months was 97%, 94% and 92%, and 95%, 92% and 90%, respectively. The new EUTOS long-term survival score was validated: the OS of patients differed significantly between the three risk groups. The probability of dying in remission was 1% after 24 months. The current management of patients with tyrosine kinase inhibitors resulted in responses and outcomes in the range reported from clinical trials. These data from a large population-based, patient sample provide a solid benchmark for the evaluation of new treatment policies.

Low or undetectable numbers of Philadelphia chromosome-positive leukemic stem cells (Ph + CD34 + CD38 neg ) in chronic myeloid leukemia patients in complete cytogenetic remission after tyrosine kinase inhibitor therapy

Low or undetectable numbers of Philadelphia chromosome-positive leukemic stem cells (Ph + CD34 + CD38 neg ) in chronic myeloid leukemia patients in complete cytogenetic remission after tyrosine kinase inhibitor therapy